ALBERT

Description:    Millions of fish ascend through fishways in South America every year, but there is no evidence that downstream passage is occurring in large dams. Based on this concern, this study monitored the fish ladder at Lajeado Dam, Tocantins River, a large Amazonian tributary. To investigate the extent of downstream movements through the fishway, ascending and descending movements were quantified between November 2007 and October 2008. Monitoring showed that the ladder is restrictive to many species in both directions, but downstream passage was much more limited: almost all fish captured in the ladder (99.5%) were ascending the facility. Consequently, the numerical ratio between ascending and descending fish (ind./m 2 ) showed high positive values throughout the year (1508:1 on average); migratory species showed higher ratios. All results showed that downstream passage through the ladder is very limited, and that the facility allows only one-way movements (i.e., upstream). This is the first empirical evidence showing that a ladder is critically deficient for downstream passage of fishes in South America. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0787-0 Authors Carlos Sérgio Agostinho, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Fernando Mayer Pelicice, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Elineide Eugênio Marques, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Anderson Brito Soares, Núcleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Rua 3, Quadra 17, Jardim dos Ipês, Porto Nacional, TO 77500-000, Brazil Deusimar Augusto Alves de Almeida, Investco S.A., Miracema do Tocantins, TO, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Marine sponges of the class Hexactinellida (glass sponges) are among the most understudied groups of Porifera, and molecular approaches to investigating their evolution have only recently emerged. Although these first results appeared reliable as they largely corroborated morphology-based hypotheses, they were almost exclusively based on ribosomal RNA genes (rDNA) and should, therefore, be further tested with independent types of genetic data, such as protein-coding genes. To this end, we established the mitochondrial-encoded cytochrome oxidase subunit I gene (COI) as an additional marker, and conducted phylogenetic analyses on DNA- and amino-acid level, as well as a supermatrix analysis based on combined COI DNA and rDNA alignments. Furthermore, we increased taxon sampling compared to previous studies by adding seven additional species. The COI-based phylogenies were largely congruent with the rDNA-based phylogeny but suffered from poor bootstrap support for many nodes. However, addition of the COI sequences to the rDNA data set increased resolution of the overall molecular phylogeny. Thus, although obtaining COI sequences from glass sponges turned out to be quite challenging, this gene appears to be a valuable supplement to rDNA data for molecular evolutionary studies of this group. Some implications of our extended phylogeny for the evolution and systematics of Hexactinellida are discussed. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0727-z Authors Martin Dohrmann, Department of Earth & Environmental Sciences, Palaeontology & Geobiology, LMU Munich, Richard-Wagner-Straße 10, 80333 Munich, Germany Karri M. Haen, Department of Ecology, Evolution & Organismal Biology, Iowa State University, 253 Bessey Hall, Ames, IA 50011, USA Dennis V. Lavrov, Department of Ecology, Evolution & Organismal Biology, Iowa State University, 253 Bessey Hall, Ames, IA 50011, USA Gert Wörheide, Department of Earth & Environmental Sciences, Palaeontology & Geobiology, LMU Munich, Richard-Wagner-Straße 10, 80333 Munich, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Two sympatric and divergent adaptive ecotypes of Littorina saxatilis (RB and SU) are known to hybridize showing partial premating isolation in the wild. Previous studies have revealed that morphological intermediate forms (presumably hybrids) present fitness (viability, sexual selection and fecundity) similar to that from pure ecotypes at the mid-shore. However, the absence of postzygotic isolation due to genetic incompatibility cannot be ruled out unless it is measured directly on true F 1 hybrids. In this study, we overcome this problem and present data on 56 individual crosses including the four possible mating combinations (RB/RB, RB/SU, SU/RB and SU/SU) to compare fertilization and fecundity rates (including young progeny viability) between the four type crosses. Pooled RB female crosses showed apparently larger fertility and fecundity than pooled SU female crosses, probably because of differences in fecundity and laboratory survivorship between ecotypes. However, similar fertilization and fecundity rates were found for both RB and SU females when mated with different male types, supporting the idea that genetic-incompatibility-based postzygotic isolation can be ignored as a major determinant of this polymorphism in nature. Content Type Journal Article Pages 1-6 DOI 10.1007/s10750-011-0788-z Authors M. Saura, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain M. Martínez-Fernández, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain M. J. Rivas, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain A. Caballero, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain E. Rolán-Alvarez, Departamento de Bioquímica, Xenética e Inmunoloxía, Facultade de Bioloxía, Universidade de Vigo, 36310 Vigo, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Rewetting can strongly affect the matter balance of peatlands. Owing to evidence of increasing CH 4 emissions and P mobilisation after rewetting, the effects of peatland restoration on climate, eutrophication risks and related controversies are discussed. Our study focuses on the role of helophytes in the carbon and nutrient balance of rewetted fen grasslands of NE Germany. We hypothesise that the helophytes Carex riparia , Glyceria maxima , Phalaris arundinacea , Phragmites australis and Typha latifolia differ in biomass production and nutrient standing stock according to site conditions and harvest time. We analysed the helophyte biomass three times a year and continuously measured water levels and quality. Biomass production, nutrient standing stock and litter accumulation were highly species specific and depended on nutrient availability, mean water levels and harvesting time. We conclude that helophytes store considerable amounts of carbon and temporarily improve the water quality by withdrawing high amounts of nutrients from the top soil during the growing season, and by reducing nutrient discharges. Restoring peatlands as effective nutrient and carbon sinks in the landscape should favour highly productive potentially peat-forming helophytes as Phragmites australis by establishing adequate water levels. If nutrients are to be removed from the degraded peatland, then management can combine the restoration of helophyte stands by rewetting with harvesting measures. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0782-5 Authors Karsten Schulz, Institute of Botany and Landscape Ecology, University of Greifswald, Grimmer Str. 88, 17487 Greifswald, Germany Tiemo Timmermann, Institute of Botany and Landscape Ecology, University of Greifswald, Grimmer Str. 88, 17487 Greifswald, Germany Peggy Steffenhagen, LUP—Luftbild Umwelt Planung GmbH, Große Weinmeisterstraße 3a, 14469 Potsdam, Germany Stefan Zerbe, Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano, Italy Michael Succow, Michael Succow Foundation, Institute of Botany and Landscape Ecology, Grimmer Str. 88, 17487 Greifswald, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Ecologically specialized species may be more susceptible to anthropogenic impacts than generalist species. Japan’s native bitterlings (subfamily Acheilognathinae), which are specialized to spawn on the gills of certain freshwater mussels, have been declining dramatically during the last few decades. To identify factors affecting the local occurrence of the threatened bitterling species Tanakia lanceolata , we measured its presence and absence, along with several environmental factors, at 68 sites within agricultural canal networks in the Lake Mikata basin, Fukui Prefecture, Japan. Based on the theoretical information approach of Akaike’s information criterion, generalized linear mixed models were constructed. These revealed that the species’ occurrence is strongly affected by five major factors: the presence of freshwater mussels Anodonta sp., water depth, floating plants coverage, the presence of bullfrogs, and submerged plants coverage. The probability of the presence of T. lanceolata was higher at shallower sites with lower floating plants coverage, located within channels containing mussel beds. These results suggest that mussel-containing channel systems are high-priority conservation zones for T. lanceolata . Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0790-5 Authors Akira Terui, Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan Shin-ichiro S. Matsuzaki, National Institute for Environmental Studies, Tsukuba-shi, Ibaraki 305-8506, Japan Kohji Kodama, Fukui Prefectural Fisheries Experimental Station, Urazoko, Tsuruga-shi, Fukui 914-0843, Japan Masamitsu Tada, Fukui Prefectural Coastal Nature Center, 18-2 Sekumi, Mikatakaminaka-gun, Fukui 919-1464, Japan Izumi Washitani, Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Daphnia subfossils from lake sediments are useful for exploring the impacts of environmental stressors on aquatic ecosystems. Unfortunately, taxonomic resolution of Daphnia remains is coarse, as only a small portion of the animal is preserved, and so the identification of daphniid subfossils typically relies upon postabdominal claws. Daphniid claws can be assigned to one of two species complexes: D. longispina or D. pulex . Both complexes contain species with differing environmental optima, and therefore improved taxonomic resolution of subfossil daphniid claws would aid paleolimnological analyses. To identify morphological features that may be used to help differentiate between species within complexes, we used species presence/absence data from net tows to select lakes in central Ontario (Canada) containing only a single species from a particular complex, then used remains preserved in surface sediments of these lakes to isolate four Daphnia species: D.   ambigua and D.   mendotae from the D. longispina complex, and D. pulicaria and D. catawba from the D. pulex complex. Our analyses demonstrate that, within the D.   longispina complex, postabdominal claw length (PCL) and spinule length can be used to distinguish D. mendotae from D. ambigua . In addition, within the D. pulex complex, there are differences between D. pulicaria and D. catawba in the relative lengths of the proximal and middle combs on the postabdominal claw. However, the number of stout spines on the middle comb is an unreliable character for differentiating species. Overall, our data demonstrate that greater resolution within Daphnia species complexes is possible using postabdominal claws; however, the process is arduous, and applicability will likely decrease with the number of taxa present. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0779-0 Authors Jennifer B. Korosi, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada Adam Jeziorski, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada John P. Smol, Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The European Union’s Water Framework Directive has set a target of achieving good ecological status for all aquatic environments in Europe by 2015. In order to determine the quality of aquatic environments, biological indicators such as diatoms are often used. However, biotic diatom indices can be difficult and time consuming to use because of complexity of species determination. We investigated whether the biological traits of diatoms in rivers (life-forms, size classes and ecological guilds) could be used to assess organic pollution and trophic level. We worked on a data set comprising 315 diatom species, determined at 328 river stations of south-east France and a variety of parameters. The abundances of some biological traits differed significantly between the different organic pollution and trophic levels, particularly stalked diatoms, and the motile and low-profile guilds. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0786-1 Authors Vincent Berthon, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Agnès Bouchez, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Frédéric Rimet, INRA, UMR CARRTEL, 75 av. de Corzent, BP 511, 74203 Thonon-les-Bains Cedex, France Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Quantitative genetic studies in natural populations are of growing interest to speciation research since divergence is often believed to arise through micro-evolutionary change, caused by natural selection on functional morphological traits. The species flock of cichlid fishes in Africa’s oldest lake, Lake Tanganyika, offers a rare opportunity to study this process. Using the cichlid species Tropheus moorii , we assessed the potential for microevolution in a set of morphological traits by estimating their quantitative genetic basis of variation. Two approaches were employed: (1) estimation of trait heritabilities ( h 2 ) in situ from a sample of wild caught fish, and (2) estimation of h 2 from first generation offspring produced in a semi-natural breeding experiment. In both cases, microsatellite data were used to infer pedigree structure among the sampled individuals and estimates of h 2 were made using an animal model approach. Although power was limited by the pedigree structures estimated (particularly in the wild caught sample), we nonetheless demonstrate the presence of significant additive genetic variance for aspects of morphology that, in the cichlid species Tropheus moorii , are expected to be functionally and ecologically important, and therefore likely targets of natural selection. We hypothesize that traits showing significant additive genetic variance, such as the mouth position have most likely played a key role in the adaptive evolution of the cichlid fish Tropheus moorii . Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0785-2 Authors Martin Koch, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Alastair J. Wilson, Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT UK Michaela Kerschbaumer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Thomas Wiedl, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Christian Sturmbauer, Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Genetic variability within and among Bulinus truncatus of the Albertine Rift freshwater bodies were assessed to investigate the degree of inbreeding and gene flow in the snail populations. The effect of ploidy on the genetic structuring of B.   truncatus is also described. We characterized the genetic structure of seven B.   truncatus populations from Lake Albert, Lake Kivu, and Katosho swamp in Tanzania using five polymorphic microsatellite loci. Genetic differentiation was quantified using pairwise FST values and Nei’s standard genetic distances. Different alleles were observed across all loci and genetic diversity was low although it varied greatly across populations; observed heterozygosity was, however, higher than the expected heterozygosity in three of the populations studied. Significant heterozygote deficiencies were observed coupled with significant linkage disequilibria in five populations for all the five loci examined in this study. We found significant genetic differentiation among the seven freshwater bodies; private alleles were observed across all loci indicating restricted or absence of gene flow between populations. Limited snail dispersal and the reproductive biology of B.   truncatus are the major forces shaping the genetic variation observed. Low genetic variation within B.   truncatus populations exposes them to a high parasite infection risk as predicted in the Red Queen hypothesis. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0749-6 Authors Allen Nalugwa, Molecular Biology Laboratory, Makerere University, College of Agricultural and Environmental Sciences, P.O. Box 7298, Kampala, Uganda Aslak Jørgensen, Laboratory of Molecular Systematics, The Natural History Museum of Denmark, Sølvgade 83, 1307 Copenhagen K, Denmark Silvester Nyakaana, Molecular Biology Laboratory, Makerere University, College of Agricultural and Environmental Sciences, P.O. Box 7298, Kampala, Uganda Thomas K. Kristensen, The Mandahl-Barth Research Centre for Biodiversity and Health, DBL-Parasitology, Health and Development, Department of Veterinary Disease Biology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 57, 1871 Frederiksberg C, Denmark Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Previous phylogenetic investigations on the mayfly Baetis rhodani Pictet from several European countries, excluding Italy, strongly suggested the presence of cryptic species. Our paper reports a DNA-taxonomy phylogenetic analysis of B. rhodani with additional populations coming from Italian and UK sites, and aims to identify potential cryptic species with a coalescent-based method (GMYC model) and to understand the mechanisms of local coexistence of cryptic species. Twenty-five haplotypes of Italian samples and five haplotypes of UK samples were identified and added to a large European dataset. A total of 11 potential cryptic species have been recognised, and three of them co-occured in one Italian area. Such cryptic species seem to be phylogenetically over-dispersed on the tree and temporally segregated, and the seasonal substitution pattern of cryptic species could explain the apparently widespread distribution of the B. rhodani complex and its ability to adapt to different temperatures and food resources, justifying some of the differences observed in the relationship between water temperature, growth rates and phenology documented from field studies. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0778-1 Authors Livia Lucentini, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Manuela Rebora, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Maria Elena Puletti, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Lilia Gigliarelli, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Diego Fontaneto, Division of Biology, Imperial College London, Silwood Park Campus, SL5 7PY Ascot, Berkshire, UK Elda Gaino, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Fausto Panara, Dipartimento di Biologia Cellulare e Ambientale, Università degli Studi di Perugia, Via Pascoli, 06123 Perugia, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description: Preface: Restoration, biogeochemistry and ecological services of wetlands Content Type Journal Article Pages 1-4 DOI 10.1007/s10750-011-0783-4 Authors Dominik Zak, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Central Chemical Laboratory, Müggelseedamm 301, 12587 Berlin, Germany Robert McInnes, Bioscan (UK) Ltd., The Old Parlour, Little Baldon Farm, Oxford, OX44 9PU UK Jörg Gelbrecht, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Central Chemical Laboratory, Müggelseedamm 301, 12587 Berlin, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We compared land cover, riparian vegetation, and instream habitat characteristics with stream macroinvertebrate assemblages in 25 catchments in the Carpathian Mountains in Central Europe. This study area was particularly selected because of its diverse history of forest and agricultural ecosystems linked to geopolitical dynamic, which provide a suite of unique landscape scale, land cover settings in one ecoregion. Canonical Correspondence Analysis (CCA) showed that variation in composition and structure of macroinvertebrate assemblages was primarily related to four land cover types, and not to riparian or instream habitat. These were the portions in the catchment areas of (1) broadleaved forest, (2) fine-grained agricultural landscape mosaic with scattered trees (e.g., pre-industrial cultural landscape), (3) mixed forest, and (4) natural grassland without trees. Principal Component Analysis (PCA) suggested that land cover types and stream channel substrates co-varied. The PCA also showed that chemical variables, including organic carbon, had higher values in the agricultural landscape compared to natural forests. The major source of variation among taxa in streams was higher abundance of Diptera in agricultural landscapes and of Plecoptera, Coleoptera, Trichoptera, and Amphipoda in forests. Gastropoda and Oligochaeta were more abundant in open, fine-grained agricultural landscape mosaics with scattered trees. Ephemeroptera taxa were quite indifferent to these gradients in catchment land cover, but showed a tendency of being more abundant in the pre-industrial cultural landscape. Our findings suggest that land cover can be used as a proxy of the composition and structure of macroinvertebrate assemblages. This means that land use management at the catchment scale is needed for efficient conservation and recovery of stream invertebrate communities. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0769-2 Authors J. Törnblom, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden P. Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden E. Degerman, National Board of Fisheries, 702 15 Örebro, Sweden L. Henrikson, Freshwater Program, WWF, Ulriksdals Slott, 170 81 Solna, Sweden T. Edman, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, 739 21 Skinnskatteberg, Sweden J. Temnerud, Department of Natural Sciences, Man-Technology-Environment Research Centre, Örebro University, Örebro, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Different groups of marine benthic organisms show contrasting latitudinal patterns of biodiversity. The widely accepted paradigm of increasing biodiversity towards the tropics does not seem to be valid for macroalgal floras of the Southern Hemisphere. We compiled a database summarizing the distributional ranges of macroalgae along the coast of Argentina to test whether biodiversity decreases towards lower latitudes, as in the Pacific coast of South America, and whether breaking points in the geographical distribution can be recognized in one or more areas of the Southwest Atlantic south of 36°S. We found a clear trend of decreasing biodiversity with decreasing latitude. The interpretation of some biodiversity declines is confounded by changes in the intensity of the sampling effort. A 51% reduction in algal species richness between 42 and 41°S coincides with the boundary between the Argentine and Magellanic Zoogeographic Provinces. This sharp breaking point is related to a thermal anomaly caused by long residence times of water masses within San Matías Gulf, suggesting an upper thermal tolerance limit for most Antarctic/sub-Antarctic seaweeds. A further reduction occurs at 38–37°S. This breaking point can be explained by the disappearance of suitable hard substrata, since rocky outcrops give place to wide extensions of sandy beaches. The impoverished algal assemblage inhabiting the northern coast of Argentina is mainly related to the reduction or disappearance of the Antarctic/sub-Antarctic floristic component. This area is characterised by a predominance of widely distributed species, Chlorophytes and opportunistic filamentous or foliose algae. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0780-7 Authors María G. Liuzzi, Museo Argentino de Ciencias Naturales, Av. Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina Juan López Gappa, Museo Argentino de Ciencias Naturales, Av. Ángel Gallardo 470, C1405DJR Buenos Aires, Argentina María L. Piriz, Morgan 2455, U9120AFM Puerto Madryn, Chubut, Argentina Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Transposable elements play a vital role in genome evolution and may have been important for the formation of the early metazoan genome, but only little is known about transposons at this interface between unicellular opisthokonts and Metazoa. Here, we describe the first miniature transposable elements (MITEs, Queen1 and Queen2 ) in sponges. Queen1 and Queen2 are probably derived from Tc1/mariner-like MITE families and are represented in more than 3,800 and 1,700 copies, respectively, in the Amphimedon queenslandica genome. Queen elements are located in intergenic regions as well as in introns, providing the potential to induce new splicing sites and termination signals in the genes. Further possible impacts of MITEs on the evolution of the metazoan genome are discussed. Content Type Journal Article Pages 1-5 DOI 10.1007/s10750-011-0775-4 Authors Dirk Erpenbeck, Department of Earth- and Environmental Sciences & GeoBio-CenterLMU, Ludwig-Maximilians Universität, Richard-Wagner-Str. 10, 80333 München, Germany Jürgen Schmitz, Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany Gennady Churakov, Institute of Experimental Pathology, ZMBE, University of Münster, Von-Esmarch-Str. 56, 48149 Münster, Germany Dorothée Huchon, Department of Zoology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, 69978 Israel Gert Wörheide, Department of Earth- and Environmental Sciences & GeoBio-CenterLMU, Ludwig-Maximilians Universität, Richard-Wagner-Str. 10, 80333 München, Germany Bernard M. Degnan, School of Biological Sciences, University of Queensland, Brisbane, 4072 Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    High-resolution biostratigraphy has been established on the basis of fossil ostracodes from cores of the Cretaceous Continental Scientific Drilling borehole-Songke 1 (south) (SK1(s)) in the Songliao Basin, northeast China. More than 80 species belonging to 13 genera have been identified and 15 ostracode assemblage zones have been recognized. On the basis of ostracode paleoecological analysis, paleoenvironments, for example lake levels and salinity, have been reconstructed. Two inferred deep-water phases occurred during the deposition of the lower Qingshankou and lower Nenjiang formations, whereas shallower water phases probably occurred during deposition of the upper Quantou and uppermost Qingshankou to Yaojia formations. The salinity of paleo-Songliao lake is interpreted as predominantly freshwater to oligohaline. Oligohaline to mesohaline water environments may have occurred during the first and middle third members of the Qingshankou formation and the lower first and lower second members of the Nenjiang formation. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0765-6 Authors Dangpeng Xi, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Shun Li, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Xiaoqiao Wan, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Xia Jing, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Qinghua Huang, Daqing Oilfield, Daqing, Heilongjiang, People’s Republic of China Jean-Paul Colin, Impassse des Biroulayres, 33610 Cestas, France Zhuo Wang, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Weiming Si, School of Earth Sciences and Resources, China University of Geosciences, Xueyuan Road, Haidian District, Beijing, 100083 People’s Republic of China Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Jenynsia multidentata is one of the most abundant freshwater fishes in the subtropical region of South America and when abundant it appears to have a major impact on lake ecosystems function. We studied the life-history traits and population structure of J. multidentata in a shallow lake in Uruguay, and collected literature data along a subtropical to tropical freshwater gradient in South America. Our general focus was on reproductive strategy, particularly on sexual differences in growth, size and abundance. In Lake Blanca, we found strong reverse size dimorphism (RSD) and a feminized sex ratio. Both are attributed to sexual differences in growth patterns and longevity. RSD and a feminized sex ratio seem to characterise J. multidentata regardless of latitude, and together with other life traits such as small size, rapid growth, low age of maturity, the capacity of the females to keep sperm alive to fertilize several successive litters, high natural mortality and fertility, resistance to extreme environmental conditions and omnivory, they are indicative of high productivity to biomass ratio. The very high population growth rate helps to explain why fish removal, aiming to promote an increase in the zooplankton grazing pressure on phytoplankton, may not be a useful tool in eutrophic-turbid subtropical South American lakes. We also found that the duration of the breeding season deviated markedly with latitude, increasing towards the tropics, which may have major consequences for population growth rates and differential impact of this species on lake ecosystems in the different climate zones. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0784-3 Authors G. Goyenola, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay C. Iglesias, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay N. Mazzeo, Ecología y Rehabilitación de Sistemas Acuáticos, Departamento de Ecología y Evolución, Centro Universitario Regional Este/Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay E. Jeppesen, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Diatom-based indices are increasingly becoming important tools for the assessment of ecological conditions in lotic systems. The applicability of regional and foreign diatom-based water quality assessment indices to streams around São Carlos-SP, Brazil, is discussed. The relationship between measured water quality variables and diatom index scores was assessed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Though all borrowed indices were applicable to the study area because many widely distributed diatom species have similar environmental tolerances to those recorded for these species elsewhere, ecological requirements of some diatom species from Brazil need to be clarified and incorporated in a diatom-based water quality assessment protocol unique to the region. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0772-7 Authors Taurai Bere, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, São Paulo, Brazil José Galizia Tundisi, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, São Paulo, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Sponges are an important component of the benthic community, especially on coral reefs, but demographic data such as growth, recruitment or mortality are notably limited. This study examined the growth of the elephant ear sponge Ianthella basta , the largest and in some areas one of the dominating sponge species on Guam and other pacific reefs. We measured growth rates of the natural population on Guam over the course of one year and identified intra-individual growth patterns. Initial sponge sizes ranged from 200 to 35,000 cm 2 . Specific growth rates ranged from 0.08 to 6.08 with a mean specific growth rate of 1.43 ± 1.29 (SD) year −1 . Furthermore, specific growth decreased with sponge size. The age estimate for the largest sponge (1.7 m height × 9.5 m circumference) was ~8 years. Intra-individual growth was mostly apical. This study demonstrated high growth rates, which has notable implications for environmental assessments, management and potential biomedical applications. Content Type Journal Article Pages 1-8 DOI 10.1007/s10750-011-0774-5 Authors Sven Rohde, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstr. 1, 26382 Wilhelmshaven, Germany Peter J. Schupp, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstr. 1, 26382 Wilhelmshaven, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Copper poses a risk to the integrity of the Thames Estuary and Marshes special protection area (SPA) as bioaccumulation within the food chain takes place. This article describes some of the investigations carried out for the Habitats Directive Review of Consents including a review of the methods used to analyse copper samples; analysis of the long-term data sets gathered by the Environment Agency; and modelling work. Mean dissolved copper levels for 2002–2006 are below the 5 μg/l Environmental Quality Standard. Catchment modelling was used to establish total copper budgets both for sources discharging directly to the Tideway and for sources throughout the Thames catchment including sewage treatment works (STWs), industries, non-urban, and urban runoff. The total copper load to the Tideway was estimated to be 36 tonnes/year with 52% of this attributed to STWs. Modelling was used to explore the mixing, transport and fate of copper throughout the estuary taking account of partitioning and the interaction with sediments. The modelling showed how the fourth Water Industry Asset Management Programme (AMP4) improvements to the main London STWs would affect copper concentrations throughout the estuary. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0756-7 Authors Donna Murray, WRc plc, Frankland Road, Blagrove, Swindon, SN5 8YF UK Paul Dempsey, WRc plc, Frankland Road, Blagrove, Swindon, SN5 8YF UK Peter Lloyd, Environment Agency, Rivers House, Crossness STW, Belvedere Road, Abbey Wood, London, SE2 9AQ UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Restoration of drained peatlands has been promoted to reduce gaseous and aquatic carbon losses; however, there are conflicting reports as to its effectiveness. Here we report “hotspots” of organic matter decomposition as a result of rewetting a drained peatland in Wales, at the field-scale, in the medium/long-term with implications for water quality and greenhouse gas emissions. Low soil moisture levels, that characterise these hotspots before rewetting, regenerate electron acceptors and provide carbon and nutrients which stimulate phenol oxidase-mediated release of phenolic compounds from the peat matrix upon waterlogging. Electron acceptors are then consumed sequentially, eventually favouring CH 4 production and rising pH, despite accumulating SO 4 levels. The latter two processes promote positive feedback to increased phenol oxidase activities and the release of even more dissolved organic carbon (DOC) and CH 4 from the peat matrix. Hotspot formation therefore represents an inextricably linked physico-chemical and biological positive feedback mechanism. Such hotspots account for a large proportion of the mean increase in carbon loss due to rewetting of this naturally drained peatland (e.g. at maximum mean DOC concentrations: with hotspot 997%; without hotspot 102%) and are not “outliers” but important drivers of biogeochemical fluxes that should be included in budgets for carbon and other elements (e.g. sulphur). As such, understanding hotspot formation should allow improved management strategies for restoration, carbon stocks, drinking water quality and even future geo-engineering options in the face of changes in climate and atmospheric chemistry. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0733-1 Authors Nathalie Fenner, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Robert Williams, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Hannah Toberman, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Steve Hughes, Centre for Ecology & Hydrology (CEH), Bangor, LL57 2UW UK Brian Reynolds, Centre for Ecology & Hydrology (CEH), Bangor, LL57 2UW UK Chris Freeman, School of Biological Sciences, Bangor University, Bangor, LL57 2UW UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    In this article, the variability of physical settings of anchialine systems in Indonesia is discussed together with the consequences these settings have for the environment and biota within the systems. Exploration in two karstic areas (Berau, East Kalimantan and Raja Ampat, West Papua) has resulted in the discovery of 20 previously unknown anchialine systems in Indonesia. Based on parameters such as bathymetry, size, coastline, salinity, water temperature, pH, degree of connection to the sea, and the presence-absence of selected key taxa we distinguish three types of (non-cave) anchialine systems in the Indo-Pacific: (1) Marine lakes with large and deep basins containing brackish to almost fully marine waters. Marine lakes show a range in the degree of connection to the sea with the result that the higher the connection the more the lake resembles a lagoon in both water chemistry and biota, while the more isolated lakes have brackish water and contain unique species that are rarely found in the adjacent sea. (2) Anchialine pools with small and shallow basins containing brackish water and low diversity of macrofauna. (3) Blue pools in chasms that contain water with a clear halocline and are possibly connected to anchialine caves. Study of the many unique features of anchialine systems will enhance our understanding of the physical and ecological processes responsible for diversification in tropical shallow marine environments. Content Type Journal Article Pages 1-17 DOI 10.1007/s10750-011-0742-0 Authors Leontine E. Becking, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Willem Renema, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Nadiezhda K. Santodomingo, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Bert W. Hoeksema, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Yosephine Tuti, Indonesian Institute of Sciences, Research Centre for Oceanography, P.O. Box 4801/JKTF, Jakarta, 11048 Indonesia Nicole J. de Voogd, Netherlands Centre for Biodiversity Naturalis, P.O. Box 9517, 2300 RA Leiden, The Netherlands Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Chemical defenses are an effective mode of predator deterrence across benthic marine organisms, but their production may come with associated costs to the organism as limited resources are diverted away from primary processes like growth and reproduction. Organisms concentrating ecologically relevant levels of these defenses in tissues most at risk to predator attack may alleviate this cost while deterring predators. We addressed this hypothesis by investigating the deterrence of chemical extracts from the inner and outer regions of the sponges Aplysina fulva , Ircinia felix , and I. campana from a temperate hard-bottom reef in the South Atlantic Bight. Assays were conducted using natural fish assemblages and sea urchins. Although, A. fulva and I. felix have higher concentrations of defensive metabolites in the outer and inner regions, respectively, extracts from these regions did not display enhanced deterrency against fish or mobile invertebrate predators. Likewise, extracts from both regions of the sponge Ircinia campana , which has a uniform distribution of defensive chemicals throughout, did not differ in their ability to deter either group of predators. Since chemical defenses were effective deterrents at lower concentrations, secondary metabolite allocation patterns observed among these sponges are likely not driven by predation pressure from generalist fish and mobile invertebrate predators on these reefs. Alternatively, these patterns may be driven by other ecological stressors, another suite of predators, or may be more effective at deterring predators when combined with structural defenses. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0792-3 Authors Christopher J. Freeman, Department of Biology, University of Alabama at Birmingham, 1300 University Boulevard, Campbell Hall Room 464, Birmingham, AL 35294, USA Daniel F. Gleason, Department of Biology, Georgia Southern University, P.O. Box 8042, Statesboro, GA 30460, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Early to late Pliocene sedimentary strata present across the northern Bass Strait hinterland, southeastern Australia yield extensive fossil proxy data relevant to the interpretation of high sea level coastal palaeomorphology. Within the Pliocene Whalers Bluff Formation exposed in coastal cliffs near the township of Portland, Victoria, marine microfossil faunas delineate two broad cycles of deposition. Both these sedimentary cycles are bound below by unconformity surfaces. Within the lower sedimentary cycle, a basal stress-tolerant (low diversity) marginal marine microfossil fauna devoid of ostracods and suggestive of bottom-water hypoxia, is succeeded by a diverse shallow marine ostracod fauna dominated by stenohaline species indicative of a sheltered (but open) oceanic embayment. This lower sedimentary cycle has an early Pliocene (Zanclean) age. Equivalent shallow marine (e.g. coastal embayment) deposits occur broadly across the coastal hinterland of southeastern Australia—reflecting the generally higher global sea levels of this time. The upper cycle in the cliff exposures at Portland is late Pliocene (Piacenzian) in age. Equivalent deposits across the Bass Strait hinterland are restricted to former incised river valley settings. Euryhaline estuarine/coastal lagoon Ostracoda are present throughout the upper cycle in the Portland cliffs. These are associated with a low diversity microfauna at the base of the upper cycle and a high diversity microfauna towards the top of the cycle. Early Pliocene coastal marine deposits can be distinguished from late Pliocene coastal marine deposits across the northern Bass Strait hinterland on the basis of the presence or absence of certain open marine (‘stenohaline’) ostracod species. Content Type Journal Article Pages 1-20 DOI 10.1007/s10750-011-0777-2 Authors Mark T. Warne, School of Life and Environmental Sciences, Deakin University (Melbourne Campus), 221 Burwood Highway, Burwood, VIC 3135, Australia Brent Soutar, School of Life and Environmental Sciences, Deakin University (Melbourne Campus), 221 Burwood Highway, Burwood, VIC 3135, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The Three Gorges Dam was built in 2005 with a storage capacity of 39.3 billion m 3 , ranking 22nd in the world. However, since the impoundment of the reservoir, serious blooms of phytoplankton have occurred. Rotifers, having a key role in the freshwater aquatic food web, are important grazers of phytoplankton and an essential food resource to higher trophic consumers. To explore the impacts of phytoplankton blooms on the rotifer community, daily and vertical surveys of rotifers were conducted in a bay of the Three Gorges Reservoir (Xiangxi Bay). Altogether 46 rotifer species were registered, and Synchaeta tremula , Polyarthra vulgaris , and Brachionus calyciflorus were the most abundant species accounting for 36, 26, and 16% of the mean rotifer densities, respectively. Although these dominant species always prevailed in the rotifer community, their proportions changed significantly from non-bloom phase to bloom phase, e.g., the significance of S. tremula deceased from 46.8 to 33.2%, while P. vulgaris and B. calyciflorus increased from 23.9 and 13.9% to 26.2 and 16.2%, respectively. In the vertical water column, all the rotifer following phytoplankton displayed an aggregated distribution, concentrating at the upper layers (0.5–5 m), especially during the bloom phase. From the non-bloom phase to the bloom phase, rotifer densities, the dominant rotifers, Shannon–Wiener and Margalef’s diversity increased significantly, while the evenness displayed the opposite trend. Non-metric multidimensional scaling analysis (NMDS) revealed that the samples in the non-bloom phase were well separated from those in the bloom phase. This means that the outbreak of the diatom bloom in the Xiangxi Bay had significant impacts on the rotifer community. Further investigations are needed to address the impacts of the changes of rotifer community on higher trophic levels. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0793-2 Authors Shuchan Zhou, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Qinghua Cai, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Yaoyang Xu, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Xinqin Han, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 People’s Republic of China Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The complete mitochondrial DNA (mtDNA) genome of the Eunapius subterraneu s (Porifera, Demospongiae), a unique stygobitic sponge, was analyzed and compared with previously published mitochondrial genomes from this group. The 24,850 bp long mtDNA genome is circular with the same gene composition as found in other metazoans. Intergenic regions (IGRs) comprise 24.7% of mtDNA and are abundant with direct and inverted repeats and palindromic elements as well as with open reading fames (ORFs) whose distribution and homology was compared with other available mt genomes with a special focus on freshwater sponges. Phylogenetic analyses based on concatenated amino acid sequences from 12 mt protein genes placed E.   subterraneus in a well-supported monophyletic clade with the freshwater sponges, Ephydatia muelleri and Lubomirskia baicalensis . Our study showed high homology of mtDNA genomes among freshwater sponges, implying their recent split. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0789-y Authors Bruna Pleše, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Lada Lukić-Bilela, Institute for Genetic Engineering and Biotechnology, Gajev trg 4, 71 000 Sarajevo, Bosnia and Herzegovina Branka Bruvo-Mađarić, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Matija Harcet, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Mirna Imešek, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Helena Bilandžija, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Helena Ćetković, Department of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, P.P. 180, 10002 Zagreb, Croatia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    A survey was conducted for the presence of cyanobacteria toxins in Lake Kotokel due to a few cases of Haff disease registered in 2008–2009 caused by consumption of fish from Lake Kotokel, and wildlife mortality including large fish kill. The aims of this study were to determine what cyanotoxins (if any) were present in the lake, to describe phytoplankton composition including morphology, density, and species diversity of cyanobacteria, as well as to evaluate the trophic state of the lake. Samples were collected from both nearshore and central sites in August of 2009. Aphanocapsa holsatica dominated the phytoplankton. The presence of toxigenic genotypes of Microcystis spp. and Anabaena lemmermannii was detected by sequencing of PCR-amplified aminotransferase domain of microcystin synthetase gene. LR, RR, and YR microcystin (MC) variants were detected with liquid chromatography-UV mass spectrometry. The data do not shed light on the etiology of Haff disease in Lake Kotokel region, nevertheless taking into account the recreational importance of the lake and its direct connection to Lake Baikal, a necessity to monitor cyanobacteria in these water bodies is evident. This is the first report on simultaneous detection of MC-producing genotypes and MCs in the Lake Baikal region. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0724-2 Authors Olga I. Belykh, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Ekaterina G. Sorokovikova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Galina A. Fedorova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Oksana V. Kaluzhnaya, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Evgeniya S. Korneva, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Maria V. Sakirko, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Tatyana A. Sherbakova, Limnological Institute of the Siberian Branch of RAS, 3, Ulan-Batorskaya St, Irkutsk, Russia 664033 Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Currently, the distribution of the European native white-clawed crayfish ( Austropotamobius pallipes ) is restricted, fragmented and mainly located in headwater streams. Many European countries have active programmes for its conservation and some also have reintroduction programmes. Here, we used the ephemeropteran communities as a bioindicator of A. pallipes presence. Results from 36 brooks showed that the ephemeropteran richness is statistically higher in sites with crayfish compared to sites without crayfish. We propose using two Leptophlebiidae species ( Habrophlebia lauta and Paraleptophlebia submarginata ) as bioindicators of crayfish presence. Content Type Journal Article Pages 1-6 DOI 10.1007/s10750-011-0717-1 Authors Frédéric Grandjean, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Joelle Jandry, Laboratoire de Chimie de l’Eau et de l’Environnement, Université de Poitiers, UMR-CNRS 6008, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Elodie Bardon, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Aurore Coignet, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Marie-Cécile Trouilhé, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Bernard Parinet, Laboratoire de Chimie de l’Eau et de l’Environnement, Université de Poitiers, UMR-CNRS 6008, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Catherine Souty-Grosset, Laboratoire Ecologie, Evolution, Symbiose, Université de Poitiers, UMR-CNRS 6556, 40 avenue du Recteur Pineau, 86022 Poitiers cedex, France Michel Brulin, OPIE-benthos, La Minière, B.P. 30, 78041 Guyancourt cedex, France Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The anchovy/sardine complex is an important fishery resource in some of the largest upwelling systems in the world. Synchronous, but out of phase, fluctuations of the two species in distant parts of the oceans have prompted a number of studies dedicated to determining the phenomena, atmospheric and oceanic, responsible for the observed synchronicity and the biological mechanisms behind the population changes of the two species. Anchovy and sardine are of high commercial value for the fishing sector in Greece; this study investigates the impact of large-scale climatic indices on the anchovy/sardine complex in the Greek seas using fishery catches as a proxy for fish productivity. Time series of catches for both species were analysed for relationships with teleconnection indices and local environmental variability. The connection between the teleconnection indices and local weather/oceanic variation was also examined in an effort to describe physical mechanisms that link large-scale atmospheric patterns with anchovy and sardine. The West African Summer Monsoon, East Atlantic Jet and Pacific–North American (PNA) pattern exhibit coherent relationships with the catches of the two species. The first two aforementioned patterns are prominent atmospheric modes of variability during the summer months when sardine is spawning and anchovy juveniles are growing. PNA is related with El Niño Southern Oscillation events. Sea Surface Temperature (SST) appears as a significant link between atmospheric and biological variability either because higher temperatures seem to be favouring sardine growth or because lower temperatures, characteristic of productivity-enhancing oceanic features, exert a positive influence on both species. However at a local scale, other parameters such as wind and mesoscale circulation describe air–sea variability affecting the anchovy/sardine complex. These relationships are non-linear and in agreement with results of previous studies stressing the importance of optimal environmental windows. The results also show differences in the response of the two species to environmental forcing and possible interactions between the two species. The nature of these phenomena, e.g., if the species interactions are direct through competition or indirect through the food web, remains to be examined. Content Type Journal Article Pages 1-17 DOI 10.1007/s10750-011-0693-5 Authors Isidora Katara, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Graham J. Pierce, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Janine Illian, School of Mathematics and Statistics, The Observatory, University of St. Andrews, Buchanan Gardens, KY16 9LZ St. Andrews, UK Beth E. Scott, School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, AB24 2TZ Aberdeen, UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    This study evaluated whether the alpha and beta diversity of fishes in vegetated littoral zones of floodplain lakes in the Pantanal are randomly distributed on three different spatial scales: within the lake, among lakes, and between regions. Three alternative hypotheses were contrasted: (1) that regional diversity is generated at local scale, depending on the internal environmental heterogeneity of lakes, (2) that the diversity of fishes in floodplain lakes is produced at intermediate spatial scales, depending on structural differences and on the landscape matrix between lakes, and (3) that the diversity of fishes in the littoral zone is generated at regional scale, due to regional differences in land-use pattern and the presence of a geographical barrier represented by the river. Our results indicate that the regional diversity of fishes in the vegetated littoral zone of lakes in the northern Pantanal is a consequence of high diversity at the local level ( α ) and the wide differences in species composition among lakes and between regions. This suggests that we need to maintain environmental heterogeneity, represented by the structural differences among the lakes and their landscape matrix as well as regional differences in the flood pattern, if we hope to preserve the diversity of fishes in the region. Besides, it is necessary to establish new conservation units at the different Pantanal subregions, which should incorporate a set of lakes with different landscape features such as size, shape, and distance from and degree of connection to rivers. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0697-1 Authors Alexandro Cezar Florentino, Programa de Pós-Graduação em Biologia de Água Doce e Pesca Interior, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo, 2936, Petrópolis, Manaus, AM CEP 69060-001, Brazil Jerry Penha, Laboratório de Ecologia de Populações, Instituto de Biociências, Universidade Federal de Mato Grosso, Av. Fernando Correa da Costa s/n, Coxipó, Cuiabá, Mato Grosso 78060-900, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Synurophytes are planktonic protists whose cells are covered with silica scales. According to the temperature-size rule, protists decrease in size with increasing temperature. Here, we showed that inorganic silica scales responded to increasing temperature in the same way as the cells did. Two species, Mallomonas tonsurata and Synura petersenii , were cultivated at five temperature levels (5, 10, 15, 20 and 25°C) and the methods of geometric morphometrics were applied for scale size and shape data analyses. We observed that the shape of the scales was significantly affected by the cultivation temperature. The overall shape change from rounded, circular scales to oval or more elongated scales seemed to be a general feature in synurophytes and may be considered a consequence of rising temperature. Moreover, the difference in shape remained significant even if the effect of size (allometric effect) was separated. Finally, we compared the level of the scales’ morphological variation among all temperature treatments. The results indicated that the cultivation temperature of 25°C negatively affected cellular processes involved in scale biogenesis. The use of the scale shape data has potential in palaeoecological research. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0743-z Authors Martina Pichrtová, Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Praha 2, 128 01 Czech Republic Yvonne Němcová, Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Praha 2, 128 01 Czech Republic Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Nodularia spumigena , like many cyanobacteria, produces specialised reproductive structures, known as akinetes, which are believed to allow survival under unfavourable conditions. This study investigated the effects of salinity, nitrogen and phosphorus concentration at two irradiances on akinete differentiation in a N. spumigena isolate from the Gippsland Lakes, Victoria, Australia. A computer image analysis program was used to photograph filaments and assess production of akinetes over time in separate experiments for each environmental parameter. Heterocyst production and cell morphology were also examined. The results suggest that akinete production increases over time. Production of akinetes is further increased at low and high salinities and with the addition of nitrate. Higher irradiance increases akinete differentiation, although in combination with different phosphorus concentrations causes varied effects. The development and sedimentation of akinetes may provide an inoculum for reoccurring blooms. Heterocysts were only observed during experiments with varying salinity and nitrogen exposures. Light quantity appeared to play a large role in heterocyst production. The ability of N. spumigena to produce akinetes and heterocysts is likely to be part of the reason for its success and continual occurrence in estuarine environments low in nitrogen, such as the Gippsland Lakes, Victoria, Australia. Factors known to reduce heterocyst and akinete production will provide new insight to possible management controls for this species. Content Type Journal Article Pages 1-16 DOI 10.1007/s10750-011-0714-4 Authors Jackie H. Myers, School of Biological Sciences, Monash University (Clayton Campus), Clayton, VIC 3800, Australia John Beardall, School of Biological Sciences, Monash University (Clayton Campus), Clayton, VIC 3800, Australia Graeme Allinson, Centre Aquatic Pollution Identification Management (CAPIM), Bio21 Institute, The University of Melbourne, 30 Flemington Road, Parkville, VIC 3025, Australia Scott Salzman, School of Information Systems, Deakin University (Warrnambool Campus), 423, Warrnambool, VIC 3280, Australia Simon Robertson, Fish Ageing Services Pty Ltd, 396, Portarlington, VIC 3223, Australia Leanne Gunthorpe, Department of Primary Industries, Fisheries Victoria, DPI Queenscliff Centre, 114, Queenscliff, VIC 3225, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Some plants have high ability to absorb heavy metals in high concentrations. In this study, Spartina maritima was tested in conjunction with low molecular weight organic acids (LMWOA), in order to evaluate the possible use of this plant in phytoremediation processes in salt marshes. Three different LMWOA (citric acid, malic acid and acetic acid) were applied to contaminated intact cores of S. maritima colonized sediment and several heavy metals (Cd, Zn, Pb, Cu, Cr and Ni) were analyzed in sediment and plant parts. Acetic acid application proved to be the most efficient, enhancing greatly the uptake of all metals analyzed. Citric acid also showed good results, while malic acid proved to be very inefficient in most of the cases. The highest enhancement was observed for Cr with a 10-fold increase of the uptake upon application of acetic acid, while improving the Pb uptake proved to be the most difficult, probably due to its low solubility. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0731-3 Authors B. Duarte, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal J. Freitas, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal I. Caçador, Centro de Oceanografia, Instituto de Oceanografia, Campo Grande, 1749-1016 Lisbon, Portugal Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    A constructed wetland (2.1 ha; 2% of catchment area) in southeast Sweden, in a catchment with 35% arable land on clay soils, was investigated with respect to phosphorus (P) retention, focusing on particulate P (PP) and sediment accretion. The aims were to (i) estimate P retention and identify the dominating retention processes; (ii) investigate how well estimates of P retention based on inflow-outflow measurements compared with the amount of P accumulated in the sediment. In- and outflow of P was measured during 4 years with continuous flow measurements and flow-proportional weekly composite samples. P in the accumulated sediment was estimated based on core samples and analyzed using sequential fractionation. Total P load during 4 years was 65 kg ha −1 and intensive sampling events detected 69% as PP. Based on inflow-outflow estimates the mean P retention was 2.8 kg ha −1  year −1 , or 17%, but the amount of P accumulated in the inlet zone equated 78% of the TP load. This discrepancy showed the need to add studies of sediment accumulation to inflow-outflow estimates for an improved understanding of the P retention. The dominating P forms in the sediment were organic P (38%) and P associated with iron or aluminum (39%), i.e., potentially mobile forms. In areas colonized by Typha latifolia , the amount of P in the upper sediment layer (390 kg) was more than double the total P load of 136 kg. Cycling and release in those areas is a potential source of P that deserves further attention. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0728-y Authors Karin M. Johannesson, IFM Biology, section Ecology, Linköping University, 581 83 Linköping, Sweden Jonas L. Andersson, WRS Uppsala AB, 753 22 Uppsala, Sweden Karin S. Tonderski, IFM Biology, section Ecology, Linköping University, 581 83 Linköping, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Despite the growing concern about the importance of silicon (Si) in controlling ecological processes in aquatic ecosystems, little is known about its processing in riparian vegetation, especially compared to nitrogen (N) and phosphorus (P). We present experimental evidence that relative plant uptake of N and P compared to Si in riparian vegetation is dependent on mowing practices, water-logging and species composition. Results are obtained from a controlled and replicated mesocosm experiment, with a full-factorial design of soil water logging and mowing management. In our experiments, the Si excluding species Plantago lanceolata was dominant in the mown and non-waterlogged treatments, while Si accumulating meadow grasses and Phalaris arundinacea dominated the waterlogged treatments. Although species composition, management and soil moisture interacted strongly in their effect on relative Si:N and Si:P uptake ratios, the uptake of N to P remained virtually unchanged over the different treatments. Our study sheds new light on the impact of riparian wetland ecosystems on nutrient transport to rivers. It indicates that it is essential to include Si in future studies of the impact of riparian vegetation on nutrient transport, as these are often implemented as a measure to moderate excessive N and P inputs. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0737-x Authors Eric Struyf, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Wiktor Kotowski, Department of Plant Ecology and Environmental Conservation, University of Warsaw, Warsaw, Poland Sander Jacobs, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Stefan Van Damme, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Kris Bal, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Wout Opdekamp, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Hans Backx, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Dimitri Van Pelt, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Patrick Meire, Department of Biology, Ecosystem Management Research Group, University of Antwerp, Universiteitsplein 1C, B2610 Wilrijk, Antwerp, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Environmental flows are applied to regulated rivers, predominantly with the aim of benefiting native fauna. However, the outcomes for biodiversity and the mechanisms that underpin changes due to these manipulations are poorly understood. We examined the effects of elevated water release, of the magnitude used for riffle maintenance, on the movement and habitat use of the locally-threatened two-spined blackfish, Gadopsis bispinosus , in the Cotter River, a regulated upland stream in south-eastern Australia. We compared the behaviour of radio-tagged individuals during baseline flow conditions (0.12 m 3  s −1 ) and during elevated flow releases (1.74 m 3  s −1 ). Eight individuals (196 ± 8 mm TL) were radio-tracked at one site over 22 days, and six individuals (180 ± 5 mm TL) were monitored by fixed telemetry stations at a second site for 1 month. At both the sites, two-spined blackfish were nocturnal and occupied small linear ranges (23 ± 6 m). They preferentially used pools, but also used runs and riffles. Elevated discharge did not significantly affect movement, activity or dispersal of two-spined blackfish. Two individuals utilised inundated vegetation during high flow. Despite a small number of behavioural changes, there was no response to elevated flow at the population level. It is likely that the benthic nature of this species precludes its behaviour being affected by a 15-fold increase in-stream discharge. However, the indirect effects of flows of this magnitude on two-spined blackfish, and their responses to discharges of greater magnitude, remain to be investigated. Content Type Journal Article Pages 1-15 DOI 10.1007/s10750-011-0750-0 Authors B. T. Broadhurst, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia J. G. Dyer, Department of Environmental Management and Ecology, La Trobe University, Wodonga, VIC 3690, Australia B. C. Ebner, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia J. D. Thiem, Parks, Conservation & Lands, Territory & Municipal Services, GPO Box 158, Canberra, ACT 2601, Australia P. A. Pridmore, Department of Environmental Management and Ecology, La Trobe University, Wodonga, VIC 3690, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Phytoplankton biomass–nutrient relationship is widely used by lake managers to assess the eutrophication impact and to set the nutrient targets. Submerged vegetation and large zooplankton grazing have long been identified as factors weakening the relationship by decoupling phytoplankton from nutrients. Proving this decoupling unambiguously is difficult because, in natural systems, many factors act together, blurring each other’s effect. In this article, we present the results of continuous monitoring of 13 ponds where the effects of submerged vegetation and zooplankton grazing were enhanced by biomanipulation (fish removal). The monitoring allowed these effects to be assessed and compared with the pre-biomanipulation situations when phytoplankton biomass was mainly nutrient driven. The comparison showed a strong weakening effect of submerged vegetation and large zooplankton grazing on the chlorophyll a –total phosphorus relationship suggesting that a considerable degree of ecological quality of ponds affected by eutrophication can be restored even when nutrient-loading reduction is not feasible. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0726-0 Authors Samuel Teissier, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Anatoly Peretyatko, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Sylvia De Backer, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Ludwig Triest, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Sampling benthic macroinvertebrates in large rivers has several limitations, arising not only from the selectivity of traditional sampling gears but also from difficulty in capturing organisms that inhabit the deeper zones and high current velocities. Considering the importance of benthic macroinvertebrates as a food resource for fishes, the sampling restrictions in sediment collection done by dredges, and the importance of surveying benthos biodiversity, the objective of this study was to evaluate the stomach contents of five commonly-occurring invertivorous fish species as a means of complementing a benthic macroinvertebrate inventory. Three sampling campaigns (fish and benthic macroinvertebrate) were conducted in a reach of the Araguari River (Minas Gerais, Brazil), approximately 9 km long and 90 m wide. Astyanax altiparanae Garutti & Britski 2000, Leporinus friderici (Bloch 1794), Leporinus amblyrhynchus Garavello & Britski 1987, Iheringichthys labrosus (Lütken 1874) and Pimelodus maculatus Lacepède 1803 were the fish species collected and studied. To determine benthic macroinvertebrate taxonomic richness, a total of 54 Van Veen sediment samples were obtained. We compared lists of the benthic taxa found in fish stomachs with those from the sediment samples. The differences in the taxonomic composition of the benthic macroinvertebrate communities between the sediment samples and each fish species stomachs contents were assessed through NMDS and ANOSIM analyses, using a Sorensen similarity index with the presence/absence of taxa data. Independent of sampling period, additional benthic macroinvertebrate families or classes were provided by identifying fish stomach contents. We found a total of 30 taxa in this study, including 5 unique taxa (or 17% of the total) in the sediment samples, 9 unique taxa (30%) in the stomach samples, and 16 taxa (53%) common to both. The NMDS and ANOSIM analyses showed a significant separation between Van Veen sediment samples and two fish species stomach contents— L. amblyrhynchus and P. maculatus . These results indicate that fish can be used as additional samplers and are an efficient method to complement the benthic taxonomic inventory obtained through traditional sediment sampling techniques in large areas, as river segments and catchments. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0747-8 Authors Daniel M. Maroneze, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Taynan H. Tupinambás, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Carlos B. M. Alves, Nuvelhas/Projeto Manuelzão, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, CEP 31270-901 Belo Horizonte, MG, Brazil Fábio Vieira, Centro de Transposição de Peixes, Universidade Federal de Minas Gerais, Agência Shopping Del Rey, C. P. 4011, CEP 31250-970 Belo Horizonte, MG, Brazil Paulo S. Pompeu, Nuvelhas/Projeto Manuelzão, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, CEP 31270-901 Belo Horizonte, MG, Brazil Marcos Callisto, Laboratório de Ecologia de Bentos, Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, C.P. 486, Pampulha, CEP 30161-970 Belo Horizonte, MG, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    New habitats are an interesting tool to monitor colonization processes in the light of changes in genetic structure and evolutionary potential of populations. Cladocerans are cyclical parthenogens that offer the possibility to track genetic changes during the colonization process due to the alternation of sexual and asexual phases. The locally called “malladas” are shallow and temporary peridunal ponds in Eastern Spain that were silted in the 1960s and have been recently dug to their original basin. We here describe the colonization process in two of these newly restored ponds by the cladoceran Daphnia magna during their first 3 years. This colonization process followed three critical steps: population founding by the initial colonists, arrival of secondary immigrants and consolidation of the population structure. We found a low number of genotype colonists followed by the establishment of secondary immigrants and a slight decrease in gene flow with time. We discuss the importance of dispersal, founder effects, natural selection, inbreeding depression and genetic drift during the colonization process in the light of the most recent literature. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0741-1 Authors Raquel Ortells, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Carla Olmo, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Xavier Armengol, Departament de Microbiologia i Ecologia, Institut Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, c/ Dr. José Beltrán nº 2, 46980 Paterna, Valencia, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    In aquatic sciences, the agreement between laboratory and field observations remains a challenge. Using kinetic modeling, this research aims to compare the decomposition in laboratory and in situ conditions. In the in situ incubations, the mass decreases of the aquatic macrophytes ( Echinodorus tenellus , Hydrocotyle verticillata , Najas microcarpa and Pontederia parviflora ) were described using a litter bag technique and in the laboratory their decomposition was maintained under controlled conditions. The plants and water samples were collected from a tropical reservoir (Brazil). To describe the particulate organic carbon (POC) decay we adopted a two stage kinetic model that considered the heterogeneity of resources. The released organic carbon (i.e., losses related to mineralization, dissolution and sedimentation of smaller particles than the litter bag mesh) were used to compare the results derived from the field and laboratory incubations. Despite the methodological differences, the results show equivalence among the POC decay. The decomposition measured by litter bags method was 1.32 faster, owing to the effects of losses by sedimentation of the smaller particles, abrasion, action of decomposer organisms (e.g., fragmentation and enzymatic attack) and synergy among these factors. From a mathematical modeling approach, the results validate the use of decomposition data obtained under controlled conditions providing estimations of energy and matter fluxes within aquatic ecosystems. However, it is necessary to adopt a coefficient to acquire the similarity (e.g., 1.32). Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0625-4 Authors D. S. Silva, Programa de Pós-Graduação em Ecologia de Ecótonos, Universidade Federal de Tocantins (UFT), Av. NS 15, ALCNO 14, Bloco IV, 109 Norte, Palmas, TO 77001-090, Brazil M. B. Cunha-Santino, Departamento Hidrobiologia, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235, São Carlos, SP Brazil E. E. Marques, Programa de Pós-Graduação em Ecologia de Ecótonos, Universidade Federal de Tocantins (UFT), Av. NS 15, ALCNO 14, Bloco IV, 109 Norte, Palmas, TO 77001-090, Brazil I. Bianchini, Departamento Hidrobiologia, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235, São Carlos, SP Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We investigated the population dynamics of the rotifer Brachionus rotundiformis fed with the alga Isochrysis galbana at two food concentrations (3 × 10 4 and 40 × 10 4  cells ml −1 ) and four salinity levels (5, 10, 20, and 30) in the presence and absence of two copepod species, Pseudodiaptomus annandalei and Apocyclops royi and one cladoceran, Diaphanosoma aspinosum . Both the density and population growth rate of B. rotundiformis increased at higher food concentration and at salinity levels of 10 and 20. Among the microcrustaceans, only P. annandalei had a significant negative effect on the growth rate of the rotifer population because of its efficient predation. In contrast, the presence of both A. royi and D. aspinosum did not affect the growth rates at any of the salinity and food levels. Brachionus rotundiformis had significantly larger size during the log-phase, particularly if P. annandalei was present. Thus, B. rotundiformis grows better at higher food level and medium salinity levels. Unlike the larger calanoid, P. annandalei , B. rotundiformis can definitely coexist with relatively small cyclopoid copepods ( A. royi ) and cladocerans ( D. aspinosum ), because of the absence of interference. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0615-6 Authors Shin-Hong Cheng, Tungkang Biotechnology Research Center, Fisheries Research Institute, Tungkang, Pingtung, 928 Taiwan Samba Kâ, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Ram Kumar, Ecosystem Research Laboratory, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi, 110019 India Chung-Su Kuo, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Jiang-Shiou Hwang, Institute of Marine Biology, National Taiwan Ocean University, Keelung, 202 Taiwan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We hypothesised that (i) a summer heat wave would increase the thermal stability of lakes and (ii) the size and trophic state differences would modify the lakes’ responses to heating. Within 2 years, 2008 and 2009, we studied the thermal and optical regimes of two adjacent stratified lakes in northern Italy, the oligo-mesotrophic Lake Monate (2.5 km 2 , max. depth 34 m) and the eutrophic Lake Varese (14.8 km 2 , 26 m). After the cold winter 2008–2009, a heat wave starting in May turned the whole year 2009 the second hottest after 2003. The particular sequence of meteorological events resulted in extreme vertical temperature gradients and unusually high thermal stability of both lakes. All calculated thermal parameters showed the highest values in 2009 while also the values for 2008 exceeded considerably those published for these lakes in the past. Due to the large wind exposed surface, wind mixing was supposedly the dominating mechanism of heat transfer in the shallower eutrophic Lake Varese where, due to low water transparency, large amount of solar energy trapped in the upper layers markedly increased the thermal stability. In the deeper and more transparent Lake Monate, the deeper penetrating solar irradiance contributed to better energy dissipation within the water column and smaller interannual differences in thermal stability. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0691-7 Authors Peeter Nõges, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Tiina Nõges, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Michela Ghiani, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Bruno Paracchini, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Joaquin Pinto Grande, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Fabrizio Sena, European Commission, Joint Research Centre, Institute for Environment and Sustainability, Via Enrico Fermi, 2749, 21027 Ispra, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Recent submarine caves are inhabited by endemic faunas adapted to oligotrophism, darkness and a tranquil environment. Many of their representatives are archaic types of animals resembling fossils from very early times in evolution. This article compares fossil fauna from Jurassic neptunian dykes (originally sea bed clefts) from the Western Carpathians with the Recent cave-dwelling fauna. The ostracods Pokornyopsis feifeli are particularly important. In the Western Carpathians, these were exclusively found in the Middle/Late Jurassic fissure fillings, but in the non-Tethyan Germanic Jurassic this species was found in deep-marine claystones. They are phylogenetic forerunners of the recent genus Danielopolina inhabiting both anchialine caves and deep seas. This indicates a Jurassic migration of deep-marine fauna to cryptic habitats. Other examples of cryptic communities include the Upper Jurassic cavity-dwelling fauna dominated by serpulids and scleractinian corals. Associated suspension feeders include thecideidine brachiopods, oysters, bryozoans, sponges, crinoids and sessile foraminifers. Serpulid-dominated bioconstructions have recent analogies in the Mediterranean and Carribean seas. Different type of dyke communities represent the Late Jurassic fauna of small sized ammonites which originated from both Tethyan and Boreal paleobioprovinces. It has not been established whether these amonites were juvenile, dwarfed specimens adapted to limited cave space or size-sorted adult specimens. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0687-3 Authors Roman Aubrecht, Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina-G, 842 15 Bratislava, Slovakia Ján Schlögl, Department of Geology and Paleontology, Faculty of Natural Sciences, Comenius University, Mlynská dolina-G, 842 15 Bratislava, Slovakia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description: Erratum to: Distribution and ecology of Hemimysis anomala , the latest invader of the Great Lakes basin Content Type Journal Article Pages 1-1 DOI 10.1007/s10750-011-0692-6 Authors Jérôme Marty, St. Lawrence River Institute, 2, Belmont Street, Cornwall, ON K6H 4Z1, Canada Kelly Bowen, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada Marten A. Koops, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada Michael Power, Biology Department, University of Waterloo, 200 University Ave. West, Waterloo, ON N2L 1G3, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Baited underwater camera (BUC) systems to estimate demersal fish abundance are becoming increasingly considered as an alternative to traditional survey methods, particularly in environments that contain sensitive habitats or protected species. Based on 27 replicate deployments of BUCs at 100 m depth in the northern North Sea, in rank order of abundance, hagfish ( Myxine glutinosa ), flatfish mainly dabs ( Limanda limanda ), whiting ( Merlangius merlangus ) and haddock ( Melanogramus aeglefinus ) were observed consistently at baits. Higher maximum numbers ( N max ) occurred during daytime in all species with the most significant effect in flatfish, 18 in daytime and 5 at night-time. Bottom current had no significant effect on numbers of whiting, flatfish or haddock. The N max of hagfish was strongly related to current speed in a non-linear way with an increase in numbers up to 10 cm s −1 and then decrease in N max at higher water speeds. Understanding and accounting for such species-specific influences is important in the design of long term monitoring surveys using baited cameras. Content Type Journal Article Pages 1-12 DOI 10.1007/s10750-011-0672-x Authors Iñigo Martinez, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Emma G. Jones, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Sarah L. Davie, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Francis C. Neat, Marine Scotland-Science, Marine Laboratory, 375 Victoria Road, Aberdeen, AB11 9DB UK Ben D. Wigham, Dove Marine Laboratory, Newcastle University, Cullercoats, North Shields, NE30 4PZ UK Imants G. Priede, University of Aberdeen, Oceanlab, Newburgh, Aberdeen, AB11 6AA UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We tested the hypothesis that species composition and persistence of phytoplankton communities in nutrient rich lowland rivers depends mainly on physical factors. The study aimed to analyse the effects of water discharge, temperature and chemistry on phytoplankton dynamic and species composition in the lowland reach of the eutrophic Po river (Italy). Both taxonomical and morpho-functional methods were used. True planktonic and tychoplanktic (i.e. detached taxa of benthic origin that remain in suspension) species were found, among which only a few taxa and functional groups prevailed. Diatoms were the most abundant, with a clear dominance of species either sensitive to the onset of water stratification or well adapted to turbid waters. Phytoplankton abundance, biomass and chlorophyll- a followed similar trends, attaining the highest values in summer, at low discharge rates. Correlation and multivariate analysis revealed that the development of a stable phytoplankton community was mainly controlled by water discharge rates. Namely, changes in water flow rates induced major variations in the community structure. The seasonal succession of phytoplankton assemblages was also related to water temperature and dissolved reactive silica availability to some extent overlapping flow effects. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0688-2 Authors Silvia Tavernini, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Enrica Pierobon, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Pierluigi Viaroli, Department of Environmental Sciences, University of Parma, Viale G.P. Usberti, 11/A, 43100 Parma, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Despite iodine being one of the most abundant of the minor elements in oxic seawater, the principal processes controlling its interconversion from iodate to iodide and vice versa, are still either elusive or largely unknown. The two major hypotheses for iodate reduction involve either phytoplankton growth in primary production, or bacteria during regeneration. An earlier study intended to exploit the unusual nature of anchialine environments revealed that iodide is oxidised to iodate in the bottom of such caves, whereas reduction of iodate occurs in the shallower parts of the water column. This investigation was made on the hypothesis that study of the nitrogen and phosphorus nutrient systems within the caves might offer a bridge between the iodine chemistry and the marine bacteria which are assumed to be the agent of change of the iodine in the caves. Accordingly, the hydrography, the nutrient chemistry, and some further iodine studies were made of two anchialine caves on the east coast of the Adriatic Sea in Croatia. Iodate and iodide were determined by differential pulse voltammetry and cathodic stripping square-wave voltammetry, respectively. Total iodine was determined indirectly, as iodate, after oxidation of reduced iodine species with UV irradiation and strong chemical oxidants. Nutrient concentrations were measured by spectrophotometry. Nutrient profiles within the well stratified water columns indicate a relatively short-lived surface source of nitrate and phosphate to the caves, with a more conventional, mid-water, nutrient regeneration system. The latter involves nitrite and ammonium at the bottom of the halocline, suggestive of both autotrophic and heterotrophic microbial activity. High iodate/low iodide deep water, and conservative behaviour of total inorganic iodine were confirmed in both systems. Iodate is reduced to iodide in the hypoxic region where nutrient regeneration occurs. The concentrations of organic iodine were surprisingly high in both systems, generally increasing toward the surface, where it comprised almost 80% of total iodine. As with alkalinity and silica, the results suggest that this refractive iodine component is liberated during dissolution of the surrounding karst rock. A major, natural flushing of one of the caves with fresh water was confirmed, showing that the cave systems offer the opportunity to re-start investigations periodically. Content Type Journal Article Pages 1-20 DOI 10.1007/s10750-011-0686-4 Authors Vesna Žic, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Victor W. Truesdale, School of Life Sciences, Oxford Brookes University, Headington, Oxford, OX3 0BP UK Vlado Cuculić, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Neven Cukrov, Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička 54, 10001 Zagreb, Croatia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Total nitrogen (TN) in Lake Okeechobee, a large, shallow, turbid lake in south Florida, has averaged between 90 and 150 μM on an annual basis since 1983. No TN trends are evident, despite major storm events, droughts, and nutrient management changes in the watershed. To understand the relative stability of TN, this study evaluates nitrogen (N) dynamics at three temporal/spatial levels: (1) annual whole lake N budgets, (2) monthly in-lake water quality measurements in offshore and nearshore areas, and (3) isotope addition experiments lasting 3 days and using 15 N-ammonium ( 15 NH 4 + ) and 15 N-nitrate ( 15 NO 3 − ) at two offshore locations. Budgets indicate that the lake is a net sink for N. TN concentrations were less variable than net N loads, suggesting that in-lake processes moderate these net loads. Monthly NO 3 − concentrations were higher in the offshore area and higher in winter for both offshore and nearshore areas. Negative relationships between the percentage of samples classified as algal blooms (defined as chlorophyll a  〉 40 μg l −1 ) and inorganic N concentrations suggest N-limitation. Continuous-flow experiments over intact sediment cores measured net fluxes (μmol N m −2  h −1 ) between 0 and 25 released from sediments for NH 4 + , 0–60 removed by sediments for NO 3 − , and 63–68 transformed by denitrification. Uptake rates in the water column (μmol N m −2  h −1 ) determined by isotope dilution experiments and normalized for water depth were 1,090–1,970 for NH 4 + and 59–119 for NO 3 − . These fluxes are similar to previously reported results. Our work suggests that external N inputs are balanced in Lake Okeechobee by denitrification. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0683-7 Authors R. Thomas James, Water Quality Treatment Technologies Division, South Florida Water Management District, West Palm Beach, FL USA Wayne S. Gardner, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Mark J. McCarthy, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Stephen A. Carini, Marine Science Institute, The University of Texas at Austin, Port Aransas, TX USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    To address the question whether the abundance of an invasive species can be explained by physical and chemical properties of the invaded ecosystems, we gathered density data of invasive zebra mussels and the physical and chemical data of ecosystems they invaded. We assembled published data from 55 European and 13 North American lakes and developed a model for zebra mussel density using a generalized additive model (GAM) approach. Our model revealed that the joint effect of surface area, total phosphorus and calcium concentrations explained 62% of the variation in Dreissena density. Our study indicates that large and less productive North American lakes can support larger local populations of zebra mussels. Our results suggest that the proliferation of an exotic species in an area can partially be explained by physical and chemical properties of the recipient environment. Content Type Journal Article Pages 1-10 DOI 10.1007/s10750-011-0689-1 Authors Rahmat Naddafi, Department of Ecology and Evolution/Erken Laboratory, Evolutionary Biology Centre, Uppsala University, Norr Malma 4200, 76173 Norrtälje, Sweden Thorsten Blenckner, Baltic Nest Institute, Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden Peter Eklöv, Department of Ecology and Evolution/Limnology, Evolutionary Biology Centre, Uppsala University, Box 573, SE-751 23 Uppsala, Sweden Kurt Pettersson, Department of Ecology and Evolution/Erken Laboratory, Evolutionary Biology Centre, Uppsala University, Norr Malma 4200, 76173 Norrtälje, Sweden Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Accurate prediction of species distributions based on sampling and environmental data is essential for further scientific analysis, such as stock assessment, detection of abundance fluctuation due to climate change or overexploitation, and to underpin management and legislation processes. The evolution of computer science and statistics has allowed the development of sophisticated and well-established modelling techniques as well as a variety of promising innovative approaches for modelling species distribution. The appropriate selection of modelling approach is crucial to the quality of predictions about species distribution. In this study, modelling techniques based on different approaches are compared and evaluated in relation to their predictive performance, utilizing fish density acoustic data. Generalized additive models and mixed models amongst the regression models, associative neural networks (ANNs) and artificial neural networks ensemble amongst the artificial neural networks and ordinary kriging amongst the geostatistical techniques are applied and evaluated. A verification dataset is used for estimating the predictive performance of these models. A combination of outputs from the different models is applied for prediction optimization to exploit the ability of each model to explain certain aspects of variation in species acoustic density. Neural networks and especially ANNs appear to provide more accurate results in fitting the training dataset while generalized additive models appear more flexible in predicting the verification dataset. The efficiency of each technique in relation to certain sampling and output strategies is also discussed. Content Type Journal Article Pages 1-24 DOI 10.1007/s10750-011-0676-6 Authors A. Palialexis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece S. Georgakarakos, Department of Marine Sciences, University of the Aegean, University Hill, 81 100 Mytilini, Lesvos, Greece I. Karakassis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece K. Lika, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece V. D. Valavanis, Marine GIS Lab, Hellenic Centre for Marine Research, Thalassocosmos, 71 003 Heraklion, Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Particulate organic matter (POM) plays an important role in nutrient dynamics in river ecosystems, but little is known about changes in the origin and quality of POM in relation to physical and seasonal changes along rivers. Using stable isotope and stoichiometric analyses, we investigated the changes in origin and quality of POM of three different size fractions (fine [FPOM], 1.2–100 μm; medium [MPOM], 100–250 μm; and coarse [CPOM], 250–1,000 μm) at 14 sites along a gravel-bed river over four seasons. FPOM and MPOM accounted for 90% of all POM at all study sites. At each site, the δ 13 C level was lower for FPOM (range: −29.0 to −21.1‰) than for MPOM (−26.9 to −17.2‰) and CPOM (−27.5 to −16.3‰). The C:N ratio was lower for FPOM (6.9–15.6) than for MPOM (6.3–17.4) and CPOM (5.7–27.1). The contribution of periphyton to POM of all size fractions had a tendency to increase downstream, though the trend was less clear and varied seasonally for MPOM and CPOM between sites in middle and downstream reaches. Contrastively, the C:N ratio in all size fractions of POM consistently decreased downstream. The downstream decrease in the C:N ratio of POM can be partly explained by the increase in the contribution of periphyton, which seems to be associated with increased discharge and enhanced periphyton dislodgement, especially in winter. In addition, an increase in bacterial biomass associated with the greater nutrient availability in pool areas is another possible reason for the decrease in the C:N ratio of POM downstream. Content Type Journal Article Pages 1-15 DOI 10.1007/s10750-011-0682-8 Authors Fumikazu Akamatsu, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Sohei Kobayashi, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Kunihiko Amano, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Satoru Nakanishi, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Yurika Oshima, Water Environment Research Group, Public Works Research Institute, 1-6 Minamihara, Tsukuba, 305-8516 Japan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The bluemouth, Helicolenus dactylopterus , is a deep-sea scorpionfish widely distributed in the Atlantic Ocean and the Mediterranean. It is a common by-catch associated to many demersal fisheries. However, there is little information about the stock structure, stock dynamics and life history parameters of the bluemouth. From the perspective of stock identification, it is important to study growth in fish populations to better understand the possible morphological differences among populations and when and why do they arise. Thus, the aim of this study was to determine the growth (allometric) trajectories of shape for several bluemouth populations in Northeast Atlantic and Mediterranean using landmark-based geometric morphometric techniques. In this study, ontogenetic allometry was present in all of the bluemouth samples. Ontogenetic shape changes were most evident in the head and pectoral area, affecting the position of the snout, preopercular spines and pectoral fins, but changes in body depth and length were also important. However, the degree to which these ontogenetic shape changes were present in bluemouth from each of the studied areas was different, indicating that their growth trajectories are not homogeneous. The importance of this finding for size-correction of the shape variables in morphometric studies for stock identification is also discussed. Content Type Journal Article Pages 1-18 DOI 10.1007/s10750-011-0675-7 Authors Rebeca Rodríguez-Mendoza, Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain Marta Muñoz, Departament de Ciències Ambientals, Universitat de Girona, Campus Montilivi, 17071 Girona, Spain Fran Saborido-Rey, Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The accurate representation of species distribution derived from sampled data is essential for management purposes and to underpin population modelling. Additionally, the prediction of species distribution for an expanded area, beyond the sampling area can reduce sampling costs. Here, several well-established and recently developed habitat modelling techniques are investigated in order to identify the most suitable approach to use with presence–absence acoustic data. The fitting efficiency of the modelling techniques are initially tested on the training dataset while their predictive capacity is evaluated using a verification set. For the comparison among models, Receiver Operating Characteristics (ROC), Kappa statistics, correlation and confusion matrices are used. Boosted Regression Trees (BRT) and Associative Neural Networks (ASNN), which are both within the machine learning category, outperformed the other modelling approaches tested. Content Type Journal Article Pages 1-26 DOI 10.1007/s10750-011-0673-9 Authors A. Palialexis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece S. Georgakarakos, Department of Marine Sciences, University of the Aegean, University Hill, 81 100 Mytilini, Lesvos, Greece I. Karakassis, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece K. Lika, Department of Biology, University of Crete, Vassilika Vouton, P.O. Box 2208, 71 409 Heraklion, Crete, Greece V. D. Valavanis, Marine GIS Lab, Hellenic Centre for Marine Research, P.O. Box 2214, 71 003 Heraklion, Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The bottom trawl fishery developed on the slope off Balearic Islands (western Mediterranean) has been analysed from different sources of information: (i) data obtained during experimental bottom trawl surveys developed annually since 2001; (ii) daily sale bills from the bottom trawl fleet, available since 2000. Considering both hydrographical and geomorphologic conditions, the study area was divided in four geographical sectors. Multivariate techniques were applied to identify assemblages and their main species, and to investigate the influence of environmental variables in the slope communities. Fishery-independent and fishery-dependent indicators were calculated, both at specific and community level, for the assemblages identified. In all cases, they were summarised using the Traffic Light approach. Three assemblages have been identified in the slope trawl fishing grounds off the Balearic Islands: (1) the almost unexploited shelf break, where teleosts predominate; (2) the upper slope, where teleosts still predominate but crustaceans are also very important (with Nephrops norvegicus as target species); (3) and the middle slope, where crustaceans predominate (with Aristeus antennatus as target species). Depth was the main factor affecting the species composition of the assemblages, although other factors such as area, year and effort level also affect. Indicators estimated from both sets of data suggested an improvement in the state of N. norvegicus , although the results suggest the influence of other factors than fishing impact in the state of this resource. For A. antennatus , marked differences have been found depending on the data source. In the upper slope, indicators suggested an improvement in the state of this assemblage, which can be related to a decreasing trend found in the fishing effort exerted in this depth range. Indicators from the middle slope showed differences for both sets of data. The characteristics of both data sources and of the species analysed are discussed as responsible of these differences. Content Type Journal Article Pages 1-19 DOI 10.1007/s10750-011-0670-z Authors Beatriz Guijarro, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain George Tserpes, Hellenic Centre for Marine Research (HCMR), Institute of Marine Biological Resources, P.O. Box 2214, 71003 Poros, Heraklion, Greece Joan Moranta, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain Enric Massutí, Instituto Español de Oceanografía, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015 Palma, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The relation of macrobenthic species turnover (beta diversity) and species plylogenetic variation with functional diversity patterns, across an environmental gradient induced by an aquaculture unit, in a coastal area of the island of Lesvos (NE Aegean) has been investigated in this study. The contribution of rare species response and species dispersal ability in the variation of functional diversity patterns along the environmental gradient, on a spatio-temporal scale, has been also examined. Our results revealed that benthic functional diversity was decreasing monotonically with increasing species turnover rate and hence with increasing spatial variability along the environmental gradient. Increased environmental stress which was detected in the immediate vicinity of the fish cages resulted to low species functional redundancy, since different species didn’t perform the same functional role at the most disturbed part of the established gradient. Functional diversity patterns were found to be correlated with species population size, whereas a strong linear relationship was also detected with phylogenetic diversity patterns, thus supporting the claim that wider local taxonomic trees can support a wider range of species functions even in small spatial scales. Rare species loss seemed to be one of the dominant factors ruling functional diversity variation. Species with the minimum possible dispersal ability, which were mostly rare, tend to diminish both in species number and population size faster than species with wider dispersal ability towards the most disturbed areas. The aforementioned results indicate that rare species variation and endemic species loss are critical factors in determining functional diversity loss across a human-induced environmental gradient in soft bottom benthic communities. Content Type Journal Article Pages 1-9 DOI 10.1007/s10750-011-0668-6 Authors Charalampos Dimitriadis, Department of Marine Sciences, Faculty of Environment, University of the Aegean, Lesvos Island, 81100 Greece Drosos Koutsoubas, Department of Marine Sciences, Faculty of Environment, University of the Aegean, Lesvos Island, 81100 Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Marine protected areas (MPAs) are attracting widespread attention worldwide as a tool for fishery management and marine ecosystem conservation. The establishment of MPAs has increased greatly in recent years mostly due to international commitments to the establishment of a global network of MPAs by 2012. MPAs have the potential to strongly affect the fishing industry, and their success depends, at least partly, on fishers’ attitudes towards this management measure. However, research on MPAs tends to focus on the ecological and conservation aspects of this management approach and not on its human dimensions. Studies in attitudes, perceptions, beliefs and preferences related to MPA issues have been identified as priority social science topics in need of research. We present a ‘rapid review’, conducted systematically, of the literature published up to September 2009 and aimed at identifying the most investigated topics related to commercial fishers’ attitudes towards MPAs, describing the main findings from these studies, and analysing the implications for management. Most published work focuses on fishers’ attitudes towards issues of governance, conservation of biodiversity and the environment, and the impact of MPAs on fishing activity. Despite the recent increase in the literature on the human dimensions of MPAs, the present review reveals that little of this literature originates from empirical studies. Hence, given the forthcoming increase in the implementation of MPAs in the near future, research on fishers’ attitudes towards these management measures is critically needed. Content Type Journal Article Pages 1-18 DOI 10.1007/s10750-011-0665-9 Authors Cristina Pita, Business School, Department of Economics, University of Aberdeen, Edward Wright Building, Dunbar Street, Aberdeen, AB24 3QY UK Graham J. Pierce, Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ UK Ioannis Theodossiou, Business School, Department of Economics, University of Aberdeen, Edward Wright Building, Dunbar Street, Aberdeen, AB24 3QY UK Karen Macpherson, NHS Quality Improvement Scotland, Delta House, 50 West Nile Street, Glasgow, G1 2NP UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The distribution of the common octopus ( Octopus vulgaris ) in the Mediterranean and Eastern Atlantic waters is evaluated using two presence-only analyses: The maximum entropy model (Maxent) and the ecological niche factor analysis (ENFA). Maxent predicts those geographical areas that satisfy the environmental or abiotic requirements of a species while ENFA explores the niche and habitat preferences of O. vulgaris . The analyses were implemented recovering the spatial information from 213 octopus presence data collected from surveys and bibliographical records. Together, these analyses provided reasonable estimates of the species distribution and the octopus habitat. Among the gathered set of explanatory environmental variables, sea bottom temperature, sea bottom salinity, surface dissolved oxygen and sea surface chlorophyll-α appear as the main variables involved in O. vulgaris distribution. These results were confronted with the available literature. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0671-y Authors Consuelo Hermosilla, Department of Ecology and Animal Biology, Campus As Lagoas Marcosende, University of Vigo, 36310 Vigo, Spain Francisco Rocha, Department of Ecology and Animal Biology, Campus As Lagoas Marcosende, University of Vigo, 36310 Vigo, Spain Vasilis D. Valavanis, Marine GIS Laboratory, Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Thalassocosmos, 71003 Heraklion Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Generally, the foliar sheaths of seagrass contribute a large biomass to the dry weight of plants, and are found to be above-sediment biomass or, sometimes, below-sediment biomass. However, the role of foliar sheaths of seagrass in nutrient uptake has not yet been established. Thus, this study was performed to test whether the growth form of foliar sheaths affects the nutrient uptake properties of the seagrass. Two separate sets of morphotypes of the seagrass Thalassia hemprichii were collected from two different tropical meadows in coastal Hainan Island, China in the South China Sea. Ammonium (NH 4 + ) and phosphate (P i ) uptake by solely blades and roots (experiment I), and above and below-sediment tissues (experiment II) of the two sets of specimens were examined in partitioned chambers using laboratory incubations. Curve profiles of the blade and root saturation uptake kinetics were shown to be similar for the two morphotypes of T. hemprichii . However, the above and below-sediment tissues uptake kinetics had different characteristics between the two morphotypes. For plants with above-sediment foliar sheaths, uptake by the above-sediment tissues contributed an important part of the whole plants’ nutrient acquisition. In contrast, for plants with below-sediment foliar sheaths, the contribution of nutrient uptake by above-sediment foliar blade tissues seemed almost negligible. Therefore, the results demonstrated that foliar sheaths of the tropical seagrass T. hemprichii were able to absorb NH 4 + and P i . Especially interesting is that the capacity for uptake by robust foliar sheaths growing beneath the sediment was remarkable (we termed this the Zhang–Huang–Thorhaug effect). The role of sheaths in nutrient acquisition found in this study is critical in elucidating seagrass nutrient uptake strategies. Content Type Journal Article Pages 1-17 DOI 10.1007/s10750-011-0662-z Authors Jing-Ping Zhang, Key Laboratory of Tropical Marine Environmental Dynamics (LED), South China Sea Institute of Oceanology, The Chinese Academy of Sciences, 164 # Xingang Road, Guangzhou, 501301 People’s Republic of China Xiao-Ping Huang, Key Laboratory of Tropical Marine Environmental Dynamics (LED), South China Sea Institute of Oceanology, The Chinese Academy of Sciences, 164 # Xingang Road, Guangzhou, 501301 People’s Republic of China Zhi-Jian Jiang, Key Laboratory of Tropical Marine Environmental Dynamics (LED), South China Sea Institute of Oceanology, The Chinese Academy of Sciences, 164 # Xingang Road, Guangzhou, 501301 People’s Republic of China Anitra Thorhaug, School of Forestry & Environmental Studies, Yale University, 1359 SW 22 Terrace, Miami, FL 33145, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    A time series of survey abundance indices for commercially important demersal fish and cephalopod species, inhabiting the narrow continental shelf of the southern Aegean Sea, is analyzed in relation to the topography of the area in order to evaluate the impact of different spatial fishery bans on the bottom-trawl fishery. With reference to the current situation, results suggested that implementation of the 1967/2006 EC Regulation, which bans bottom-trawl activities within 1.5 NM off the coast, will significantly increase (20–80%, depending on the species) the proportion of the populations that are inaccessible to the bottom-trawl fishery. It might also result in shifting of fishing activities toward deeper waters, adding fishing pressure onto slope resources inhabiting the slope. As depth determines, to a large extent, the distribution pattern of the species, it constitutes a variable of crucial importance for the spatial management of marine fisheries and should be taken into account when adopting relevant management regimes. Content Type Journal Article Pages 1-8 DOI 10.1007/s10750-011-0667-7 Authors George Tserpes, Hellenic Centre for Marine Research, PO Box 2214, 71003 Heraklion, Greece Evangelos Tzanatos, Hellenic Centre for Marine Research, PO Box 2214, 71003 Heraklion, Greece Panagiota Peristeraki, Hellenic Centre for Marine Research, PO Box 2214, 71003 Heraklion, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The European Ocean Biogeographic Information System—EurOBIS—is an integrated data system developed by the Flanders Marine Institute (VLIZ) for the EU Network of Excellence “Marine Biodiversity and Ecosystem Functioning” (MarBEF) in 2004. Its principle aims are to centralise the largely scattered biogeographical data on marine species collected by European institutions and to make these quality-controlled data freely available and easily accessible. It is in essence a distributed system in which individual datasets go through a series of quality control procedures before they are integrated into one large consolidated database. EurOBIS is freely available online at www.eurobis.org , where marine biogeographical data—with a focus on taxonomy, temporal and spatial distribution—can be consulted and downloaded for analyses. Over the last 6 years, EurOBIS has collected 228 datasets contributed by more than 75 institutes, representing over 13.6 million distribution records of which almost 12.5 million records are species level identifications. It is now the largest online searchable public source of European marine biological data, holding biogeographical information on 26,801 species and 9,221 genera. EurOBIS acts as the European node of OBIS, the Ocean Biogeographic Information System of the Census of Marine Life (CoML). EurOBIS shares its data with OBIS, which in its turn shares its content with the Global Biodiversity Information Facility (GBIF). This article describes the status of the European Ocean Biogeographic Information System, identifies data gaps, possible applications, uses and limitations. It also formulates a strategy for the growth and improvement of the system and wants to appeal for more contributions. Content Type Journal Article Pages 1-14 DOI 10.1007/s10750-011-0656-x Authors Leen Vandepitte, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Francisco Hernandez, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Simon Claus, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Bart Vanhoorne, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Nathalie De Hauwere, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Klaas Deneudt, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Ward Appeltans, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Jan Mees, Flanders Marine Institute (VLIZ), InnovOcean Site, Wandelaarkaai 7, 8400 Oostende, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Recent investigations of anchialine caves and sinkholes have identified complex food webs dependent on detrital and, in some cases, chemosynthetically produced organic matter. Chemosynthetic microbes in anchialine systems obtain energy from reduced compounds produced during organic matter degradation (e.g., sulfide, ammonium, and methane), similar to what occurs in deep ocean cold seeps and mud volcanoes, but distinct from dominant processes operating at hydrothermal vents and sulfurous mineral caves where the primary energy source is mantle derived. This review includes case studies from both anchialine and non-anchialine habitats, where evidence for in situ chemosynthetic production of organic matter and its subsequent transfer to higher trophic level metazoans is documented. The energy sources and pathways identified are synthesized to develop conceptual models for elemental cycles and energy cascades that occur within oligotrophic and eutrophic anchialine caves. Strategies and techniques for testing the hypothesis of chemosynthesis as an active process in anchialine caves are also suggested. Content Type Journal Article Pages 1-19 DOI 10.1007/s10750-011-0624-5 Authors John W. Pohlman, U.S. Geological Survey, Woods Hole Coastal and Marine Science Center, 384 Woods Hole Rd., Woods Hole, MA 02543, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The response of larval fish communities of the northeastern Aegean Sea (NEA) to interannual environmental changes is analyzed using data from four ichthyoplankton surveys covering the NEA continental shelf during June 1993, 1994, 1995, and 1996. Waters were significantly cooler, less saline and richer in zooplankton in 1993 and 1996 (‘cold’ years) than in 1994 and 1995 (‘warm’ years). A comparison of monthly SST series (1993–1997) between the NEA, the Marmara Sea, and the Western Black Sea revealed high correlations and similar trend components among these areas implying that oceanographic conditions over the NEA (and observed inter-annual differences) were most likely dominated by the properties and relative amount of Black Sea water inflow in the NEA. The relative composition of the larval fish community was significantly related to the ‘cold/warm’ regime and larval diversity was higher during the warm years. Larvae of the small-sized pelagic species, such as anchovy ( Engraulis encrasicolus ), and most mesopelagic fishes were relatively more abundant during the cold, zooplankton-rich years. Larvae of the middle-sized pelagics ( Sardinella aurita , Scomber japonicus , Trachurus mediterraneaus , Auxis rochei ) and certain benthopelagic species exhibited an opposite trend, i.e., they were more abundant during the warm years or absent during the cold years. Most of these species are known to be typical summer spawners (e.g., Serranus cabrilla , Lisa saliens , Trachinus draco , and Symphurus nigrescens) . Co-variation in larval fish production might be indicative of similar responses among species to changing physical and/or trophic regimes. Content Type Journal Article Pages 1-13 DOI 10.1007/s10750-011-0677-5 Authors Stylianos Somarakis, Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Thalassocosmos, P.O. Box 2214, Heraklio, Crete, Greece Alexis Ramfos, Department of Aquaculture and Fisheries Management, Technological and Educational Institute of Messolonghi, 30200 Messolonghi, Greece Andreas Palialexis, Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Thalassocosmos, P.O. Box 2214, Heraklio, Crete, Greece Vasilis D. Valavanis, Institute of Marine Biological Resources, Hellenic Centre for Marine Research, Thalassocosmos, P.O. Box 2214, Heraklio, Crete, Greece Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The mean body size of limnetic cladocerans decreases from cold temperate to tropical regions, in both the northern and the southern hemisphere. This size shift has been attributed to both direct (e.g. physiological) or indirect (especially increased predation) impacts. To provide further information on the role of predation, we compiled results from several studies of subtropical Uruguayan lakes using three different approaches: (i) field observations from two lakes with contrasting fish abundance, Lakes Rivera and Rodó, (ii) fish exclusion experiments conducted in in-lake mesocosms in three lakes, and (iii) analyses of the Daphnia egg bank in the surface sediment of eighteen lakes. When fish predation pressure was low due to fish kills in Lake Rivera, large-bodied Daphnia appeared. In contrast, small-sized cladocerans were abundant in Lake Rodó, which exhibited a typical high abundance of fish. Likewise, relatively large cladocerans (e.g. Daphnia and Simocephalus ) appeared in fishless mesocosms after only 2 weeks, most likely hatched from resting egg banks stored in the surface sediment, but their abundance declined again after fish stocking. Moreover, field studies showed that 9 out of 18 Uruguayan shallow lakes had resting eggs of Daphnia in their surface sediment despite that this genus was only recorded in three of the lakes in summer water samples, indicating that Daphnia might be able to build up populations at low risk of predation. Our results show that medium and large-sized zooplankton can occur in subtropical lakes when fish predation is removed. The evidence provided here collectively confirms the hypothesis that predation, rather than high-temperature induced physiological constraints, is the key factor determining the dominance of small-sized zooplankton in warm lakes. Content Type Journal Article Pages 1-15 DOI 10.1007/s10750-011-0645-0 Authors Carlos Iglesias, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Néstor Mazzeo, Grupo de Ecología y Rehabilitación de Sistemas Acuáticos, Centro Universitario Regional Este-Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay Mariana Meerhoff, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Gissell Lacerot, Sección Limnología, Facultad de Ciencias, Universidad de la República, Iguá 4225, CP 11400 Montevideo, Uruguay Juan M. Clemente, Grupo de Ecología y Rehabilitación de Sistemas Acuáticos, Centro Universitario Regional Este-Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay Flavio Scasso, Sección Limnología, Facultad de Ciencias, Universidad de la República, Iguá 4225, CP 11400 Montevideo, Uruguay Carla Kruk, Sección Limnología, Facultad de Ciencias, Universidad de la República, Iguá 4225, CP 11400 Montevideo, Uruguay Guillermo Goyenola, Grupo de Ecología y Rehabilitación de Sistemas Acuáticos, Centro Universitario Regional Este-Facultad de Ciencias, Universidad de la República, Maldonado, Uruguay Javier García-Alonso, Sección Limnología, Facultad de Ciencias, Universidad de la República, Iguá 4225, CP 11400 Montevideo, Uruguay Susanne L. Amsinck, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Juan C. Paggi, Instituto Nacional de Limnología-CONICET, Universidad Nacional del Litoral. Ciudad Universitaria. Paraje “El Pozo”, CP 3000 Santa Fé, Argentina Susana José de Paggi, Instituto Nacional de Limnología-CONICET, Universidad Nacional del Litoral. Ciudad Universitaria. Paraje “El Pozo”, CP 3000 Santa Fé, Argentina Erik Jeppesen, National Environmental Research Institute, Aarhus University, Vejlsøvej 25, 8600 Silkeborg, Denmark Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    We address the relative importance of nutrient availability in relation to other physical and biological factors in determining plant community assemblages around Everglades Tree Islands (Everglades National Park, Florida, USA). We carried out a one-time survey of elevation, soil, water level and vegetation structure and composition at 138 plots located along transects in three tree islands in the Park’s major drainage basin. We used an RDA variance partitioning technique to assess the relative importance of nutrient availability (soil N and P) and other factors in explaining herb and tree assemblages of tree island tail and surrounded marshes. The upland areas of the tree islands accumulate P and show low N concentration, producing a strong island-wide gradient in soil N:P ratio. While soil N:P ratio plays a significant role in determining herb layer and tree layer community assemblage in tree island tails, nevertheless part of its variance is shared with hydrology. The total species variance explained by the predictors is very low. We define a strong gradient in nutrient availability (soil N:P ratio) closely related to hydrology. Hydrology and nutrient availability are both factors influencing community assemblages around tree islands, nevertheless both seem to be acting together and in a complex mechanism. Future research should be focused on segregating these two factors in order to determine whether nutrient leaching from tree islands is a factor determining community assemblages and local landscape pattern in the Everglades, and how this process might be affected by water management. Content Type Journal Article Pages 1-11 DOI 10.1007/s10750-011-0641-4 Authors J. L. Espinar, Estación Biológica de Doñana (EBD-CSIC), Avda. Américo Vespucio s/n, Isla de la Cartuja, 41092 Sevilla, Spain M. S. Ross, Southeast Environmental Research Center, Florida International University, Modesto Maidique Campus, Miami, FL 33199, USA J. P. Sah, Southeast Environmental Research Center, Florida International University, Modesto Maidique Campus, Miami, FL 33199, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description: Erratum to: Seabed dynamics in a large coastal embayment: 180 years of morphological change in the outer Thames estuary Content Type Journal Article Category Erratum Pages 1-1 DOI 10.1007/s10750-011-0873-3 Authors Helene Burningham, Coastal & Estuarine Research Unit, Department of Geography, University College London, London, UK Jon French, Coastal & Estuarine Research Unit, Department of Geography, University College London, London, UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Possible causes of the increased algal blooms in Lake Victoria in the 1980s have been disputed by several authors; some suggested a top-down effect by the introduced Nile perch, whereas others suggested a bottom-up effect due to eutrophication. In this article the potential impact is established of grazing by fish on phytoplankton densities, before the Nile perch upsurge and the concomitant algal blooms in the Mwanza Gulf. The biomass and trophic composition of fish in the sublittoral area of the Mwanza Gulf were calculated based on catch data from bottom trawls, and from gill nets covering the whole water column. Estimates of phytoplankton production in the same area were made from Secchi values and chlorophyll concentrations. The total phytoplankton intake by fish was estimated at 230 mg DW m −2  day −1 . The daily gross production ranged from 6,200 to 7,100 mg DW m −2  day −1 and the net production from 1,900 to 2,200 mg DW m −2  day −1 . Thus, losses of phytoplankton through grazing by fish were about 3–4% of daily gross and 10–12% of daily net phytoplankton production. As a consequence it is unlikely that the phytoplankton blooms in the second half of the 1980s were due to a top-down effect caused by a strong decline in phytoplankton grazing by fish. Content Type Journal Article Category Primary Research Paper Pages 1-14 DOI 10.1007/s10750-011-0893-z Authors F. Witte, Institute of Biology Leiden, University of Leiden, P.O. Box 9505, 2300 RA Leiden, The Netherlands G. M. Silsbe, Netherlands Institute of Ecology, Centre for Marine and Estuarine Research (NIOO-CEME), P.O. Box 140, 4400 AC Yerseke, The Netherlands R. E. Hecky, Large Lakes Observatory, University of Minnesota, 2205 E. 5th Street, Duluth, MN 55812, USA P. C. Goudswaard, Institute of Biology Leiden, University of Leiden, P.O. Box 9505, 2300 RA Leiden, The Netherlands S. J. Guildford, Large Lakes Observatory, University of Minnesota, 2205 E. 5th Street, Duluth, MN 55812, USA M. A. Kishe-Machumu, Institute of Biology Leiden, University of Leiden, P.O. Box 9505, 2300 RA Leiden, The Netherlands J. H. Wanink, Institute of Biology Leiden, University of Leiden, P.O. Box 9505, 2300 RA Leiden, The Netherlands Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Chydorids (Cladocera, Chydoridae) have two reproductive strategies: asexual reproduction that prevails during favorable environmental conditions and sexual reproduction that is induced by environmental stimuli associated with seasonal or aperiodic environmental stresses. These modes of reproduction can be recognized in the subfossil sedimentary records as parthenogenetic shells of females (asexual reproduction) and by ephippia (sexual reproduction). We studied the interrelations between subfossil chydorid ephippia and environmental variables by analyzing surface sediment samples obtained from 76 Finnish lakes across a latitudinal gradient (60–70°N). The results showed that the total chydorid ephippia (TCE) increases along the climate gradient from ~2 to 3% in the south to ~25% in the north and suggested a significant dependence ( r  ~ −0.8, P  〈 0.001) with several climate factors, especially that of mean July air temperature. We used this relationship to create a model for reconstructing past mean July air temperatures. A linear regression of the log 10 transformed TCE as a single independent variable explained 76% (SE ± 0.76°C) of the variance of the observed mean July air temperatures. Accordingly, we propose that this novel tool may be highly suitable for reconstructing paleotemperatures in cold-temperate environments. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-15 DOI 10.1007/s10750-011-0869-z Authors Seija Kultti, Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 University of Helsinki, Finland Liisa Nevalainen, Institute for Limnology, Austrian Academy of Sciences, Mondseestraße 9, 5310 Mondsee, Austria Tomi P. Luoto, Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 University of Helsinki, Finland Kaarina Sarmaja-Korjonen, Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 University of Helsinki, Finland Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    It is usually assumed that climate change will have negative impacts on water quality and hinder restoration efforts. The long-term monitoring at Loch Leven shows, however, that seasonal changes in temperature and rainfall may have positive and negative impacts on water quality. In response to reductions in external nutrient loading, there have been significant reductions in in-lake phosphorus concentrations. Annual measures of chlorophyll a have, however, shown little response to these reductions. Warmer spring temperatures appear to be having a positive effect on Daphnia densities and this may be the cause of reduced chlorophyll a concentrations in spring and an associated improvement in water clarity in May and June. The clearest climate impact was the negative relationship between summer rainfall and chlorophyll a concentrations. This is highlighted in extreme weather years, with the three wettest summers having very low chlorophyll a concentrations and the driest summers having high concentrations. To predict water quality impacts of future climate change, there is a need for more seasonal predictions from climate models and a greater recognition that water quality is the outcome of seasonal responses in different functional groups of phytoplankton and zooplankton to a range of environmental drivers. Content Type Journal Article Category LOCH LEVEN RESEARCH Pages 1-13 DOI 10.1007/s10750-011-0923-x Authors L. Carvalho, Centre for Ecology & Hydrology, Penicuik, Midlothian, EH26 0QB UK C. Miller, School of Mathematics and Statistics, University of Glasgow, University Gardens, Glasgow, G12 8QW UK B. M. Spears, Centre for Ecology & Hydrology, Penicuik, Midlothian, EH26 0QB UK I. D. M. Gunn, Centre for Ecology & Hydrology, Penicuik, Midlothian, EH26 0QB UK H. Bennion, Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London, WC1E 6BT UK A. Kirika, Centre for Ecology & Hydrology, Penicuik, Midlothian, EH26 0QB UK L. May, Centre for Ecology & Hydrology, Penicuik, Midlothian, EH26 0QB UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Many estimates of ‘marine protected area (MPA) effects’ may be confounded by environmental heterogeneity between MPA and ‘Control’ sites. However, the magnitude and extent of such confounding is generally unknown. Here, the effects of microhabitat availability on estimates of MPA performance were explicitly explored. Abundance of a reef fish species, Ctenochaetus striatus (Quoy & Gaimard, 1825), available microhabitat, and, microhabitat preference for C. striatus within six ‘Ra’ui’ (traditionally managed MPAs) and six paired ‘Control’ sites on the island of Rarotonga, Cook Islands, were estimated. Response ratios accounting for available microhabitat qualitatively modified inferences of Ra’ui effectiveness for two of the six Ra’ui when contrasted with response ratios not accounting for available microhabitat. However, analysis of covariance (ANCOVA) indicated that available microhabitat accounted for significant variation in C. striatus densities between Ra’ui and Control, rather than protection. Our results suggest that adjusting for microhabitat availability may significantly alter our perception of the effects of Ra’ui on C. striatus. Our framework, in concert with our ANCOVA models, provides a stronger assessment of MPA effects. Further, we conclude that metrics of environmental heterogeneity should be incorporated into future assessments of MPA effectiveness, with our work describing one potential framework to accomplish this. Content Type Journal Article Category HABITAT COMPLEXITY Pages 1-18 DOI 10.1007/s10750-011-0911-1 Authors Sonja L. Miller, Victoria University Coastal Ecology Laboratory, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140 New Zealand Jeffrey S. Shima, Victoria University Coastal Ecology Laboratory, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140 New Zealand Nicole E. Phillips, Victoria University Coastal Ecology Laboratory, School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140 New Zealand Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Periphyton constitutes an important community that is useful for assessment of ecological conditions in lotic systems. The objective of this study was to assess the effects of different mixtures of Cd and Pb on periphyton growth as well as Cd and Pb mixtures toxicity to diatom assemblages in laboratory mesocosm experiments. A natural periphyton community sampled from the Monjolinho River (South of Brazil) was inoculated into five experimental systems containing clean glass substrates for periphyton colonization. The communities were exposed to mixtures of dissolved Cd and Pb concentrations of 0.01 and 0.1 mg l −1 Cd and 0.033 and 0.1 mg l −1 Pb. Periphyton ash-free dry weight, growth rate, diatom cell density and diatom community composition were analyzed on samples collected after 1, 2 and 3 weeks of colonization. High Cd concentration (0.1 mg l −1 ) has negative effects on periphyton growth while high concentration of Pb (0.1 mg l −1 ) decreased the toxic effects of Cd on periphyton growth. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Cymbopleura naviculiformis , Fragilaria capucina , Navicula cryptocephala , Encyonema silesiacum , Eunotia bilunaris , and Gomphonema parvulum ), decreases in species diversity of diatom communities with increasing Cd and Pb concentrations and exposure duration have been demonstrated in this study making diatom communities appropriate monitors of metal mixtures in aquatic systems. Content Type Journal Article Category Primary Research Paper Pages 1-11 DOI 10.1007/s10750-011-0917-8 Authors Taurai Bere, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, SP, Brazil José Galizia Tundisi, Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, São Carlos, SP, Brazil Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Long-term monitoring data (1968–2008) were used to investigate internal phosphorus (P) loading following external P loading reduction in shallow Loch Leven, Scotland. A whole-lake sediment P inventory (upper 3 cm of sediment; 2005) suggested a release-potential of 29.7 tonnes (t) from the release sensitive sediment P pools. 18.5 t was contained within shallow water sediments (〈4.5 m water depth) with 7.6 t in deeper water sediments below the photic zone (〉5 m water depth). The “observed” release (〈5.1 t), estimated using a water column P mass balance approach (1989–2008), was 〈5.1 t, indicating the presence of regulating mechanisms. Observed P release declined between 1989 and 2008, with the exception of 2003–2006. Observed P release estimates were positively correlated with annual average water column P concentration after 1989, highlighting the role of internal loading in maintaining poor water quality conditions after management intervention. Multiple regression analysis suggested that internal loading was driven by the wave mixed depth in spring (positive driver), summer water temperature (positive driver) and spring water clarity transparency (negative driver). The potential importance of biological and physico-chemical feedback mechanisms in the regulation of benthic–pelagic coupling and water quality in Loch Leven are discussed. Content Type Journal Article Category LOCH LEVEN RESEARCH Pages 1-11 DOI 10.1007/s10750-011-0921-z Authors B. M. Spears, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, UK L. Carvalho, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, UK R. Perkins, School of Earth, Ocean and Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3YE UK A. Kirika, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, UK D. M. Paterson, Sediment Ecology Research Group, Gatty Marine Laboratory, University of St. Andrews, Fife, KY16 8LB UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The aim of this study is to estimate emissions of greenhouse gases CO 2 , CH 4 and N 2 O, and the effects of drainage and peat extraction on these processes, in Estonian transitional fens and ombrotrophic bogs. Closed-chamber-based sampling lasted from January to December 2009 in nine peatlands in Estonia, covering areas with different land-use practices: natural (four study sites), drained (six sites), abandoned peat mining (five sites) and active peat mining areas (five sites). Median values of soil CO 2 efflux were 1,509, 1,921, 2,845 and 1,741 kg CO 2 -C ha −1  year −1 from natural, drained, abandoned and active mining areas, respectively. Emission of CH 4 -C (median values) was 85.2, 23.7, 0.07 and 0.12 kg ha −1  year −1 , and N 2 O-N −0.05, −0.01, 0.18 and 0.19 kg ha −1  year −1 , respectively. There were significantly higher emissions of CO 2 and N 2 O from abandoned and active peat mining areas, whereas CH 4 emissions were significantly higher in natural and drained areas. Significant Spearman rank correlation was found between soil temperature and CO 2 flux at all sites, and CH 4 flux with high water level at natural and drained areas. Significant increase in CH 4 flux was detected for groundwater levels above 30 cm. Content Type Journal Article Category WETLAND SERVICES AND MANAGEMENT Pages 1-15 DOI 10.1007/s10750-011-0934-7 Authors Jüri-Ott Salm, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Martin Maddison, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Sille Tammik, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Kaido Soosaar, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Jaak Truu, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Ülo Mander, Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, 46 Vanemuise St., 51014 Tartu, Estonia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Small headwater streams constitute a large proportion of the river channel network in many parts of the world. In this study, two multihabitat kick sampling methods (60-second and 20-second) were compared across 10 small headwater streams in the southwest and east of Ireland in spring and summer 2009 to determine the influence of sampling on various benthic macroinvertebrates in headwater streams. The performance of each method, over time and replication, was examined using a range of benthic macroinvertebrate metrics, as well as the community composition and structure recorded by both methods. The ability to recruit taxa, as well as the field sampling and laboratory processing effort required for each method, was also assessed. Results indicated that both kick sampling methods generally recorded similar metric scores with the exception of taxonomic richness ( t  = 180 s and n  = 9 replicates test) where the 20-second kicks consistently out preformed those calculated for the 60-second kicks. All other metrics compared generally performed equally as well regardless of the method used. Multivariate analysis of macroinvertebrate community assemblage, using SIMPROF, RELATE and CS-SMC analyses, further highlighted the high similarity in the macroinvertebrate assemblage recorded between both methods. Finally, the 20-second kicks recruited taxa as efficiently as 60-second kicks samples so long as replication was equal but required less sampling effort (NSE) and processing time. Therefore, the shorter 20-second kicks can be used to assess the ecological health of headwater streams, provided that adequate replication is adopted, resulting in significant effort, cost and time savings. Content Type Journal Article Category Primary Research Paper Pages 1-16 DOI 10.1007/s10750-011-0940-9 Authors Hugh B. Feeley, Freshwater Biodiversity, Ecology and Fisheries Research Group (freBEF), School of Biology and Environmental Science, Science Education and Research Centre (West), University College Dublin, Belfield, Dublin 4, Ireland Martina Woods, Freshwater Biodiversity, Ecology and Fisheries Research Group (freBEF), School of Biology and Environmental Science, Science Education and Research Centre (West), University College Dublin, Belfield, Dublin 4, Ireland Jan-Robert Baars, School of Biology and Environmental Science, Science Education and Research Centre (West), University College Dublin, Belfield, Dublin 4, Ireland Mary Kelly-Quinn, Freshwater Biodiversity, Ecology and Fisheries Research Group (freBEF), School of Biology and Environmental Science, Science Education and Research Centre (West), University College Dublin, Belfield, Dublin 4, Ireland Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    This study examined the effects of the configuration of wood structures on the use of local autumn and winter habitats by fish in a remeandering reach of a large lowland river. Fish diversity was higher at the simple wood-structure (SWS) and the log-jam (LJ) sites than at the no-wood (NW) sites during both seasons. In particular, the diversity at the LJ sites was higher than that at the SWS sites during the winter. The abundance of the four dominant fish species was generally higher at the LJ sites than at the NW sites during both seasons. The SWS and LJ sites were characterized by greater depths, finer bed materials, and more diverse flow conditions during the autumn. During the winter, the LJ sites were characterized by slower currents and finer bed materials. These habitat features satisfied the various habitat requirements of the fish observed in our study reach; during the autumn, areas with fast and slow currents were favorable for juvenile salmon, silt and sand bed materials for lamprey, and deep areas for one species of goby, while slow currents were critical in the winter for abovementioned fish species. Engineered log jams were also effective in supporting the colonization of fish during both seasons. These findings suggest that a larger and more complex wood structure, particularly log jams, plays important roles in creating local habitats suitable for various fish species during the autumn and winter and in preserving fish abundance and diversity in large lowland rivers. Content Type Journal Article Category Primary Research Paper Pages 1-12 DOI 10.1007/s10750-011-0913-z Authors Shigeya Nagayama, Department of Forest Science, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo, 060-8589 Japan Futoshi Nakamura, Department of Forest Science, Graduate School of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo, 060-8589 Japan Yôichi Kawaguchi, Ecosystem Design Institute of Technology and Science, University of Tokushima, 2-1 Minami-josanjima, Tokushima, 770-8506 Japan Daisuke Nakano, Biological Environment Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 1646 Abiko, Chiba, 270-1194 Japan Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Zebra mussel filtration rates and regulating factors have been addressed earlier in a number of studies. Still, only a few of them have taken into consideration the refiltration phenomenon, and therefore the direct extrapolation of experimental results may only give the potential filtering capacity, and hence, over- or underestimate the actual amount of seston being removed by zebra mussels in an ecosystem. The current experimental study aimed to gain insight into the refiltration effect on the clearance rate of the zebra mussels at relatively high seston concentrations, and its potential role in controlling the filtration efficiency of the zebra mussel population. The experiment was conducted in a laboratory flume following the Latin squares design with one fixed (mussel density) and three random factors (initial total particulate matter (TPM) concentration, flume “wall effect” and distance from the flume inflow area) considered. The results showed the significant effects of mussel density and the TPM concentration on the effective clearance rate (ECR) of zebra mussels. The higher ECR values were obtained at denser mussel clumps and lower TPM concentrations. The flume “wall effect” had no significant effect on the ECR, whereas the distance from the flume inflow area appeared to have a significant impact. A positive relationship between ECR and the zebra mussel density was most evident in the proximity of the TPM source. Based on the results, we assume that at high TPM concentration, refiltration may assert itself by the elevated net clearance rate of mussels within dense clumps compared to that of mussels at relatively low individual densities. This should be taken into consideration while modelling and assessing the role of the zebra mussel in energy flow and redistribution of organic matter in an ecosystem. Content Type Journal Article Category Primary Research Paper Pages 1-11 DOI 10.1007/s10750-011-0904-0 Authors Anastasija Zaiko, Coastal Research and Planning Institute, Klaipeda University, H. Manto 84, 92294 Klaipeda, Lithuania Darius Daunys, Coastal Research and Planning Institute, Klaipeda University, H. Manto 84, 92294 Klaipeda, Lithuania Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The phagotrophic flagellate Oxyrrhis marina shows a strong stoichiometric plasticity when fed differently grown Rhodomonas salina . We tested whether differently pre-conditioned O. marina displayed selective feeding behaviour from a mixture of nitrogen and phosphorus depleted R. salina . We observed selective feeding of O. marina , always selecting phosphorus rich R. salina independent of the pre-conditioning of the protists. In a second experiment, O. marina was again pre-conditioned either with nitrogen- or phosphorus-depleted R. salina and was refed with either of the differently limited R. salina in single food treatments (not in a mixture). The phagotrophic flagellate displayed compensatory feeding which means that O. marina feed more on the food source which they were not given before. Due to its stoichiometric plasticity, O. marina might handle bad quality food by following the stoichiometry of its prey and additionally by active selective feeding towards P-rich algae to enhance growth. Post-ingestion selection might as well be an important feature which means that ingested elements in excess are quickly excreted and scarce elements are ingested through accelerated food uptake. Content Type Journal Article Category Primary Research Paper Pages 1-10 DOI 10.1007/s10750-011-0900-4 Authors Cédric Léo Meunier, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Florian M. Hantzsche, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Alessandra Ö. Cunha-Dupont, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Julia Haafke, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Bettina Oppermann, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Arne M. Malzahn, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Maarten Boersma, Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, Postfach 180, 27483 Helgoland, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Does diversity beget diversity? Diversity includes a diversity of concepts because it is linked to variability in and of life and can be applied to multiple levels. The connections between multiple levels of diversity are poorly understood. Here, we investigated the relationships between genetic, bacterial, and chemical diversity of the endangered Atlanto-Mediterranean sponge Spongia lamella . These levels of diversity are intrinsically related to sponge evolution and could have strong conservation implications. We used microsatellite markers, denaturing gel gradient electrophoresis and quantitative polymerase chain reaction, and high performance liquid chromatography to quantify genetic, bacterial, and chemical diversity of nine sponge populations. We then used correlations to test whether these diversity levels covaried. We found that sponge populations differed significantly in genetic, bacterial, and chemical diversity. We also found a strong geographic pattern of increasing genetic, bacterial, and chemical dissimilarity with increasing geographic distance between populations. However, we failed to detect significant correlations between the three levels of diversity investigated in our study. Our results suggest that diversity fails to beget diversity within a single species and indicates that a diversity of factors regulates a diversity of diversities, which highlights the complex nature of the mechanisms behind diversity. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-15 DOI 10.1007/s10750-011-0884-0 Authors Charlotte Noyer, Department of Marine Ecology, Centro de Estudios Avanzados de Blanes (CEAB-CSIC), Acceso Cala St. Francesc 14, Blanes, 17300 Girona, Spain Mikel A. Becerro, Natural Products and Agrobiology Institute (IPNA-CSIC), Avda Astrofísico Francisco Sánchez 3, 38206 La Laguna (Tenerife), Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The mid-Atlantic islands of Bermuda harbor one of the richest and most diverse anchialine communities known from anywhere on Earth. However, all known anchialine caves in Bermuda (maximum depth—26 m) were dry during the last glacial period extending from approximately 9,000 to 115,000 years ago when glacial sea levels were as much as 127 m lower. Since it is highly unlikely that Bermuda’s endemic cave species evolved since the caves were flooded by sea level rise, alternate deeper habitats must have existed to shelter anchiane fauna for prolonged periods of lower sea level during the Pleistocene. In order to systematically search for such now deep water cave habitats, high-resolution multibeam sonar and remotely operated vehicles were used to map and explore the seafloor off Bermuda in 60–200 m depths along the outer shelf break edge of the submarine escarpment surrounding the Bermuda Platform and an adjacent seamount. Specific goals were to discover deep water cave and/or crevicular habitats and to characterize the nature, geological stratification and composition, and sea level history of the platform margin, in particular focusing on features directly relating to Pleistocene low sea stand events. During this sea floor survey, clearly defined paleo-shoreline features generated by wave and current erosion were found to encircle the Bermuda seamount and Challenger Bank at 60 and 120 m depths. Content Type Journal Article Category Anchialine Ecosystems Pages 1-12 DOI 10.1007/s10750-011-0883-1 Authors Thomas M. Iliffe, Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553-1675, USA Rikk Kvitek, Seafloor Mapping Lab, California State University, Monterey Bay, Seaside, CA 93955, USA Steve Blasco, Geological Survey of Canada (Atlantic), 1 Challenger Drive, P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada Katie Blasco, Geological Survey of Canada (Atlantic), 1 Challenger Drive, P.O. Box 1006, Dartmouth, NS B2Y 4A2, Canada Robert Covill, Tekmap Consulting, P.O. Box 2016, Fall River, NS B2T 1K6, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The objective of this study was to determine what ecological benefits Geodia vosmaeri ( Gv ) and Amphimedon erina ( Ae ) gain from their symbiosis. The prevailing, though untested, hypotheses are that Ae protects Gv from predators through chemical defenses and that Gv provides Ae access to substrata. Data from our experiments support these hypotheses. During field surveys, Ae was never found growing without Gv in this habitat. Ae was the only epibiont on 81% of the Gv surveyed. Field feeding assays using chemical extracts indicated that Ae is less palatable than Gv . Laboratory feeding assays using sponge tissue demonstrated that spongivorous sea stars avoided contact with Ae tissue and frequently accepted Gv tissue for consumption. In caging experiments, predator exclusion had no effect on Gv tissue loss. Amphimedon erina may benefit from the vertical substrata represented by Gv colonies because Ae grown in a vertical orientation experienced less tissue loss compared to Ae grown horizontally. Taken together, our results provide empirical support for the hypothesis that Gv is afforded chemical protection from predators through Ae and some evidence that Ae benefits from growing on Gn substrata. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-10 DOI 10.1007/s10750-011-0878-y Authors Blake Ramsby, Department of Biology, University of Mississippi, University, MS 38677, USA Andrew Massaro, Department of Biology, University of Richmond, Richmond, VA 23173, USA Emily Marshall, Department of Biology, University of Richmond, Richmond, VA 23173, USA Thomas Wilcox, 2300 Toro Canyon Road, Austin, TX 78746, USA Malcolm Hill, Department of Biology, University of Richmond, Richmond, VA 23173, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    As temperature increases the metabolic rates, the effect of warming on animals will also enhance animal-driven nutrient cycling with important consequences on ecosystem dynamics. We tested the effects of increased temperature (15 and 20°C, optimal and suboptimal temperatures, respectively) on metabolic rates of the shredder larvae Sericostoma vittatum fed on three diets, Alnus glutinosa (L.) Gaertn., Eucalyptus globulus Labill. and Quercus robur L. We measured P and N content in leaves, faeces and excreta and calculated C, N, and P assimilation efficiencies, and mass balances. Carbon assimilation efficiency (AE) was reduced at 20°C when larvae fed on Q. robur ; nitrogen-AE was reduced at 20°C in all diets and phosphorus-AE was not affected by temperature. Larvae achieved a net N gain in all treatments, however, increased temperatures had a negative effect on N incorporation into body tissue. The mass balance of P was negatively affected by temperature; larvae fed on Q. robur and on E. globulus had null balances at 15°C and negative at 20°C. Our results showed that high temperature increased nutrient excretion and affected N:P ratios in excreta, thus changes in temperature may have severe consequences on larval mediated leaf litter processing and nutrient cycling. However, the type of diet seemed to modulate the way temperature affects larval metabolism regarding excretion rate and assimilation efficiencies. The extent to which optimal–suboptimal temperature variation will alter detritivore metabolism performance, internal nutrient balance and hence, cycling of elements in the environment seems crucial under global warming scenarios. Content Type Journal Article Category Primary Research Paper Pages 1-11 DOI 10.1007/s10750-011-0837-7 Authors Verónica Díaz Villanueva, Laboratorio de Limnologia-INIBIOMA, Universidad Nacional del Comahue, Quintral 1250, 8400 Bariloche, Argentina Ricardo Albariño, Laboratorio de Limnologia-INIBIOMA, Universidad Nacional del Comahue, Quintral 1250, 8400 Bariloche, Argentina Cristina Canhoto, IMAR & Department of Zoology, University of Coimbra, 3004-517 Coimbra, Portugal Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The timely characterization of high-altitude freshwater habitats allows an assessment of the diversity of its biota and provides the basis for monitoring community change. In this study, we investigate the Cladocera fauna of 29 water bodies (pools, freshwater lakes, and surrounding swamps sampled at various occasions between 2005 and 2009) in the Rwenzori Mountains (Uganda, D. R. Congo), which are part of the East African Sky Island Complex. All sites except one are located above 3700 m altitude. We include notes on the morphology, taxonomy, distribution, and ecology of each recorded taxon and describe a new species of the Alona rustica -group ( Alona sphagnophila n.sp.; Chydoridae). We found 11 species of which seven are restricted to Lake Mahoma, the lowest lake in our study area (2990 m) ( Alona affinis barbata , A. intermedia , Alonella exisa , Alonella nana , Daphnia cf. obtusa , Pleuroxus aduncus ) and/or Lake Bujuku ( Daphnia cf. curvirostris , P.   aduncus ) (3900 m). Two taxa ( Ilyocryptus cf. gouldeni , A. sphagnophila n.sp.) are restricted to Carex/Sphagnum bogs surrounding lakes in the afroalpine zone. Pigmented populations of Chydorus cf. sphaericus occur in all the sites. It is the only cladoceran species surviving the extreme alpine and nival conditions in the Rwenzori. The species is joined by A. guttata at locations at lower altitudes (ca. 3000–4000 m), present in about half of the sites. The Rwenzori Cladocera fauna is characterized by a strong extratropical temperate component and a low level of speciation/endemism. Harboring an impoverished boreal cladoceran community, Lake Mahoma is given closer attention. At 2990 m, the lake is a cold-temperate aquatic island in the tropics and may function as a stepping stone for Palaearctic taxa. We introduce a new term for high-altitude, cold-water habitats in the tropics, which act as climatic islands for extratropical freshwater faunas, Löffler Islands , in honor of Dr Heinz Löffler. In comparison to surveys in 1961, we list five new records in Lake Mahoma, which could indicate cladoceran community changes over the past few decades at ca. 3000 m in the Rwenzori. Since the species distributions correlate to temperature and catchment properties of the lakes, the Rwenzori cladoceran fauna can be expected as sensitive indicators for local changes. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-44 DOI 10.1007/s10750-011-0892-0 Authors Kay Van Damme, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium Hilde Eggermont, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Reconstruction of past climate change and ecosystem response is important to correctly assess the impacts of global warming. In this study, we provide a paleoenvironmental record of in-lake and catchment changes in northern Poland during the Late Glacial and early Holocene using various biotic proxies (pollen, macrofossils and Cladocera) preserved in the lake sedimentary record. Chronology was derived from palynological correlation with a well-dated pollen sequence from nearby-lying Lake Ostrowite and some well-dated events of vegetation history in Central Europe. Pollen analysis provided information on regional climate change affecting vegetation dynamics, whereas macrofossils supplied substantial information on the response of local flora and fauna to climatic, geomorphological and limnological changes. Data were supplemented by analysis of Cladocera remains, which are of special importance because of their quick response to changes in trophic conditions and climate (especially temperature). The bottom of the sediment core reflects an initial stage of the lake formed during the late Alleröd. The Younger Dryas cooling apparently resulted in forest recession and presence of cold tolerant Cladocera species. Due to amelioration of climate at the end of the Younger Dryas and melting of ice, the lake deepened. The beginning of the Holocene was characterised by forest shrinkage and induced clear changes in local flora and fauna communities. The regional vegetation development deduced from the lake’s core is generally consistent with the vegetation history of central Europe. Due to the location of the site near the seashore (oceanic climate and western wind), signals of warming came earlier than inland and in eastern Poland. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-16 DOI 10.1007/s10750-011-0874-2 Authors Krystyna Milecka, Department of Biogeography and Paleoecology, Adam Mickiewicz University, Poznan, Poland Grzegorz Kowalewski, Department of Biogeography and Paleoecology, Adam Mickiewicz University, Poznan, Poland Krystyna Szeroczyńska, Institute of Geological Sciences, Polish Academy of Sciences, Warsaw, Poland Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Most works concerning growth and reproduction of Mediterranean sponges have been performed in the oligotrophic western Mediterranean while little is known about sponge dynamics in the North-western Adriatic Sea, a basin characterized by low winter temperature and eutrophy. In order to deepen our understanding of sponges in the North Adriatic Sea and verify how its peculiar trophic and physical conditions affect sponge life cycles, temporal trend of sponge cover (%) and reproductive timing of Chondrosia reniformis and Tedania ( Tedania ) anhelans were studied over a 1-year period looking for a possible relation with variations of temperature or food availability. In C. reniformis, although little variations of sponge cover were evidenced around the year, the number of individuals and their size increase during spring. Asexual reproduction , via drop-like propagules, mainly occurs in spring and summer, while sexual reproduction is characterized by a maximum number of oocytes in August. T. anhelans progressively grows from spring to summer and develops propagules on its surface that reach their maximum size in July. In autumn, the sponge undergoes a process of progressive shrinkage and almost disappears in winter when temperature reaches 7–8°C. Larvae occur during summer. In the North Adriatic Sea sponges have larger sizes, higher density and a wider period of oocytes production compared with the same species from the Mediterranean Sea, suggesting these differences could be due to high food availability characterizing the eutrophic Adriatic basin. On the contrary, the sharp water temperature variations and the very low winter temperature, 5–6°C lower than what has been reported for the Mediterranean Sea, regulate temporal variations in abundance and cause the disappearance of thermophile species during winter. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-15 DOI 10.1007/s10750-011-0877-z Authors C. G. Di Camillo, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy M. Coppari, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy I. Bartolucci, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy M. Bo, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy F. Betti, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy M. Bertolino, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy B. Calcinai, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy C. Cerrano, Dip. per lo Studio del Territorio e delle sue Risorse, Università degli Studi di Genova, Genova, Italy G. De Grandis, ARPAM Ancona, Servizio acque – Unità operativa mare/Sibilla, Ancona, Italy G. Bavestrello, Dip. Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Changes in the composition and size structure of cladoceran remains collected in sediment traps (ST) were compared at a monthly time-resolution to the changes in the cladoceran source communities in order to assess the effects of production, sedimentation and taphonomic processes on the composition, completeness of time series and size structure of cladoceran remains in a large deep monomictic subalpine lake. Cladoceran remains collected in the ST globally reflected seasonal changes in the composition of the source community for the dominant taxa ( Daphnia sp., Eubosmina spp. and. D. brachyurum ) but failed in capturing accurately the seasonal changes in the abundance of the least abundant species, B. longirostris . Using allometric relationships, the average body size of the organisms that produced the remains retrieved in the ST could be reconstructed. Although the cladoceran average body size estimated from trap remains was always smaller than that of the source communities, temporal changes in the average body size of the dominant taxa in the source community were captured by trap samples. Our results showed that, in this deep subalpine lake, cladoceran remains production, sedimentation and taphonomic processes within the water column did not alter the compositional fidelity of remains at seasonal and annual time scales for the dominant taxa. Results did not show any significant over-representation of Bosmina and subsequent under-representation of Daphnia in contrast to previous studies on small and flat lakes. Our results suggest that the frequently observed under-estimation of Daphnia in fossil assemblages could be a consequence of the mesh size used when processing sediment core samples rather than of varying magnitude of degradation processes between small or flat lakes and deep lakes. Finally, our results support the use of the size of cladoceran remains within paleo-ecological studies to assess past changes in the size structure of the source communities. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-16 DOI 10.1007/s10750-011-0868-0 Authors Benjamin Alric, National Institute for Agronomical Research (INRA), Alpine Centre for Research on Lake Ecosystems and Food Webs (CARRTEL), 75 Avenue de Corzent, BP 511, 74203 Thonon les Bains Cedex, France Marie-Elodie Perga, National Institute for Agronomical Research (INRA), Alpine Centre for Research on Lake Ecosystems and Food Webs (CARRTEL), 75 Avenue de Corzent, BP 511, 74203 Thonon les Bains Cedex, France Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Species are continuously lost and added to a local community. Dynamics of this process in a complex habitat mosaic (multiple habitats in a landscape), particularly of its rates (species turnover) are of primary concern for biodiversity conservation. Various studies suggest that species traits such as habitat specialization should affect species turnover. In communities where habitat specialization is a function of abiotic constraints, habitat specialists should respond faster to changing environment than generalists. We thus predicted a higher temporal turnover for specialists than for generalists in the presence of environmental variability (EV). In addition, we predicted that temporal turnover should decrease with increasing species richness of the communities they live in. We tested these predictions in a model system of 49 natural rock pools inhabited by 70 invertebrate species for which long-term (9 years) environmental and population dynamics data are available. We computed standard deviation of salinity measurements to represent EV for each pool. We further obtained the number of combined colonization and extinction events weighted by the number of years a species was recorded as a temporal turnover for each species in individual pools. We found that EV induced greater temporal turnover, however, the turnover depended on the species habitat traits (habitat specialization)—it has been higher in specialists but that relationship between EV and temporal turnover dissolved with increasing niche breadth (generalists). We further found that for some species, temporal turnover decreased with higher species richness and for other species, temporal turnover increased with higher species richness. The effect of species richness on temporal turnover was unrelated to species traits. This study suggests that whenever habitat is complex and heterogeneous and species pool diversified, local community dynamics becomes a composite of differential responses. Content Type Journal Article Category HABITAT COMPLEXITY Pages 1-10 DOI 10.1007/s10750-011-0871-5 Authors Shubha N. Pandit, Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada Jurek Kolasa, Department of Biology, McMaster University, 1280 Main St. West, Hamilton, ON L8S 4K1, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Sponges often exhibit tissue regression in response to stressful conditions. This study investigated whether handling stress invoked tissue regression in Ianthella basta and assessed whether sponges could recover from this regressed tissue state. Six necrotic specimens and 12 healthy explants were collected at Orpheus Is. Australia and transported to aquarium facilities. Sponges were photographed daily and an integrated density (ID) measurement was used to quantify tissue regression. Histological samples were taken from sponge explants to compare cellular organization. Bacterial communities of regressed and recovered tissue were compared using Denaturing Gradient Gel Electrophoresis (DGGE). After 12 h both necrotic and healthy sponges displayed substantial tissue regression. However, within 72 h all sponges recovered to their original condition. The ID of the sponge tissue doubled, confirming tissue recovery in I. basta . Sponges affected by tissue regression had significantly fewer choanocyte chambers and more densely packed granulated cells than recovered sponges. DGGE revealed the same microbial symbionts in both regressed and recovered sponges. Handling stress associated with collection and transportation is sufficient to invoke tissue regression in this species, but sponges can rapidly recover. This study contributes to our understanding of how sponges respond to environmental pressures, influencing population resilience and persistence. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-9 DOI 10.1007/s10750-011-0887-x Authors Heidi M. Luter, School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia Steve Whalan, School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811, Australia Nicole S. Webster, Australian Institute of Marine Science, PMB 3, Townsville, QLD 4810, Australia Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The use of subfossil cladocerans is rare for understanding environmental, cultural and archaeological developments of lakes in Europe. In 2007, we collected a 12-m long sediment core from Lake Schalkenmehrener Maar (SMM), Germany for the analyses of subfossil cladocerans. Dating of core was based on tephrochronology, radiocarbon and pollen stratigraphy. Pollen-based chronostratigraphy indicated a decline of species richness and abundance of chydorids during the Lateglacial (ca.14500 cal yr  bp ) with dominant cold preferring taxa Acroperus harpae Baird and Alona affinis Leydig. During the early Bölling, the abundance of cladocerans increased commensurate with growth of birch ( Betula L.) and pine ( Pinus L.) trees. Except a spike of Bosmina coregoni Baird during the Younger Dryas, cladoceran assemblages remained stable from the Bölling to the mid-Atlantic period. During the Neolithic (ca. 4300  bc ), the abundance of B. coregoni increased sharply with reciprocal decrease in Daphnia . However, as soon as Daphnia was dominant (ca. 4250  bc ), a reciprocal decline in abundance of B. coregoni occurred. The mid-Holocene change in cladoceran abundance coincided with the use of hardwood forest. This situation ended at ca. 4000  bc and remained unchanged throughout the Neolithic and Bronze Age (ca. 3000–1200  bc ). Low Daphnia abundance indicated reduced water quality in the Hunsrück-Eifel culture (ca. 800  bc ). A spike of B. coregoni at ca. ad 150 indicates construction of the Roman Villa Rustica and extensive farming. However, reoccurrence of Daphnia at ca. ad 470 indicates the retreat of the Romans from the Eifel region. From the early Frankish rule (ca. ad 500) to the Medieval period (ca. ad 1500), species richness reduced but abundance of B. coregoni increased indicating a switch in lake ecosystem. The loss of species richness and the lack of precise evidence of the human activity in the region in the past have impeded the restoration of the ecosystem of the Lake SMM. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-19 DOI 10.1007/s10750-011-0872-4 Authors Giri Kattel, Institute of Geosciences, Johannes Gutenberg-Universität, 55099 Mainz, Germany Frank Sirocko, Institute of Geosciences, Johannes Gutenberg-Universität, 55099 Mainz, Germany Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Integrated Constructed Wetlands (ICWs) constitute an alternative way of cleansing water in agricultural areas to conventional water treatment plants. These pond systems integrate their water treatment capabilities with other functions such as biodiversity enhancement, carbon sequestration and landscape fit, by virtue of mimicking natural wetlands. ICWs have shown to have potential to enhance macroinvertebrate diversity in agricultural areas due to their unique design flexibility. We suggest that ICWs characterised by adequate shore sloping and presence of complex habitat mosaics, as well as other design considerations, would maximise the potential of these systems to enhance macroinvertebrate diversity. In addition, it would be highly beneficial to increase the total ICW area and to increase the total number of ponds in a system accordingly from a minimum of four to at least five. This article also highlights the need not only to develop policies that focus on the creation of ICWs but also to foster a number of management practices that rely on the active involvement of farmers. The inclusion of additional ponds in selected ICW systems could be the means to inform local communities as to the importance, attractiveness and conservation value of ponds. Content Type Journal Article Category WETLAND SERVICES AND MANAGEMENT Pages 1-10 DOI 10.1007/s10750-011-0866-2 Authors Gustavo Becerra-Jurado, Freshwater Biodiversity, Ecology and Fisheries (FreBEF) Research Group, School of Biology and Environmental Science, University College of Dublin, Belfield, Dublin 4, Ireland Rory Harrington, Water and Policy Division, Department of Environment, Heritage and Local Government, Old Custom House, 106 The Quay, Waterford, Ireland Mary Kelly-Quinn, Freshwater Biodiversity, Ecology and Fisheries (FreBEF) Research Group, School of Biology and Environmental Science, University College of Dublin, Belfield, Dublin 4, Ireland Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    DNA “barcoding,” the determination of taxon-specific genetic variation typically within a fragment of the mitochondrial cytochrome oxidase 1 ( cox1 ) gene, has emerged as a useful complement to morphological studies, and is routinely used by expert taxonomists to identify cryptic species and by non-experts to better identify samples collected during field surveys. The rate of molecular evolution in the mitochondrial genomes (mtDNA) of nonbilaterian animals (sponges, cnidarians, and placozoans) is much slower than in bilaterian animals for which DNA barcoding strategies were developed. If sequence divergence among nonbilaterian mtDNA and specifically cox1 is too slow to generate diagnostic variation, alternative genes for DNA barcoding and species-level phylogenies should be considered. Previous study across the Aplysinidae (Demospongiae, Verongida) family of sponges demonstrated no nucleotide substitutions in the traditional cox1 barcoding fragment among the Caribbean species of Aplysina . As the mitochondrial genome of Aplysina fulva has previously been sequenced, we are now able to make the first comparisons between complete mtDNA of congeneric demosponges to assess whether potentially informative variation exists in genes other than cox1 . In this article, we present the complete mitochondrial genome of Aplysina cauliformis, a circular molecule 19620 bp in size. The mitochondrial genome of A. cauliformis is the same length as is A. fulva and shows six confirmed nucleotide differences and an additional 11 potential SNPs. Of the six confirmed SNPs, NADH dehydrogenase subunit 5 ( nad5 ) and nad2 each contain two, and in nad2 both yield amino acid substitutions, suggesting balancing selection may act on this gene. Thus, while the low nucleotide diversity in Caribbean aplysinid cox1 extends to the entire mitochondrial genome, some genes do display variation. If these represent interspecific differences, then they may be useful alternative markers for studies in recently diverged sponge clades. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-9 DOI 10.1007/s10750-011-0879-x Authors Erik A. Sperling, Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA Rafael D. Rosengarten, Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA Maria A. Moreno, Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA Stephen L. Dellaporta, Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Alpine lakes may be particularly useful as sentinels of climate change because they are highly sensitive to environmental conditions. To explore the potential biotic consequences of climate change in these systems, we conducted paleo- and neoecological observational studies, as well as a short-term experiment to examine Daphnia responses to changing environmental conditions in Rocky Mountain alpine lakes. Our analysis of a sediment core from Emerald Lake representing two periods from the Holocene revealed a significant positive relationship between the abundance of Daphnia remains and fossil Aulacoseira lirata , a diatom associated with deeper mixing depths. In addition, we detected a significant increase in mean Daphnia density in the long-term record (1991–2005) from Pipit Lake, a trend that correlated well with increases in mean surface temperature. In our survey of Daphnia in 10 lakes in the Canadian Rocky Mountains, Daphnia abundance was positively correlated with both dissolved organic carbon concentration and temperature. Finally, our short-term incubation experiment demonstrated significant effects of physical conditions (i.e., temperature and/or UV radiation) and water chemistry on the juvenile growth rate of Daphnia . Overall, our findings highlight the sensitivity of Daphnia to changes in mixing depth, water temperature, and dissolved organic matter, three limnological variables that are highly sensitive to changes not only in air temperature, but also to precipitation and location of the treeline in alpine catchments. Thus, we conclude that Daphnia abundance could serve as a powerful sentinel response to climate change in alpine lakes of the Rocky Mountains. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-15 DOI 10.1007/s10750-011-0888-9 Authors Janet M. Fischer, Department of Biology, Franklin and Marshall College, Lancaster, PA 17604-3003, USA Mark H. Olson, Department of Biology, Franklin and Marshall College, Lancaster, PA 17604-3003, USA Craig E. Williamson, Department of Zoology, Miami University, 212 Pearson Hall, Oxford, OH 45056, USA Jennifer C. Everhart, Department of Biology, Franklin and Marshall College, Lancaster, PA 17604-3003, USA Paula J. Hogan, Department of Zoology, Miami University, 212 Pearson Hall, Oxford, OH 45056, USA Jeremy A. Mack, Department of Zoology, Miami University, 212 Pearson Hall, Oxford, OH 45056, USA Kevin C. Rose, Department of Zoology, Miami University, 212 Pearson Hall, Oxford, OH 45056, USA Jasmine E. Saros, School of Biology and Ecology, University of Maine, Orono, ME 04469, USA Jeffery R. Stone, Climate Change Institute, University of Maine, Orono, ME 04469, USA Rolf D. Vinebrooke, Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The presence of aquatic macrophytes is a key factor in the selection of habitats by fish in floodplain lakes because these plants enhance the physical and biological complexities of aquatic habitats. The seasonal flood pulse may influence this interaction, but there is no information in the literature about the effects that flood events may have on macrophytes assemblages and its associated effects on fish assemblages. Thus, this article aimed to investigate whether species richness, evenness and similarities in fish assemblage composition differed between littoral areas vegetated with macrophytes and unvegetated areas, before and after a flood. We sampled three lakes in the floodplain of the upper Paraná River basin. Sampling was conducted before (December 2004 and January 2005) and after (early March, late March and May 2005) a flood event. Overall, species richness and evenness were higher in macrophytes-covered areas. Before the flood, the composition of fish assemblages was distinct when comparing vegetated and unvegetated areas. After the flood, the similarity in fish assemblage composition was higher, indicating a homogenization effect of floods for fish inhabiting littoral areas of floodplain lakes. After the flood, opportunistic species dominated the fish assemblages in aquatic macrophytes, apparently restructuring assemblages in the littoral, restarting a succession process. Thus, the observed homogenization effect of the flood could minimize biological interactions and could induce fish assemblages to begin a new process of structurization. Content Type Journal Article Category HABITAT COMPLEXITY Pages 1-11 DOI 10.1007/s10750-011-0870-6 Authors L. C. Gomes, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Departamento de Biologia, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia), Universidade Estadual de Maringá, Bolsista Produtividade em Pesquisa do CNPq, Avenida Colombo, 5790, Maringá, PR 87020-900, Brazil C. K. Bulla, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Departamento de Biologia, Universidade Estadual de Maringá, Avenida Colombo, 5790, Maringá, PR 87020-900, Brazil A. A. Agostinho, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Departamento de Biologia, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupélia), Universidade Estadual de Maringá, Bolsista Produtividade em Pesquisa do CNPq, Avenida Colombo, 5790, Maringá, PR 87020-900, Brazil L. P. Vasconcelos, Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais, Departamento de Biologia, Universidade Estadual de Maringá, Avenida Colombo, 5790, Maringá, PR 87020-900, Brazil L. E. Miranda, U.S. Geological Survey, Mississippi Cooperative Fish and Wildlife Research Unit, Box 9691, Mississippi State, MS 39762, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Recognizing and understanding present-day biodiversity and biogeographical patterns and how these relate to contemporary and past climate is pivotal to predict the effect of future climate on marine biodiversity and promote adequate conservation policies. Sponges constitute an important and dominant component of the marine benthos and are therefore an excellent model group for such investigations. In this study, we assessed the diversity patterns and the zoogeographical affinities of the Northeast Atlantic and Mediterranean shallow-water demosponge assemblages. Data on the distribution of 745 species throughout 28 areas was compiled from the literature and used to build a presence/absence matrix. Diversity patterns were assessed from estimates of species richness ( S ) and taxonomic distinctness (AvTD). The Mediterranean Sea proved to be more diverse both in terms of species richness and taxonomic distinctness ( S  = 539, AvTD = 94.74) than the Northeast Atlantic ( S  = 480, AvTD = 92.42) and the two regions together were found to constitute a diversity hotspot harbouring approximately 11% of the global demosponge diversity. We found an Atlantic N–S and a Mediterranean NW–SE gradient of increasing taxonomic distinctness that is strongly correlated to both contemporary ( R 2  = 0.5667; P  〈 0.01) and historical values ( R 2  = 0.7287; P  〈 0.01) of sea surface temperature (SST) at the Last Glacial Maximum (LGM). The zoogeographical affinities examined through classification (cluster analysis) and ordination (non-metric multidimensional scaling, nMDS) based on the Bray–Curtis similarity index, revealed the presence of three groups approximately corresponding to the Northern European Seas, Lusitanian and Mediterranean provinces outlined in the ‘Marine Ecoregions of the World’ (MEOW) classification system. Geographical distance and oceanographic circulation were shown to constitute important factors in shaping the zoogeographical affinities among areas. The vast majority of the species occurring in the Northeast Atlantic and the Mediterranean (67 and 57%, respectively) was shown to have extremely restricted geographical ranges, as single-area or narrow-range (2–3 areas) endemics, which raises some concerns regarding their conservation. Content Type Journal Article Category SPONGE RESEARCH DEVELOPMENTS Pages 1-19 DOI 10.1007/s10750-011-0880-4 Authors Joana R. Xavier, Evolutionary Biology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Kruislaan 318, 1098 SM Amsterdam, The Netherlands Rob W. M. Van Soest, Netherlands Centre for Biodiversity, Zoological Museum of Amsterdam, P.O. Box 94766, 1090 GT Amsterdam, The Netherlands Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Lake depth is an important limnological attribute defining the structure and function of freshwater aquatic ecosystems. Lake levels have fluctuated and lake depths changed through the Holocene reflecting regional climate variations and sediment accumulation. Cladoceran remains preserved in sediments have been widely used for qualitative (P/L ratio) and quantitative (inference models) lake-depth reconstructions. In addition to estimations of prediction errors for performance power of modern data sets, it is important also to evaluate the reliability of reconstructed environmental values and to ensure that they are ecologically and paleoclimatically meaningful. In this study, we reconstructed the Holocene lake-depth history of a northern boreal lake using the Cladocera P/L ratio and a Cladocera—lake-depth inference model. These results were evaluated by comparison with reconstructions based on other proxies (aquatic macrofossils, sediment composition and sedimentation pattern) derived from three radiocarbon-dated sediment cores from the same lake. Whilst the reconstructions based on Cladocera and on the combination of other proxies yielded similar long-term trends, the absolute water depth values derived from the quantitative cladoceran model deviated from what was indicated by the other proxies. Therefore, we strongly recommend that also other, independent methods should be used simultaneously when reconstructing past water depths using Cladocera remains. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-18 DOI 10.1007/s10750-011-0885-z Authors Susanna Siitonen, Environmental Change Research Unit, Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Minna Väliranta, Environmental Change Research Unit, Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Jan Weckström, Environmental Change Research Unit, Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Sari Juutinen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, 00014 Helsinki, Finland Atte Korhola, Environmental Change Research Unit, Department of Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The anthropogenic impact on wetlands has increased during the last centuries when infrastructures such as canals or dams, have proliferated. In this article, we have used cladoceran sub-fossils to investigate the effects of a canal on lake El Tobar (Spain). The canal has been transferring water from a reservoir, built in another valley, into this lake since its construction in the mid-1960s. Cladoceran remains were analyzed in two sediment profiles from each of the two sub-basins of the lake. The sedimentary sequences showed that the mentioned human activity provoked a clear shift in the cladoceran community. A PCA was performed with samples from both sub-basins to detect the direction and nature of the changes. Before water transference, the phytophilous chydorid community, represented by Acroperus angustatus in one sub-basin and by both A. angustatus and Graptoleberis testudinaria in the other sub-basin, were well developed. After the construction of the canal and the inflow of additional yet different water from the reservoir, the proportion of chydorids relative to total cladoceran diminished considerably; this was mainly due to the invasion of Bosmina longirostris. These results indicate that the hydrological alteration caused a shift from an oligotrophic, shallower lake with a rich plant-associated cladoceran community to a more eutrophic lake with a predominant planktonic cladoceran community; and that cladoceran remains are a powerful tool to detect hydrological changes and eutrophication. Content Type Journal Article Category CLADOCERA AS INDICATORS Pages 1-13 DOI 10.1007/s10750-011-0876-0 Authors Charo López-Blanco, Department of Microbiology and Ecology, University of Valencia, 46100 Burjassot, Valencia, Spain María Rosa Miracle, Department of Microbiology and Ecology, University of Valencia, 46100 Burjassot, Valencia, Spain Eduardo Vicente, Department of Microbiology and Ecology, University of Valencia, 46100 Burjassot, Valencia, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    In this study, a bioassessment was conducted to determine the effectiveness of best management practices (BMPs) implemented in farms in the Upper Delaware River watershed, NY (USA). Diatom and macroinvertebrate communities were analyzed across 17 low-order streams, designated as reference, BMP, or non-BMP. Streams lacking improvements (non-BMP) had significantly greater specific conductance, pH, TDP, NH 4 + -N, and NO 3 − -N than did reference streams. Diatom model affinity (DMA) values were significantly greater in reference and BMP streams than in non-BMP streams; non-BMP streams bordered on a “severely impacted” rating. The Trophic Diatom Index (TDI) varied two-fold among stream classes, with non-BMP 〉 BMP 〉 reference. TDI and DMA values were highly correlated, and both varied significantly with conductance, TDP, NH 4 + -N, and NO 3 − -N. Macroinvertebrate taxa, EPT richness, and Simpson’s diversity did not differ significantly among stream classes. Macroinvertebrate metrics (HBI, Bioassessment Profile, Percent Model Affinity) varied by stream class, but none indicated greater water quality in BMP sites. Nonetheless, each correlated significantly with conductance and TDP in the directions predicted by each model. Our data suggest that diatoms are more sensitive to moderate increases in nutrients, conductivity, and pH in high-gradient agricultural streams, and may be more useful in assessing stream management practices. Content Type Journal Article Category Primary Research Paper Pages 1-18 DOI 10.1007/s10750-011-0933-8 Authors Kurt W. Gabel, Louis Calder Center—Biological Field Station and Department of Biological Sciences, Fordham University, Armonk, New York, USA John D. Wehr, Louis Calder Center—Biological Field Station and Department of Biological Sciences, Fordham University, Armonk, New York, USA Kam M. Truhn, Louis Calder Center—Biological Field Station and Department of Biological Sciences, Fordham University, Armonk, New York, USA Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Loch Leven is a large, shallow lake in lowland Scotland, UK. Scientific research began here almost 200 years ago. Early research characterised the biodiversity and physical characteristics of the loch, providing an important historical background for future research. In the mid-1960s, this ad hoc approach was superseded by a more structured research programme under the umbrella of the International Biological Programme. This was the beginning of the Loch Leven long-term monitoring programme. Today, the results of these studies form one of the longest and most comprehensive limnological datasets for shallow freshwater lakes in the world, comprising more than 500 physical, chemical and biological variables collected at two-weekly intervals. To celebrate the 40th anniversary of the start of the long term monitoring programme, and to highlight the scientific investigations still being conducted at Loch Leven, the NERC Centre for Ecology & Hydrology (CEH) organised a symposium entitled “Loch Leven: 40 years of scientific research” in Kinross, Scotland, UK, on 11 December 2008. This examined the role of long-term monitoring in developing our understanding of the links between pollution, climate change and ecological responses in shallow lakes. This article introduces a series of papers summarising the scientific results presented at this meeting. Content Type Journal Article Category LOCH LEVEN RESEARCH Pages 1-7 DOI 10.1007/s10750-011-0929-4 Authors L. May, Centre for Ecology & Hydrology, Penicuik, EH26 0QB Midlothian, UK B. M. Spears, Centre for Ecology & Hydrology, Penicuik, EH26 0QB Midlothian, UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Controlled observations in Roscoe Bay examined whether Aurelia labiata medusae would respond to three environmentally significant stimuli: low salinity, seawater movement and seawater depth. Significantly more upward-swimming medusae turned and swam down or sideways when they encountered an experimentally created low-salinity plume than did upward-swimming medusae that encountered a seawater plume or a seawater plume containing milk powder. Downward-swimming medusae that encountered a plume containing freshwater continued swimming down. Significantly more upward-swimming medusae exposed to an experimentally created stream of seawater that gently pushed them horizontally turned and swam down than did upward-swimming medusae not exposed to the seawater stream. Downward-swimming medusae continued to swim down when pushed horizontally. A stronger seawater stream that tumbled as well as pushed medusae horizontally was less effective. In a shallow area near the time of a low tide, most medusae were in the top metre of a 2 m water column whilst in an adjacent area where the water was 4–6 m deep, almost all medusae were below 1.5 m. These observations add to a growing body of evidence that the ecological distribution of A . labiata is influenced by their ability to respond adaptively to significant environmental stimuli. Content Type Journal Article Category Primary Research Paper Pages 1-8 DOI 10.1007/s10750-011-0915-x Authors David J. Albert, Roscoe Bay Marine Biology Laboratory, 4534 W 3rd Avenue, Vancouver, BC V6R 1N2, Canada Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    The introduction of exotic species is a major cause of ecological disturbance and has recently been shown to promote the decline of some amphibian populations. In Western Europe, several amphibian species have been introduced in recent decades, among them Discoglossus pictus , impact of which in native amphibian communities is still unknown. We studied the potential impact of D. pictus by analysing the degree of niche overlap, assuming the possible existence of competitive interactions with native species. We have studied the structure of the anuran assemblage at local level, defining the morphospace occupied by native species and the habitat occupied by the different ecomorphs. The analysis of distance matrices suggested that there was a covariation between morphological characters and habitat selection. We determined the position of D. pictus within the morphospace of the native anuran community, patterns of co-occurrence among alien, and native species and habitat selection. The potential effect of climate on local assemblages had been controlled based on data obtained from climate models. These analysis showed that D. pictus was clustered with the benthic guild, selected positively small ephemeral ponds and was a thermophilic species. Based on these results, a greater degree of niche overlap was expected with Bufo calamita and Pelodytes punctatus. The definition of morphological groups can be useful to understand the invaded assemblage structure and the potential effect of an alien frog on native communities. Content Type Journal Article Category Primary Research Paper Pages 1-13 DOI 10.1007/s10750-011-0936-5 Authors Daniel Escoriza, Institute of Aquatic Ecology and Department of Environmental Science, Faculty of Sciences, University of Girona, Campus Montilivi, 17071 Girona, Spain Dani Boix, Institute of Aquatic Ecology and Department of Environmental Science, Faculty of Sciences, University of Girona, Campus Montilivi, 17071 Girona, Spain Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Loch Leven has been designated as a UK Ramsar Site (1976), a Site of Special Scientific Interest (1985) and a Special Protection Area (2000) due to its importance as a site for overwintering waterfowl. However, no comprehensive assessment of trends in waterfowl at the local versus national scale has been conducted at the site. Coherence between trends in 5-year mean species abundance for Loch Leven and Underhill Indexing Method values for Scotland (or GB in the case of geese) were assessed using principal components analysis for ten study species between 1968 and 2006. Five species showed trends at Loch Leven that were coherent with those at the Scottish scale (Eurasian Teal, Mute Swan, Great Cormorant, Pink-footed and Greylag geese). These species may not respond positively to local scale management. However, the other five species (Mallard, Coot, Great Crested Grebe, Tufted Duck and Pochard) showed distinct differences between local and national trends. A study of the feeding ecology for these species, the re-establishment of ringing effort and an assessment of waterfowl–wetland relationships are recommended to determine how changes in local food resources and habitat quality interact with macro-scale population dynamics to influence local and regional patterns of abundance. Content Type Journal Article Category LOCH LEVEN RESEARCH Pages 1-20 DOI 10.1007/s10750-011-0927-6 Authors D. Carss, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, Scotland, UK B. M. Spears, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, Scotland, UK L. Quinn, Centre for Ecology & Hydrology, Penicuik, Midlothian EH26 OQB, Scotland, UK R. Cooper, Scottish Natural Heritage, Battleby, Redgorton, Perth, PH1 3EW Scotland, UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    This article assesses changes in the macrophyte community of Loch Leven over a period of 100 years. Evidence is presented that shows that these changes are associated with eutrophication and with subsequent recovery from eutrophication when anthropogenic nutrient inputs to the loch were reduced. This study uses macrophyte survey data from 1905, 1966, 1972, 1975, 1986, 1993, 1999 and 2008. In each of the four most modern surveys, the loch was divided into 19 sectors, each with at least one transect ranging from the shallowest to the deepest occurrence of macrophytes. From these data, a range of indicators of recovery were derived at the whole lake scale: the relative abundance of taxa, taxon richness and evenness. All of these metrics showed an improvement since 1972. Species richness, measured at the scales of survey sector and individual samples, also appeared to have increased in recent years. All of these measures, coupled with ordination of the presence/absence composition data from all survey years, indicate that the macrophyte community in the loch is recovering towards the state that was recorded in 1905. Content Type Journal Article Category Loch Leven Research Pages 1-9 DOI 10.1007/s10750-011-0924-9 Authors B. Dudley, Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB UK I. D. M. Gunn, Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB UK L. Carvalho, Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB UK I. Proctor, Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB UK M. T. O’Hare, Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB UK K. J. Murphy, Division of Environmental & Evolutionary Biology, University of Glasgow, University Avenue, Glasgow, G12 8QQ UK A. Milligan, Division of Environmental & Evolutionary Biology, University of Glasgow, University Avenue, Glasgow, G12 8QQ UK Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158

Description:    Biomanipulation through fish removal is a tool commonly used to restore a clear-water state in lakes. Biomanipulation of ponds is, however, less well documented, although their importance for biodiversity conservation and public amenities is undisputed. In ponds, a more complete fish removal can be carried out as compared to lakes and therefore a stronger response is expected. Fish recolonization can, however, potentially compromise the longer term success of biomanipulation. Therefore, we investigated the impact of fish recolonization on zooplankton, phytoplankton, and nutrients for several years after complete drawdown and fish removal in function of submerged vegetation cover in 12 peri-urban eutrophic ponds situated in Brussels (Belgium). Fish recolonization after biomanipulation had a considerable impact on zooplankton grazers, reducing their size and density substantially, independent of the extent of submerged vegetation cover. Only ponds with 〈30% cover of submerged vegetation shifted back to a turbid state after fish recolonization, coinciding with an increase in density of small cladocerans, rotifers, and cyclopoid copepods. In ponds with 〉30% submerged vegetation cover, macrophytes prevented an increase in phytoplankton growth despite the disappearance of large zooplankton grazers. Our results suggest that macrophytes, rather than by providing a refuge for zooplankton grazers, control phytoplankton through other associated mechanisms and confirm that the recovery of submerged macrophytes is essential for biomanipulation success. Although the longer term effect of biomanipulation is disputable, increased ecological quality could be maintained for several years, which is particularly interesting in an urban area where nutrient loading reduction is often not feasible. Content Type Journal Article Category POND RESEARCH AND MANAGEMENT Pages 1-16 DOI 10.1007/s10750-011-0902-2 Authors Sylvia De Backer, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Samuel Teissier, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Ludwig Triest, Plant Biology and Nature Management (APNA), Department of Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium Journal Hydrobiologia Online ISSN 1573-5117 Print ISSN 0018-8158