ALBERT

Description: Modern competition research started with G.E. Hutchinson’s, Homage to Santa Rosalia, and his now-famous question “why are there so many species?” (Hutchinson 1959,1961). This confronted observed species richness with the competitive exclusion principle, a principle that had been derived from theory and from highly artificial experiments. It would always have been easy to point at the “artificial” character of the competitive exclusion principle. Indeed many researchers have refused to deal with Hutchinson’s question because they considered it a pseudo-problem, which arose from a contradiction between overly simplified theory and complicated reality. However, those who took Hutchinson’s challenge seriously have gained fundamental insights into how competition plays out in nature, how species coexist, and how communities function. In this final chapter we attempt to synthesize these insights as they have been presented in this book. We focus on six key topics: - Identification of major trade-off axes (Sect. 8.1) - Confirmation of the “intermediate disturbance hypothesis”, and detection of interactions among competition, resource supply, predation and disturbance in field experiments (Sect. 8.2) - The interplay of space colonization, dispersal and neighborhood competition in sessile communities (Sect. 8.3) - Potential for chaotic, self-generated heterogeneity in communities (Sect. 8.4) - Role of exclusive resources in competition among mobile animals (Sect. 8.5) - Coexistence by slow exclusion (Sect. 8.6)

Description: Horizontal starch gel electrophoresis was employed to investigate levels of genetic differentiation between 13 samples of the neritic squid species Loligo forbesi Steenstrup obtained from throughout the majority of its known geographical range. Six enzyme loci identified in a preliminary study as being polymorphic were screened for variation between samples. No significant differences in allele distribution were detected between any of the samples obtained from the Faroe Bank in the north to Lisbon in the south, suggesting that squid throughout this range in the vicinity of the continental shelf are able to maintain panmixia, and effectively belong to a single population sharing a common gene pool. No clinal variation in allele distribution was detected throughout this range, a result which complements the findings of a detailed morphological companion study of the same individuals. Comparison of this homogenous European continental shelf population with squid from the Azores revealed highly significant (P〈0.01) differences in allele distribution at five of the six polymorphic enzyme loci studied. A genetic identity value (I) equivalent to 0.93 over 33 loci was obtained. Analysis of F-statistics suggested migration rates between sites to be as low as one individual per five generations, a rate deemed insufficient under most models to prevent divergence by random genetic drift. The large distance and oceanic depths separating the Azores from continental Europe seem to present an effective barrier to gene flow to L. forbesi, a squid belonging to a family considered to be confined in distribution to relatively shallow, near coastal waters. The two populations of squid in the Azores and along the European continental shelf currently both ascribed to L. forbesi should therefore probably best be regarded as relative subspecies.

Description: Beak lengths (lower rostral length and upper rostral length) were taken for a sample of Moroteuthis ingens which were captured on the Chatham Rise, New Zealand. Beak lengths were plotted against both mantle length and wet weight to determine the relationship between these parameters for future use in biomass estimates in predator analysis. Although M. ingens is markedly sexually dimorphic, with females reaching 5 times the weight of males, there was no obvious sexual dimorphism in either lower or upper rostral length. This resulted in sex-specific relationships between both LRL and mantle length, LRL and weight; and URL and mantle length, and URL and weight. Males appeared to have a curvilinear relationship between beak length and mantle length and beak length and weight (even for log-transformed data). There was also considerable spread in the data in the plot between beak length and weight for females of similar weight. These characteristics of the data makes biomass estimates based on rostral length measurements for this species difficult. Other beak parameters may prove more useful for estimating biomass of M. ingens.

Description: Body size at sexual maturity, egg-size distributions, and potential reproductive output have been estimated for female and male squid, Loligo forbesi Steenstrup, off the west coast of Scotland. Two size modes at maturity were found in both sexes, but separation into size cohorts was more pronounced in males (180 and 350 mm mantle length, ML). Preliminary ageing studies based on statolith ring-counts suggest that these size modes are not due to different age groups at breeding. Females have a single size mode of mature eggs in the proximal oviduct, but may have at least two size modes of eggs within the ovary. This finding is interpreted as evidence of batch-spawning in this squid. There was a weak relationship between total egg numbers (range 1000 to 16000) and body size (range 196 to 318 mm ML) and between mature egg size and body size. Males showed a strong positive relationship between spermatophore length and body length but a weak relationship between total number of spermatophores and body size. The results are discussed in the context of flexibility of breeding strategies in the loliginids and variety of life-cycle patterns.

Description: This study assesses the potential of the tropical loliginid squid Photololigo sp. to lay multiple batches of eggs and examines changes in somatic growth during reproduction. Histological analysis of the ovary and the relative size of the oviduct to mantle weight and ovary weight were used to determine the potential for multiple spawning. Ovaries of mature females always had immature and mature oocytes present, suggesting that not all the oocytes were maturing simultaneously and that multiple batches of eggs were being produced. Furthermore, poor correlations of oviduct weight with body size and ovary weight indicated that mature oocytes were not accumulating in the oviduct for a single spawning event. Both these observations supported the hypothesis that Photololigo sp. has the potential to lay multiple batches of eggs throughout its life. Specific growth rates, length-weight relationships, relative growth of somatic and reproductive tissue and microscopic assessment of muscle tissue were compared between immature and mature females. Growth rates of immature females were almost twice as fast as those of mature females. Mature females also had no large muscle fibres present, suggesting that energy for reproduction was mobilised from the muscle tissue.

Description: A total of 96 species of sponge were recorded in a bathymetric survey conducted within the iSimangaliso Wetland Park. Non-random processes are hypothesised to account for the decline in species richness with increasing depth, and the data add support to Rapoport’s rule. Morphological and colour diversity were strongly correlated and decreased with depth. Five communities could be identified at the 30% level of similarity using cluster analysis, and these correspond to intertidal and shallow subtidal (to 10 m), deep sub-photic zone (coral reefs: 10–30 m), deep reefs (40–90 m), canyon margin (100–140 m) and canyon (140–360 m). The data add support to recently hypothesised bathymetric zones around South Africa.

Description: Cold-water coral (CWC) reefs constitute one of the most complex deep-sea habitats harboring a vast diversity of associated species. Like other tropical or temperate framework builders, these systems are facing an uncertain future due to several threats, such as global warming and ocean acidification. In the case of Mediterranean CWC communities, the effect may be exacerbated due to the greater capacity of these waters to absorb atmospheric CO2 compared to the global ocean. Calcification in these organisms is an energy-demanding process, and it is expected that energy requirements will be greater as seawater pH and the availability of carbonate ions decrease. Therefore, studies assessing the effect of a pH decrease in skeletal growth, and metabolic balance are critical to fully understand the potential responses of these organisms under a changing scenario. In this context, the present work aims to investigate the medium- to long-term effect of a low pH scenario on calcification and the biochemical composition of two CWCs from the Mediterranean, Dendrophyllia cornigera and Desmophyllum dianthus. After 314 d of exposure to acidified conditions, a significant decrease of 70 % was observed in Desmophyllum dianthus skeletal growth rate, while Dendrophyllia cornigera showed no differences between treatments. Instead, only subtle differences between treatments were observed in the organic matter amount, lipid content, skeletal microdensity, or porosity in both species, although due to the high variability of the results, these differences were not statistically significant. Our results also confirmed a heterogeneous effect of low pH on the skeletal growth rate of the organisms depending on their initial weight, suggesting that those specimens with high calcification rates may be the most susceptible to the negative effects of acidification.

Description: In the Mediterranean deep-sea, scleractinian cold-water corals (CWC) are observed to survive at the uppermost end of their presumed thermal distribution range (4–13 °C). Here, we show that 2 common CWC species (i.e. Dendrophyllia cornigera and Desmophyllum dianthus) maintained in aquaria can indeed tolerate considerably elevated seawater temperatures (17.5 ± 0.1 °C), while growing at similar (D. dianthus) or significantly higher (D. cornigera) rates than conspecifics cultured in parallel for 87 days at ambient Mediterranean deep-sea temperature (12.5 ± 0.1 °C). Neither differences in coral appearance nor mortality were evident for both species at either temperature. D. dianthus grew significantly faster (0.23 ± 0.08 % day−1) than D. cornigera (0.05 ± 0.01 % day−1) under ambient thermal conditions. Growth of D. cornigera increased significantly (0.14 ± 0.07 % day−1) at elevated temperature, while Desmophyllum dianthus growth showed no significant difference under both conditions. These findings suggest that D. dianthus and D. cornigera may be capable of surviving in warmer environments than previously reported, and thus challenge temperature as the paramount limiting environmental factor for the occurrence of some CWC species.

Description: One concept of evolutionary ecology holds that a living fossil is the result of past evolutionary events, and is adapted to recent selective forces only if they are similar to the selective forces in the past. We describe the present environment of the living coelacanth Latimeria chalumnae Smith, 1939 at Grande Comore, western Indian Ocean and report depth-dependent cave distribution, temperature, salinity and oxygen values which are compared to the fish's distribution and its physiological demands. We studied the activity pattern, feeding behaviour, prey abundance and hunting success to evaluate possible links between environmental conditions, feeding ecology and evolutionary success of this ancient fish. Transmitter tracking experiments indicate nocturnal activity of the piscivorous predator which hunts between approximately 200 m below the surface to 500 m depth. Fish and prey density were measured between 200 and 400 m, both increase with depth. Feeding tracks and feeding strikes of the coelacanth at various depths were simulated with the help of video and laser techniques. Along a 9447 m video transect a total of 31 potential feeding strikes occurred. Assuming 100% hunting success, medium-sized individuals would obtain 122 g and large females 299 g of prey. Estimates of metabolic rates revealed for females 3.7 ml O2 kg−1 h−1 and for males 4.5 ml O2 kg−1 h−1. Today coelacanths are considered to be a specialist deep-water form and to inhabit, with their ancient morphology, a contemporary environment where they compete with advanced, modern fish.

Description: Uraninite solubility in 0.001–2.0 m HCl solutions was experimentally studied at 500°C, 1000 bar, and hydrogen fugacity corresponding to the Ni/NiO buffer. It was shown that the following U(IV) species dominate in the aqueous solution: U(OH)40, U(OH)2Cl20, and UOH Cl30 Using the results of uraninite solubility measurement, the Gibbs free energies of U(IV) species at 500°C and 1000 bar were calculated (kJ/mol): −9865.55 for UO2(aq), −1374.57 for U(OH)2 Cl20, and −1265.49 for UOH Cl30, and the equilibrium constants of uraninite dissolution in water and aqueous HCl solutions were estimated: UO2(cr) = UO2(aq), pK0 = 6.64; UO2(cr) + 2HCl0 = U(OH)2 Cl20, pK2 = 3.56; and UO2(cr) + 3HCl0 = UOHcl30 + H2O, pK3 = 3.05. The value pK1 ≈ 5.0 was obtained as a first approximation for the equilibrium UO2(cr) + H2O + HCl0 = U(OH)3Cl0. The constant of the reaction UO2(cr) + 4HCl0 = UCl40 + 2H2O (pK4 = 7.02) was calculated taking into account the ionization constants of U Cl40 and U(OH)40, obtained by extrapolation from 25 to 500°C at 1000 bar using the BR model. Intense dissolution and redeposition of gold (material of experimental capsules) was observed in our experiments. The analysis and modeling of this phenomenon suggested that the UO2 + x/UO2 redox pair oxidized Au(cr) to Au+(aq), which was then reduced under the influence of stronger reducers.

Description: Sediment transport processes in the northern North Atlantic have been investigated on the basis of various numerical models. A general circulation model has been used to investigate large-scale particle transport, a reduced gravity plume model has been used to investigate particle transport by cascading from the shelves into the deep basins, an ocean slice model has been used to investigate particle exchange processes between a bottom current and the ambient water mass, and a Bottom Boundary Layer model has been used to investigate particle interactions influencing the settling behavior of suspended particles. In this paper, the various processes investigated in these models are described (i) schematically, (ii) on the basis of field data, if available, and (iii) by employing results from numerical simulations. In a first attempt the northern North Atlantic will be divided into separate process defined areas, which can be used in carbon budgeting, for example.

Description: Since the discovery of dense animal communities associated with deep-sea hydrothermal venting (Lonsdale 1977), biological knowledge of those animals has accumulated (Van Dover 2000). Some unique animals associated with vent fields were found to depend on chemosynthetic primary production (Corliss et al. 1979). Subsequently, similar chemosynthetic animal assemblages were also discovered associated with deep-sea methane-seep areas, whale falls, and sunken wood (Pauli et al. 1984; Smith et al. 1989). To understand the pathways of adaptation to these environments, species shared between different habitats are of particular interest (Distel et al. 2000; Lorion et al. 2008). On a global scale, the number of species shared between vents and seeps is less than 10% of the total recorded vent or seep species (e.g. Tunnicliffe et al. 1998, 2003; Sibuet and Olu 1998). In the vent and seep communities around Japan, however, this figure exceeds 20% (based on a faunal list provided by Fujikura et al. 2008), although the Identification of species is still in progress. This relatively high abundance of both vent- and seep-inhabiting species suggests close relationships between vent and seep communities around Japan. A high similarity between megafaunal communities at vents and seeps around Japan was already noted by Fujikura et al. (1995); however, that study was based on species abundances investigated at only a single vent and two methane-seep communities. To date, at least 55 vent and seep communities have been discovered around Japan (Fujikura et al. 2008), and further analyses are required to elucidate the nature of this similarity. In this chapter, we focus on similarities between megafaunal communities inhabiting vents and seeps. As Kojima (2002) has already provided an review with an almost complete list of studies on vent and seep animals around Japan as of the time of publication, here we only provide brief, essential Information on their geologic settings and ecologic characteristics. Then, we summarize the species distributional records with Statistical analyses based on previous studies of those communities around Japan and discuss their proximity. In addition, we also summarize recent genetic studies of both vent- and seep-inhabiting species, i.e., three Calyptogena clams, Lamellibrachia and Paraescarpia tubeworms, and Bathymodiolus musseis, and discuss the Connectivity among populations of these species. Finally, we discuss whether the similarity of communities is accompanied by population Connectivity.

Description: SLC26A11 (human)/Slc26a11 (mouse), also known as kidney brain anion transporter (KBAT), is a member of the SLC26 anion transporter family and shows abundant mRNA expression in the brain. However, its exact cellular distribution and subcellular localization in the brain and its functional identity and possible physiological roles remain unknown. Expression and immunostaining studies demonstrated that Slc26a11 is abundantly expressed in the cerebellum, with a predominant expression in Purkinje cells. Lower expression levels were detected in hippocampus, olfactory bulb, cerebral cortex, and subcortical structures. Patch clamp studies in HEK293 cells transfected with mouse cDNA demonstrated that Slc26a11 can function as a chloride channel that is active under basal conditions and is not regulated by calcium, forskolin, or co-expression with cystic fibrosis transmembrane regulator. Single and double immunofluorescent labeling studies demonstrated the localization of vacuolar (V) H+-ATPase and Slc26a11 (KBAT) in the plasma membrane in Purkinje cells. Functional studies in HEK293 cells indicated that transfection with Slc26a11 stimulated acid transport via endogenous V H+-ATPase. We conclude that Slc26a11 (KBAT) is prominently distributed in output neurons of various subcortical and cortical structures in the central nervous system, with specific expression in Purkinje cells and that it may operate as a chloride channel regulating acid translocation by H+-ATPase across the plasma membrane and in intracellular compartments.

Description: The future demands on professional archaeological prospection will be its ability to cover large areas in a time and cost efficient manner with very high spatial resolution and accuracy. The objective of the 2010 in Vienna established Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology in collaboration with its nine European partner organizations is the advancement of the state-of-the-art by focusing on the development of remote sensing, geophysical prospection and virtual reality applications, as well as of novel integrated interpretation approaches dedicated to non-invasive spatial archaeology combining cutting-edge near-surface prospection methods with advanced computer science. Within the institute’s research program different areas for distinct case studies in Austria, Germany, Norway, Sweden and the UK have been selected as basis for the development and testing of new concepts for efficient and universally applicable tools for spatial, non-invasive archaeology. The collective resources and expertise available amongst the new research institute and associated partners permit innovative approaches to the archaeological exploration, documentation and investigation of the cultural heritage contained in entire archaeological landscapes. First promising results illustrate the potential of the proposed methodology and concepts.

Description: The emission rates of eight volatile halogenated compounds by three tropical brown seaweed species collected from Cape Rachado, west coast Peninsular Malaysia, under different irradiances have been determined. A purge-and-trap sample preparation system with a gas chromatograph and mass-selective detector was used to measure a suite of halocarbons released by Sargassum binderi Sonder ex J. Agardh, Padina australis Hauck, and Turbinaria conoides (J. Agardh) Kützing. All species are widely distributed in Peninsular Malaysia, with S. binderi a dominant seaweed species at our survey site. Release of few halocarbons was found to be influenced by irradiance. Correlations were also observed between emission of certain halocarbons with photosynthetic activity, especially bromo-and iodinated compounds (0.6 〈 r 〈0.9; p 〈 0.01) suggesting that environmental factors such as light can affect the release of these volatile halogenated compounds by the seaweeds into the atmosphere. Compared with temperate and polar brown seaweeds, tropical species, such as T. conoides, may emit higher levels of bromoform, CHBr3, and other halocarbons. It is therefore important to investigate the contribution of tropical seaweeds towards the local atmospheric composition of halocarbons.

Description: The natural feeding of 485 Octopus mimus (164 to 3088 g) was studied in relation to the species' life cycle and environmental seasonal variations off the north of Chile from autumn 1991 to summer 1992. Analysis of digestive-tract contents revealed that O. mimus preyed upon 25 different prey items belonging to five zoological groups (Teleostei, Mollusca, Crustacea, Echinodermata and Polychaeta). Cannibalism was only occasional. The results indicate that the diet and food intake of this species are significantly affected by sex and maturation. Senescent individuals ingest a small amount of food, and their diet is mainly based on small, not very motile prey. The food intake, expressed as body weight, of non-senescent individuals is higher in females than in males. Seasonal changes in sea-water temperature seem to be followed by adjustments in food intake. Like other Octopus species, O. mimus appears to be an opportunistic predator.

Description: The relationship between reproduction and condition was studied in a 15 mo sample of 919 maturing, mature and post-spawning female Octopus mimus (388 to 3714 g) caught in Iquique (North Chile). O. mimus is a semelparous species, with reproduction taking place all year round. Investment in reproductive tissues was, on average, 9.9% of mature female body weight, independent of season. However, somatic growth during maturation was dependent on season and varied between 26 and 63% of the whole-body growth in weight. The condition of females did not vary markedly until spawning, although seasonal variations were apparent, winter being the most unfavourable. Condition deteriorated dramatically after spawning, during parental care of the eggs. During this period, somatic-tissue depletion, mainly from the muscles, was 〉25% of the total body weight of mature females. The fecundity of O. mimus was probably limited by the costs associated with parental care of the eggs.

Description: The crystalline parts of the Bergsträsser (western) Odenwald and the southern Spessart expose Variscan I-type granitoids of the mid-German crystalline rise that formed during subduction of the Rheic ocean and collision of Avalonia and Armorica about 365 and 330 Ma ago. We present geochemical, Sr-Nd isotopic, single zircon 207Pb/206Pb evaporation and conventional U-Pb data from a diorite-granodiorite complex of the southern Spessart and from a flasergranitoid of the Bergsträsser Odenwald unit II. Both intrusions provide almost identical zircon ages (332.4 ± 1.6 Ma for Odenwald and 330.4 ± 2.0 Ma for Spessart). Lack of inherited or pre-magmatic zircon components connotes magma genesis in deep crustal hot zones despite low temperature estimates (758–786 °C) derived from zircon saturation thermometry. Investigated rock samples display normal- to high-K calc-alkaline metaluminous (Spessart) and weakly peraluminous (Odenwald) geochemical characteristics. The Spessart pluton has lower εNd(T) values (−2.3 to −3.0) and higher 87Sr/86Sri ratios (0.7060 to 0.7066) compared to Odenwald flasergranitoid (εNd(T) = −0.8 and 87Sr/86Sri = 0.7048). In terms of the tectonic setting, the diorite-granodiorite complex of the southern Spessart forms the continuation of the north Armorican arc segment exposed in the Bergsträsser Odenwald. Taking into account previously reported geochemical and isotopic results, it is concluded that the Spessart pluton does not match compositions of Odenwald unit II granitoids but likely represents the north-eastward extension of unit III.

Description: Bottom shots have been used for a number of years in seismic studies on the ocean floor. Most experiments utilized explosives as the energy source, though researchers have recognized the usefulness of collapsing water voids to produce seismoacoustic signals. Implosive sources, however, suffered generally from a lack of control of source depth. We present a new experimental tool, called SEEBOSEIS, to carry out seismic experiments on the seafloor utilizing hollow glass spheres as controlled implosive sources. The source is a 10-inch BENTHOS float with penetrator. Inside the sphere we place a small explosive charge (two detonators) to destabilize the glass wall. The time of detonation is controlled by an external shooting device. Test measurements on the Ninetyeast Ridge, Indian Ocean, show that the implosive sources can be used in seismic refraction experiments to image the subbottom P- wave velocity structure in detail beyond that possible with traditional marine seismic techniques. Additionally, the implosions permit the efficient generation of dispersed Scholte waves, revealing upper crustal S-wave velocities. The frequency band of seismic energy ranges from less than 1 Hz for Scholte modes up to 1000 Hz for diving P-waves. Therefore, broadband recording units with sampling rates 〉2000 Hz are recommended to sample the entire wave field radiated by implosive sources.

Description: Regression trees represent one of the most popular tools in predictive data mining applications. However, previous studies have shown that their performances are not completely satisfactory when the dependent variable is highly skewed, and severely degrade in the presence of heavy-tailed error distributions, especially for grossly mis-measured values of the dependent variable. In this paper the lack of robustness of some classical regression trees is investigated by addressing the issue of highly-skewed and contaminated error distributions. In particular, the performances of some non robust regression trees are evaluated through a Monte Carlo experiment and compared to those of some trees, based on M-estimators, recently proposed in order to robustify this kind of methods. In conclusion, the results obtained from the analysis of a real dataset are presented.

Description: Overpressure generation due to rapid sediment deposition can result in low effective stresses within the sediment column. It has been proposed that these large overpressures are the main preconditioning factor for causing large-scale submarine slope failure on passive continental margins, such as those in the Gulf of Mexico and offshore Norway. The rate of overpressure generation depends on the sedimentation rate, sediment compressibility and permeability. The Gulf of Mexico and the Norwegian continental slope have experienced comparatively high sediment input, but large-scale slope failure also occurs in locations with very low sedimentation rates such as the Northwest African continental margin. Here we show results from 2D numerical modelling of a 2° continental slope subjected to deposition rates of 0.15 m/ka. These results do not indicate any evidence for significant overpressure or slope instability. We conclude that factors other than overpressure must be fundamental for initiating slope failure, at least in locations with low sedimentation rates.

Description: There has been a good deal of interest in the potential of marine vegetation as a sink for anthropogenic C emissions (“Blue Carbon”). Marine primary producers contribute at least 50% of the world’s carbon fixation and may account for as much as 71% of all carbon storage. In this paper, we analyse the current rate of harvesting of both commercially grown and wild-grown macroalgae, as well as their capacity for photosynthetically driven CO2 assimilation and growth. We suggest that CO2 acquisition by marine macroalgae can represent a considerable sink for anthropogenic CO2 emissions and that harvesting and appropriate use of macroalgal primary production could play a significant role in C sequestration and amelioration of greenhouse gas emissions.

Description: Inhibitors of bacterial quorum sensing have been proposed as potentially novel therapeutics for the treatment of certain bacterial diseases. We recently reported a marine Halobacillus salinus isolate that secretes secondary metabolites capable of quenching quorum sensing phenotypes in several Gram-negative reporter strains. To investigate how widespread the production of such compounds may be in the marine bacterial environment, 332 Gram-positive isolates from diverse habitats were tested for their ability to interfere with Vibrio harveyi bioluminescence, a cell signaling-regulated phenotype. Rapid assay methods were employed where environmental isolates were propagated alongside the reporter strain. “Actives” were defined as bacteria that interfered with bioluminescence without visible cell-killing effects (antibiotic activity). A total of 49 bacterial isolates interfered with bioluminescence production in the assays. Metabolite extracts were generated from cultures of the active isolates, and 28 reproduced the bioluminescence inhibition against V. harveyi. Of those 28, five extracts additionally inhibited violacein production by Chromobacterium violaceum. Chemical investigations revealed that phenethylamides and a cyclic dipeptide are two types of secondary metabolites responsible for the observed activities. The active bacterial isolates belonged primarily to either the genus Bacillus or Halobacillus. The results suggest that Gram-positive marine bacteria are worthy of further investigation for the discovery of quorum sensing antagonists.

Description: North Pacific flatfishes are gaining increased popularity on the German market. Isoelectric focusing of sarcoplasmic proteins and PCR-based DNA analysis were applied to identify fillets of nine Alaskan Flatfish species: Artheresthes stomias (Arrow-tooth flounder), Limanda aspera (Yellowfin sole), Isopsetta isolepis (Butter sole), Lepidopsetta bilineata (Southern rock sole), Lepidopsetta polyxystra (Northern rock sole), Hippoglossus stenolepis (Pacific halibut), Hippoglossoides elassodon (Flathead sole), Platichthys stellatus (Starry flounder), and Glyptocephalus zachirus (Rex sole). Characteristic protein patterns were obtained for raw fillets of several species. Reactivity of flatfish DNA against five pairs of primers was tested, amplifying segments of the mitochondrial cytochrome b, cytochrome oxidase subunit I, 16S rRNA gene, as well as the nuclear parvalbumin gene. Amplicons of the cytochrome b gene were sequenced and used for single-strand conformation polymorphism analysis. The survey of deep-frozen commercial yellowfin sole fillets resulted in the detection of 17% of the fillets being mislabelled; Northern rock sole, butter sole and flathead sole had been used as substitutes.

Description: Marine habitats worldwide are increasingly pressurized by climate change, especially along the Antarctic Peninsula. Well-studied areas in front of rapidly retreating tidewater glaciers like Potter Cove are representative for similar coastal environments and, therefore, shed light on habitat formation and development on not only a local but also regional scale. The objective of this study was to provide insights into habitat distribution in Potter Cove, King George Island, Antarctica, and to evaluate the associated environmental processes. Furthermore, an assessment concerning the future development of the habitats is provided. To describe the seafloor habitats in Potter Cove, an acoustic seabed discrimination system (RoxAnn) was used in combination with underwater video images and sediment samples. Due to the absence of wave and current measurements in the study area, bed shear stress estimates served to delineate zones prone to sediment erosion. On the basis of the investigations, two habitat classes were identified in Potter Cove, namely soft-sediment and stone habitats that, besides influences from sediment supply and coastal morphology, are controlled by sediment erosion. A future expansion of the stone habitat is predicted if recent environmental change trends continue. Possible implications for the Potter Cove environment, and other coastal ecosystems under similar pressure, include changes in biomass and species composition.

Description: A polyphasic analysis was carried out to clarify the taxonomic status of four marine actinomycete strains that share a phylogenetic relationship and phenotypic characteristics with the genus Salinispora. These strains formed a distinct lineage within the Salinispora 16S rRNA and gyrB trees and were found to possess a range of phenotypic properties and DNA:DNA hybridization values that distinguished them from the type strains of the two validly named species in this genus, Salinisporatropica (CNB-440T, ATCC BAA-916T) and Salinispora arenicola (CNH-643T, ATCC BAA-917T). The combined genotypic and phenotypic data support this conclusion. It is proposed that the strains be designated as Salinisporapacifica sp. nov., the type strain of which is CNR-114T (DSMZ YYYYT = KACC 17160T).

Description: Human disturbances, such as overfishing, may disrupt predator-prey interactions and modify food webs. Underwater surveys were carried out at six shallow-water reef barrens in temperate waters of northern-central Chile from October to December 2010 to describe the effects of predation, habitat complexity (low, medium and high) and refuge availability on the abundance and population structure of the rock shrimp Rhynchocinetes typus (Rhynchocinetidae), an important mesoconsumer on subtidal hard substrata. Three sites were within managed (restricted access) areas for fishermen, and three were unmanaged (open-access). Field observations and tethering experiments were conducted to examine the relationship between fish and shrimp abundances, and the relative predation rates on shrimps. Direct effects of predation on R. typus body-size distribution were examined from shrimps collected in the field and fish stomachs. The presence and the abundance of R. typus increased with habitat reef complexity and refuge availability. Shrimp abundance was negatively related to fish abundance in managed areas, but not in open-access areas, where shrimp densities were the highest. Also, predation rates and body-size distribution of shrimps were unrelated, although fish consumed more large shrimps than should be expected from their distribution in the field. R. typus occurred most often in shelters with wide openings, offering limited protection against predators, but providing potential aggregation sites for shrimps. Overall, direct effects of predation on shrimp densities and population structure were weak, but indirect effects on shrimp distribution within reefs appear to have been mediated through behavioural responses. Our study highlights the need to assess both numerical and behavioural responses of prey to determine the effects of predator loss on mesoconsumer populations.

Description: Whilst a range of animals have been shown to respond behaviourally to components of the Earth’s magnetic field, evidence of the value of this sensory perception for small animals advected by strong flows (wind/ocean currents) is equivocal. We added geomagnetic directional swimming behaviour for North Atlantic loggerhead turtle hatchlings (Carettacaretta) into a high-resolution (1/4°) global general circulation ocean model to simulate 2,925-year-long hatchling trajectories comprising 355,875 locations. A little directional swimming (1–3 h per day) had a major impact on trajectories; simulated hatchlings travelled further south into warmer water. As a result, thermal elevation of hatchling metabolic rates was estimated to be between 63.3 and 114.5% after 220 days. We show that even small animals in strong flows can benefit from geomagnetic orientation and thus the potential implications of directional swimming for other taxa may be broad.

Description: The effect of phototrophic biofilm activity on advective transport of cadmium (Cd), copper (Cu), nickel (Ni), and lead (Pb) in sandy sediments was examined using percolated columns. Cd and Ni in the effluent exhibited clear diel cycles in biofilm-containing columns, with concentrations at the end of dark periods exceeding those during illumination by up to 4.5- and 10-fold for Ni and Cd, respectively. Similar cycles were not observed for Pb or Cu. Breakthrough of the latter metals was greatly retarded and incomplete relative to Cd and Ni, and trends in biofilm treatments did not differ greatly from those in control columns. Inhibition of photosystem II by DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) proved that diel cycles of Cd and Ni were controlled by oxygenic photosynthesis, and microsensor measurements showed that metal cycles closely matched metabolic activity-driven pH variations. The sorption edge pH for the sand/biofilm substrate followed the order Ni 〉 Cd 〉 Cu 〉 Pb, and for Ni and Cd, was within the pH 7–10 range observed in the biofilm-containing column. Adsorption dynamics over the light periods matched pH increases, but desorption during dark periods was incomplete and slower than the rate of change of pH. Over a diel cycle, desorption was less than adsorption, resulting in net binding of dissolved metals due to the biofilm metabolic activity. Extraction with selective reagents indicated that the adsorbed metals were readily exchangeable, and potentially bioavailable. Thus, phototrophic benthic biofilms can control the transport of some metals across the sand–water interface, and processes in this very thin surficial layer should be considered when evaluating chemical fluxes in permeable sediments.

Description: Although long-distance transport of marine organisms is constrained by numerous oceanic and biological factors, some species have evolved life-histories reliant on such movements. We examine the factors that promote long-distance transport in a transoceanic migrant, young loggerhead sea turtles (Caretta caretta), from the southeastern U.S. Empirical data from near-surface buoys and simulations in two ocean circulation models indicated that passive drifters are often retained for long periods shoreward of oceanic fronts that delineate coastal and offshore waters. Further simulations revealed that offshore swimming aided newly hatched turtles in moving past fronts and increased turtles’ probability of survival, reaching distant foraging grounds, and encountering favorable temperatures. Swimming was most beneficial in regions that were more favorable under scenarios assuming passive drift. These results have broad implications for understanding the movement processes of many marine species, highlighting likely retention of more planktonic species and potential for dispersal in more nektonic species.

Description: The four rhopalia of cubomedusae are integrated parts of the central nervous system carrying their many eyes and thought to be the centres of visual information processing. Rhopalial pacemakers control locomotion through a complex neural signal transmitted to the ring nerve and the signal frequency is modulated by the visual input. Since electrical synapses have never been found in the cubozoan nervous system all signals are thought to be transmitted across chemical synapses, and so far information about the neurotransmitters involved are based on immunocytochemical or behavioural data. Here we present the first direct physiological evidence for the types of neurotransmitters involved in sensory information processing in the rhopalial nervous system. FMRFamide, serotonin and dopamine are shown to have inhibitory effect on the pacemaker frequency. There are some indications that the fast acting acetylcholine and glycine have an initial effect and then rapidly desensitise. Other tested neuroactive compounds (GABA, glutamate, and taurine) could not be shown to have a significant effect.

Description: Based on various lines of evidence such as the widespread occurrence of basalts, pumice, volcanic glass shards and their transformational products (zeolites, palagonites, and smectite-rich sediments), we suggest the presence of a volcanic province in the Central Indian Basin (CIB). In addition to the rocks studied, the occurrence of many morpho-tectonic features such as seamounts, abyssal hills and major fracture zones at 73 degrees E, 75 degrees 45'E and 79 degrees E, have helped in correlating and in deciphering the source of the rock types. Further, the large manganese nodule fields in the CIB are seen to occur in conjunction with the volcanic materials, since the latter forms nuclei and substrates for ferromanganese deposits. It is concluded that a spatial relation exists between the occurrence of the volcanic materials and the ferromanganese deposit in the CIB

Description: This study investigates the types of subaqueous deposits that occur when hot pyroclastic flows turbulently mix with water at the shoreline through field studies of the Znp marine tephra in Japan and flume experiments where hot tephra sample interacted with water. The Znp is a very thick, pumice-rich density current deposit that was sourced from subaerial pyroclastic flows entering the Japan Sea in the Pliocene. Notable characteristics are well-developed grain size and density grading (lithic-rich base, pumice-rich middle, and ash-rich top), preponderance of sedimentary lithic clasts picked up from the seafloor during transport, fine ash depletion in coarse facies, and presence of curviplanar pumice clasts. Flume experiments provide a framework for interpreting the origin and proximity to source of the Znp tephra. On contact of hot tephra sample with water, steam explosions produced a gas-supported pyroclastic density current that advanced over the water while a water-supported density current was produced on the tank floor from the base of a turbulent mixing zone. Experimental deposits comprise proximal lithic breccia, medial pumice breccia, and distal fine ash. Experiments undertaken with cold, water-saturated slurries of tephra sample and water did not produce proximal lithic breccias but a medial basal lithic breccia beneath an upper pumice breccia. Results suggest the characteristics and variations in Znp facies were strongly controlled by turbulent mixing and quenching, proximity to the shoreline, and depositional setting within the basin. Presence of abundant curviplanar pumice clasts in submarine breccias reflects brittle fracture and dismembering that can occur during fragmentation at the vent or during quenching. Subsequent transport in water-supported pumiceous density currents preserves the fragmental textures. Careful study is needed to distinguish the products of subaerial versus subaqueous eruptions.

Description: The diet of emperor penguins Aptenodytes forsteri was studied during late austral summer at Drescher Inlet, eastern Weddell Sea, Antarctica. Antarctic krill Euphausia superba was a major component of the food, accounting for 75% of all prey items. Emperor penguins appear to feed on krill during shallow dives under the fast sea ice. Fish, mainly nototheniids, accounted for less than 20% by number of all prey. An evaluation of the main prey types in terms of mass indicated, however, that fish represented up to 75% approximately of prey mass. Feeding experiments were performed on captive penguins and showed that squid beaks can accumulate for up to 3 weeks within the stomach without any clear signs of erosion. The lack of cephalopod soft parts in the samples makes it likely that all squid beaks were derived from animals captured some time previously. Squid seems to be a very minor dietary component of emperor penguins at the Drescher Inlet.

Description: Acoustic telemetry was used to examine patterns of activity and space utilisation of coelacanths, nocturnal predators which spend the day in submarine caves. Nine coelacanths (Latimeria chalumnae) were tracked, each for a period of 1 to 16 nights at Grande Comore, West Indian Ocean. Activities lasted on average 9 h, usually starting shortly after sunset and ending before sunrise. Vertically, coelacanths moved up and down at and below cave level by following the bottom contour, mainly between 180 and 400 m depth. The deepest record was 698 m, the shallowest 133 m. Most time was spent between 200 and 300 m depth. Large individuals performed deep excursions to depths below 400 m, usually once per night. The fish spent most time in water temperatures of 15 to 19 °C; they rarely ventured into waters warmer than 22 °C measured at depths shallower than 160 m depth. Horizontally, coelacanths stayed in narrow areas ranging from 〈1 to 10 km of coastline. Coelacanths are extremely slow drift-hunters with an estimated average swimming speed of 3.2 m min−1, often travelling not more than 3 km per night. They probably take advantage of local upwelling and downwelling and slow currents occurring parallel to the steep slopes. This study shows that coelacanths are inhabitants of the subphotic zone, where they are active mainly below the depth of their daytime refuges.

Description: A method for attaching acoustic transmitters externally to deep-water fishes in situ is described. Tags, each comprising a transmitter connected to a dart, were fired at fish from a pneumatic gun held by the manipulator arm of a submersible. The method was applied successfully for tagging coelacanths and may have application for use with other species of fishes living at depths to about 1000 m. The usefulness of direct observation for monitoring the effects of tags on fish is evaluated in relation to the effects of the tagging method on coelacanths.

Description: This article reports the results of a study of submarine groundwater discharge (SGD) to coastal waters of Majorca (NW Mediterranean). The overall aim is to evaluate the relevance of SGD of the island and chemically characterize the components that are supplied to the coastal waters through this pathway. Although other discharge areas are identified, we particularly focus on SGD in bays and areas of increased sea water residence time where effects of the discharges are expected to be most notable. Analysis at four selected embayments with different land-use characteristics indicated a link between human activities (mainly agriculture and urban) and compounds arriving to the coast. A pathway for these elements is the diffuse discharge along the shoreline, as suggested by the inverse relationship between salinity and nutrients in nearshore porewaters. A general survey was conducted at 46 sites around the island, and used dissolved radium as a qualitative indicator of SGD. Measurements of nutrients (P and N), pCO2 and TOC were performed to characterize the elements delivered to the coastal environment. Most nearshore samples showed 224Ra enrichment (mean ± SE, 7.0 ± 0.6 dpm 100 l−1) with respect to offshore waters (1.1 ± 0.2 dpm 100 l−1); however, 224Ra measurements along the coast were highly variable (1.0–38.1 dpm 100 l−1). Coastal samples with enhanced radium levels showed elevated pCO2 with respect to atmospheric concentrations, which together with high pCO2 in groundwater (〉5,000 ppm) indicates that SGD is an important vector of CO2 to coastal waters. Moreover, a relationship between 224Ra and phytoplankton biomass was established, suggesting an important impact of SGD on coastal productivity. The results presented here provide a first approximation of the SGD effect in the coastal waters of Majorca, and indicate that SGD could be an important source of nutrients and CO2 to the coast, strongly influencing the productivity and biogeochemical cycling of the coastal waters of Majorca.

Description: Escalation theory proposes enemy-related selection as the most relevant factor of natural selection among individual organisms. When hazardous to predators, prey might be considered enemies that influence predator evolution. Opisthobranch molluscs that prey on chemically defended prey are an interesting study case on this subject. Predation on chemically defended species paved the way for opisthobranchs to enter in an arms race, developing means to detoxify and/or excrete harmful compounds, which led to the sequestration of those compounds and their self-defensive use, an escalation of defenses. Here we aim to understand whether the opisthobranch predator is better protected than its chemically defended prey, using as predator–prey model, a nudibranch (Hypselodoriscantabrica) and the sponge it preys upon (Dysidea fragilis), and from which it obtains deterrent chemical compounds. Specimens of both species were collected on the Portuguese coast, and their crude extracts were analyzed and used in palatability tests. Nudibranchs revealed a higher natural concentration of crude extract, probably due to a progressive accumulation of the compounds. Both predator and prey extracts revealed similar mixtures of deterrent metabolites (furanosesquiterpenes). Palatability tests revealed a more effective deterrence in the nudibranch extracts because significant rejection rates were observed at lower concentrations than those necessary for the sponge extracts to have the same effect. We concluded that the predator is chemically better protected than its prey, which suggests that its acquisition of chemical defenses reveals a defensive escalation.

Description: The family Rhodobacteraceae can be considered a paradigm of modern taxonomy of prokaryotes. Taking into account the number of species and genera that conforms the family, together with the knowledge about their abundance and vast global distribution, it surprises that most of them have been described relatively recent to our days. Two notable exceptions are Rhodonostoc capsulatum (Molisch, Die purpurbakterien nach neuen untersuchungen, vols i–vii. G. Fischer, Jena, pp 1–95, 1907) and Micrococcus denitrificans Beijerinck and Minkman (Zentbl Bakteriol, Parasitenkd, Infektionskr Hyg. Abt II 25:30–63, 1910), early basonyms of Rhodobacter capsulatus and Paracoccus denitrificans, respectively. The fact that so many descriptions within this family are recent means that some studies have been concomitant and pose a challenge not only for pure taxonomic studies but also for interpreting other studies in which a rapidly evolving nomenclature had to be used anyway. The metabolic and ecological diversity of the group adds further complexity. In spite of all these difficulties, the picture is far from being a chaos and it can be considered an exciting and important bacterial group to study. Rhodobacteraceae are, fundamentally, aquatic bacteria that frequently thrive in marine environments. They comprise mainly aerobic photo- and chemoheterotrophs but also purple non-sulfur bacteria which perform photosynthesis in anaerobic environments. They are deeply involved in sulfur and carbon biogeochemical cycling and symbiosis with aquatic micro- and macroorganisms. One hundred genera are currently recognized as members of the family although the Stappia group, Ahrensia, Agaricicola, and Rhodothalassium do not belong, phylogenetically, to the family. The 90 other genera are distributed in 5 phylogenetic groups (the Rhodobacter, the Paracoccus, the Rhodovulum, the Amaricoccus, and the Roseobacter clades) that might be considered a family on its own.

Description: Digital terrain models (DTMs), finding a wide range of applications in the exploration of water areas, are mainly created on the basis of bathymetric data from a multibeam echosounder. The estimation of DTM accuracy dependent on the choice of the survey parameters is difficult due to the lack of reference surface. These authors have developed the methodology of simulation called virtual survey, which enables examining how various parameters of the echosounder, survey and DTM construction algorithms affect the errors of the created models. They are aimed at precise estimation of the model accuracy and the optimization of depth measurement work. The article includes the results of the examination of the effect of parameters determining the density of measurement points on the accuracy of the obtained GRID model. It has been proved that a significant reduction of recorded data density leads to only a slight increase in the modeling error, which makes the bathymetric survey much more cost-effective.

Description: During a sea survey session performed using a multibeam echosounder millions of measurement points are generated. Sea surveys should be carried out in such a way, that the maximum accuracy of created seabed models (DTM) is achieved and the standards specified by the IHO S-44 guidelines are met. One of the requirements is so called full sea floor search, which means the ability of a system to detect all the cubic features at least 1 m in size. Spatial distribution of measurement points is irregular and the distances between closest data points are varying, depending on many factors (on survey parameters, depth or distance between the beam and the vessel). Due to those reasons, it is difficult for the users of hydrographic systems to evaluate the degree of coverage of seabed by measurement points, and therefore to confirm fulfilment of the normative requirements. As a solution we propose visualisation methods for measurement data collected in sea surveys. Specific features of such a visualisation are explained and a method for creating the images is presented, along with some exemplary results.

Description: Carbonate precipitates on mounds and along tectonic scarps off the Costa Rica margin are manifestations of subduction-induced dewatering. The long-term dewatering history is recorded in mineralogical, petrological and isotope signals of carbonates recovered from these sites. The carbonates are strongly depleted in δ13C (−11 to −53‰ PDB) and enriched in δ18O (+4 to +8‰ PDB). Thermogenic methane and biogenic methane were identified as sources of the carbon. Chemoherm carbonates and seepage-associated carbonates formed in a focused flow regime have lighter δ13C values, while others formed in a more diffusive flow regime have slightly enriched C isotope values. Three fluid components were inferred based on the calculation of equilibrium δ18O: clay dehydration water, gas hydrate water and seawater. Calculated equilibrium δ18O values of carbonates from different down-core depths as well as from different precipitation stages show that the δ18O of the precipitating fluid is progressively depleted with time. Dolostones showing a methane-C source and a well constrained O-isotope signature are thought to have formed at depth in the sediment and subsequently became exhumed. Glauconitic sandstones cemented by methane-derived carbonate provide evidence that fluid and solid material have been expelled by the mud volcano.

Description: A detailed analysis of beak length to body size and mass measurements was carried out for the glacial squid Psychroteuthis glacialis, which is an endemic cephalopod species in the Southern Ocean. Beak lengths (lower rostral length) were measured from 211 specimens which had been sampled in the Atlantic sector of the Southern Ocean. The basic idea was to find some calibration model in order to inter- or extrapolate missing mantle length and/or wet body mass data by means of beak lengths. The relationships between beak length and mantle length/wet body mass bear essential information for future use in biomass estimates in Southern Ocean top predators, since beaks of P. glacialis occur frequently in the stomach contents of Antarctic seabirds, seals and toothed whales. Therefore, lower rostral lengths were plotted against both mantle length and wet body mass to determine the relationship between these variables. The relationships had limited scatter and very high coefficients of determination, showing that lower rostral length is a good predictor of the squid's mantle length and wet mass. A non-linear 3rd order polynomial regression of lower rostral length against mantle length was identified as the best fitted calibration model, explaining 93% (R 2) of the associated variance. The relationship between lower rostral length and wet body mass was empirically well fitted through regressing ln-transformed values of lower rostral length against wet body mass, explaining 95% (R 2) of the associated variance. The present investigation provides measurements for a wide size range of P. glacialis individuals compared to earlier studies, which were limited on very small data sets.

Description: Based on an empirical orthogonal function analysis of satellite altimeter data, guidance from numerical model results, and CANEK transport estimates, we propose an index, based on differences in satellite-measured sea surface height anomalies, for measuring the influence of Gulf of Mexico Loop Current intrusion on vertically integrated transport variability through the Yucatan Channel. We show that the new index is significantly correlated at low frequencies (cut-off 120 days) with the cable estimates of transport between Florida and the Bahamas. We argue that the physical basis for the correlation is the geometric connectivity between the Yucatan Channel and the Straits of Florida.

Description: Grateloupia turuturu Yamada is an economically valuable red alga with great potential in nutraceuticals and pharmaceuticals. Filaments of G. turuturu are of primary importance in germplasm preservation and sporeling culture, although filaments were not present in its life cycle. In this study, effects of temperature (10, 15, 20, 25, and 30 °C) and irradiance (10, 30, 60, and 90 μmol photons m−2 s−1) with photoperiod 10:14 h (light/dark) on filament development were investigated. Our results indicated that 25 °C was the optimal temperature for the formation of discoid crusts regardless of the irradiance. Conditions of 20 °C and 60 μmol photons m−2 s−1 promoted the development of discoid crusts and formation of upright thalli.

Description: Objective: Hypersensitivity pneumonitis due to dry sausage mould has been reported in workers who brush off the excess mould which coats dry sausage. Prevalence of symptoms and sensitization to mould among these pork-butchery workers is unknown. The aim of the study was to assess the clinical, radiographic, functional, and immunological features in exposed and non-exposed workers in semi-industrial pork butcheries. Patients and methods: Symptoms, and serum precipitins against mould extracts, were studied in workers in semi-industrial pork butcheries. Of 600 workers asked to participate, 123 (20.5%) were included. Fifty-nine workers, exposed to dry (raw) sausage mould and Penicillium nalgiovense were compared with 64 non-exposed subjects, for symptoms, chest X-rays, spirometry and CO-transfer measurements. Precipitating antibodies were detected by immunoelectrophoresis and electrosyneresis. Results: Sneezing, cough, dyspnoea, nasal obstruction, headache, and discomfort were significantly more frequent in the exposed group at work and after work than in the control group (P 〈 0.05). The prevalence of precipitating antibodies for sausage mould was higher in the exposed group (37%) than in the non-exposed group (9%) (P 〈 0.01). The mean number of precipitating lines measured by electrosyneresis was higher in exposed workers than in non-exposed workers for mould extract (1.09 vs 0.28, P 〈 0.05) and for Penicillium nalgiovense (1.77 vs 0.33, P 〈 0.05). No specific X-ray opacity or lung function impairment was found in either group. Conclusions: Clinical symptoms and sensitization to Penicillium nalgiovense are frequent among workers exposed to mould during brushing in dry sausage plants.

Description: The chemical composition (alkalinity, pH, NH4+, PO43-, Si, H2S, Cl-, Ca2+,and SO42-) of interstitial water was studied in the sediments of the Sea of Okhotsk at sites of methane emission. Variations in alkalinity were observed in the sediments from a typical seawater value (2.3 mM/kg) to 63 mM/kg. It is demonstrated that they are caused by the processes of sulfate reduction and methane generation. Based on the balance relationships, an equationwas constructed connecting changes in alkalinity with variations of Ca2+, SO42- and NH4+ in interstitial solutions.

Description: Stratigraphy is the fundament for the establishment and clarification of numerous questions in geology. The problem of the stratification of fossil sediments played a decisive role in the past, and continues to do so today. If one wishes to gain insight regarding the nature of the formation of today’s deposits, and avoid serious errors in the comparison of the same, one must, of necessity, first concern oneself with the sequence of recent sediment layers.

Description: Fluxes of phosphate across the sediment–water interface have been measured using inhibitors of bacterial activity sterilization and chloramphenicol and a control in order to quantify the influence of bacterial abundance on them. Results show that phosphate concentration in the interstitial water decreased when bacteria were present, in relation to treated aquaria. The measured (Jo) and theoretical fluxes (Jd) of phosphate also were higher when bacterial activity was suppressed. Mass balance calculated for Carbon, Nitrogen and Phosphorus in the sediment revealed a loss of theses compounds when bacterial activity was suppressed, and a net accumulation of Carbon and Phosphorus, and loss of Nitrogen under natural conditions.

Description: Bacterial light production involves enzymes-luciferase, fatty acid reductase, and flavin reductase-and substrates-reduced flavin mononucleotide and long-chain fatty aldehyde-that are specific to bioluminescence in bacteria. The bacterial genes coding for these enzymes, luxA and luxB for the subunits of luciferase; luxC, luxD, and luxE for the components of the fatty acid reductase; and luxG for flavin reductase, are found as an operon in light-emitting bacteria, with the gene order, luxCDABEG. Over 30 species of marine and terrestrial bacteria, which cluster phylogenetically in Aliivibrio, Photobacterium, and Vibrio (Vibrionaceae), Shewanella (Shewanellaceae), and Photorhabdus (Enterobacteriaceae), carry lux operon genes. The luminescence operons of some of these bacteria also contain genes involved in the synthesis of riboflavin, ribEBHA, and in some species, regulatory genes luxI and luxR are associated with the lux operon. In well-studied cases, lux genes are coordinately expressed in a population density-responsive, self-inducing manner called quorum sensing. The evolutionary origins and physiological function of bioluminescence in bacteria are not well understood but are thought to relate to utilization of oxygen as a substrate in the luminescence reaction.

Description: Fertilization depends on distribution and aggregation patterns of sea urchins which influence gamete contact time and may potentially enhance their vulnerability to ocean acidification. In this study, we conducted fertilization experiments to assess the effects of selected pH scenarios on fertilization success of Strongylocentrotus droebachiensis, from Spitsbergen, Arctic. Acidification was achieved by aerating seawater with different CO2 partial pressures to represent pre-industrial and present conditions (measured ~180–425 µatm) and future acidification scenarios (~550–800, ~1,300, ~2,000 µatm). Fertilization success was defined as the proportion of successful/unsuccessful fertilizations per treatment; eggs were classified according to features of their fertilization envelope (FE), hyaline layer (HL) and achievement of cellular division. The diagnostic findings of specific pathological aberrations were described in detail. We additionally measured intracellular pH changes in unfertilized eggs exposed for 1 h to selected acidification treatments using BCECF/AM. We conclude that (a) acidified conditions increase the proportion of eggs that failed fertilization, (b) acidification may increase the risk of polyspermy due to failures in the FE formation supported by the occasional observation of multiple sperms in the perivitelline space and (c) irregular formation of the embryo may arise due to impaired formation of the HL. The decrease in fertilization success could be also related to the observed changes in intracellular pH at pCO2 ~ 1,000 μatm or higher.

Description: Bioturbation of bottom sediments at the sediment–water interface is currently gaining more attention in studies dealing with the functioning of aquatic ecosystems. Such bioturbation can be caused by a variety of benthic macroinvertebrates or benthivorous fish that forage and burrow various bottom tubes, holes and pits. Thus, the processes involved may either be a result of direct interception by benthic animals, e.g., through bioresuspension of particles or through food ingestion and biodeposition, or of other indirect effects, e.g., changes in the physical properties of sediments or through the constructions mentioned above, along with corresponding changes in pond ecosystem functioning. The most distinct effect of benthivorous fish bioturbation activities is an increase in the turbidity of the water, which can lead to many subsequent knock-on effects, including inhibition of phytoplankton and submersed macrophyte growth with resulting alterations in physico-chemical water conditions. The importance of benthic macroinvertebrates and fish in bioturbation processes is also indicated by an increase in the numbers of resting cyanobacterial colonies recruited due to bioturbation of bottom sediments.

Description: The 5th International Workshop on Modeling the Ocean (IWMO http://www.uib.no/en/IWMO2013/-58927/iwmo-2013-bergen-norway) was held in June 17–20, in Bergen, Norway. The historic city of Bergen is the gateway to the fjords and a center for oceanic research. The workshop was hosted by the University of Bergen and also sponsored by the Research Council of Norway. Approximately 80 researchers worldwide participated in the workshop. Professor Mellor, Princeton University, gave the keynote lecture. The 5th IWMO meeting in Bergen was the first IWMO held in Europe, followed on the footsteps of previous meetings, IWMO-2009 in Taipei, Taiwan (Oey et al. 2010a, b), IWMO-2010 in Norfolk, USA (Ezer et al. 2011), IWMO-2011 in Qingdao, China (Oey et al. 2013a), and IWMO-2012 in Yokohama, Japan (Oey et al. 2013b). The participants presented approximately 60 oral talks and 20 posters, covering a wide range of ocean modeling and data analysis topics, as described below. In the spirit of promoting young s ...

Description: The Adula Nappe in the Central Alps is a mixture of various pre-Mesozoic continental basement rocks, metabasics, ultrabasics, and Mesozoic cover rocks, which were pervasively deformed during Alpine orogeny. Metabasics, ultrabasics, and locally garnet–mica schists preserve eclogite-facies assemblages while the bulk of the nappe lacks such evidence. We provide garnet major-element data, Lu profiles, and Lu–Hf garnet geochronology from eclogites sampled along a north–south traverse. A southward increasing Alpine overprint over pre-Alpine garnets is observed throughout the nappe. Garnets in a sample from the northern Adula Nappe display a single growth cycle and yield a Variscan age of 323.8 ± 6.9 Ma. In contrast, a sample from Alpe Arami in the southernmost part contains unzoned garnets that fully equilibrated to Alpine high-pressure (HP) metamorphic conditions with temperatures exceeding 800 °C. We suggest that the respective Eocene Lu–Hf age of 34.1 ± 2.8 Ma is affected by partial re-equilibration after the Alpine pressure peak. A third sample from the central part of the nappe contains separable Alpine and Variscan garnet populations. The Alpine population yields a maximum age of 38.8 ± 4.3 Ma in line with a previously published garnet maximum age from the central nappe of 37.1 ± 0.9 Ma. The Adula Nappe represents a coherent basement unit, which preserves a continuous Alpine high-pressure metamorphic gradient. It was subducted as a whole in a single, short-lived event in the upper Eocene. Controversial HP ages and conditions in the Adula Nappe may result from partly preserved Variscan assemblages in Alpine metamorphic rocks.

Description: Ecosystems and their biodiversity have to be protected and preserved as sources of services and goods. The human population controls and modifies ecosystems to improve its health conditions and welfare. The consequences of human activities should be carefully monitored and ecosystems should be managed to protect all of the species and preserve their functioning. The development of strategies for ecosystem management benefits from the use of computational techniques to model the dynamics of species that interact with their abiotic and biotic environment. Life scientists and computer scientists need to work together to define and analyse ecosystem models. However, there is a multifaceted gap between the approaches used in life science and those used in computer science. Such gap is both cultural and technical, and results in a number of challenges. In this paper we identify these challenges and provide technical and cultural proposals for solving them.

Description: Russian and German scientists have investigated the extreme environmental system in and around the Laptev Sea in the Siberian Arctic. For the first time a major comprehensive research program combining the efforts of several projects addressed both oceanic and terrestrial processes, and their consequences for marine and terrestrial biota, landscape evolution as well as land-ocean interactions. The primary scientific goal of the multidisciplinary program was to decipher past climate variations and their impact on contemporary environmental changes. Extensive studies of the atmosphere, sea ice, water column, and sea-floor on the Laptev Sea Shelf, as well as of the vegetation, soil development, carbon cycle, permafrost behaviour and lake hydrology, and sedimentationon Taymyr Peninsula and Severnaya Zemlya Archipelago were performed during the past years under a framework of joint research activities. They included land and marine expeditions during spring (melting), summer (ice free), and autumn (freezing) seasons. The close bilateral cooperation between many institutions in Russia and Germany succeeded in drawing a picture of important processes shaping the marine and terrestrial environment in northern Central Siberia in Late Quaternary time. The success of the projects, which ended in late 1997, resulted in the definition and establishment of a new major research effort which will concentrate on establishing a better understanding of the paleoclimatic and paleoenvironmental record of the area. This is important because it allows to be able to judge rates and extremes of potential future environmental changes.

Description: A multidisciplinary analysis of intraplate volcanic complexes interbedded with shallow and deeper marine sediments of a Late Miocene carbonate platform (Iblean Plateau, Sicily) has allowed a detailed paleo-environmental reconstruction. Our approach includes sedimentology, physical volcanology, stratigraphy, geochemistry/mineralogy, paleontology and 40Ar/39Ar dating. Four volcanic complexes are distinguished from each other. Two comprise an eastern shallow water platform (diatreme field and Carlentini complex) and two a western deeper water environment representing a seamount belt on the carbonate ramp (Valle Guffari seamount and Mineo complex). The late Miocene volcanism was not time-equivalent: episodic eruptions took place from the Late Tortonian (ca. 9.38 Ma at Mt. Carrubba) to Early Messinian (ca. 6.46 Ma at Valle Guffari). Explosive volcanism of the diatreme field may be related geodynamically to the period of periodic sea-level oscillations at the onset of the Messinian Salinity Crisis. Marine diatomites preserved in the crater areas of two diatremes are the only remnants of Early Messinian diatomites in the eastern Iblean Mountains.

Description: Meltponds on Arctic sea ice have previously been reported to be devoid of marine metazoans due to fresh-water conditions. The predominantly dark frequently also green and brownish meltponds observed in the Central Arctic in summer 2007 hinted to brackish conditions and considerable amounts of algae, possibly making the habitat suitable for marine metazoans. Environmental conditions in meltponds as well as sympagic meiofauna in new ice covering pond surfaces and in rotten ice on the bottom of ponds were studied, applying modified techniques from sea-ice and under-ice research. Due to the very porous structure of the rotten ice, the meltponds were usually brackish to saline, providing living conditions very similar to sub-ice water. The new ice cover on the surface had similar characteristics as the bottom layer of level ice. The ponds were thus accessible to and inhabitable by metazoans. The new ice cover and the rotten ice were inhabited by various sympagic meiofauna taxa, predominantly ciliates, rotifers, acoels, nematodes and foraminiferans. Also, sympagic amphipods were found on the bottom of meltponds. We suggest that, in consequence of global warming, brackish and saline meltponds are becoming more frequent in the Arctic, providing a new habitat to marine metazoans.

Description: Prey regurgitation during capture is a potential important confounding effect in fish dietary ecology studies as it may lead to overestimation of stomach vacuity and underestimation of prey consumption. This study investigates patterns of prey regurgitation and stomach vacuity among five grouper and three snapper species in shallow water off French Polynesia and tests the effectiveness of piercing swim-bladders after capture as a method to prevent regurgitation. Groupers exhibited a moderate overall regurgitation rate of 15.6% of full stomachs and a high true (i.e., after accounting for regurgitation) stomach vacuity rate of 40.5%. In contrast, snappers showed high regurgitation (mean 31.7%) and low true stomach vacuity (14.6%). Not accounting for regurgitation would have resulted in a moderate overestimation of stomach vacuity in groupers, but an almost 3-fold overestimation in snappers. Swim-bladder decompression by piercing after capture prove a highly effective method to reduce regurgitation (more than 2-fold for groupers and near 8-fold for snappers). This study enables a more general understanding of prey regurgitation in two commercially valuable fish families, thus improving understanding of the dietary ecology of these fishes. This information is particularly important in the context of prey consumption estimates and subsequent estimations of the impact of fish predators on ecosystems.

Description: The temporal variation in the stable carbon and nitrogen isotope ratios of particulate organic matter (POM) in the Rhone River was investigated on a monthly basis during a 2-year period (2004–2005). In spite of high month-to-month variation, interannually consistent seasonal trends appeared, with significantly lower δ13C (〈−28.2‰) in spring than in the other seasons. In contrast, δ15N did not exhibit significant temporal variation. In spring and summer, high chlorophyll a and b concentrations were associated with low C/N values (〈8) and a high percentage of organic carbon (%C) and organic nitrogen (%N), testifying to high development of autochthonous riverine phytoplankton (mainly diatoms and chlorophytes). In fall and winter, higher δ13C (〉−27.2‰) and C/N (〉8) values, and lower %C, %N, and chlorophylls concentrations indicated the predominance of allochthonous terrestrial detritus material in the river POM. The lower δ13C values recorded in spring–summer, when the phytoplankton biomass was high, were related to the lower carbon isotopic signatures of freshwater diatoms and chlorophytes compared to those of terrestrial plants. Overall, Rhone River POM was mainly composed of terrestrially derived material (90%), with autochthonous phytoplankton representing only 10% as a mean, in spite of a higher mean contribution of phytoplankton (27%) to river POM in summer.

Description: Nutritional imbalances between predator and prey are the rule rather than the exception at the lower end of food webs. We investigated the role of different grazers in the propagation of nutritionally imbalanced primary production by using the same primary producers in a three-trophic-level food chain and a four-trophic-level food chain experimental setup. The three-trophic-level food chain consisted of a classic single-cell primary producer (Rhodomonas salina), a metazoan grazer (the copepod Acartia tonsa) and a top predator (the jellyfish Gonionemus vertens), while we added a protozoan grazer (Oxyrrhis marina) as primary consumer to the food chain to establish the four-trophic-level food chain. This setup allowed us to investigate how nutrient-limitation effects change from one trophic level to another, and to investigate the performance of two components of our experimental food chains in different trophic positions. Stoichiometry and fatty acid profiles of the algae showed significant differences between the nutrient-depleted [no N and no P addition (−P), respectively] and the nutrient-replete (f/2) treatments. The differences in stoichiometry could be traced when O. marina was the first consumer. Copepods feeding on these flagellates were not affected by the nutritional imbalance of their prey in their stoichiometry, their respiration rates nor in their developmental rates. In contrast, when copepods were the primary consumer, those reared on the −P algae showed significantly higher respiration rates along with significantly lower developmental rates. In neither of our two experimental food chains did the signals from the base of the food chains travel up to jelly fish, our top predator.

Description: A one-dimensional model is used to analyze, at the local scale, the response of the equatorial Atlantic Ocean under different meteorological conditions. The study was performed at the location of three moored buoys of the Pilot Research Moored Array in the Tropical Atlantic located at 10° W, 0° N; 10° W, 6° S; and 10° W, 10° S. During the EGEE-3 (Etude de la circulation océanique et de sa variabilité dans le Golfe de Guinee) campaign of May-June 2006, each buoy was visited for maintenance during 2 days. On board the ship, high-resolution atmospheric parameters were collected, as were profiles of temperature, salinity, and current. These data are used here to initialize, force, and validate a one-dimensional model in order to study the diurnal oceanic mixed-layer variability. It is shown that the diurnal variability of the sea surface temperatures is mainly driven by the solar heat flux. The diurnal response of the near-surface temperatures to daytime heating and nighttime cooling has an amplitude of a few tenths of degree. The computed diurnal heat budget experiences a net warming tendency of 31 and 27 W m‑2 at 0° N and 10° S, respectively, and a cooling tendency of 122 W m‑2 at 6° S. Both observed and simulated mixed-layer depths experience a jump between the nighttime convection phase and the well-stabilized diurnal water column. Its amplitude changes dramatically depending on the meteorological conditions occurring at the stations and reaches its maximum amplitude (~50 m) at 10° S. At 6° and 10° S, the presence of barrier layers is observed, a feature that is clearer at 10° S. Simulated turbulent kinetic energy (TKE) dissipation rates, compared to independent microstructure measurements, show that the model tracks their diurnal evolution reasonably well. It is also shown that the shear and buoyancy productions and the vertical diffusion of TKE all contribute to the supply of TKE, but the buoyancy production is the main source of TKE during the period of the simulation.

Description: Background, aim, and scope Dissolved humic substances (HSs) are exogenous stressors to aquatic plants and animals which activate a variety of transcriptional and biochemical reactions or block photosynthesis. While there are consistent indications which structures may lead to reduced photosynthetic activity, there is much less clear information available on which HS structures or building blocks act as stressors in animals. Consequently, this work was designed to comparatively study the impact of natural organic matter (NOMs) from different sources on major anti-stress mechanisms in one single animal. We utilized major antioxidant responses and relative expression levels of stress proteins (small HSPs and HSP70) and expected that different HSs provoke different response patterns. Materials and methods We tested the freshwater amphipod Gammarus pulex which was collected from several shallow creeks in Northern Germany. All specimens were maintained in aerated 5-L tanks with filtered water from their natural environment at 10°C with prior acclimation. Animals were fed ad libitum with a commercial preparation once every second day. The exposure water was exchanged with the same frequency. NOMs were isolated from three different sources: two from small brown-water lakes in Northern Germany by reverse osmosis and the third one as an aqueous extract from a black layer of a Brazilian sandbar soil (State of Rio de Janeiro). The rationale was to apply NOMs of contrasting quality. Chemical fingerprint features of the NOMs were taken by high-performance size exclusion chromatography. As stress parameters in the animals, the activities of peroxidase and catalase were recorded quantitatively, and stress proteins, HSP70, as well as small α-crystalline HSPs were analyzed semiquantitatively. Results The three NOMs clearly differed in molecular masses, humic substance contents, the moieties of polysaccharides, and low-molecular-weight substances. With the exception of one short-term response, the peroxidase activity increased after 3 to 12 h exposure, whereas the catalase activity did not show any significant modulation. With one exception, the stress protein expression increased after 30 min exposure in a biphasic pattern, and the sHSPs responded less strongly than HSP70. Discussion Although the quality of the exposed NOMs differs significantly, a rather uniform response pattern appears in the animals. Obviously, the contrasting contents of HSs and polysaccharides did not affect the anti-stress response of the exposed gammarids which is in contrast to previous lifespan studies with Caenorhabditis elegans. Furthermore, all NOM sources led to increased contents of both HSP70 and sHSPs. To the best of our knowledge, this is the first protein study to show that also small HSPs are expressed when the animals are exposed against humic material. Conclusions Since the response patterns of the exposed gammarids, in contrast to the initial hypothesis, are rather uniform and since HSs are parts of life on Earth, we furthermore presume that they may have been a primordial exogenous trigger for the development of anti-stress systems in exposed organisms. Recommendations and perspectives Effect studies of chemical stresses on organisms should consider exposure to both natural triggers and xenobiotic compounds in low concentrations—in order to prospectively differentiate between these triggers and, subsequently, classify them.

Description: The tissue distribution and ontogeny of Na+/K+-ATPase has been examined as an indicator for ion-regulatory epithelia in whole animal sections of embryos and hatchlings of two cephalopod species: the squid Loligo vulgaris and the cuttlefish Sepia officinalis. This is the first report of the immunohistochemical localization of cephalopod Na+/K+-ATPase with the polyclonal antibody α (H-300) raised against the human α1-subunit of Na+/K+-ATPase. Na+/K+-ATPase immunoreactivity was observed in several tissues (gills, pancreatic appendages, nerves), exclusively located in baso-lateral membranes lining blood sinuses. Furthermore, large single cells in the gill of adult L. vulgaris specimens closely resembled Na+/K+-ATPase-rich cells described in fish. Immunohistochemical observations indicated that the amount and distribution of Na+/K+-ATPase in late cuttlefish embryos was similar to that found in juvenile and adult stages. The ion-regulatory epithelia (e.g., gills, excretory organs) of the squid embryos and paralarvae exhibited less differentiation than adults. Na+/K+-ATPase activities for whole animals were higher in hatchlings of S. officinalis (157.0 ± 32.4 µmol gFM−1 h−1) than in those of L. vulgaris (31.8 ± 3.3 µmol gFM−1 h−1). S. officinalis gills and pancreatic appendages achieved activities of 94.8 ± 18.5 and 421.8 ± 102.3 µmolATP gFM−1 h−1, respectively. High concentrations of Na+/K+-ATPase in late cephalopod embryos might be important in coping with the challenging abiotic conditions (low pH, high pCO2) that these organisms encounter inside their eggs. Our results also suggest a higher sensitivity of squid vs. cuttlefish embryos to environmental acid-base disturbances.

Description: The phytoplankton of the Bahía Blanca Estuary, Argentina, has been surveyed since 1978. Chlorophyll a, phytoplankton abundance, species composition and physico-chemical variables have been fortnightly recorded. From 1978 to 2002, a single winter–early spring diatom bloom has dominated the main pattern of phytoplankton interannual variability. Such pattern showed noticeable changes since 2006: the absence of the typical winter bloom and changes in phenology, together with the replacement of the dominant blooming species, i.e. Thalassiosira curviseriata, and the appearance of different blooming species, i.e. Cyclotella sp. and Thalassiosira minima. The new pattern showed relatively short-lived diatom blooms that spread throughout the year. In addition, shifts in the phytoplankton size structure toward small-sized diatoms, including the replacement of relatively large Thalassiosira spp. by small Cyclotella species and Chaetoceros species have been noticed. The changes in the phenology and composition of the phytoplankton are mainly attributed to warmer winters and the extremely dry weather conditions evidenced in recent years in the Bahía Blanca area. Changing climate has modified the hydrological features in the inner part of the estuary (i.e. higher temperatures and salinities) and potentially triggered the reorganization of the phytoplankton community. This long-term study provides evidence on species-specific and structural changes at the bottom of the pelagic food web likely related to the recent hydroclimatic conditions in a temperature estuary of the southwestern Atlantic.

Description: Somatic mutations are an underappreciated source of genetic variation within multi-cellular organisms. The resulting genetic mosaicism should be particularly abundant in large clones of vegetatively propagating angiosperms. Little is known on the abundance and ecological correlates of genetic mosaicism in field populations, despite its potential evolutionary significance. Because sexual reproduction restores genetic homogeneity, we predicted that in facultatively clonally reproducing organisms, the prevalence of genetic mosaicism increases with increasing clonality. This was tested among 33 coastal locations colonized by the ecologically important marine angiosperm Zostera marina, ranging from Portugal to Finland. Genetic mosaics were detectable as complex microsatellite genotypes at two hypervariable loci that revealed additional mosaic alleles, suggesting the presence of one or more divergent cell lineages within the same ramet. The proportions of non-mosaic genotypes in a population sharply decreased below a clonal richness of 0.2. Accordingly, more genetic mosaics were found at the southern and northern limit of the distribution of Z. marina in Europe where sexual reproduction is rare or absent. The genetic mosaics observed at neutral microsatellite markers suggest the possibility of within-clone variation at selectively relevant loci and supports the notion that members of clones are seldom genetically identical.

Description: A new species of the pelagic marine copepod family Oncaeidae, Oncaea serrulata, is described from the Mediterranean Sea. The species belongs to the notopus-group of Oncaeidae, which are characterized by a long, free exopod on leg 5. It differs from Oncaea notopus Giesbrecht 1891 and any other described species of this group by a combination of morphological characters, including: (1) the relative lengths of distal endopod spines on swimming legs 2 and 3, (2) the denticulate ornamentation of the exopod segment and the two exopodal setae on leg 5, (3) the proportional lengths of the caudal setae, and (4) the comparatively small body length. The species occurs widespread in the Mediterranean Sea in mesopelagic and deep-sea layers down to 3,000 m depth and was also found in near-bottom sediment traps moored at a bottom depth of 2,347 m in the Ligurian Sea. O. serrulata appears to be the only representative of the notopus-group in the Mediterranean Sea and seems to have consistently been confounded with the allegedly cosmopolitan O. notopus Giesbrecht in most earlier studies in this area. The taxonomic history of Giesbrecht’s O. notopus, which was originally described from the Pacific, is summarized and morphological identification parameters applicable for the species identification of notopus-type oncaeids are discussed. In the future, identification may be facilitated by using genetic barcodes in comparison with those recently analysed for the Mediterranean O. serrulata (as Oncaea sp. 7 sensu Böttger-Schnack 1997). Published data on the zoogeographical and vertical distribution as well as the abundance of notopus-type oncaeids in the Mediterranean Sea are reviewed. Possible causes for the lack of positive records of this taxon in Mediterranean studies earlier than 1980 are discussed.

Description: Regional erosion of the Rock Garden ridge top, a bathymetric high within New Zealand’s Hikurangi Subduction Margin, is likely associated with its gas hydrate system. Seismic data reveal gas pockets that appear partially trapped beneath the shallow base of gas hydrate stability. Steady-state fluid flow simulations, conducted on detailed two-dimensional geological models, reveal that anomalous fluid pressure can develop close to the sea floor in response to lower-permeability hydrate-bearing sediments and underlying gas pockets. Transient simulations indicate that large-scale cycling of fluid overpressure may occur on time scales of a few to tens of years. We predict intense regions of hydro-fracturing to preferentially develop beneath the ridge top rather than beneath the flanks, due to more pronounced overpressure generation and gas migration through hydrate-bearing sediments. Results suggest that sediment weakening and erosion of the ridge top by hydro-fracturing could be owed to fluid dynamics of the shallow gas hydrate system.

Description: Analogue experiments in part I led to the conclusion that pyroclastic flows depositing very highgrade ignimbrite move as dilute suspension currents. In the thermo–fluid–dynamical model developed, the degree of cooling of expanded turbulent pyroclastic flows dynamically evolves in response to entrainment of air and mass loss to sedimentation. Initial conditions of the currents are derived from column-collapse modeling for magmas with an initial H2O content of 1–3 wt.% erupting through circular vents and caldera ring-fissures. The flows spread either longitudinally or radially from source up to a runout distance that increases with higher mass flux but decreases with higher gas content, temperature, bottom slope and coarser initial grain size. Progressive dilution by entrainment and sedimentation causes pyroclastic currents to transform into buoyant ash plumes at the runout distance. The ash plumes reach stratospheric heights and distribute 30–80% of the erupted material as widespread co-ignimbrite ash. Pyroclastic suspension currents with initial mass fluxes of 107-1012 kg/s can spread for tens of kilometers with only limited cooling, although they move as supercritical, strongly entraining currents for the eruption conditions considered here. With increasing eruption mass flux, cooling during passage through the fountain diminishes while cooling during flow transport increases. The net effect is that eruption temperature exerts the prime control on emplacement temperature. Pyroclastic suspension currents can form welded ignimbrite across their entire extent if eruption temperature is To11.3.Tmw, the minimum welding temperature. High eruption rates, a large fraction of fine ash, and a ring-fissure vent favor the formation of extensive high-grade ignimbrite. For very hot eruptions produc ing sticky, partially molten pyroclasts, analysis of particle aggregation systematics shows that factors favoring longer runout also favor more efficient aggregation, which reduces runout. As a result, very high-grade ignimbrites cannot spread more than a few tens of kilometers from their source. In cooler pyroclastic currents, particles do not aggregate, and the sedimentation process may involve re-entrainment of particles, which potentially leads to more extensive cooling and longer runout; such effects, however, are only significant when net erosion of substrate occurs. Model results can be employed to estimate mass flux and duration of ignimbrite eruptions from measured ignimbrite masses and aspect ratios. The model also provides an alternative explanation of the observed decrease in H/Lratios with ignimbrite mass.

Description: Detailed geological and petrological-geochemical study of rocks of the lava complex of Young Shiveluch volcano made it possible to evaluate the lava volumes, the relative sequence in which the volcanic edifice was formed, and the minimum age of the onset of eruptive activity. The lavas of Young Shiveluch are predominantly magnesian andesites and basaltic andesites of a mildly potassic calc-alkaline series (SiO2 = 55.0–63.5 wt %, Mg# = 55.5–68.9). Geologic relations and data on the mineralogy and geochemistry of rocks composing the lava complex led us to conclude that the magnesian andesites of Young Shiveluch volcano are of hybrid genesis and are a mixture of silicic derivatives and a highly magnesian magma that was periodically replenished in the shallow-depth magmatic chamber. The fractional crystallization of plagioclase and hornblende at the incomplete segregation of plagioclase crystals from the fractionating magmas resulted in adakitic geochemical parameters (Sr/Y = 50–71, Y 〈 18 ppm) of the most evolved rock varieties. Our results explain the genesis of the rock series of Young Shiveluch volcano without invoking a model of the melting of the subducting Pacific slab at its edge.

Description: The bacterial diversity of sea ice from Kiel Bight obtained during the rare event of solid ice cover in spring 1996 was analysed by molecular genetic approaches using an improved double gradient denaturing gradient gel electrophoretic method (DG-DGGE) to separate 16S rDNA fragments of approximately 500 bp. The excellent separation of individual bands within these gradient gels allowed us to obtain sequence information and to allocate the phylogenetic position of representative bacteria from the sea ice. The band pattern of the gradient gels revealed a vertical stratification of the bacterial species distribution within the ice and the presence of characteristic bacteria for each layer. According to their 16S rDNA sequences, major bands of the gradient gels represented bacteria closely related to fermenting species of the genera Propionibacterium and Bacteroides and to anoxygenic phototrophic purple sulfur bacteria (Chromatiaceae). Their abundance in horizons of the inner ice core may indicate the existence of oxygen-deficient and anoxic zones or niches and possible primary production by anoxygenic photosynthesis within the investigated Baltic Sea sea ice. This is the first phylogenetic evidence of the presence, and most probably the development, of phototrophic purple sulfur bacteria in sea ice.

Description: The geologic evidence for worldwide uplift of mountain ranges in the Neogene is ambiguous. Estimates of paleoelevation vary, according to whether they are based on the characteristics of fossil floras, on the masses and grain sizes of eroded sediments, or on calculations of increased thickness of the lithosphere as a result of faulting. Detrital erosion rates can be increased both by increased relief in the drainage basin and by a change to more seasonal rainfall patterns. The geologic record provides no clear answer to the question whether uplift caused the climatic deterioration of the Neogene or whether the changing climate affected the erosion system in such a way as to create an illusion of uplift. We suggest that the spread of C4 plants in the Late Miocene may have altered both the erosion and climate systems. These changes are responsible for the apparent contradictions between data supporting uplift and those supporting high elevations in the past.

Description: The response of rocky shore ecosystems to increased nutrient availability was examined in eight land-based mesocosms designed for hard-bottom littoral communities built at Marine Research Station Solbergstrand (Norway). The average seawater volume in each basin was 9 m3 with an average water residence time of about 2 h. A tidal regime resembling that in the fjord was maintained in the basins, and waves were generated regularly. NH4NO3 and H3PO4, at a constant molar NP ratio of 16:1, was added into 6 basins at concentrations 1, 2, 4, 8, 16, 32 μM DIN above the background DIN concentration during 1 1/2 years. Two mesocosms were kept as control treatment. Marine communities were introduced into the basins two years prior to the start of nutrient dosage. The effects of nutrient enrichment were few and only marginal during the first year of nutrient addition, while some effects became more obvious during the second year. The growth rate of the periphyton and fast-growing macroalgae communities was stimulated by nutrient enrichment, while the response was less evident among the perennial fucoids. The structure of the macroalgal communities, however, did not change during 16 months' measurements. In contrast, growth on artificial rock substrates during the same period of time revealed intensive growth of the fast-growing Ulva lactuca in high-dosed basins compared with low-dosed and control basins, which were dominated by the fucoid Fucus serratus. The fauna communities exhibited only a minor response to nutrient treatment. The common periwinkle Littorina littorea, however, appeared with increased abundance in the high-dosed basins. The total system metabolism tended to increase slightly, but not significantly, with increased nutrient loading.

Description: A total of 386 Macrourus whitsoni from Antarctic waters were examined for ecto- and endoparasites. Sixty-five M. whitsoni collected near Halley Bay (Weddell Sea) and 321 specimens from the continental slope off King George Island (South Shetland Islands) were studied for sphyriid copepods directly after being caught. A subsample of 25 specimens from the Weddell Sea and of 9 specimens from King George Island were studied for the presence of other metazoan parasites. Twenty-two species were found, including one myxozoan, six digeneans, one monogenean, three cestodes, seven nematodes, one acanthocephalan and three crustacean species/taxa. While Auerbachia monstrosa and Capillaria sp. are reported for the first time from around the Antarctic, the other parasites have been recorded earlier in the Southern Ocean. Many parasite species found have a wide zoogeographical range and a low host-specificity. The parasite fauna of M. whitsoni revealed several similarities with its congeners M. carinatus and M. holotrachys from Antarctic and sub-Antarctic waters. This can be explained by a wide host range of many macrourid deep-sea parasites, together with an overlap in distribution patterns of their hosts. Other supporting factors are host migration and a close phylogenetic relationship between the hosts, which enable the parasites to infest all three macrourids. Eight new host and 14 new locality records are established.

Description: Based on the re-interpretation of published data, the von Bertalanffy growth function parameters of the coelacanth, Latimeria chalumnae, are estimated as L∞=218 cm total length, s.e. 23; K=0.059 (year−1), s.e. 0.012; t0=−3.3 (year), s.e. 0.5, corresponding to a life span of 48 years. The length–weight relationship of the form W=a*TL∧b, with wet weight (W) in g and total length (TL) in cm, is estimated as a=0.0278, b=2.89, r2=0.893, n=87, range=42.5–183 cm TL. Using extreme value theory, the maximum length for female coelacanths is estimated as 199 cm TL (95% confidence interval=175–223 cm TL) and for males as 168 cm TL (95% confidence interval 155–180 cm TL). Based on data from seven females with embryos or mature eggs, the length-at-first-maturity for females is estimated to be about 150 cm TL, corresponding to an age of about 16 years. Based on the value of t0=−3.3 years and on the presence of three scale rings found in a newborn coelacanth, the period of embryogenesis lasts for about three years, the longest known in vertebrates. The natural mortality rate is estimated at M=0.12. Population food consumption is found to be 1.4 times the existing biomass per year, and gross food conversion efficiency indicates that only 10% of the consumed food is utilized for somatic growth.

Description: We examined the thermoregulatory behaviour (TRB) of roosting Humboldt penguins (Spheniscus humboldti) in north central Chile during summer and winter, when ambient temperatures (Ta) are most extreme. Each body posture was considered to represent a particular TRB, which was ranked in a sequence that reflected different degrees of thermal load and was assigned an arbitrary thermoregulatory score. During summer, birds exhibited eight different TRBs, mainly oriented to heat dissipation, and experienced a wide range of Ta (from 14 to 31°C), occasionally above their thermoneutral zone (TNZ, from 2 to 30°C), this being evident by observations of extreme thermoregulatory responses such as panting. In winter, birds exhibited only three TRBs, mainly oriented to heat retention, and experienced a smaller range of Ta (from 11 to 18°C), always within the TNZ, even at night. The components of behavioural responses increased directly with the heat load which explains the broader behavioural repertoire observed in summer. Since penguins are primarily adapted in morphology and physiology to cope with low water temperatures, our results suggest that behavioural thermoregulation may be important in the maintenance of the thermal balance in Humboldt penguins while on land.

Description: The production of defence metabolites is assumed to be costly in metabolic terms. If this holds true, low-light stress should reduce the ability of seaweeds to defend themselves chemically against herbivory and fouling. We investigated the effect of energy limitation on the defensive status of seaweeds by assessing their attractiveness to mesograzers and their activity against a bivalve macrofouler in comparison with non-stressed conspecifics. The macroalgae Codium decorticatum (Woodw.) M. Howe, Osmundaria obtusiloba (C. Agardh) R. E. Norris, Pterocladiella capillacea (S. G. Gmel.) Santel. and Hommer., Sargassum vulgare C. Agardh and Stypopodium zonale (Lamour.) Papenf. collected at the southeastern Brazilian coast were exposed to six levels of irradiation (between 1 and 180 μmol photons m−2 s−1) for 10–14 days. After this period, algae from all treatment levels were: (a) processed as artificial food and offered to an amphipod community dominated by Elasmopus brasiliensis Dana and (b) extracted to test for differences in settlement rates of the fouling mussel Perna perna L. on filter paper loaded with the crude extracts. Generally, photosynthesis rates and growth were reduced under low light conditions. Attractiveness to herbivores and macrofoulers, however, was insensitive to energy limitation. We discuss possible explanations for the observed absence of a relationship between light availability and algal defence including the change in nutritional value of the algal tissue, the allocation of resources towards defence instead of growth and the absence of costs for defence.

Description: We quantified the nitrogen and enzyme hydrolyzable amino acid (EHAA) concentrations of sediments prior to and after corals sloughed, ingested, and egested sediments layered onto their surfaces, for the three coral species Siderastrea siderea, Agaricia agaricites, and Porites astreoides in Jamaica. The percent nitrogen of the sediments egested by all three species was lower than in the sediments available to the corals. Additionally, the sediments sloughed (not ingested) by A. agaricites and P. astreoides were lower in percent nitrogen, while the sediments sloughed by S. siderea had the same percent nitrogen as that of the available sediments. The percent nitrogen of the sediments sloughed and egested by P. astreoides showed significant negative and positive relationships, respectively, to increasing sediment loads, while the percent nitrogen of the sediments sloughed and egested by both S. siderea and A. agaricites showed no relationship to sediment load. EHAA concentrations were not significantly different between the sloughed and available sediments but were significantly lower in the sediments egested by S. siderea and A. agaricites (EHAA concentrations were not measured for P. astreodies sediment fractions). Comparisons of the nitrogen and EHAA concentrations in the sloughed and egested sediments to what was available prior to coral processing show that maximum ingestion was between 0.1 and 0.2 µg N µg−1 coral N cm−2 and between 0.5 and 0.6 µg EHAA·cm−2. Maximum assimilation efficiencies were estimated to be 30–60% of the available nitrogen. The data show that corals ingest and alter the nitrogen concentration of particles that land on their surfaces. The corals’ abilities to process these sediments, and the sediments’ possible contributions to coral nutrition, are discussed based on these results.

Description: A new mandibular sensor is presented here based on the use of a Hall sensor, attached to one mandible, opposite a magnet, attached to the other mandible. Changes in sensor voltage, proportional to magnetic field strength, and thus inter-mandibular angle, are recorded in a logger. This system was tested on seven captive Adélie penguins (Pygoscelis adeliae) and three gentoo penguins (Pygoscelis papua) during: (1) feeding trials on land, where birds were given known quantities and types of food; and (2) trials in water where birds were allowed to swim and dive freely. In addition, six free-living Magellanic penguins (Spheniscus magellanicus) were equipped with the system for single foraging trips. Angular signatures were looked for in instances when both captive and free-living birds might open their beaks, and it was discovered that five major behaviours could be identified: ingestion, breathing, calling, head shaking and preening. Captive feeding trials showed that prey mass could be determined with reasonable accuracy (r 2=0.92), and there was some indication that prey type could be resolved if recording frequency were high enough. Vocalisations in Adélie penguins (arc calls) took 〈0.7 s for mean maximum beak angles of 4.2° (SD 1.3), and were distinguished by their relatively gradual change in beak angle and by their high degree of symmetry. Beak shakings were distinguishable by their short duration (multiple peaks of 〈0.5 s) and minimal maximum angle (〈0.5°). Preening behaviour was apparent due to multiple decreasing peaks (angles 〈8°). Breathing could be subdivided into that during porpoising, where a characteristic double peak in beak angle was recorded, and that during normal surface rests between dives. During porpoising, only the primary peak (mean maximum beak angle 25.1°, SD 4.7) occurred when the bird was out of the water (mean maximum for second peak 5.9°, SD 4.1). During normal surface rests in free-living birds, breaths could be distinguished as a series of beak openings and closures, showing variation in amplitude and frequency according to an apparent recovery from the previous dive and preparation for the subsequent dive to come. The mandibular measuring system presented shows considerable promise for elucidating many hitherto intractable aspects of the behaviour of free-living animals.

Description: Ferromanganese crusts from the Atlantic, Indian and Pacific Oceans record the Nd and Pb isotope compositions of the water masses from which they form as hydrogenous precipitates. The10Be/9Be-calibrated time series for crusts are compared to estimates based on Co-contents, from which the equatorial Pacific crusts studied are inferred to have recorded ca. 60 Ma of Pacific deep water history. Time series of ɛNd show that the oceans have maintained a strong provinciality in Nd isotopic composition, determined by terrigenous inputs, over periods of up to 60 Ma. Superimposed on the distinct basin-specific signatures are variations in Nd and Pb isotope time series which have been particularly marked over the last 5 Ma. It is shown that changes in erosional inputs, particularly associated with Himalayan uplift and the northern hemisphere glaciation have influenced Indian and Atlantic Ocean deep water isotopic compositions respectively. There is no evidence so far for an imprint of the final closure of the Panama Isthmus on the Pb and Nd isotopic composition in either Atlantic or Pacific deep water masses.

Description: The REE-Ti silicate chevkinite has been recognised previously in Miocene ignimbrites from Gran Canaria, and in correlative offshore syn-ignimbrite turbidites. We have estimated the partition coefficients of REE, Y, Zr and Nb for chevkinite and co-existing peralkaline rhyolitic (comendite) glass using synchrotron-XRF-probe analyses (SYXRF) in order to evaluate the role of this mineral in the REE budget of felsic peralkaline magmas. The Zr/Nb ratio of the chevkinite is 1.55–1.7, strongly contrasting with Zr/Nb of 6.5 in the associated glass. Zr shows a three-fold enrichment in chevkinite relative to the residual melt, whereas Nb is enriched by a factor 〉10. The enrichment of Ce and La in chevkinite is even more significant, namely 19 wt(%) Ce and 12 wt(%) La, compared to 236 ppm Ce and 119 ppm La in the glass. Chevkinite/glass ratios are 988±30 for La, 806±30 for Ce, 626±30 for Pr, 615±40 for Nd, 392±50 for Sm, 225±30 for Eu, 142±25 for Gd, 72±20 for Dy. For trace elements, we derived KdTE of 74±25 for Y, 〉8 for Hf, 〉50 for Th, 15±5 for Nb and 3.55±0.4 for Zr. Mineral/glass ratios for co-existing titanite are 28±10 for La, 86±20 for Ce, 98±30 for Pr, 134±35 for Nd, 240±50 for Sm, 50±20 for Eu, 96±25 for Gd, 82±25 for Dy, 99±30 for Y, 45±10 for Nb and 3±0.5 for Zr. Based on these data, the removal of only 0.05 wt% of chevkinite from a magma with initially 300 ppm Ce would deplete the melt by 93 ppm to yield 207 ppm Ce in the residual liquid. Chevkinite thus appears, when present, to be the controlling mineral within the LREE budget of evolved peralkaline magmas.

Description: Long-term dynamics (1960–1997) of the cladoceran species Bosmina coregoni maritima, Evadne nordmanni and Podon spp. are described for the Gdansk Deep and the Gotland Basin (Central Baltic Sea). By using correlation analyses on seasonal time-series, the influence of temperature and salinity on the abundance of cladoceran species was investigated. A clear affinity to higher temperature was found for B. coregoni maritima in summer as well as for E. nordmanni and Podon spp. in spring. In addition to temperature, association tests with salinity revealed besides species-specific preferences, regional and temporal differences. Contrary to B. coregoni maritima, both other species were positively associated to salinity in summer and autumn in the Gdansk Deep. In the Gotland Basin only E. nordmanni was positively correlated to salinity in autumn. Differences in the response to hydrographic variables are possibly stage specific, i.e. between resting eggs and adults, or due to a different adaptation to the abiotic environment.

Description: Pore water profiles from 24 stations in the South Atlantic (located in the Guinea, Angola, Cape, Guyana, and Argentine basins) show good correlations of oxygen and silicon, suggesting microbially mediated dissolution of biogenic silica. We used simple analytical transport and reaction models to show the tight coupling of the reconstructed process kinetics of aerobic respiration and silicon regeneration. A generic transport and reaction model successfully reproduced the majority of Si pore water profiles from aerobic respiration rates, confirming that the dissolution of biogenic silica (BSi) occurs proportionally to O2 consumption. Possibly limited to well-oxygenated sediments poor in BSi, benthic Si fluxes can be inferred from O2 uptake with satisfactory accuracy. Compared to aerobic respiration kinetics, the solubility of BSi emerged as a less influential parameter for silicon regeneration. Understanding the role of bacteria for silicon regeneration requires further investigations, some of which are outlined. The proposed aerobic respiration control of benthic silicon cycling is suitable for benthic–pelagic models. The empirical relation of BSi dissolution to aerobic respiration can be used for regionalization assessments and estimates of the silicon budget to in crease the understanding of global primary and export production patterns.

Description: The pelagic marine copepod family Oncaeidae is highly diversified (over 100 species worldwide) and includes a great number of sibling species, which are difficult to identify morphologically, because of their very small size (0.18–1.2 mm total length as adults). Global investigations of oncaeid biodiversity are severely hampered by insufficient taxonomic knowledge, in particular for species which have first been described from the European Mediterranean Sea (type locality). Many of these species have been reported as key taxa of small-sized copepod communities in very distant oceanic regions. However, due to the taxonomic uncertainties it cannot be excluded that at least some of these allegedly cosmopolitan species in reality represent a complex of distinct, yet closely related, species. To improve the basis for the identification of Oncaeidae of Mediterranean origin, new diagnostic characters in combination with traditional methods were applied in the present study. Copepods were sampled with fine nets of 0.1 mm mesh size down to a maximum depth of 1,000 m on a west-east-transect in the Mediterranean Sea. Oncaeid species and form variants were predefined morphologically and the genetic identity of the morphospecies was analysed by about 650 and 500 bp region of the mitochondrial COI and 12S srRNA gene sequence, respectively (barcoding). A total of 67 individuals from 24 oncaeid species and forms were successfully analysed, including 12 species and one form of Mediterranean origin. For Oncaeidae, the 12S amplification turned out to be more successful (23 species) than the COI amplification (13 species and 1 form). Together, the morphological and molecular results are discussed with respect to three topics: (1) confirmation of a genetic distinction of three Triconia species, which have been interpreted as sibling species by morphological characters, (2) genetic distance of species within the ovalis-complex of oncaeids and (3) the taxonomic status of two form variants of Oncaea mediterranea (Claus).

Description: Previous studies in Silurian carbonates from Gotland (Sweden) have led to a model for the development of limestone–marl alternations. This model postulates that early diagenesis of precursor sediments without strong primary differences can result in a differentiation by selective dissolution of aragonite in marl beds and reprecipitation of calcite cement in limestone beds. This model is described as a set of mathematical equations that quantify the diagenetic processes (aragonite dissolution and calcite reprecipitation) that occur during the formation of limestone–marl interbeds from a hypothetical homogeneous precursor sediment. The calculations demonstrate that resulting hypothetical limestone–marl alternations show characteristic mathematical relationships between the ratios of the bed thicknesses of limestones and marls on one side, and the carbonate contents, on the other. By reversing this model, the original mineralogical composition of the precursor sediment of real-world rhythmic successions can be determined. In this study, alternations from the Silurian of Gotland, the Cambrian, Devonian, and Mississippian of North America, the Jurassic of France and Germany, and the Cretaceous of France are shown to exhibit mathematical relationships similar to those calculated for hypothetical precursor sediments without primary differences. Therefore, the mineralogical composition of their precursor sediments can be estimated. In contrast, the clear mismatch shown by the Lower Jurassic Belemnite Marls from Dorset indicates that these rhythms did not suffer an early diagenetic overprint. Our model helps to differentiate between rhythmites with strong depositional variations and those without; however, it cannot indicate whether a given alternation is the product of rhythmic diagenesis of a homogeneous precursor sediment or the result of diagenetic enhancement of subtle underlying sedimentary rhythms. For horizontally correlated patterns, such as laterally extensive beds and layers of nodules, an a priori unknown external signal has to be assumed.

Description: Hydrothermal activity in the Central Bransfield Basin revealed an active low-temperature vent field on top of a submarine volcanic structure. A temperature anomaly was detected and the sea floor showed various patches of white silica (opal-A) precipitate exposures and some yellow–brown Fe-oxyhydroxide crusts. Enriched dissolved methane concentrations were encountered. Sediment was near 24°C just after the grab came on deck. No dense population of chemosynthetically based macrofauna known from other hydrothermal venting areas was present, except for pogonophora. The observations suggest that the sedimented hydrothermal field at Hook Ridge is a low-temperature end-member branch from a deeper hydrothermal source.

Description: Savo Island is the 6-km-diameter emergent summit of an andesitic-dacitic stratovolcano, rising from the Iron Bottom Sound, 35 km NW of Honiara, Solomon Islands. Savo has erupted at least three times within recorded history and the 3,000 inhabitants maintain extensive oral traditions of past events. Through description and interpretation of the volcaniclastic sequences on the island, in conjunction with historical accounts and oral traditions, we reconstruct the eruptive processes on Savo. Block-and-ash flow (BAF) deposits are volumetrically dominant on the island within three main depositional environments: near-vent sequences, thick medial channel sequences and distal fan sequences. The deposits comprise universally non-vesicular and highly porphyritic (40–70% phenocrysts), high-silica andesite and dacite clasts. These appear to have been derived from collapsing lava domes during an 1560–1570 a.d. eruption. However, eyewitness descriptions and crater morphology suggest that similar deposits formed from dome explosions or collapses of eruption columns during later eruptions (1830–1840a.d.).Thehigh-sodiummagmas(ca.5–7wt% Na2O) apparently crystallised and strongly degassed prior to eruption. Shallow explosions were possibly caused by entrapment of magmatic gases beneath a dome or conduit plug of highly crystalline, near solid magma. Repeated sealing of the vent may have been due to inward collapse of the highly altered rocks of the surrounding hydrothermal system; these rocks probably were saturated due to contemporaneous high intensity rainfall events. BAFs were hot enough to char vegetation and attain aligned clast TRM (thermal remnant magnetism) up to 3 km from the vent, many being accompanied by ash-cloud surges. Changes with distance in the BAF deposits appear mostly dependent on flow confinement and are limited to an overall decrease in thickness and maximum clast size, and an increased definition of weak planar fabrics. In distal fan sequences, there is strong evidence for syn- and posteruptive redeposition of primary deposits. Since the Savo population is concentrated on coastal volcaniclastic fans, we consider the greatest volcanic risk to life is from BAFs, associated ash-cloud surges and lahars. Hence, the main channels and fans are designated as the highest of three relative hazard zones on a simple map prepared to aid local education and planning initiatives on Savo.

Description: We analyzed bare human footprints in Holocene tuff preserved in two pits in the Acahualinca barrio in the northern outskirts of Managua (Nicaragua). Lithology, volcanology, and age of the deposits are discussed in a companion paper (Schmincke et al. Bull Volcanol doi: 10.1007/s00445-008-0235-9, 2008). The footprint layer occurs within a series of rapidly accumulated basaltic–andesitic tephra that is regionally correlated to the Masaya Triple Layer Tephra. The people were probably trying to escape from a powerful volcanic eruption at Masaya Caldera 20 km farther south that occurred at 2.1 ka BP. We subdivided the swath of footprints, up to 5.6 m wide, in the northern pit (Pit I) into (1) a central group of footprints made by about six individuals, the total number being difficult to determine because people walked in each other’s footsteps one behind the other and (2) two marginal groups on either side of the central group with more widely spaced tracks. The western band comprises tracks of three adjacent individuals and an isolated single footprint farther out. The eastern marginal area comprises an inner band of deep footprints made by three individuals and, farther out, three clearly separated individuals. We estimate the total number of people as 15–16. In the southern narrow and smaller pit (Pit II), we recognize tracks of ca. 12 individuals, no doubt made by the same group. The group represented in both pits probably comprised male and female adults, teenagers and children based on differences in length of footprints and of strides and depth of footprints made in the soft wet ash. The smallest footprints (probably made by children) occur in the central group, where protection was most effective. The footprint layer is composed of a lower 5–15-cm thick, coarse-grained vesicle tuff capped by a medium to fine-grained tuff up to 3 cm thick. The surface on which the people walked was muddy, and the soft ash was squeezed up on the sides of the foot imprints and between toes. Especially, deep footprints are mainly due to local thickening of the water-rich ash, multiple track use, and differences in weight of individuals. The excellent preservation of the footprints, ubiquitous mudcracks, sharp and well-preserved squeeze-ups along the margins of the tracks and toe imprints, and the absence of raindrop impressions all suggest that the eruption occurred during the dry season. The people walked at a brisk pace, as judged from the tight orientation of the swath and the length of the strides. The directions of a major erosional channel in the overlying deposits that probably debouched into Lake Managua and the band of footprints are strictly parallel, indicating that people walked together in stride along the eastern margin of a channel straight toward the lake shore, possibly a site with huts and/or boats for protection and/or escape.