ALBERT

Description:    Climatic changes in Arctic regions are likely to have significant impacts on vegetation composition and physiological responses of different plant types, with implications for the regional carbon (C) cycle. Here, we explore differences in allocation and turnover of assimilated C in two Subarctic tundra communities. We used an in situ 13 C pulse at mid-summer in Swedish Lapland to investigate C allocation and turnover in four contrasting tundra plant communities. We found a high rate of turnover of assimilated C in leaf tissues of Betula nana and graminoid vegetation at the height of the growing season, with a mean residence time of pulse-derived 13 C of 1.1 and 0.7 days, respectively. One week after the pulse, c. 20 and 15%, respectively, of assimilated label-C remained in leaf biomass, representing most likely allocation to structural biomass. For the perennial leaf tissue of the graminoid communities, a remainder of approximately 5% of the pulse-derived C was still traceable after 1 year, whereas none was detectable in Betula foliage. The results indicate a relatively fast C turnover and small belowground allocation during the active growing season of recent assimilates in graminoid communities, with comparatively slower turnover and greater investment in belowground allocation by B. nana vegetation. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00300-012-1167-6 Authors Jens-Arne Subke, School of Natural Sciences, Biological and Environmental Sciences, University of Stirling, Stirling, FK9 4LA UK Andreas Heinemeyer, Environment Department, Stockholm Environment Institute, University of York, York, YO10 5DD UK Harry W. Vallack, Environment Department, Stockholm Environment Institute, University of York, York, YO10 5DD UK Vincenzo Leronni, Department of Agro-Environmental and Territorial Sciences, University of Bari, Via Giovanni Amendola 165/A, 70126 Bari, Italy Robert Baxter, School of Biological and Biomedical Sciences, University of Durham, Durham, DH1 3LE UK Phil Ineson, Environment Department, Stockholm Environment Institute, University of York, York, YO10 5DD UK Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    Two gadoid fishes, Arctogadus glacialis and Boreogadus saida , often coexist (i.e. sympatric) in the fjords and shelf areas of the Arctic seas, where they likely share the same food resources. Diet composition from stomach contents, i.e. frequency of occurrence (FO) and Schoener’s index (SI), and stable isotope signatures (δ 13 C and δ 15 N) in muscle of these sympatric gadoids were examined from two fjords in NE Greenland—Tyrolerfjord (TF, ~74ºN, sill present) and Dove Bugt (DB, ~76ºN, open). Twenty-three prey taxa and categories were identified and both gadoids ate mostly crustaceans. The SI values of 0.64–0.70 indicated possible resource competition, whereas FO differed significantly. A. glacialis fed mainly on the mysid Mysis oculata and other benthic-associated prey, whereas B. saida ate the copepod Metridia longa and other pelagic prey. Both diet and stable isotopes strongly suggest a spatial segregation in feeding habitat, with A. glacialis being associated with the benthic food web (mean δ 13 C = −20.81‰, δ 15 N = 14.92‰) and B. saida with the pelagic food web (mean δ 13 C = −21.25‰, δ 15 N = 13.64‰). The dietary differences and isotopic signals were highly significant in the secluded TF and less clear in the open DB, where prey and predators may be readily advected from adjacent areas with other trophic conditions. This is the first study on the trophic position of A. glacialis inferred from analyses of stable isotopes. The subtle interaction between the Arctic gadoids should be carefully monitored in the light of ocean warming and on-going invasions of boreal fishes into the Arctic seas. Content Type Journal Article Category Original Paper Pages 1-11 DOI 10.1007/s00300-012-1170-y Authors Jørgen S. Christiansen, Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway Haakon Hop, Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway Einar M. Nilssen, Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway John Joensen, Department of Arctic and Marine Biology, University of Tromsø, 9037 Tromsø, Norway Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    The effects of ocean acidification will be pronounced in high-latitude marine communities, although little is known on how reproduction in free-spawning polar invertebrates will respond. Using the circum-Antarctic sea star Odontaster validus , we examined fertilisation, larval survival and development under a controlled seawater treatment (temperature = −0.5 °C, pH 8.1, p CO 2 (aq) = 326.6 μatm, TA = 2,274.2 μmol kg soln −1 ), two near-future pH treatments (pH 7.8 and 7.6) and an extreme treatment (pH 7.0). At a sperm concentration of 3.5 × 10 5 sperm ml −1 , percentage of fertilisation was 98–90 % across a pH 8.1–7.0 range. At near-future pH ranges (pH 7.8 and 7.6), fertilisation was not significantly lower than in the control pH 8.1 except at the lowest sperm concentration (2.2 × 10 3 sperm ml −1 ) where fertilisation was reduced to 60 and 61 % in pH 7.6 and 7.8, respectively. Larval survival was not significantly affected by a decrease in pH of 0.3 units, but at pH 7.6 survival was significantly reduced. This difference was apparent at 9 days, and at the end of the experiment at 58 days, survival was 55 % compared with 85 % in the ambient treatment. Near-future changes to pH yielded smaller larvae, a result of both subtle differences in their morphology and slowed development rates, while larvae at pH 7.0 showed evidence of abnormal development. O. validus fertilisation and larval success declines in seawater pH conditions expected in coastal Antarctica over the coming decades, although the responses observed are within the range observed in warmer-water echinoderms. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00300-012-1255-7 Authors Maria J. Gonzalez-Bernat, Department of Marine Science, University of Otago, Dunedin, New Zealand Miles Lamare, Department of Marine Science, University of Otago, Dunedin, New Zealand Mike Barker, Department of Marine Science, University of Otago, Dunedin, New Zealand Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    Comprehensive ecological research is still lacking for many of the species that dominate the Antarctic benthos, preventing an adequate understanding of their potential response to environmental change. Here, population dynamics were explored in one of the most ubiquitous nearshore Antarctic benthic amphipods, Orchomenella franklini . Sex, reproductive status and body length were recorded for over 6,000 individuals, sampled from a variety of locations and times at Casey station in East Antarctica. Several life history traits were revealed for O. franklini that exemplify adaptations predicted for a polar environment. These include delayed reproduction, extended brood incubation, low fecundity, longevity and seasonal breeding linked to the summer phytoplankton bloom. There was also preliminary evidence of inter-annual and spatial fluctuations in population structure, potentially reflecting local environmental heterogeneity such as sea-ice duration. The influence of both large scale and local environmental conditions on the ecology of O. franklini provides insight into the vulnerability of this species to environmental change. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00300-012-1246-8 Authors Helena P. Baird, Terrestrial and Nearshore Ecosystems Theme, Australian Antarctic Division, 103 Channel Highway, Kingston, TAS 7050, Australia Jonathan S. Stark, Terrestrial and Nearshore Ecosystems Theme, Australian Antarctic Division, 103 Channel Highway, Kingston, TAS 7050, Australia Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    Processes that structure subarctic marine communities, particularly in glaciated regions, are not well understood. This understanding is needed as a baseline and to manage these communities in the face of future climate-driven changes. This study investigates two coastal regions of Southeast Alaska with the goals to (a) identify and compare patterns of subtidal community structure for macroalgal, fish, macroinvertebrate (〉5 cm), and small epibenthic invertebrate (〈5 cm) communities between inner coast and outer coast sites and (b) link patterns of community structure to habitat and environmental parameters. Species assemblage and benthic habitat data were used to compare species diversity and community composition at 6 m and 12 m depths at nine inner coast and nine outer coast sites. Multivariate analysis was applied to reduce environmental variables to major gradients, to resolve community structure, and to relate community structure to habitat and environmental variables. Increased salinity and decreased temperature at outer coast sites compared with inner coast sites were associated with community structure, with greater species diversity at outer coast sites at 6 m depth. Invertebrate community composition was associated with benthic habitat, including crust and coralline algae for macroinvertebrates, and algal cover and substrate for small epibenthic invertebrates. This research suggests that marine communities in glaciated regions are strongly influenced by freshwater input and that future climate-driven changes in freshwater input will likely result in marine community composition changes. Content Type Journal Article Category Original Paper Pages 1-22 DOI 10.1007/s00300-012-1231-2 Authors Jodi L. Pirtle, School of Fisheries and Ocean Sciences, Juneau Center, University of Alaska Fairbanks, 17101 Point Lena Loop Road, Juneau, AK 99801, USA Sonia N. Ibarra, School of Fisheries and Ocean Sciences, Juneau Center, University of Alaska Fairbanks, 17101 Point Lena Loop Road, Juneau, AK 99801, USA Ginny L. Eckert, School of Fisheries and Ocean Sciences, Juneau Center, University of Alaska Fairbanks, 17101 Point Lena Loop Road, Juneau, AK 99801, USA Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    A new brittle star attributable to the genus Ophiacantha is described from Antarctic waters, in the diffuse limits of the Antarctic Polar Front at Shag Rocks, South Georgia. The new species can be differentiated from its Southern Ocean congeners by the striations on the arm plates. Several adult individuals were observed brooding their juveniles, as the arms of the juveniles were seen emerging from the genital slits of the parent. The present paper reports this discovery, providing a description and illustrations of Ophiacantha wolfarntzi n. sp., a comparison of the species with its closest congeners and an identification key for Ophiacantha species reported from sub-Antarctic and Antarctic waters. Content Type Journal Article Category Original Paper Pages 1-12 DOI 10.1007/s00300-012-1242-z Authors Rafael Martín-Ledo, Área de Zoología, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain Chester J. Sands, Natural Environment Research Council, British Antarctic Survey, Cambridge, UK Pablo J. López-González, Biodiversidad y Ecología de Invertebrados Marinos, Departamento de Zoología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    High-latitude ecosystems are among the most vulnerable to long-term climate change, yet continuous, multidecadal indicators by which to gauge effects on biology are scarce, especially in freshwater environments. To address this issue, dendrochronology (tree-ring analysis) techniques were applied to growth-increment widths in otoliths from lake trout ( Salvelinus namaycush ) from the Chandler Lake system, Alaska (68.23°N, 152.70°W). All otoliths were collected in 1987 and exhibited highly synchronous patterns in growth-increment width. Increments were dated, the widths were measured, and age-related growth declines were removed using standard dendrochronology techniques. The detrended time series were averaged to generate an annually resolved chronology, which continuously spanned 1964–1984. The chronology positively and linearly correlated with August air temperature over the 22-year interval ( p  〈 0.01), indicating that warmer summers were beneficial for growth, perhaps by increasing fish metabolic rate or lake productivity. Given the broad distribution of lake trout within North America, this study suggests that otolith chronologies could be used to examine responses between freshwater ecosystems and environmental variability across a range of temporal and spatial scales. Content Type Journal Article Category Original Paper Pages 1-7 DOI 10.1007/s00300-012-1245-9 Authors B. A. Black, Marine Science Institute, University of Texas at Austin, 750 Channel View Drive, Port Aransas, TX 78373, USA V. R. von Biela, U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA C. E. Zimmerman, U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, AK 99508, USA R. J. Brown, U.S. Fish and Wildlife Service, 101 12th Avenue, Fairbanks, AK 99701, USA Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    The Patagonian blennie Eleginops maclovinus is a coastal and estuarine species, important in recreational and commercial fisheries, and with aquaculture potential. This study assessed the effect of temperature on feeding and the allocation of energy in growth and swimming in a sub-Antarctic population. For growth experiments, two groups of 8 juveniles were reared at 4 and 10 °C (corresponding to winter and summer habitat temperatures, respectively) for 3 months. Swimming experiments were conducted at 5 and 10 °C, measuring the oxygen consumption before and after forced swimming for 1 min at a speed of 10 total lengths (TL)/s. Temperature affects growth. TL increased 0.09 cm at 4 °C versus 0.30 cm at 10 °C. Body mass grew 0.49 g at 4 °C versus 1.65 g at 10 °C, whereas the Fulton’s condition factor increased 0.021 at 4 °C versus 0.080 at 10 °C. The ingested food was more than twofold higher at 10 than at 4 °C, while the feces produced at 4 °C was about twofold higher. The scope between baseline and peak oxygen consumption after forced swimming was affected by temperature, being 4.51 at 5 °C and 3.03 at 10 °C. The percentage energy expenditure until the return of baseline oxygen consumption values showed a marked temperature effect, being higher at 5 °C. We propose the existence of a trade-off in the allocation of energy between swimming activity and growth, with proportionally more energy being consumed at low temperatures for swimming than for other physiological functions like growth. Content Type Journal Article Category Original Paper Pages 1-8 DOI 10.1007/s00300-012-1228-x Authors Fabián A. Vanella, Laboratorio de Ecología, Fisiología Y Evolución, Centro Austral de Investigaciones Científicas (CADIC), CONICET, Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina Claudia C. Boy, Laboratorio de Ecología, Fisiología Y Evolución, Centro Austral de Investigaciones Científicas (CADIC), CONICET, Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina Daniel A. Fernández, Laboratorio de Ecología, Fisiología Y Evolución, Centro Austral de Investigaciones Científicas (CADIC), CONICET, Bernardo Houssay 200, Ushuaia, Tierra del Fuego, Argentina Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    The vegetation of the Antarctic tundra is dominated by mosses and lichens. Deschampsia antarctica, the Antarctic hairgrass, is one of two vascular plant species which grow along the west coast of the Antarctic Peninsula. However, little is known about its recruitment and interaction with non-vascular tundra plants. Although several authors propose that tolerance and/or competition should be the main forms of interaction between moss carpets and D. antarctica , no relevant studies exist so far. We investigated whether positive interactions are predominant at the Shetland Islands and the west coast of the Antarctic Peninsula and focussed on the role that moss carpets play in the recruitment of D. antarctica . Across the studied zone, D. antarctica showed a significant association with moss carpets, with higher frequencies as well as more and larger individuals than on bare ground. At one site, we conducted moss removal and seedlings transplant experiments to assess the relevance of the moss carpets for different life stages of hairgrass. All experimental individuals survived until the following summer whether the moss carpet was removed or not, but growth rate was significantly lower in tussocks with moss carpets removed. Likewise, tiller size was higher in plants growing in moss carpets than on bare ground. The detected positive interactions with mosses seem to be important for the expansion of D. antarctica , raising the question about their importance under future climate change scenarios. Content Type Journal Article Category Original Paper Pages 1-10 DOI 10.1007/s00300-012-1229-9 Authors M. Angélica Casanova-Katny, Centro de Biotecnología, Universidad de Concepción, Concepción, Chile Lohengrin A. Cavieres, Departamento de Botánica, Universidad de Concepción, Concepción, Chile Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060

Description:    The southern Barents Sea is considered to be the most productive area in the Arctic Ocean; however, there are no assessments of daily production rates in the coastal waters. During the summer and autumn of 2007, we investigated the variation of mesozooplankton community structure relative to environmental conditions at 12 coastal stations. Copepods dominated the total zooplankton biomass and abundance during both periods. Diversity indices and the total biomass of zooplankton communities differed significantly between the two seasons. Cluster analyses revealed two distinct groups of stations which were associated with Ura Bay and the adjacent open sea, respectively. Daily production rates of the copepod species examined were calculated using three methods based on: (1) a temperature-dependent equation and (2) two multiple regressions that consider temperature, body weight, and chlorophyll a concentration. Significant seasonal differences for daily production rates were found using all three model equations ( p  〈 0.05): 358 ± 188–1,775 ± 791 versus 198 ± 85–1,584 ± 559 μg dry mass m −3  day −1 . Results of principal components analyses demonstrated that the abundance and biomass of herbivorous species were related to variation in chlorophyll a concentration while the abundance and biomass of other species (omnivorous copepods and Ctenophora) were related mainly with water temperature and salinity. Mesozooplankton biomass was higher during this study relative to previous studies. Computed copepod production rates were higher compared with other Arctic seas confirming a high productive potential of the coastal southern Barents Sea. Content Type Journal Article Category Original Paper Pages 1-22 DOI 10.1007/s00300-012-1175-6 Authors Vladimir G. Dvoretsky, Murmansk Marine Biological Institute (MMBI), Vladimirskaya St. 17, Murmansk, 183010 Russia Alexander G. Dvoretsky, Murmansk Marine Biological Institute (MMBI), Vladimirskaya St. 17, Murmansk, 183010 Russia Journal Polar Biology Online ISSN 1432-2056 Print ISSN 0722-4060