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  • 2010-2014  (108)
  • 1990-1994  (33)
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  • 1
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The surface deposit feeding speciesPygospio elegans andMacoma balthica are dominant members of many sandy bottom communities of northern boreal regions. The feeding mode of both species and the tube-building ofP. elegans are assumed to affect community structure by interactions with other species. The weight of tubes ofP. elegans varied between 2 and 13 g DW/100 cm2 at the two stations investigated and during the year, which is equivalent to 230–1500 cm of tubes per 100 cm2 of sediment surface. Sediment stability may be affected directly or indirectly by the amount of tubes present.M. balthica shows a linear relation between the maximum size of particles which can be inhaled and animal length. In Kiel Bay, particles〉0.5 mm are out of the range of this species. In summer, the potential feeding area (PFA) of aP. elegans population at one station in Kiel Bay was 1.8 times the available surface area. The PFA of three different populations ofM. balthica in Kiel Bay exceeded the available surface area by factors of 2.6, 2.7, and 3.2. These findings indicate strong intra- and interspecific competition for food. Additionally, the feeding of both species may strongly affect the recruitment of benthic species via pelagic larvae. Experiments are proposed to evaluate the significance of the investigated behavioural aspects for community structure.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Population dynamics of the epizoic bivalve Lissarca notorcadensis living on spines of cidaroid sea urchins in the Weddell Sea were investigated. Total production (somatic & gonad) of the suspension feeding bivalve ranged between 16.5 and 487.4 mg AFDM y−1 per sea urchin. Annual sedimentation rates are not sufficient to maintain the production of the Lissarca sub-populations carried by the sea urchins, and resuspension of organic matter is most likely to be an important food source. The ratio of the number of freshly settled juveniles to the number of embryos brooded is between 0.054 and 0.207 and seems negatively related to the biomass already present, indicating intraspecific competition for space. Interspecific competition for space is caused by the strong preference of L. notorcadensis as well as other epizoa (colonial anthozoans and bryozoans) for the spines located on the aboral hemispere of the sea urchins.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR — Poore and Wilson1, and Rex et al.2, give evidence for a distinct decline in species diversity in deep-sea communities from the tropics towards north polar re-gions; and for a less clear trend but high interregional variability in the Southern Hemisphere. Poore and Wilson1 included some ...
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two species of the echinoid genus Sterechinus were documented from 92 trawl stations and 55 photographic stations in the eastern and southern Weddell Sea between 100 and 1200 m water depth. We found two species occuring along the whole shelf and slope, S. neumayeri being more abundant above 450 m water depth and S. antarcticus dominating the deeper regions. The size-frequency distributions of both species indicate differences in growth, mortality and longevity. First estimates of abundance and biomass of S. neumayeri and S. antarcticus are 0.085 ind/m2 & 0.005 gAFDW/m2 and 0.022 ind/m2 & 0.005 gAFDW/m2, respectively.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2014-05-05
    Description: Correlating metal to calcium (Me/Ca) ratios of marine biogenic carbonates, such as bivalve shells, to environmental parameters has led to contradictory results. Biogenic carbonates represent complex composites of organic and inorganic phases. Some elements are incorporated preferentially into organic phases, and others are incorporated into inorganic phases. Chemical sample pretreatment to remove the organic matrix prior to trace element analysis may increase the applicability of the investigated proxy relationship, though its efficiency and side effects remain questionable. We treated inorganic calcium carbonate and bivalve shell powder (Arctica islandica) with eight different chemical treatments including H2O2, NaOH, NaOCl, and acetone and analyzed the effects on (1) Me/Ca ratios (Sr/Ca, Mg/Ca, Ba/Ca, and Mn/Ca), (2) organic matter (≈N) content, and (3) mineralogical composition of the calcium carbonate. The different treatments (1) cause element and treatment specific changes of Me/Ca ratios, (2) vary in their efficiency to remove organic matter, and (3) can even alter the phase composition of the calcium carbonate (e.g., formation of Ca(OH)2 during NaOH treatment). Among all examined treatments there were none without any side effects. In addition, certain Me/Ca changes we observed upon chemical treatment contradict our expectations that lattice-bound elements (Sr and Ba) should not be affected, whereas non-lattice-bound elements (Mg and Mn) should decrease upon removal of the organic matrix. For instance, we observe that NaOCl treatment did not alter Sr/Ca ratios but caused unexpected changes of the Mg/Ca ratios. The latter demonstrates that the buildup of complex biogenic composites like the shell of Arctica islandica are still poorly understood.
    Type: Article , PeerReviewed
    Format: text
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  • 6
    Publication Date: 2014-09-01
    Description: The ongoing process of ocean acidification already affects marine life, and according to the concept of oxygen and capacity limitation of thermal tolerance, these effects may be intensified at the borders of the thermal tolerance window. We studied the effects of elevated CO2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4 °C (winter) or to 10 °C (spring/summer) at either ambient (0.04 kPa, normocapnia) or predicted future PCO2 levels (0.11 kPa, hypercapnia). Cold-exposed (4 °C) groups revealed thermal stress exacerbated by PCO2 indicated by a high mortality overall and its increase from 55 % under normocapnia to 90 % under hypercapnia. We therefore excluded the 4 °C groups from further experimentation. Scallops at 10 °C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between normocapnia- and hypercapnia-exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared with normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal’s performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.
    Type: Article , PeerReviewed
    Format: text
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  • 7
    Publication Date: 2019-08-06
    Type: Article , PeerReviewed
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  • 8
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    PANGAEA
    In:  Supplement to: Degen, Renate; Vedenin, Andrey; Gusky, Manuela; Boetius, Antje; Brey, Thomas (2015): Patterns and trends of macrobenthic abundance, biomass and production in the deep Arctic Ocean. Polar Research, 34(1), 24008, https://doi.org/10.3402/polar.v34.24008
    Publication Date: 2023-01-13
    Description: The few existing studies on macrobenthic communities of the deep Arctic Ocean report low standing stocks, and confirm a gradient with declining biomass from the slopes down to the basins as commonly reported for deep-sea benthos. In this study we have further investigated the relationship of faunal abundance (N), biomass (B) as well as community production (P) with water depth, geographical latitude and sea ice concentration. The underlying dataset combines legacy data from the past 20 years, as well as recent field studies selected according to standardized quality control procedures. Community P/B and production were estimated using the multi-parameter ANN model developed by Brey (2012). We could confirm the previously described negative relationship of water depth and macrofauna standing stock in the Arctic deep-sea. Furthermore, the sea-ice cover increasing with high latitudes, correlated with decreasing abundances of down to 〈 200 individuals/m**2, biomasses of 〈 65 mg C/m**2 and P of 〈 75 mg C/m**2/y. Stations under influence of the seasonal ice zone (SIZ) showed much higher standing stock and P means between 400 - 1400 mg C/m**2/y; even at depths up to 3700 m. We conclude that particle flux is the key factor structuring benthic communities in the deep Arctic ocean, explaining both the low values in the ice-covered Arctic basins and the high values along the SIZ.
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 9
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    PANGAEA
    In:  Supplement to: Krause-Nehring, Jacqueline; Brey, Thomas; Thorrold, Simon R (2012): Centennial records of lead contamination in northern Atlantic bivalves (Arctica islandica). Marine Pollution Bulletin, 64(2), 233-240, https://doi.org/10.1016/j.marpolbul.2011.11.028
    Publication Date: 2023-01-13
    Description: In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.
    Keywords: Grab; GRAB; HELG; ICEL; Iceland; off Helgoland, North Sea; VIRG; Virginia, USA
    Type: Dataset
    Format: application/zip, 3 datasets
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  • 10
    Publication Date: 2023-01-13
    Keywords: Age; AGE; Grab; GRAB; LA-ICP-MS Thermo Finnigan Element 2; Lead/Calcium ratio; Lead/Calcium ratio, standard deviation; Lead/Calcium ratio, standard error; VIRG; Virginia, USA
    Type: Dataset
    Format: text/tab-separated-values, 184 data points
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