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  • 1
    Electronic Resource
    Electronic Resource
    Bomb signals in old Antarctic brachiopods (1996)
    [s.l.] : Nature Publishing Group
    Nature 380 (1996), S. 207-208 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Skeletal check-marks are commonly used to assess the age and growth of organisms. They are usually assumed to be formed annually. By using radiocarbon bomb signals to calibrate growth checks in shells of Antarctic brachiopods, we show that they were laid down with a sub-biennial periodicity. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/380207b0
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Antarctic benthic diversity (1994)
    [s.l.] : Nature Publishing Group
    Nature 368 (1994), S. 297-297 
    Details
    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
    URL: http://dx.doi.org/10.1038/368297a0
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  • 3
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    Euphausiid respiration model revamped. Latitudinal and seasonal shaping effects on krill respiration rates (2014)
    ELSEVIER SCIENCE BV
    In:  EPIC3Ecological Modelling, ELSEVIER SCIENCE BV, 291, pp. 233-241, ISSN: 0304-3800
    Details
    Publication Date: 2018-02-05
    Description: Euphausiids constitute a major biomass component in shelf ecosystems and play a fundamental role in the rapid vertical transport of carbon from the ocean surface to the deeper layers during their daily vertical migration (DVM). DVM depth and migration patterns depend on oceanographic conditions with respect to temperature, light and oxygen availability at depth, factors that are highly dependent on season in most marine regions. Here we introduce a global krill respiration ANN (artificial neural network) model including the effect of latitude (LAT), the day of the year (DoY), and the number of daylight hours (DLh), in addition to the basal variables that determine ectothermal oxygen consumption (temperature, body mass and depth). The newly implemented parameters link space and time in terms of season and photoperiod to krill respiration. The ANN model showed a better fit (r2 = 0.780) when DLh and LAT were included, indicating a decrease in respiration with increasing LAT and decreasing DLh. We therefore propose DLh as a potential variable to consider when building physiological models for both hemispheres. For single Euphausiid species investigated in a large range of DLh and DoY, we also tested the standard respiration rate for seasonality with Multiple Linear Regression (MLR) and General Additive model (GAM). GAM successfully integrated DLh (r2 = 0.563) and DoY (r2 = 0.572) effects on respiration rates of the Antarctic krill, Euphausia superba, yielding the minimum metabolic activity in mid-June and the maximum at the end of December. We could not detect DLh or DoY effects in the North Pacific krill Euphausia pacifica, and our findings for the North Atlantic krill Meganyctiphanes norvegica remained inconclusive because of insufficient seasonal data coverage. We strongly encourage comparative respiration measurements of worldwide Euphausiid key species at different seasons to improve accuracy in ecosystem modeling.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
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  • 4
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    Euphausiid respiration model revamped: latitudinal and seasonal shaping effects on krill respiration rates (2014)
    ELSEVIER SCIENCE BV
    In:  EPIC3Ecological Modelling, ELSEVIER SCIENCE BV, 291, pp. 233-241, ISSN: 0304-3800
    Details
    Publication Date: 2019-07-16
    Description: Euphausiids constitute a major biomass component in shelf ecosystems and play a fundamental role in the rapid vertical transport of carbon from the ocean surface to the deeper layers during their daily vertical migration (DVM). DVM depth and migration patterns depend on oceanographic conditions with respect to temperature, light and oxygen availability at depth, factors that are highly dependent on season in most marine regions. Here we introduce a global krill respiration ANN (Artificial Neural Network) model including the effect of latitude (LAT), the day of the year (DoY), and the number of daylight hours (DLh), in addition to the basal variables that determine ectothermal oxygen consumption (temperature, body mass and depth). The newly implemented parameters link space and time in terms of season and photoperiod to krill respiration. The ANN model showed a better fit (r2=0.780) when DLh and LAT were included, indicating a decrease in respiration with increasing LAT and decreasing DLh. We therefore propose DLh as a potential variable to consider when building physiological models for both hemispheres. For single Euphausiid species investigated in a large range of DLh and DoY, we also tested the standard respiration rate for seasonality with Multiple Linear Regression (MLR) and General Additive model (GAM). GAM successfully integrated DLh (r2= 0.563) and DoY (r2= 0.572) effects on respiration rates of the Antarctic krill, Euphausia superba, yielding the minimum metabolic activity in mid-June and the maximum at the end of December. We could not detect DLh or DoY effects in the North Pacific krill Euphausia pacifica, and our findings for the North Atlantic krill Meganyctiphanes norvegica remained inconclusive because of insufficient seasonal data coverage. We strongly encourage comparative respiration measurements of worldwide Euphausiid key species at different seasons to improve accuracy in ecosystem modelling.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 5
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    Macrofaunal irrigation traits enhance predictability of nutrient fluxes across the sediment-water interface (2019)
    Inter-Research
    In:  EPIC3Marine Ecology Progress Series, Inter-Research, 632, pp. 27-42, ISSN: 0171-8630
    Details
    Publication Date: 2020-01-10
    Description: This study shows that macrofaunal irrigation traits constitute a valuable complement to sediment reworking traits in estimating macrofaunal impact on nutrient fluxes across the sediment-water interface. We correlated density, biomass, community bioturbation potential (BPc, an index based on reworking traits, body mass and density) and community irrigation potential (IPc, an index based on irrigation traits, body mass and density) with nitrite, nitrate, ammonium, silicate and phosphate flux data under different environmental conditions. Generalized linear models performed best with a combination of environmental conditions and irrigation trait-based indices. This was not only a direct effect of the irrigation traits, but also of the scaling factor 0.75 employed in IPc to infer metabolic activity from body mass. Accordingly, predictive models of nutrient flux across the sediment-water interface will profit greatly from incorporating macrofaunal irrigation behaviour by means of trait-based indices.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 6
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    Do drivers of biodiversity change differ in importance across marine and terrestrial systems—Or is it just different research communities' perspectives? (2017)
    ELSEVIER SCIENCE BV
    In:  EPIC3Science of The Total Environment, ELSEVIER SCIENCE BV, 574, pp. 193-203, ISSN: 0048-9697
    Details
    Publication Date: 2019-02-15
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 7
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    Growth and production of the venerid bivalve Eurhomalea exalbida in the Beagle Channel, Tierra del Fuego (2002)
    ELSEVIER SCIENCE BV
    In:  EPIC3Journal of Sea Research, ELSEVIER SCIENCE BV, 48, pp. 209-216, ISSN: 1385-1101
    Details
    Publication Date: 2019-07-16
    Description: Growth, mortality and productivity of the hard clam E. exalbida from Ushuaia Bay, Beagle Channel were investigated. The parameters of the von Bertalanffy growth function were estimated to be H = 73.98 mm, K = 0.180 y 1, t0 = 0.147 y. Maximum individual production amounted to 2.742 g shell free wet mass (SFWM) at 49.5 mm shell height. Animals between 40 mm and 70 mm shell height contribute most to overall population somatic production P of 133.89 g SFWM m-2 y-1. Mean annual biomass B amounted to 1122.69 g SFWM m-2 y-1. Annual P/B ratio and mortality rate Z were estimated to 0.119 y-1 and 0.141 y-1, respectively. Slow growth and low turnover makes this population less suitable for sustainable commercial exploitation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
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  • 8
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    Trophic look at soft-bottom communities — Short-term effects of trawling cessation on benthos (2014)
    ELSEVIER SCIENCE BV
    In:  EPIC3Journal of Sea Research, ELSEVIER SCIENCE BV, 85, pp. 18-28, ISSN: 1385-1101
    Details
    Publication Date: 2019-07-16
    Description: The trophic structure of the German Bight soft-bottom benthic community was evaluated for potential changes after cessation of bottom trawling. Species were collected with van-Veen grabs and beam trawls. Trophic position (i.e. nitrogen stable isotope ratios, δ15N) and energy flow (i.e. species metabolism approximated by body mass scaled abundance) of dominant species were compared in trawled areas and an area protected from fisheries for 14 months in order to detect trawling cessation effects by trophic characteristics. At the community level, energy flow was lower in the protected area, but we were unable to detect significant changes in trophic position. At the species level energy flow in the protected area was lower for predating/scavenging species but higher for interface feeders. Species trophic positions of small predators/scavengers were lower and of deposit feeders higher in the protected area. Major reasons for trophic changes after trawling cessation may be the absence of artificial and additional food sources from trawling likely to attract predators and scavengers, and the absence of physical sediment disturbance impacting settlement/survival of less mobile species and causing a gradual shift in food availability and quality. Our results provide evidence that species or community energy flow is a good indicator to detect trawling induced energy-flow alterations in the benthic system, and that in particular species trophic properties are suitable to capture subtle and short-term changes in the benthos following trawling cessation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 9
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    Oxygen budgets in subtidal arctic (Kongsfjorden, Svalbard) and temperate (Helgoland, North Sea) microphytobenthic communities (2014)
    Inter-Research
    In:  EPIC3Marine Ecology Progress Series, Inter-Research, 504, pp. 27-42, ISSN: 0171-8630
    Details
    Publication Date: 2019-07-16
    Description: We compared primary production and respiration of temperate (Helgoland, North Sea) and subtidal Arctic (Kongsfjorden, Svalbard) microphytobenthic communities during summer. The diatom communities were generally characterized as cosmopolitan, displayed no site specificity, and had similar chl a and fucoxanthin concentrations. Their net and gross photosynthesis rates and light adaptation intensities, derived from laboratory microsensor measurements, were also similar, despite differences in water temperature. Daily oxygen fluxes across the sediment− water interface were estimated by combining laboratory microprofile and planar optode measurements with in situ data on oxygen penetration and light dynamics. During the study period, the Svalbard sediments were on average net heterotrophic,while the Helgoland sediments were net autotrophic (−22.4 vs. 9.2 mmol O2 m−2 d−1). This was due to high infaunal abundance in the Svalbard sediments that caused high oxygen uptake rates in the sediments and consumption below the sediment euphotic zone. Additionally, bioirrigation of the sediment due to infaunal burrow ventilation was reduced by light; thus, the sedimentary oxygen inventory was reduced with increasing light. Conversely, light-enhanced the oxygen inventory in the Helgoland sediments. Oxygen dynamics in the Svalbard sediments were therefore dominated by bioirrigation, whereas in the Helgoland sediments they were dominated by photosynthetic oxygen production.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 10
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    Choosing the lesser evil – A case study on quantification of sediment reworking rates in multi corer type sediment cores (2019)
    ELSEVIER SCIENCE BV
    In:  EPIC3Journal of Experimental Marine Biology and Ecology, ELSEVIER SCIENCE BV, 514-15(1-9), pp. 1-9, ISSN: 0022-0981
    Details
    Publication Date: 2019-03-21
    Description: Macrofaunal sediment reworking activity is a key driver of ecosystem functioning in marine systems. So far sediment reworking rates can only accurately be assessed by measurements as inference from community parameters is limited. In this case study we test the applicability of 2-D optical florescent sediment profile imaging (f-SPI) on multi corer type incubation cylinders. f-SPI has to date been applied to flat-surfaced (i.e. rectangular) cores only, while multi corer type incubation cylinders were analyzed by the spatially low resolved and invasive slicing technique. Here we apply both methods to cylindrical sediment cores (10 cm diameter). Cores were taken from by two common communities (i.e. Nucula-community and Amphiura-community) in the southern German Bight. Both f-SPI and the slicing technique showed similar vertical luminophore profiles. However the slicing technique found no significant differences between the two communities, whereas f-SPI showed significant differences for all investigated sediment reworking parameters: sediment reworking rate, non-locality index, mean weighted luminophore depth, and the maximal luminophore depth. Consequently, this may lead to different conclusions about the sediment reworking behaviors of the two communities. Likely the slicing method failed to detect significant differences between the Nucula- and Amphiura-community, owing to insufficient spatial accuracy. The f-SPI method, on the other hand, did not capture the full extent of maximal sediment reworking depth due to wall-effects. We conclude that both methods have specific drawbacks and advantages. While slicing is preferable when focusing on the absolute maximal sediment reworking depth especially with predominantly sessile communities, f-SPI is better suited to capture general sediment reworking patterns of most other communities. We demonstrate further that the bias, which is introduced by the distortion effect on imaging due to optical perspective and cylinder wall curvature of rounded cylinders using f-SPI, is negligible. Accordingly our results indicate that the distortion effects by curvature of the rounded cylinder walls will not cause underestimations of sediment reworking parameters in the f-SPI approach. Consequently f-SPI is suitable for the investigation of sediment reworking in natural communities by means of multi corer type samples.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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