References of "Dauby, Patrick"
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See detailThe crustacean scavenger guild in Antarctic shelf, bathyal and abyssal communities
De Broyer, Claude; Nyssen, Fabienne ULg; Dauby, Patrick ULg

in Deep-Sea Research Part II, Topical Studies in Oceanography (2004), 51(14-16), 1733-1752

Peracarid crustaceans form a significant part of the macrobenthic community that is responsible for scavenging on large food falls onto the sea floor. Although several studies are available about ... [more ▼]

Peracarid crustaceans form a significant part of the macrobenthic community that is responsible for scavenging on large food falls onto the sea floor. Although several studies are available about scavengers from tropical and temperate seas, very little information has been published about such species living in Antarctic waters, particularly at greater depths. The present paper is based on a collection of 31 baited trap sets deployed in the Weddell Sea, Scotia Sea, and off the South Shetland Islands, and presents results on the geographical and bathymetric distribution of the different taxa and on the eco-functional role of scavengers. <br /> <br />Some 68,000 peracarid crustaceans from 62 species were collected. About 98% of individuals belonged to the amphipod superfamily Lysianassoidea, and 2% to the isopod family Cirolanidae. Of these species, 31, including 26 lysianassoids (1400 individuals), were collected deeper than 1000 m. <br /> <br />High species richness was discerned for the eastern Weddell Sea shelf compared with other Antarctic areas. The Antarctic slope also seems to be richer in species than other areas investigated in the world, while in the abyss, scavenger species richness appears to be lower in Antarctica. A richness gradient was thus observed from the shelf to the deep. For amphipods, a number of species extend their distribution from the shelf to the slope and only one to the abyssal zone. <br /> <br />Amphipod species showed degrees of adaptation to necrophagy. The functional adaptations of the mandible and the storage function of the gut are discussed. Feeding experiments conducted on lysianassoid species collected at great depths and maintained in aquaria showed a mean feeding rate of about 1.4–4.1% dry body weight day−1, which is consistent with data obtained from other species. [less ▲]

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See detailExperimental determination of the feeding rate for some Antarctic amphipod species
Dauby, Patrick ULg; Nyssen, Fabienne ULg; Scailteur, Yves et al

Poster (2003, April)

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See detailAmphipods: the second food source for top-predators in the Southern Ocean?
Dauby, Patrick ULg; Nyssen, Fabienne ULg; De Broyer, Claude

Poster (2003, April)

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See detailParticularités des organismes des abysses et des sources hydrothermales.
Dauby, Patrick ULg; Coulon, Pierre

Article for general public (2003)

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See detailCarbon and nitrogen isotopic ratios of the seagrass Posidonia oceanica: Depth-related variations
Lepoint, Gilles ULg; Dauby, Patrick ULg; Fontaine, Michael ULg et al

in Botanica Marina (2003), 46(6), 555-561

Nitrogen (delta(15)N) and carbon (delta(13)C) isotopic compositions of Posidonia oceanica were determined during three seasons along a bathymetric gradient (438 m depth).The delta(15)N values are low (2.2 ... [more ▼]

Nitrogen (delta(15)N) and carbon (delta(13)C) isotopic compositions of Posidonia oceanica were determined during three seasons along a bathymetric gradient (438 m depth).The delta(15)N values are low (2.2+/-0.9%) and variable.They do not show any relation to depth or sampling dates. There is a significant difference between the delta(15)N values of the youngest and the oldest leaves, probably as a result of N resorption and senescing during leaf ageing. The delta(13)C values of young Posidonia leaves vary with depth, showing the relationship between delta(13)C values and primary productivity rate, and the use of a bicarbonate/CO2 mixture as an inorganic carbon source. The delta(13)C values of the oldest P. oceanica leaves are depleted in C-13 compared to those of young leaves. This modification of the C-13 signatures in relation to leaf age is particularly important between 20 and 29 m depth. This modification could be related to photosynthetic rate change during ageing, but also to change in carbohydrate composition and content. [less ▲]

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See detailAmphipods as food sources for higher trophic levels in the Southern Ocean: a synthesis
Dauby, Patrick ULg; Nyssen, Fabienne ULg; de Broyer, Claude

in Antarctic biology in a global context (2003)

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See detailStructural and ecofunctional biodiversity of the amphipod crustacean benthic taxocoenoses in the Southern Ocean
De Broyer, Claude; Chapelle, Gauthier; Duchesne, Paul-André et al

in Belgian Scientific Research Programme on the Antarctic-Phase 4. Vol 1. Marine Biota and Global Change (2003)

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See detailCTD measurements, with emphasis on Elephant Island surroundings
Dauby, Patrick ULg

in Berichte zur Polar- und Meeresforschung (2003), 470

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See detailBiodiversity pattern in the Southern Ocan: lessons from Crustacea.
De Broyer, Claude; Jazdzewski, Krzystov; Dauby, Patrick ULg

in Huiskes, Ad (Ed.) Antarctic Biology in a Global Context (2003)

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See detailBiodiversity, molecular phylogeny, and trophodynamics of amphipod crustaceans in the Antarctic deep-sea
De Broyer, Claude; Dauby, Patrick ULg; Nyssen, Fabienne et al

in Berichte zur Polar- und Meeresforschung (2003), 470

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See detailExperimental evidence for N recycling in the leaves of the seagrass Posidonia oceanica
Lepoint, Gilles ULg; Defawe, Olivier; Gobert, Sylvie ULg et al

in Journal of Sea Research (2002), 48(3), 173-179

A one-year in situ experiment using N-15 as a tracer was designed to assess the N recycling in the leaves of the seagrass Posidonia oceanica (L.) Delile. R oceanica was shown to partly recycle the ... [more ▼]

A one-year in situ experiment using N-15 as a tracer was designed to assess the N recycling in the leaves of the seagrass Posidonia oceanica (L.) Delile. R oceanica was shown to partly recycle the internal nitrogen pool of its leaves in order to contribute to new leaf growth. The leaves sampled in June 1999 contained 20% of the quantity of N-15 found in June 1998. N recycling caused a difference between N and biomass turnover rate (0.8 vs 1.3 y(-1)) of Posidonia leaves. This 40% difference should correspond to the contribution of recycled N to the annual N requirement of Posidonia leaves. The N recycling appears to be insufficient to significantly reduce the quantitative impact of N loss due to autumnal leaf fall. However, new leaf growth between June and October is mainly sustained by this recycling because the tracer concentration in new leaves was the same as in the other leaves. By contrast, tracer concentration decreased drastically between October 1998 and June 1999, showing the more important contribution of N uptake during winter and spring. Nevertheless, recycling occurs throughout the year as demonstrated by the presence of tracer in the youngest leaves of shoots sampled one year after the tracer addition. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailA la recherche de la vie dans les profondeurs de l'Océan Antarctique
Dauby, Patrick ULg

Conference given outside the academic context (2002)

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See detailAnnual nitrogen budget of the seagrass Posidonia oceanica as determined by in situ uptake experiments
Lepoint, Gilles ULg; Millet, S.; Dauby, Patrick ULg et al

in Marine Ecology. Progress Series (2002), 237

The uptake of nitrate and ammonium by the roots and leaves of Posidonia oceanica were determined between February 1993 and June 1999 by in situ experiments using the isotope 15 of nitrogen (N-15) as a ... [more ▼]

The uptake of nitrate and ammonium by the roots and leaves of Posidonia oceanica were determined between February 1993 and June 1999 by in situ experiments using the isotope 15 of nitrogen (N-15) as a tracer in a nutrient-poor coastal zone of the NW Mediterranean Sea (Revellata Bay, Corsica). Nitrate and ammonium leaf uptakes are recorded at 0.05 and 0.1 muM respectively. The high variability observed cannot be explained solely by the variation of the substrate concentrations in the water column. For leaves, mean specific uptake rates were 43 +/- 45 and 43 +/- 64 mug N g N-1 h(-1). Nitrate and ammonium leaf uptake fluxes (g N m(-2) yr(-1)) seem to have the same importance on an annual basis. :Nitrate uptake occurs mainly in winter and early spring, when nitrate concentrations in the water column are highest. The uptake of N, and mainly of ammonium, is significant throughout the year with maxima at the beginning of spring, but it is insufficient to meet the annual N requirement of the plant. Posidonia root biomass was very high and corresponded to high specific N uptake rates by the roots. Ammonium was incorporated by the roots 6 times faster than nitrate. In the sediment, this uptake capacity is limited by the nutrient diffusion rate, and the root uptake is therefore insufficient to meet the N requirements of the plant. In fact, P. oceanica of Revellata Bay have a complex N budget involving uptake and recycling processes and allowing the plants to meet their N requirements in one of the most nutrient-poor areas of the NW Mediterranean Sea. We calculated that leaf and root would contribute to 40 and 60% of the annual N uptake, respectively, and 60% of the annual N requirement of the plant. [less ▲]

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See detailAmphipods: The second food source for top-predators in the Southern Ocean?
Dauby, Patrick ULg; Nyssen, Fabienne; De Broyer, Claude

Poster (2002, July)

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See detailCarbon and nitrogen stable isotope ratios of subtidal benthic invertebrates in an estuarine mangrove ecosystem (Andhra Pradesh, India)
Bouillon, Steven; Raman, A. V.; Dauby, Patrick ULg et al

in Estuarine Coastal and Shelf Science (2002), 54(5), 901-913

In order to assess the relative trophic importance of mangrove litterfall and aquatic primary production in the mangrove creeks of the Coringa Wildlife Sanctuary (Andhra Pradesh, India) and the adjacent ... [more ▼]

In order to assess the relative trophic importance of mangrove litterfall and aquatic primary production in the mangrove creeks of the Coringa Wildlife Sanctuary (Andhra Pradesh, India) and the adjacent semi-enclosed Kakinada Bay, carbon and nitrogen stable isotope ratios were determined in a variety of benthic invertebrate species collected at 22 sites during the pre-monsoon period (May-June) of 1997 and 1999. delta(13)C values showed little interspecific variation at any given location, but there was a distinct spatial gradient in consumer delta(13)C values of about 7parts per thousand, with more depleted values in the mangrove creeks ( - 23.6 +/- 0.6parts per thousand), and gradually increasing in the mangrove outlets ( - 21.5 +/- 0.9parts per thousand), a relatively restricted zone in the south-eastern part of Kakinada Bay adjacent to the mangroves ( - 18.8 +/- 0.8parts per thousand), and the central and northern part of the Bay ( - 16.7 +/- 1.4parts per thousand) which opens into the Bay of Bengal. This gradient is much larger than that observed during a previous study in suspended organic matter (maximum about 2.7parts per thousand) and during this study in sediment organic matter (about 1.5-2.5parts per thousand). The observed carbon stable isotope ratios thus suggest a marked selectivity of the benthic invertebrate community for pelagic and benthic microalgal food sources and indicate that mangrove-derived and other terrestrial carbon is not a significant food source for benthic invertebrate communities in this ecosystem during the pre-monsoon period. Furthermore, delta(13)C values of sediment organic matter (SOM) suggest that terrestrial carbon is not a major contributor to the SOM-pool in this ecosystem. Evidence for seaward migration of Penaeid prawns was provided by some individuals caught in the North Bay which displayed low delta(13)C values of characteristic of fauna found in the mangrove creeks or outlets. Nitrogen stable isotope ratios were found to be a useful indicator of trophic level, even though there remained some overlap between delta(15)N values of presumed low and higher trophic levels. Benthic invertebrates showed a delta(15)N gradient of about 3.2parts per thousand between the mangrove creeks and the Central and North Bay whereas sediment delta(15)N values showed a smaller spatial gradient of about 1.6parts per thousand. This gradient which is hypothesized to reflect differences in inorganic nitrogen sources and availability. (C) 2001 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detailPotential impact of the main benthic amphipods on the Eastern Weddell Sea shelf ecosystem (Antarctica)
Dauby, Patrick ULg; Scailteur, Yves; Chapelle, Gauthier et al

in Arntz, Wolf; Clarke, Andy (Eds.) Ecological Studies in the Antarctic Sea-Ice Zone (2002)

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See detailBiodiversity of the Southern Ocean: the "Ant'Phipoda" Project
De Broyer, Claude; Duchesne, Paul-André; Jazdzewski, Krzyzstof et al

Poster (2001, August)

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See detailAmphipods as food sources for higher trophic levels in the Southern Ocean
Dauby, Patrick ULg; Nyssen, Fabienne; De Broyer, Claude

Conference (2001, August)

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