References of "Dauby, Patrick"
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See detailDeûs meûs al rikwîre dès p'titès bièsses nin k'nohowes d'vin lès baheûrs abôminabes dè Pole Sûd
Dauby, Patrick ULg

Conference given outside the academic context (2005)

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See detailApplications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems
Lepoint, Gilles ULg; Dauby, Patrick ULg; Gobert, Sylvie ULg

in Marine Pollution Bulletin (2004), 49(11-12), 887-891

Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators ... [more ▼]

Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem. (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailToxards a SCAR Marine Biodiversity Information Network (SCAR MarBIN)
De Broyer, Claude; Danis, Bruno; Meerhaege, Angelo et al

Poster (2004, September)

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See detailTowards a SCAR 'Marine Biodiversity Information Network'
De Broyer, Claude; Danis, Bruno; Meerhaeghe, A et al

Poster (2004, July)

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See detailCombination of trophic biomarkers to distinguish among Antarctic amphipods trophic guilds
Nyssen, Fabienne ULg; Dauby, Patrick ULg; Graeve, Martin

Conference (2004, July)

Peracarid crustaceans and amphipods in particular are an important group in the Southern Ocean and one of the most diverse in the macrozoobenthos. As a part of a multidisciplinary study of the amphipods ... [more ▼]

Peracarid crustaceans and amphipods in particular are an important group in the Southern Ocean and one of the most diverse in the macrozoobenthos. As a part of a multidisciplinary study of the amphipods ecological roles in Antarctic benthic systems, about 150 specimens belonging to 25 species of 10 of the most common amphipod families occurring in the Southern Ocean have been involved in this study of amphipod trophic patterns. Beside “classical” stomach content analysis or field observations, the use of naturally occurring stable isotopes of carbon (δ13C) and nitrogen (δ15N) has recently provided new insights into food web ecology. This method is based on the direct relationship established between the isotopic signature of an organism and that of its preys. Nitrogen-15 typically shows a step-wise increase with trophic level within a food chain. Closer to the value of the diet, carbon-13 is preferentially used to assess the relative proportion of potential primary sources in a trophic web (ex.: pelagic vs benthic contribution to food intake). Furthermore, for several species, the lipid signature – which has already been used successfully to help understand marine trophodynamics – and more particularly the fatty acid composition has been investigated as trophic biomarkers to reveal more precisely to which trophic guild they belong to. [less ▲]

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See detailContributions of benthic and planktonic primary producers to nitrate and ammonium uptake fluxes in a nutrient-poor shallow coastal area (Corsica, NW Mediterranean)
Lepoint, Gilles ULg; Gobert, Sylvie ULg; Dauby, Patrick ULg et al

in Journal of Experimental Marine Biology and Ecology (2004), 302(1), 107-122

By using the stable isotope N-15, we have measured in situ the uptake of nitrate and ammonium by the seagrass Posidonia oceanica, its leaf epiphyte community, the brown macroalgae Halopteris scoparia and ... [more ▼]

By using the stable isotope N-15, we have measured in situ the uptake of nitrate and ammonium by the seagrass Posidonia oceanica, its leaf epiphyte community, the brown macroalgae Halopteris scoparia and the suspended particulate organic matter (SPOM). In Revellata Bay (Gulf of Calvi, Westem Corsica), which is a very nutrient-poor region, the specific uptake rates (V) (mug N g N 1 h(- 1)) of SPOM measured at ambient concentrations are 10-1000 higher than those of benthic primary producers. Macroalgae have intermediary v, between the seagrass leaf and leaf epiphytes. V are quite variable and the reasons for this variability remain unclear. Despite the difference of specific uptake rates found between benthic and pelagic primary producers, when integrating the uptake fluxes for a water Column of 10 m depth, the contribution of benthic primary producers to N uptake fluxes (g N m(-) (2) h(-) (1)) is significant, corresponding on average to 40% of total uptake flux. This results from the dominance in terms of N biomass of benthic primary producers in this shallow nutrient-poor area. When reported for the entire volume of the Revellata Bay, the contribution of benthic primary producers is reduced to 5 - 10% of total N uptake flux. Although this contribution could appear relatively low, it results in a significant direct transfer of inorganic nitrogen from the water column to the benthic compartment. By this transfer, the benthic plants act as a biological pump incorporating the pelagic N into the benthic compartment for a time longer than the characteristic time of phytoplankton dynamics (month-years vs. day-week). (C) 2003 Elsevier B.V. Alt rights reserved. [less ▲]

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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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