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Makoto Sampei, Louis Fortier, Patrick Raimbault, Kohei Matsuno, Yoshiyuki Abe, Bernard Quéguiner, Augustin Lafond, Marcel Babin, Toru Hirawake |
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Title |
An estimation of the quantitative impacts of copepod grazing on an under sea-ice spring phytoplankton bloom in western Baffin Bay, Canadian Arctic |
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Journal |
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Year |
2021 |
Publication |
Elementa: Science of the Anthropocene |
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Volume |
9 |
Issue |
1 |
Pages |
00092 |
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Abstract |
This study aimed to quantify the impact of copepod grazing on the productivity of phytoplankton during an under sea-ice spring phytoplankton bloom (USPB) in western Baffin Bay. To quantify positive and/or negative impacts of copepod grazing on primary production and the interaction between copepod grazing and phytoplankton species, we sampled seawater and zooplankton under the landfast sea ice every 2–3 days between May 24 and July 10, 2016. Samples were analyzed for estimation of primary production, chlorophyll-a (chl-a) concentration, diatom abundance, and copepod fecal pellet (FP) production/grazing rate. Analyses of chl-a concentration, primary production, and FP production/grazing rate revealed clear temporal changes and a mismatch between primary production and copepod consumption. The FP production/grazing rate reached a maximum (9.4/31.2 mg C m–2 d–1) on June 16 before the USPB phase and suddenly decreased to 0.7/2.4 mg C m–2 d–1 on June 21, despite an increase in primary production to 74.0 mg C m–2 d–1. The copepod grazing rate (3.7 mg C m–2 d–1) was low relative to primary production (344.6 mg C m–2 d–1) during the USPB phase (after June 20). While our estimates illustrate that copepod grazing did not limit the maximum daily primary production during the USPB, the low grazing pressure (2% of primary production) may have been an additional contributor to the reduction in total primary productivity at the end of the USPB period due primarily to the low supply of regenerated nitrogen-containing nutrients to drive regenerated production. |
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1164 |
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2325-1026 |
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yes |
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8255 |
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Manfred R. Enstipp, Charles-André Bost, Céline Le Bohec, Nicolas Chatelain, Henri Weimerskirch, Yves Handrich |
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Title |
The early life of king penguins: ontogeny of dive capacity and foraging behaviour in an expert diver |
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Journal |
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Year |
2021 |
Publication |
The Journal of Experimental Biology |
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Volume |
224 |
Issue |
12 |
Pages |
jeb242512 |
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Keywords |
Animals Behavior, Animal Bio-logging Diving Feeding Behavior Foraging proficiency Ontogeny Seabirds Spheniscidae Temperature Wiggles |
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Abstract |
The period of emancipation in seabirds, when juveniles change from a terrestrial existence to a life at sea, is associated with many challenges. Apart from finding favourable foraging sites, they have to develop effective prey search patterns and physiological capacities that enable them to capture sufficient prey to meet their energetic needs. Animals that dive to forage, such as king penguins (Aptenodytes patagonicus), need to acquire an adequate breath-hold capacity, allowing them to locate and capture prey at depth. To investigate the ontogeny of their dive capacity and foraging performance, we implanted juvenile king penguins before their first departure to sea and also adult breeders with a data-logger recording pressure and temperature. We found that juvenile king penguins possess a remarkable dive capacity when leaving their natal colony, enabling them to conduct dives in excess of 100 m within their first week at sea. Despite this, juvenile dive/foraging performance, investigated in relation to dive depth, remained below the adult level throughout their first year at sea, probably reflecting physiological limitations as a result of incomplete maturation. A significantly shallower foraging depth of juveniles, particularly during their first 5 months at sea, could also indicate differences in foraging strategy and targeted prey. The initially greater wiggle rate suggests that juveniles fed opportunistically and also targeted different prey from adults and/or that many of the wiggles of juveniles reflect unsuccessful prey-capture attempts, indicating a lower foraging proficiency. After 5 months, this difference disappeared, suggesting sufficient physical maturation and improvement of juvenile foraging skills. |
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137,394 |
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1477-9145 |
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yes |
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8473 |
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Manon Clairbaux, Paul Mathewson, Warren Porter, Jérôme Fort, Hallvard Strøm, Børge Moe, Per Fauchald, Sebastien Descamps, Hálfdán H. Helgason, Vegard S. Bråthen, Benjamin Merkel, Tycho Anker-Nilssen, Ingar S. Bringsvor, Olivier Chastel, Signe Christensen-Dalsgaard, Jóhannis Danielsen, Francis Daunt, Nina Dehnhard, Kjell Einar Erikstad, Alexey Ezhov, Maria Gavrilo, Yuri Krasnov, Magdalene Langset, Svein-H. Lorentsen, Mark Newell, Bergur Olsen, Tone K. Reiertsen, Geir Helge Systad, Thorkell L. Thórarinsson, Mark Baran, Tony Diamond, Annette L. Fayet, Michelle G. Fitzsimmons, Morten Frederiksen, Hugh G. Gilchrist, Tim Guilford, Nicholas P. Huffeldt, Mark Jessopp, Kasper L. Johansen, Amy-Lee Kouwenberg, Jannie F. Linnebjerg, Heather L. Major, Laura McFarlane Tranquilla, Mark Mallory, Flemming R. Merkel, William Montevecchi, Anders Mosbech, Aevar Petersen, David Grémillet |
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Title |
North Atlantic winter cyclones starve seabirds |
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Journal |
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Year |
2021 |
Publication |
Current Biology |
Abbreviated Journal |
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Volume |
31 |
Issue |
17 |
Pages |
3964-3971.e3 |
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Keywords |
at-sea distribution cyclones energy expenditure GLS tracking seabird migration seascape ecology |
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Abstract |
Each winter, the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called “winter wrecks.”1, 2, 3 During these, thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics4,5 by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear.6 We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community by coupling winter tracking data for ∼1,500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia, and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model7 and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high intensity impacted birds from all studied species and breeding colonies during winter but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland, and the Barents Sea. Our broad-scale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming.8 |
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330,388 |
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ISSN |
0960-9822 |
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yes |
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Serial |
8294 |
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Author |
Manon Clairbaux, William W. L. Cheung, Paul Mathewson, Warren Porter, Nicolas Courbin, Jérôme Fort, Hallvard Strøm, Børge Moe, Per Fauchald, Sebastien Descamps, Hálfdán Helgason, Vegard S. Bråthen, Benjamin Merkel, Tycho Anker-Nilssen, Ingar S. Bringsvor, Olivier Chastel, Signe Christensen-Dalsgaard, Jóhannis Danielsen, Francis Daunt, Nina Dehnhard, Kjell-Einar Erikstad, Alexeï Ezhov, Maria Gavrilo, Yuri Krasnov, Magdalene Langset, Svein-Håkon Lorentsen, Mark Newell, Bergur Olsen, Tone Kirstin Reiertsen, Geir Systad, Þorkell L. Þórarinsson, Mark Baran, Tony Diamond, Annette L. Fayet, Michelle G. Fitzsimmons, Morten Frederiksen, Grant H. Gilchrist, Tim Guilford, Nicholas P. Huffeldt, Mark Jessopp, Kasper L. Johansen, Amy L. Kouwenberg, Jannie F. Linnebjerg, Laura McFarlane Tranquilla, Mark Mallory, Flemming R. Merkel, William Montevecchi, Anders Mosbech, Aevar Petersen, David Grémillet |
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Title |
Meeting Paris agreement objectives will temper seabird winter distribution shifts in the North Atlantic Ocean |
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Journal |
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Year |
2021 |
Publication |
Global Change Biology |
Abbreviated Journal |
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Volume |
27 |
Issue |
7 |
Pages |
1457-1469 |
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330, 388 |
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ISSN |
1365-2486 |
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yes |
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Serial |
7987 |
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Author |
Manuele Bazzichetto, François Massol, Marta Carboni, Jonathan Lenoir, Jonas J. Lembrechts, Rémi Joly, David Renault |
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Title |
Once upon a time in the far south: Influence of local drivers and functional traits on plant invasion in the harsh sub-Antarctic islands |
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Journal |
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Year |
2021 |
Publication |
Journal of Vegetation Science |
Abbreviated Journal |
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Volume |
32 |
Issue |
4 |
Pages |
e13057 |
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Keywords |
alien plants anthropogenic propagule pressure cold environments human disturbances plant invasiveness species distribution models topoclimate |
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Abstract |
Aim Here, we aim to: (a) investigate the local effect of environmental and anthropogenic factors on alien plant invasion in sub-Antarctic islands; and (b) explore whether and how functional traits affect alien species dependence on anthropogenic factors in these environments. Location Possession Island, Crozet archipelago (French sub-Antarctic islands). Methods Single-species distribution models were used to explore the effect of high-resolution topoclimatic and human-related variables on the occurrence of six alien plants colonizing French sub-Antarctic islands. Furthermore, plant responses to human-related variables and the effect of those variables in interaction with plant traits were analysed by means of a multi-species distribution model. This allowed identifying functional features mediating the influence of human activities on the occurrence probability of alien plant species. Results We observed two main invasion patterns: (a) species predicted to occur close to the introduction sites, whose occurrence probability appeared to be strongly affected by anthropogenic factors; and (b) species predicted to occur nearly everywhere on Possession Island, except in areas featuring particularly harsh climatic conditions. Differences in the influence of human-related variables on the occurrence of the alien species were mostly related to their life history, plant height and residence time, with perennial and low-statured species introduced earlier appearing less dependent on human-induced dispersal and disturbance. Conclusions We conclude that both topoclimatic and anthropogenic factors affect plant invasion on sub-Antarctic islands. Specifically, species predicted to occur close to their introduction sites appear much more dependent on human presence and activity, potentially due to the lack of key functional traits allowing them to spread successfully across Possession Island under the harsh sub-Antarctic climate. Yet, particularly severe abiotic conditions are a major constraint which equally limits the occurrence of all alien plants, irrespective of their dependence on anthropogenic factors. |
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136 |
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ISSN |
1654-1103 |
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yes |
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8298 |
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Author |
Margot Arnould-Pétré, Charlène Guillaumot, Bruno Danis, Jean-Pierre Féral, Thomas Saucède |
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Title |
Individual-based model of population dynamics in a sea urchin of the Kerguelen Plateau (Southern Ocean), Abatus cordatus, under changing environmental conditions |
Type |
Journal |
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Year |
2021 |
Publication |
Ecological Modelling |
Abbreviated Journal |
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Volume |
440 |
Issue |
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Pages |
109352 |
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Keywords |
Climate change Dynamic energy budget Ecological modelling Endemic echinoderm Individual-based model Kerguelen Model sensitivity |
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Abstract |
The Kerguelen Islands are part of the French Southern Territories, located at the limit of the Indian and Southern oceans. They are highly impacted by climate change, and coastal marine areas are particularly at risk. Assessing the responses of species and populations to environmental change is challenging in such areas for which ecological modelling can constitute a helpful approach. In the present work, a DEB-IBM model (Dynamic Energy Budget – Individual-Based Model) was generated to simulate and predict population dynamics in an endemic and common benthic species of shallow marine habitats of the Kerguelen Islands, the sea urchin Abatus cordatus. The model relies on a dynamic energy budget model (DEB) developed at the individual level. Upscaled to an individual-based population model (IBM), it then enables to model population dynamics through time as a result of individual physiological responses to environmental variations. The model was successfully built for a reference site to simulate the response of populations to variations in food resources and temperature. Then, it was implemented to model population dynamics at other sites and for the different IPCC climate change scenarios RCP 2.6 and 8.5. Under present-day conditions, models predict a more determinant effect of food resources on population densities, and on juvenile densities in particular, relative to temperature. In contrast, simulations predict a sharp decline in population densities under conditions of IPCC scenarios RCP 2.6 and RCP 8.5 with a determinant effect of water warming leading to the extinction of most vulnerable populations after a 30-year simulation time due to high mortality levels associated with peaks of high temperatures. Such a dynamic model is here applied for the first time to a Southern Ocean benthic and brooding species and offers interesting prospects for Antarctic and sub-Antarctic biodiversity research. It could constitute a useful tool to support conservation studies in these remote regions where access and bio-monitoring represent challenging issues. |
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1044 |
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0304-3800 |
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yes |
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8002 |
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Maria Federica Marcucci, Igino Coco, Stefano Massetti, Alessio Pignalberi, Victoriya Forsythe, Michael Pezzopane, Alexander Koustov, Simona Longo, David Biondi, Enrico Simeoli, Giuseppe Consolini, Monica Laurenza, Aurélie Marchaudon, Andrea Satta, Alessandro Cirioni, Angelo De Simone, Angelo Olivieri, Alessandro Baù, Alberto Salvati |
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Title |
Echo occurrence in the southern polar ionosphere for the SuperDARN Dome C East and Dome C North radars |
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Journal |
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Year |
2021 |
Publication |
Polar Science |
Abbreviated Journal |
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Volume |
28 |
Issue |
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Pages |
100684 |
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Keywords |
Echo occurrence IRI model Polar cap radars Ray-tracing |
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Abstract |
In this paper, echo occurrence rates for the Dome C East (DCE) and the new Dome C North (DCN) radars are studied. We report the ionospheric and ground scatter echo occurrence rates for selected periods around equinoxes and solstices in the final part of the solar cycle XXIV. The occurrence maps built in Altitude Adjusted Corrected Geomagnetic latitude and Magnetic Local Time coordinates show peculiar patterns highly variable with season. The comparisons of the radar observations with the International Reference Ionosphere model electron density and with ray tracing simulations allow us to explain the major features of observed patterns in terms of electron density variations. The study shows the great potential of the DCE and DCN radar combination to the Super Dual Auroral Radar Network (SuperDARN) convection mapping in terms of monitoring key regions of the high-latitude ionosphere critical for understanding of the magnetospheric dynamics. |
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312 |
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1873-9652 |
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yes |
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8020 |
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María José Frugone, Theresa L. Cole, María Eugenia López, Gemma Clucas, Pável Matos-Maraví, Nicolás A. Lois, Pierre Pistorius, Francesco Bonadonna, Phil Trathan, Andrea Polanowski, Barbara Wienecke, Andrea Raya-Rey, Klemens Pütz, Antje Steinfurth, Ke Bi, Cynthia Y. Wang-Claypool, Jonathan M. Waters, Rauri C. K. Bowie, Elie Poulin, Juliana A. Vianna |
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Title |
Taxonomy based on limited genomic markers may underestimate species diversity of rockhopper penguins and threaten their conservation |
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Year |
2021 |
Publication |
Diversity and Distributions |
Abbreviated Journal |
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Volume |
27 |
Issue |
11 |
Pages |
2277-2296 |
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Keywords |
Eudyptes genomics rockhopper penguins species delimitation |
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Abstract |
Aim Delimiting recently diverged species is challenging. During speciation, genetic differentiation may be distributed unevenly across the genome, as different genomic regions can be subject to different selective pressures and evolutionary histories. Reliance on limited numbers of genetic markers that may be underpowered can make species delimitation even more challenging, potentially resulting in taxonomic inconsistencies. Rockhopper penguins of the genus Eudyptes comprise three broadly recognized taxa: northern (E. moseleyi), southern (E. chrysocome) and eastern rockhopper (E. filholi). Their taxonomic status has been controversial for decades, with researchers disagreeing about whether E. chrysocome and E. filholi are distinct species or conspecific. Our goal is to evaluate genome-wide patterns of divergence to evaluate genetic differentiation and species delimitation in rockhopper penguins, and to assess which mechanisms may underlie previous discordance among nuclear versus mitochondrial analyses. Location Sub-Antarctic and temperate coastal regions of the Southern Hemisphere. Methods We generated reduced-representation genomic libraries using double digest restriction-site associated DNA (ddRAD) sequencing to evaluate genetic differentiation, contemporary migration rates and admixture among colonies of rockhopper penguins. Results The extent of genetic differentiation among the three taxa was consistently higher than population-level genetic differentiation found within these and other penguin species. There was no evidence of admixture among the three taxa, suggesting the absence of ongoing gene flow among them. Species delimitation analyses based on molecular data, along with other lines of evidence, provide strong support for the taxonomic distinction of three species of rockhopper penguins. Main conclusions Our results provide strong support for the existence of three distinct species of rockhopper penguins. The recognition of this taxonomic diversity is crucial for the management and conservation of this widely distributed species group. This study illustrates that widespread dispersive seabird lineages lacking obvious morphological differences may nevertheless have complex evolutionary histories and comprise cryptic species diversity. |
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354 |
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1472-4642 |
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yes |
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8421 |
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Marina Renedo, David Amouroux, Céline Albert, Sylvain Bérail, Vegard S. Bråthen, Maria Gavrilo, David Grémillet, Hálfdán H. Helgason, Dariusz Jakubas, Anders Mosbech, Hallvard Strøm, Emmanuel Tessier, Katarzyna Wojczulanis-Jakubas, Paco Bustamante, Jérôme Fort |
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Title |
Contrasting Spatial and Seasonal Trends of Methylmercury Exposure Pathways of Arctic Seabirds: Combination of Large-Scale Tracking and Stable Isotopic Approaches |
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Journal |
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Year |
2021 |
Publication |
Environmental Science & Technology |
Abbreviated Journal |
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Volume |
54 |
Issue |
21 |
Pages |
13619-13629 |
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Abstract |
Despite the limited direct anthropogenic mercury (Hg) inputs in the circumpolar Arctic, elevated concentrations of methylmercury (MeHg) are accumulated in Arctic marine biota. However, the MeHg production and bioaccumulation pathways in these ecosystems have not been completely unraveled. We measured Hg concentrations and stable isotope ratios of Hg, carbon, and nitrogen in the feathers and blood of geolocator-tracked little auk Alle alle from five Arctic breeding colonies. The wide-range spatial mobility and tissue-specific Hg integration times of this planktivorous seabird allowed the exploration of their spatial (wintering quarters/breeding grounds) and seasonal (nonbreeding/breeding periods) MeHg exposures. An east-to-west increase of head feather Hg concentrations (1.74–3.48 μg·g–1) was accompanied by significant spatial trends of Hg isotope (particularly Δ199Hg: 0.96–1.13‰) and carbon isotope (δ13C: −20.6 to −19.4‰) ratios. These trends suggest a distinct mixing/proportion of MeHg sources between western North Atlantic and eastern Arctic regions. Higher Δ199Hg values (+0.4‰) in northern colonies indicate an accumulation of more photochemically impacted MeHg, supporting shallow MeHg production and bioaccumulation in high Arctic waters. The combination of seabird tissue isotopic analysis and spatial tracking helps in tracing the MeHg sources at various spatio-temporal scales. |
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388 |
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0013-936X |
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8023 |
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Author |
Marina Renedo, Zoyne Pedrero, David Amouroux, Yves Cherel, Paco Bustamante |
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Title |
Mercury isotopes of key tissues document mercury metabolic processes in seabirds |
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2021 |
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Chemosphere |
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263 |
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127777 |
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Demethylation Detoxification Metabolism Methylmercury Moult |
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Abstract |
Seabirds accumulate significant amounts of mercury (Hg) due to their long-life span together with their medium to high trophic position in marine food webs. Hg speciation and Hg isotopic analyses of total Hg in different tissues (pectoral muscles, liver, brain, kidneys, blood and feathers) were assessed to investigate their detoxification mechanisms. Three species with contrasted ecological characteristics were studied: the Antarctic prion (zooplankton feeder), the white-chinned petrel (pelagic generalist consumer) and the southern giant petrel (scavenger on seabirds and marine mammals). The difference of mass-dependent fractionation (MDF, δ202Hg) values between liver and muscles (up to 0.94 ‰) in all three seabirds strongly suggests hepatic demethylation of the isotopically lighter methylmercury (MeHg) and subsequent redistribution of the isotopically heavier fraction of MeHg towards the muscles. Similarly, higher δ202Hg values in feathers (up to 1.88 ‰) relative to muscles and higher proportion of MeHg in feathers (94–97%) than muscles (30–70%) likely indicate potential MeHg demethylation in muscle and preferential excretion of MeHg (isotopically heavier) in the growing feathers during moult. The extents of these key detoxification processes were strongly dependent on the species-specific detoxification strategies and levels of dietary MeHg exposure. We also found higher mass-independent fractionation (MIF, Δ199Hg) values in feathers relative to internal tissues, possibly due to different integration times of Hg exposure between permanently active organs and inert tissues as feathers. Hg isotope variations reported in this study show evidence of detoxification processes in seabirds and propose a powerful approach for deep investigation of the Hg metabolic processes in seabirds. |
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109 |
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0045-6535 |
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8084 |
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