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Author Francesco Enrichi, Dorthe Dahl-Jensen, Jørgen Peder Steffensen, Carlo Barbante
Title Theoretical and Experimental Analysis for Cleaning Ice Cores from EstisolTM 140 Drill Liquid Type Journal
Year 2021 Publication Applied Sciences Abbreviated Journal
Volume 11 Issue 9 Pages 3830
Keywords Beyond EPICA drilling Estisol ice cores
Abstract To reconstruct climate history of the past 1.5 Million years, the project: Beyond EPICA Oldest Ice (BEOI) will drill about 2700 m of ice core in East Antarctica (2021–2025). As drilling fluid, an aliphatic ester fluid, EstisolTM 140, will be used. Newly drilled ice cores will be retrieved from the drill soaked in fluid, and this fluid should be removed from the cores. Most of it will be vacuum-cleaned off in a Fluid Extraction Device and wiped off with paper towels. Based on our experiences in Greenland deep ice coring, most of the residual fluid can be removed by storing the cores openly on shelves in a ventilated room. After a week of “drying”, the cores have a dry feel, handling them do not give “wet” gloves and they can easily be marked with lead pencils. This paper presents a theoretical investigation and some simple testing on the “drying” process. The rates of sublimation of ice and evaporation of fluid have been calculated at different temperatures. The calculations show that sublimation of the ice core should not occur, and that evaporation of fluid should be almost negligible. Our test results support these calculations, but also revealed significant fluid run-off and dripping, resulting in the removal of most of the fluid in a couple of days, independent of temperature and ventilation conditions. Finally, we discuss crucial factors that ensure optimal long-term ice core preservation in storage, such as temperature stability, defrosting cycles of freezers and open core storage versus storage of cores in insulated crates.
Programme 1202
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Call Number Serial 8247
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Author Emilia Trudnowska, Léo Lacour, Mathieu Ardyna, Andreas Rogge, Jean Olivier Irisson, Anya M. Waite, Marcel Babin, Lars Stemmann
Title Marine snow morphology illuminates the evolution of phytoplankton blooms and determines their subsequent vertical export Type Journal
Year 2021 Publication Nature Communications Abbreviated Journal
Volume 12 Issue 1 Pages 2816
Keywords Carbon cycle Marine biology
Abstract The organic carbon produced in the ocean’s surface by phytoplankton is either passed through the food web or exported to the ocean interior as marine snow. The rate and efficiency of such vertical export strongly depend on the size, structure and shape of individual particles, but apart from size, other morphological properties are still not quantitatively monitored. With the growing number of in situ imaging technologies, there is now a great possibility to analyze the morphology of individual marine snow. Thus, automated methods for their classification are urgently needed. Consequently, here we present a simple, objective categorization method of marine snow into a few ecologically meaningful functional morphotypes using field data from successive phases of the Arctic phytoplankton bloom. The proposed approach is a promising tool for future studies aiming to integrate the diversity, composition and morphology of marine snow into our understanding of the biological carbon pump.
Programme 1164
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ISSN 2041-1723 ISBN Medium
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Notes Approved yes
Call Number Serial 8250
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Author Natasha Roy, James Woollett, Najat Bhiry, Isabel Lemus-Lauzon, Ann Delwaide, Dominique Marguerie
Title Anthropogenic and climate impacts on subarctic forests in the Nain region, Nunatsiavut: Dendroecological and historical approaches Type Journal
Year 2021 Publication Écoscience Abbreviated Journal
Volume 28 Issue 3-4 Pages 361-376
Keywords approches historiques croissance démographique Dendrochronologie Dendrochronology détente de croissance radiale growth release historical approaches Nain Nunatsiavut population growth
Abstract Several recent dendrochronological, macrofossil and palynological studies have surveyed modern spruce forests at multiple locations in the Nain region of coastal Nunatsiavut (north-central Labrador) in order to reconstruct past forest composition, growth rates, species diversity and harvesting patterns. The present paper synthesizes original and previously collected data to evaluate the extent to which the dynamics of the region’s spruce forests over the past five centuries have been related to anthropogenic impacts. In three key case studies, Picea growth release events demonstrate multiple isolated forest disturbances prior to the late 19th century. In general, these events correspond to the local human settlement history rather than to regional climatic trends, suggesting that ongoing human impacts on the forest extend as far back as the 17th century. Disturbance regimes accelerated by ca 1875 and afterward in all of the study sites. This increase in forest disturbance corresponds to increased demands for wood triggered by socio-economic changes experienced by the region’s Inuit and Settler communities. Ongoing surveys demonstrate the presence of markers of human exploitation of forests throughout the study region, and especially in coastal locations, suggesting that anthropogenic impacts are in fact generalised and not limited to specific areas of recent settlement.
Programme 1080
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ISSN 1195-6860 ISBN Medium
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Notes Approved yes
Call Number Serial 8251
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Author M. Legrand, R. Weller, S. Preunkert, B. Jourdain
Title Ammonium in Antarctic Aerosol: Marine Biological Activity Versus Long-Range Transport of Biomass Burning Type Journal
Year 2021 Publication Geophysical Research Letters Abbreviated Journal
Volume 48 Issue 11 Pages e2021GL092826
Keywords aerosol black carbon ammonium Antarctic biomass burning et marine biota oxalate potassium
Abstract Year-round records of the ionic composition of Antarctic aerosol were obtained at the inland Dome C (DC) and coastal Neumayer (NM) sites, with additional observations of black carbon (BC) at NM. Discussions focus on the origin of ammonium in Antarctica. This first Antarctic atmospheric study of several species emitted by biomass burning (BB) indicates that BC and oxalate reach a maximum in October in relation to BB activity in the southern hemisphere. Ammonium reaches a maximum 2 months later, suggesting that BB remains a minor ammonium source there. The ammonium maximum in December coincides with the occurrence of diatom blooms in the austral ocean, suggesting that oceanic ammonia emissions are the main source of ammonium in Antarctica. The ammonium to sulfur-derived biogenic species molar ratio of 0.15 in summer suggests far lower ammonia emissions from the Antarctic oceans than midlatitude southern oceans.
Programme 903
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ISSN 1944-8007 ISBN Medium
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Notes Approved yes
Call Number Serial 8252
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Author Christopher Burot, Rémi Amiraux, Patricia Bonin, Sophie Guasco, Marcel Babin, Fabien Joux, Dominique Marie, Laure Vilgrain, Hermann J. Heipieper, Jean-François Rontani
Title Viability and stress state of bacteria associated with primary production or zooplankton-derived suspended particulate matter in summer along a transect in Baffin Bay (Arctic Ocean) Type Journal
Year 2021 Publication Science of The Total Environment Abbreviated Journal
Volume 770 Issue Pages 145252
Keywords Bacterial viability EPS isomerase Micro- and macro-zooplankton Salinity stress Sea ice algae
Abstract In the framework of the GreenEdge Project (whose the general objective is to understand the dynamic of the phytoplankton spring bloom in Arctic Ocean), lipid composition and viability and stress state of bacteria were monitored in sea ice and suspended particulate matter (SPM) samples collected in 2016 along a transect from sea ice to open water in Baffin Bay (Arctic Ocean). Lipid analyses confirmed the dominance of diatoms in the bottommost layer of ice and suggested (i) the presence of a strong proportion of micro-zooplankton in SPM samples collected at the western ice covered St 403 and St 409 and (ii) a high proportion of macro-zooplankton (copepods) in SPM samples collected at the eastern ice covered St 413 and open water St 418. The use of the propidium monoazide (PMA) method allowed to show a high bacterial mortality in sea ice and in SPM material collected in shallower waters at St 409 and St 418. This mortality was attributed to the release of bactericidal free fatty acids by sympagic diatoms under the effect of light stress. A strong cis-trans isomerization of bacterial MUFAs was observed in the deeper SPM samples collected at the St 403 and St 409. It was attributed to the ingestion of bacteria stressed by salinity in brine channels of ice by sympagic bacterivorous microzooplankton (ciliates) incorporating trans fatty acids of their preys before to be released in the water column during melting. The high trans/cis ratios also observed in SPM samples collected in the shallower waters at St 413 and St 418 suggest the presence of positively or neutrally buoyant extracellular polymeric substances (EPS)-rich particles retained in sea ice and discharged (with bacteria stressed by salinity) in seawater after the initial release of algal biomass. Such EPS particles, which are generally considered as ideal vectors for bacterial horizontal distribution in the Arctic, appeared to contain a high proportion of dead and non-growing bacteria.
Programme 1164
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ISSN 0048-9697 ISBN Medium
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Notes Approved yes
Call Number Serial 8253
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Author Christo Buizert, T. J. Fudge, William H. G. Roberts, Eric J. Steig, Sam Sherriff-Tadano, Catherine Ritz, Eric Lefebvre, Jon Edwards, Kenji Kawamura, Ikumi Oyabu, Hideaki Motoyama, Emma C. Kahle, Tyler R. Jones, Ayako Abe-Ouchi, Takashi Obase, Carlos Martin, Hugh Corr, Jeffrey P. Severinghaus, Ross Beaudette, Jenna A. Epifanio, Edward J. Brook, Kaden Martin, Jérôme Chappellaz, Shuji Aoki, Takakiyo Nakazawa, Todd A. Sowers, Richard B. Alley, Jinho Ahn, Michael Sigl, Mirko Severi, Nelia W. Dunbar, Anders Svensson, John M. Fegyveresi, Chengfei He, Zhengyu Liu, Jiang Zhu, Bette L. Otto-Bliesner, Vladimir Y. Lipenkov, Masa Kageyama, Jakob Schwander
Title Antarctic surface temperature and elevation during the Last Glacial Maximum Type Journal
Year 2021 Publication Science Abbreviated Journal
Volume 372 Issue 6546 Pages 1097-1101
Keywords
Abstract Water-stable isotopes in polar ice cores are a widely used temperature proxy in paleoclimate reconstruction, yet calibration remains challenging in East Antarctica. Here, we reconstruct the magnitude and spatial pattern of Last Glacial Maximum surface cooling in Antarctica using borehole thermometry and firn properties in seven ice cores. West Antarctic sites cooled ~10°C relative to the preindustrial period. East Antarctic sites show a range from ~4° to ~7°C cooling, which is consistent with the results of global climate models when the effects of topographic changes indicated with ice core air-content data are included, but less than those indicated with the use of water-stable isotopes calibrated against modern spatial gradients. An altered Antarctic temperature inversion during the glacial reconciles our estimates with water-isotope observations.
Programme 902
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Call Number Serial 8254
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Author Makoto Sampei, Louis Fortier, Patrick Raimbault, Kohei Matsuno, Yoshiyuki Abe, Bernard Quéguiner, Augustin Lafond, Marcel Babin, Toru Hirawake
Title An estimation of the quantitative impacts of copepod grazing on an under sea-ice spring phytoplankton bloom in western Baffin Bay, Canadian Arctic Type Journal
Year 2021 Publication Elementa: Science of the Anthropocene Abbreviated Journal
Volume 9 Issue 1 Pages 00092
Keywords
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.
Programme 1164
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ISSN 2325-1026 ISBN Medium
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Notes Approved yes
Call Number Serial 8255
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Author F. Bultelle, I. Boutet, S. Devin, F. Caza, Y. St-Pierre, R. Péden, P. Brousseau, P. Chan, D. Vaudry, F. Le Foll, M. Fournier, M. Auffret, B. Rocher
Title Molecular response of a sub-antarctic population of the blue mussel (Mytilus edulis platensis) to a moderate thermal stress Type Journal
Year 2021 Publication Marine Environmental Research Abbreviated Journal
Volume 169 Issue Pages 105393
Keywords 2DE Abiotic stress Biomonitoring Gills Indicator species Kerguelen island Mytilus sp. qRT-PCR Temperature
Abstract The Kerguelen Islands (49°26′S, 69°50′E) represent a unique environment due to their geographical isolation, which protects them from anthropogenic pollution. The ability of the endemic mussel, part of the Mytilus complex, to cope with moderate heat stress was explored using omic tools. Transcripts involved in six major metabolic functions were selected and the qRT-PCR data indicated mainly changes in aerobic and anaerobic energy metabolism and stress response. Proteomic comparisons revealed a typical stress response pattern with cytoskeleton modifications and elements suggesting increased energy metabolism. Results also suggest conservation of protein homeostasis by the long-lasting presence of HSP while a general decrease in transcription is observed. The overall findings are consistent with an adaptive response to moderate stresses in mussels in good physiological condition, i.e. living in a low-impact site, and with the literature concerning this model species. Therefore, local blue mussels could be advantageously integrated into biomonitoring strategies, especially in the context of Global Change.
Programme 409
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ISSN 0141-1136 ISBN Medium
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Notes Approved yes
Call Number Serial 8256
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Author Samantha C. Patrick, Julien G. A. Martin, Caroline C. Ummenhofer, Alexandre Corbeau, Henri Weimerskirch
Title Albatrosses respond adaptively to climate variability by changing variance in a foraging trait Type Journal
Year 2021 Publication Global Change Biology Abbreviated Journal
Volume 27 Issue 19 Pages 4564-4574
Keywords bet-hedging intra-individual variability resource acquisition salt-water immersion logger seabirds Southern Oscillation Index
Abstract The ability of individuals and populations to adapt to a changing climate is a key determinant of population dynamics. While changes in mean behaviour are well studied, changes in trait variance have been largely ignored, despite being assumed to be crucial for adapting to a changing environment. As the ability to acquire resources is essential to both reproduction and survival, changes in behaviours that maximize resource acquisition should be under selection. Here, using foraging trip duration data collected over 7 years on black-browed albatrosses (Thalassarche melanophris) on the Kerguelen Islands in the southern Indian Ocean, we examined the importance of changes in the mean and variance in foraging behaviour, and the associated effects on fitness, in response to the El Niño Southern Oscillation (ENSO). Using double hierarchical models, we found no evidence that individuals change their mean foraging trip duration in response to a changing environment, but found strong evidence of changes in variance. Younger birds showed greater variability in foraging trip duration in poor conditions as did birds with higher fitness. However, during brooding, birds showed greater variability in foraging behaviour under good conditions, suggesting that optimal conditions allow the alteration between chick provisioning and self-maintenance trips. We found weak correlations between sea surface temperature and the ENSO, but stronger links with sea-level pressure. We suggest that variability in behavioural traits affecting resource acquisition is under selection and offers a mechanism by which individuals can adapt to a changing climate. Studies which look only at effects on mean behaviour may underestimate the effects of climate change and fail to consider variance in traits as a key evolutionary force.
Programme 109
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ISSN 1365-2486 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8257
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Author Daniel C. Jones, Filipe R. Ceia, Eugene Murphy, Karine Delord, Robert W. Furness, Ariane Verdy, Matthew Mazloff, Richard A. Phillips, Paul M. Sagar, Jean-Baptiste Sallée, Ben Schreiber, David R. Thompson, Leigh G. Torres, Philip J. Underwood, Henri Weimerskirch, José C. Xavier
Title Untangling local and remote influences in two major petrel habitats in the oligotrophic Southern Ocean Type Journal
Year 2021 Publication Global Change Biology Abbreviated Journal
Volume 27 Issue 22 Pages 5773-5785
Keywords Antarctic Circumpolar Current (ACC) biogeography conservation grey petrels high seas hotspot open ocean primary productivity Procellaria cinerea seabirds
Abstract Ocean circulation connects geographically distinct ecosystems across a wide range of spatial and temporal scales via exchanges of physical and biogeochemical properties. Remote oceanographic processes can be especially important for ecosystems in the Southern Ocean, where the Antarctic Circumpolar Current transports properties across ocean basins through both advection and mixing. Recent tracking studies have indicated the existence of two large-scale, open ocean habitats in the Southern Ocean used by grey petrels (Procellaria cinerea) from two populations (i.e., Kerguelen and Antipodes islands) during their nonbreeding season for extended periods during austral summer (i.e., October to February). In this work, we use a novel combination of large-scale oceanographic observations, surface drifter data, satellite-derived primary productivity, numerical adjoint sensitivity experiments, and output from a biogeochemical state estimate to examine local and remote influences on these grey petrel habitats. Our aim is to understand the oceanographic features that control these isolated foraging areas and to evaluate their ecological value as oligotrophic open ocean habitats. We estimate the minimum local primary productivity required to support these populations to be much <1% of the estimated local primary productivity. The region in the southeast Indian Ocean used by the birds from Kerguelen is connected by circulation to the productive Kerguelen shelf. In contrast, the region in the south-central Pacific Ocean used by seabirds from the Antipodes is relatively isolated suggesting it is more influenced by local factors or the cumulative effects of many seasonal cycles. This work exemplifies the potential use of predator distributions and oceanographic data to highlight areas of the open ocean that may be more dynamic and productive than previously thought. Our results highlight the need to consider advective connections between ecosystems in the Southern Ocean and to re-evaluate the ecological relevance of oligotrophic Southern Ocean regions from a conservation perspective.
Programme 109
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ISSN 1365-2486 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8258
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