|
Lucia Sabbatini, Francesco Cavaliere, Giorgio Dall’Oglio, Antonio Miriametro, Licia Pizzo, Dario Mancini, Guido Torrioli. (2011). COCHISE: the first light of the Italian millimetre telescope at Concordia (Dome C, Antarctica) (Vol. 31).
Abstract: COCHISE (Cosmological Observations at Concordia with High-sensitivity Instrument for Source Extraction) is a 2.6 m telescope located on the high Antarctic Plateau near the Italian–French Concordia Base. The telescope is mainly devoted to Cosmological observations, able to operate between 200 μm and 3 mm of wavelength. In this paper we describe the main characteristics of the instrument. We also report on the first light, obtained during summer 2010–2011: this result marks the beginning of millimetre astrophysical observations at Concordia. Responsivity, noise equivalent temperature and field of view of the instrument are reported. At present COCHISE is the largest telescope located at Concordia. Beside the scientific expectations, the use of this kind of instrument in the Antarctic environment poses technological aspects of relevant interest: thus COCHISE can be considered as a pathfinder for future Antarctic telescopes.
Programme: 1105
|
|
|
Jørgen Berge, Malin Daase, Paul E. Renaud, William G. Ambrose, Gerald Darnis, Kim S. Last, Eva Leu, Jonathan H. Cohen, Geir Johnsen, Mark A. Moline, Finlo Cottier, Øystein Varpe, Natalia Shunatova, Piotr Bałazy, Nathalie Morata, Jean-Charles Massabuau, Stig Falk-Petersen, Ksenia Kosobokova, Clara J. M. Hoppe, Jan Marcin Węsławski, Piotr Kukliński, Joanna Legeżyńska, Daria Nikishina, Marine Cusa, Monika Kędra, Maria Włodarska-Kowalczuk, Daniel Vogedes, Lionel Camus, Damien Tran, Emma Michaud, Tove M. Gabrielsen, Andrei Granovitch, Anya Gonchar, Rupert Krapp, Trine A. Callesen. (2015). Unexpected Levels of Biological Activity during the Polar Night Offer New Perspectives on a Warming Arctic (Vol. 25).
|
|
|
Solveig Bourgeois, Philippe Kerhervé, Maria Ll. Calleja, Gaël Many, Nathalie Morata. (2016). Glacier inputs influence organic matter composition and prokaryotic distribution in a high Arctic fjord (Kongsfjorden, Svalbard) (Vol. 164).
Abstract: With climate change, the strong seasonality and tight pelagic-benthic coupling in the Arctic is expected to change in the next few decades. It is currently unclear how the benthos will be affected by changes of environmental conditions such as supplies of organic matter (OM) from the water column. In the last decade, Kongsfjorden (79°N), a high Arctic fjord in Svalbard influenced by several glaciers and Atlantic water inflow, has been a site of great interest owing to its high sensitivity to climate change, evidenced by a reduction in ice cover and an increase in melting freshwater. To investigate how spatial and seasonal changes in vertical fluxes can impact the benthic compartment of Kongsfjorden, we studied the organic matter characteristics (in terms of quantity and quality) and prokaryotic distribution in sediments from 3 stations along a transect extending from the glacier into the outer fjord in 4 different seasons (spring, summer, autumn and winter) in 2012–2013. The biochemical parameters used to describe the sedimentary organic matter were organic carbon (OC), total nitrogen, bulk stable isotope ratios, pigments (chorophyll-a and phaeopigments) and biopolymeric carbon (BPC), which is the sum of the main macromolecules, i.e. lipids, proteins and carbohydrates. Prokaryotic abundance and distribution were estimated by 4′,6-diamidino-2-phenylindole (DAPI) staining. This study identifies a well-marked quantitative gradient of biogenic compounds throughout all seasons and also highlights a discrepancy between the quantity and quality of sedimentary organic matter within the fjord. The sediments near the glacier were organic-poor (<0.3%OC), however the high primary productivity in the water column displayed during spring was reflected in summer sediments, and exhibited higher freshness of material at the inner station compared to the outer basin (means C-chlorophyll-a/OC ~5 and 1.5%, respectively). However, sediments at the glacier front were depleted in BPC (~0.2–0.3mgCg−1DW) by 4.5 and 9 times compared to sediments from the inner and outer stations. δ13C values in sedimentary organic matter of Kongsfjorden varied between −23.8 and −19.3‰ and reflected distinct sources of organic matter between basins. Bacterial total cell numbers in sediments of Kongsfjorden were <2×108cellsml−1 and the prokaryotic community structure was strongly influenced by the marked environmental biogenic gradients. Overall, the spatial variability prevailed over the seasonal variability in sediments of Kongsfjorden suggesting that glacier inputs prominently control the functioning of this benthic ecosystem and its communities. Regional index terms: Norway, Svalbard, Kongsfjorden.
Keywords: Bacteria Biomarkers Biopolymeric carbon Climate change Pigments Polar zones
Programme: 1092
|
|
|
Catherine Lalande, Brivaëla Moriceau, Aude Leynaert, Nathalie Morata. (2016). Spatial and temporal variability in export fluxes of biogenic matter in Kongsfjorden (Vol. 39).
Abstract: The marine ecosystem of Kongsfjorden experiences large variations in primary productivity due to pronounced seasonal variations in sunlight, glacier melt, and ice cover. The objective of this study was to assess spatial and seasonal variability in the downward export of biogenic matter in Kongsfjorden. Short-term sediment traps were deployed for periods ranging from 21 to 52 h at three stations from the inner fjord to the outer fjord in May, August, and October 2012 and at one mid-fjord station in January 2013. Total particulate matter, particulate organic carbon, phytoplankton cells, chlorophyll a, biogenic particulate silica, and zooplankton fecal pellet fluxes were measured to determine the magnitude and composition of the material exported in the fjord. The amount and composition of export fluxes reflected a large phytoplankton bloom grazed upon by zooplankton in May, the melting of glaciers and the intrusion of Atlantic Water in August, the end of the glacier melt period in October, and the polar night in January. Overall, seasonal changes in the phytoplankton community impacted export efficiency in the fjord, directly through phytoplankton sinking and indirectly through zooplankton grazing. Results obtained in this study may reflect the magnitude and composition of export fluxes to expect in coming years in Kongsfjorden, especially under conditions of warmer Atlantic Water and longer glacier melt periods.
Programme: 1092
|
|
|
Maria Ll. Calleja, P. Kerhervé, S. Bourgeois, M. Kędra, A. Leynaert, E. Devred, M. Babin, N. Morata. (2017). Effects of increase glacier discharge on phytoplankton bloom dynamics and pelagic geochemistry in a high Arctic fjord (Vol. 159).
Abstract: Arctic fjords experience extremely pronounced seasonal variability and spatial heterogeneity associated with changes in ice cover, glacial retreat and the intrusion of continental shelf’s adjacent water masses. Global warming intensifies natural environmental variability on these important systems, yet the regional and global effects of these processes are still poorly understood. In the present study, we examine seasonal and spatial variability in Kongsfjorden, on the western coast of Spitsbergen, Svalbard. We report hydrological, biological, and biogeochemical data collected during spring, summer, and fall 2012. Our results show a strong phytoplankton bloom with the highest chlorophyll a (Chla) levels ever reported in this area, peaking 15.5µg/L during late May and completely dominated by large diatoms at the inner fjord, that may sustain both pelagic and benthic production under weakly stratified conditions at the glacier front. A progressively stronger stratification of the water column during summer and fall was shaped by the intrusion of warm Atlantic water (T>3°C and Sal>34.65) into the fjord at around 100m depth, and by turbid freshwater plumes (T<1°C and Sal<34.65) at the surface due to glacier meltwater input. Biopolymeric carbon fractions and isotopic signatures of the particulate organic material (POM) revealed very fresh and labile material produced during the spring bloom (13C enriched, with values up to −22.7‰ at the highest Chl a peak, and high in carbohydrates and proteins content – up to 167 and 148µg/L, respectively-), and a clear and strong continental signature of the POM present during late summer and fall (13C depleted, with values averaging −26.5‰, and high in lipid content – up to 92µg/L-) when freshwater melting is accentuated. Our data evidence the importance of combining both physical (i.e. water mass dominance) and geochemical (i.e. characteristics of material released by glacier runoff) data in order to understand the timing, intensity and characteristics of the phytoplankton bloom in Kongsfjorden, a continuously changing system due to sustained warming. In a scenario where glacial retreat is predicted to increase the impacts of meltwater discharge and associated delivery of organic and inorganic material to the surrounding waters, special attention is required in order to predict the consequences for Arctic fjords and adjacent shelf ecosystems.
Keywords: Arctic Carbon and nitrogen stable isotopes Diatom bloom Fjords Glaciers Kongsfjorden Norway Organic matter Spitsbergen Svalbard
Programme: 1092
|
|
|
Silvia De Cesare, Tarik Meziane, Laurent Chauvaud, Joëlle Richard, Mikael K. Sejr, Julien Thébault, Gesche Winkler, Frédéric Olivier. (2017). Dietary plasticity in the bivalve Astarte moerchi revealed by a multimarker study in two Arctic fjords (Vol. 567).
Abstract: Arctic coastal ecosystems are likely to be strongly affected by predicted environmental changes such as sea-ice decline and increase in freshwater input and turbidity. These changes are expected to impact primary production dynamics and consequently benthic consumers. The trophic relationship between primary producers and benthic primary consumers were compared in 2 Arctic fjords with different seasonal ice-cover: Young Sound (NE Greenland, a high-Arctic fjord) and Kongsfjorden (Svalbard Archipelago, a sub-Arctic fjord). For comparison, we selected the filter-feeding bivalve Astarte moerchi (belonging to the complex A. borealis), which has a broad geographical distribution in the Arctic. The bivalve digestive glands and food sources were characterized with fatty acids (FAs), bulk stable isotopes, and compound-specific stable isotopes of individual FAs. Our results suggest that diatoms of pelagic and/or benthic origin are the main contributors to the A. moerchi diet in Young Sound and make up a less important fraction of the diet in the Kongsfjorden population. A contribution by sympagic diatoms is clearly excluded in the sub-Arctic fjord and needs to be further assessed in the Arctic fjord. The A. moerchi diet in sub-Arctic Kongsfjorden is more diversified, varies with season, and has contributions from dinoflagellates and macroalgal detritus. These results, together with higher concentrations of total FAs in the Young Sound population, demonstrated and characterized the trophic plasticity of this bivalve species. Based on these results, we discuss potential effects of environmental factors (shifts in trophic resources, increase in turbidity) for A. moerchi populations in changing Arctic ecosystems.
Keywords: Arctic benthos Climate change Compound-specific carbon stable isotopes Fatty acids Filter-feeding bivalves Pelagic-benthic coupling Trophic markers
Programme: 1092
|
|
|
Jane Younger, Louise Emmerson, Colin Southwell, Patrick Lelliott, Karen Miller. (2015). Proliferation of East Antarctic Adélie penguins in response to historical deglaciation (Vol. 15).
Abstract: Major, long-term environmental changes are projected in the Southern Ocean and these are likely to have impacts for marine predators such as the Adélie penguin (Pygoscelis adeliae). Decadal monitoring studies have provided insight into the short-term environmental sensitivities of Adélie penguin populations, particularly to sea ice changes. However, given the long-term nature of projected climate change, it is also prudent to consider the responses of populations to environmental change over longer time scales. We investigated the population trajectory of Adélie penguins during the last glacial-interglacial transition to determine how the species was affected by climate warming over millennia. We focussed our study on East Antarctica, which is home to 30 % of the global population of Adélie penguins.
Keywords: Bayesian skyline plot Climate change ecology Demography Holocene Last glacial maximum Molecular ecology Palaeoecology Pygoscelis adeliae Seabirds
Programme: 1091
|
|
|
Jilda Alicia Caccavo, Thierry Raclot, Timothée Poupart, Yan Ropert-Coudert, Frédéric Angelier. (2021). Anthropogenic activities are associated with shorter telomeres in chicks of Adélie penguin (Pygoscelis adeliae) (Vol. 44).
Abstract: Defining the impact of anthropogenic stressors on Antarctic wildlife is an active aim for investigators. Telomeres represent a promising molecular tool to investigate the fitness of wild populations, as their length may predict longevity and survival. We examined the relationship between telomere length and human exposure in Adélie penguin chicks (Pygoscelis adeliae) from East Antarctica. Telomere length was compared between chicks from areas with sustained human activity and on neighboring protected islands with little or no human presence. Adélie penguin chicks from sites exposed to human activity had significantly shorter telomeres than chicks from unexposed sites in nearby protected areas, with exposed chicks having on average 3.5% shorter telomeres than unexposed chicks. While sampling limitations preclude our ability to draw more sweeping conclusions at this time, our analysis nonetheless provides important insights into measures of colony vulnerability. More data are needed both to understand the proximate causes (e.g., stress, feeding events) leading to shorter telomeres in chicks from human exposed areas, as well as the fitness consequences of reduced telomere length. We suggest to further test the use of telomere length analysis as an eco-indicator of stress in wildlife among anthropized sites throughout Antarctica.
Programme: 1091
|
|
|
Marlène Dupraz, Céline Toty, Valérie Noël, Agustin Estrada-Peňa, Jacob González-Solís, Thierry Boulinier, Jean-Pierre Dujardin, Karen D. McCoy. (2016). Linking morphometric and genetic divergence with host use in the tick complex, Ornithodoros capensis sensu lato (Vol. 46). Bachelor's thesis, , .
Abstract: Host specific adaptations in parasites can lead to the divergence of conspecific populations. However, this divergence can be difficult to measure because morphological changes may not be expressed or because obvious changes may simply reflect phenotypic plasticity. Combining both genetic and phenotypic information can enable a better understanding of the divergence process and help identify the underlying selective forces, particularly in closely-related species groups. Here, we link genetic and morphometric data to understand divergence patterns within the Ornithodoros (Carios) capensis complex, a group of soft ticks (Argasidae) exploiting colonial seabirds across the globe. Species designations in this complex were historically based on larval morphology and geographic location. However, recent work has suggested that divergence within the group may be at least partially linked to host specificity. We therefore first examined population genetic structure of ticks in relation to host use and geography. These analyses revealed strong structure in relation to host use, both when populations were sympatric and widely allopatric, with a secondary effect of geography. They also demonstrated the presence of several novel and presumably undescribed species exploiting these seabird hosts. We then used geometric morphometrics (landmark and outline analyses) to test whether host-associated genetic divergence is always accompanied by the same phenotypic changes. We found that morphological variation (size and shape) correlated well with genetic structure; tick size and shape varied strongly in relation to host type, and weakly with geography. These results support the hypothesis that speciation in this tick group has been more strongly shaped by host use than by geographic barriers per se. The revealed phenetic patterns now require detailed investigation to link them with host-specific selective forces.
Keywords: Adaptation Ectoparasite Host specificity Morphometry Population genetic structure Tropical seabirds
Programme: 109,1151
|
|
|
C. Barbraud, K. Delord, C. Marteau, H. Weimerskirch. (2009). Estimates of population size of white-chinned petrels and grey petrels at Kerguelen Islands and sensitivity to fisheries (Vol. 12).
Abstract: White-chinned petrels Procellaria aequinoctialis and grey petrels Procellaria cinerea are among the most frequently killed seabird species by accidental bycatch, and both species have received strong conservation concern. Data on population size are required to evaluate the impact of bycatch and to establish management plans. We estimated the population size of both species at Kerguelen, Southern Indian Ocean, from 2004 to 2006 by explicitly taking into account detection probability of burrows using distance sampling and burrow occupancy. A total of 31 line-transects were distributed across the eastern part of Kerguelen, representing a total length of 566 km. Detectability was low (from 0.19 to 0.54 for white-chinned petrels, 0.58 for grey petrels). Burrow densities varied from 1.37±0.67 to 25.77±5.23 burrows ha−1 for white-chinned petrels and was 2.78±0.79 burrows ha−1 for grey petrels. For white-chinned petrels, these densities were extrapolated to the entire surface area of vegetation and there were 234 000 (186 000–297 000) active burrows on Kerguelen. For grey petrels, the number of active burrows for the eastern part of Kerguelen was 3400 (1900–5600). Based on these estimates, the potential biological removal method suggests that the additional mortality on birds caused by the fisheries operating around Kerguelen can be considered a serious threat for the species at least at the regional scale of the Southern Indian Ocean, especially for grey petrels.
Keywords: abundance burrow density distance sampling grey petrel Kerguelen Procellaria white-chinned petrel
Programme: 109
|
|