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V. Haberle, A. Marchaudon, A. Chambodut, P.-L. Blelly. (2022). Direct Determination of Geomagnetic Baselines During Quiet Periods for Low- and Mid-Latitude Observatories (Vol. 127).
Abstract: The geomagnetic field is composed of a variety of sources that act on a wide range of timescales and amplitudes. The separation of magnetic storm effects from quiet variations is needed to accurately quantify impacts of space weather events. The extraction of such quiet contributions within geomagnetic measurements is achieved by the determination of baselines, which, ideally, is done by a simple algorithm which captures quiet sources suitably well, while being applicable to an extensive network of magnetic observatories independent of the period of time. In this work, we apply signal filtering techniques on the horizontal components of geomagnetic field measurements from low- and mid-latitude observatories to determine baselines. The variations within the baseline are investigated for magnetically quiet periods between 1991 and 2019, focusing on long-term trends, seasonal and local time dependencies, and day-to-day variability. The analysis confirms that the contributing quiet sources include the secular variation and the solar quiet (Sq) current system. The non-negligible day-to-day variability, that is typical for Sq in low- and mid-latitudes, is embedded within the baseline. Thus, the filter approach extracts quiet magnetic field variations well. Comparisons with other baseline methods show good agreements. We conclude that the filter approach can be used to determine baselines automatically during magnetically quiet periods without the need of further apriori information and is applicable on a wide network of magnetic observatories. It marks the first step for deriving magnetic indices for (near) real-time space weather applications.
Keywords: magnetic baseline magnetic observatory data quiet geomagnetic field Sq current
Programme: 139
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. (2022). (Vol. 22).
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. (2022). Metabolic heat loss in southern elephant seals (Mirounga leonina) differs with stage of moult and between habitats (Vol. 104).
Keywords: Heat loss Marine mammals Moult Pinnipeds Skin temperature Thermoregulation
Programme: 1201
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. (2022). Long-term monitoring reveals topographical features and vegetation that explain winter habitat use of an Arctic rodent (Vol. 8).
Abstract: The quality of wintering habitats, such as depth of snow cover, plays a key role in sustaining population dynamics of Arctic lemmings. However, few studies so far investigated habitat use during the Arctic winter. Here, we used a unique long-term time series to test whether lemmings are associated with topographical and vegetational habitat features for their wintering sites. We examined yearly numbers and distribution of 22 769 winter nests of the collared lemming Dicrostonyx groenlandicus (Traill, 1823) from an ongoing long-term research on Traill Island, Northeast Greenland, collected between 1989 and 2019, and correlated this information with data on dominant vegetation types, elevation, and slope. We found that the number of lemming nests was highest in areas with a high proportion of Dryas heath, but was also correlated with other vegetation types, suggesting some flexibility in resource use of wintering lemmings. Furthermore, lemmings showed a higher use for sloped terrain, probably as it enhances the formation of deep snow drifts, which increases the insulative characteristics of the snowpack and protection from predators. With global warming, prime lemming winter habitats may become scarce through alteration of snow physical properties, potentially resulting in negative consequence for the whole community of terrestrial vertebrates.
Programme: 1036
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. (2022). (Vol. 8).
Keywords: Brazil geofacts Late Glacial Maximum Pedra Furada Peopling of the Americas
Programme: 1217
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Yanzhi Cao, Zhuang Jiang, Becky Alexander, Jihong Cole-Dai, Joel Savarino, Joseph Erbland, Lei Geng. (2022). On the potential fingerprint of the Antarctic ozone hole in ice-core nitrate isotopes: a case study based on a South Pole ice core (Vol. 22).
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. (2022). Assessing marine ecosystem complexity: isotopic integration of the trophic structure of seabird communities from the Southern Ocean (Vol. 694).
Keywords: Antarctica Body size Habitat Penguins Procellariiformes Stable isotopes Trophic position
Programme: 109
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Yves Cherel, Karine Delord, Christophe Barbraud, Henri Weimerskirch. (2022). Diet, isotopic niche, and spatial distribution of the white-headed petrel (Pterodroma lessonii) at Kerguelen Islands (Vol. 45).
Keywords: Fish Food Myctophidae Procellariiformes Seabirds Southern ocean Squid
Programme: 109
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Yves Cherel, Pierrick Bocher. (2022). Diet of the soft-plumaged petrel (Pterodroma mollis) at Kerguelen Islands and a review of the food of gadfly petrels (Pterodroma spp.) worldwide (Vol. 169).
Abstract: Little is known on the food and feeding ecology of the soft-plumaged petrel Pterodroma mollis, which is the single gadfly petrel Pterodroma spp. with a circumpolar breeding distribution within the Southern Ocean. Our primary goal was to describe its diet at Kerguelen Islands, which is the southernmost breeding locality of the species. Soft-plumaged petrels fed on fish (71% by mass), and secondarily on crustaceans (22%), while cephalopods (7%) and other items (
Keywords: Fish Food Myctophidae Procellariiformes Seabirds Southern Ocean Squid Tropics
Programme: 109
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Chastel O., Blévin P., Humann?Guilleminot S., Helfenstein F., Tartu S., Angelier F., Sebastiano M., Costantini D., Shaffer S., Bustamante P., Labadie P., Budzinski H., Herzke D., Moe B., Bustnes J.O., Gabrielsen G.W. . (2021). Contaminants of growing concern: Poly- and Perfluoroalkylated Substances (PFAS) and their physiological consequences in seabirds.
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