Limited studies have been conducted on mercury concentrations in the polar cryosphere and the factors affecting the distribution of mercury within sea ice and snow are poorly understood. Here we present the first comprehensive seasonal study of elemental and total mercury concentrations in the Antarctic sea ice environment covering data from measurements in air, sea ice, seawater, snow, frost flowers, and brine. The average concentration of total mercury in sea ice decreased from winter (9.7 ng L) to spring (4.7 ng L) while the average elemental mercury concentration increased from winter (0.07 ng L) to summer (0.105 ng L). The opposite trends suggest potential photo- or dark oxidation/reduction processes within the ice and an eventual loss of mercury via brine drainage or gas evasion of elemental mercury. Our results indicate a seasonal variation of mercury species in the polar sea ice environment probably due to varying factors such as solar radiation, temperature, brine volume, and atmospheric deposition. This study shows that the sea ice environment is a significant interphase between the polar ocean and the atmosphere and should be accounted for when studying how climate change may affect the mercury cycle in polar regions.
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http://dx.doi.org/10.1021/acs.est.6b02700 | DOI Listing |
Alzheimers Dement
December 2024
Allen Institute for Brain Science, Seattle, WA, USA.
Background: Applying single-cell RNA sequencing (scRNA-seq) to the study of neurodegenerative disease has propelled the field towards a more refined cellular understanding of Alzheimer's disease (AD); however, directly linking protein pathology to transcriptomic changes has not been possible at scale. Recently, a high-throughput method was developed to generate high-quality scRNA-seq data while retaining cytoplasmic proteins. Tau is a cytoplasmic protein and when hyperphosphorylated is integrally involved in AD progression.
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January 2025
Department of Geography, Centre for Northern Studies (CEN), & Takuvik International Research Laboratory, Université Laval, Québec, QC, Canada.
The Arctic is among the most rapidly warming regions on Earth, and climate change has triggered widespread alterations to its cryosphere and ecosystems. Among these, high Arctic lakes are highly sensitive to rising temperatures due to the influence of ice cover on multiple limnological processes. Here, we studied the sediments of three lakes on northern Ellesmere Island (82.
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January 2025
Irreversible Climate Change Research Center, Yonsei University, Seoul, Republic of Korea.
The recent sea ice changes in the Northern Hemisphere (NH), necessitate elucidating the sea ice variability over the past 2.6 million years (Ma), when the Earth's glacial cycles transitioned from ∼41 to ∼100 kyr periodicity, following the Mid-Pleistocene Transition (MPT) period (0.7-1.
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January 2025
Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, USA.
Understanding the causes of past atmospheric methane (CH) variability is important for characterizing the relationship between CH, global climate and terrestrial biogeochemical cycling. Ice core records of atmospheric CH contain rapid variations linked to abrupt climate changes of the last glacial period known as Dansgaard-Oeschger (DO) events and Heinrich events (HE). The drivers of these CH variations remain unknown but can be constrained with ice core measurements of the stable isotopic composition of atmospheric CH, which is sensitive to the strength of different isotopically distinguishable emission categories (microbial, pyrogenic and geologic).
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