English
norskBlar i forfatter "Schneider, Andrea"
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Bivalve shell horizons in seafloor pockmarks of the last glacial-interglacial transition suggest a thousand years of methane emissions in the Arctic Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-05)We studied discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (1200 m water depth) and western Svalbard (798000 N, 068550 W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20–30 cm thick and centered at ... -
Diagenetic alteration of benthic foraminifera from a methane seep site on Vestnesa Ridge (NW Svalbard)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-08)Anomalously low δ<sup>13</sup>C values in foraminiferal calcite tests are due to diagenetic alteration in methane seep sites. Our study applies diagenetically altered fossil benthic foraminiferal tests as geochemical tracers in reconstructing natural past methane seepage episodes at Vestnesa Ridge offshore NW Svalbard. We combine examinations of the test wall microstructure, mineralogical and stable ... -
Diagenetically altered benthic foraminifera reveal paleo-methane seepage
(Doctoral thesis; Doktorgradsavhandling, 2018-05-02)Methane is a powerful greenhouse gas and its atmospheric concentrations varied throughout the geological history. Large amounts of methane are stored in seafloor sediments and society is apprehensive that some of this methane may enter the water column and atmosphere. Vestnesa Ridge, located offshore north-western Svalbard, is one of the northernmost known active methane seeps. This PhD project ... -
Freshwater ostracods (Crustacea) and environmental variability of polygon ponds in the tundra of the Indigirka Lowland, north-east Siberia
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)Freshwater ostracods (Crustacea, Ostracoda) are valuable biological indicators. In Arctic environments, their habitat conditions are barely known and the abundance and diversity of ostracods is documented only in scattered records with incomplete ecological characterization. To determine the taxonomic range of ostracod assemblages and their habitat conditions in polygon ponds in the Indigirka Lowland, ... -
Lupus nephritis progression in FcγRIIB-/-yaa mice is associated with early development of glomerular electron dense deposits and loss of renal DNase I in severe disease.
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-11-30)FcγRIIB<sup>-/-</sup>yaa mice develop severe lupus glomerulonephritis due to lack of an inhibitory immune cell receptor combined with a Y-chromosome linked autoimmune accelerator mutation. In the present study, we have investigated nephritis development and progression in FcγRIIB<sup>-/-</sup>yaa mice to find shared features with NZB/NZW F1 lupus prone mice and human disease. We sacrificed 25 male ... -
Methane seepage at Vestnesa Ridge (NW Svalbard) since the Last Glacial Maximum
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-21)<p>Multiple proxies in the geological record offshore NW Svalbard track shallow subseafloor diagenesis and seafloor methane seepage during the Last Glacial Maximum (LGM) extent and the disintegration of the Svalbard Barents Sea Ice Sheet (SBIS). Vestnesa Ridge, located at 79°N and in 1200 m water depth, is one of the northernmost known active methane seep sites and is characterised by a subseafloor ... -
The Permafrost Young Researchers Network (PYRN) is getting older – the past, present, and future of our evolving community
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-07)A lasting legacy of the International Polar Year (IPY) 2007–2008 was the promotion of the Permafrost Young Researchers Network (PYRN), initially an IPY outreach and education activity by the International Permafrost Association (IPA). With the momentum of IPY, PYRN developed into a thriving network that still connects young permafrost scientists, engineers, and researchers from other disciplines. ... -
Removal of methane through hydrological, microbial, and geochemical processes in the shallow sediments of pockmarks along eastern Vestnesa Ridge (Svalbard)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)The recent discovery of methane seeps in the Arctic region requires a better understanding of the fate of methane in marine sediments if we are to understand the contributions of methane to Arctic ecosystems and climate change. To further this goal, we analyze pore water data from five pockmarks along eastern Vestnesa Ridge, a sediment drift northwest of Svalbard, to quantify the consumption ...
