Gas chromatography-mass spectrometry selected ion monitoring and gas chromatography-tandem mass spectrometry selected reaction monitoring analyses of mono-, di- and tri-unsaturated C highly branched isoprenoid alkene biomarkers in sea ice and sediment samples: A comparative study.

Rationale: The efficiency of selected ion monitoring (SIM) and selected reaction monitoring (SRM) analyses for the quantification of three mono-, di- and tri-unsaturated highly branched isoprenoid (HBI) alkenes (IP , IPSO and HBI III, respectively), often used as proxies for the occurrence of Arctic and Antarctic sea ice or the adjacent open waters, was compared.

Methods: Gas chromatography (GC)-mass spectrometry (MS)/SIM and GC/MS/MS/SRM analyses were carried out on dilute solutions made from purified standards of these three HBIs, and then on hydrocarbon fractions of several sediment and sea ice sample extracts. More efficient and specific SRM transitions were selected after collision-induced dissociation of each precursor ion at different collision energies.

Regime shift in Arctic Ocean sea ice thickness.

Manifestations of climate change are often shown as gradual changes in physical or biogeochemical properties. Components of the climate system, however, can show stepwise shifts from one regime to another, as a nonlinear response of the system to a changing forcing. Here we show that the Arctic sea ice regime shifted in 2007 from thicker and deformed to thinner and more uniform ice cover.

Unprecedented decline of Arctic sea ice outflow in 2018.

Fram Strait is the major gateway connecting the Arctic Ocean and North Atlantic Ocean, where nearly 90% of the sea ice export from the Arctic Ocean takes place. The exported sea ice is a large source of freshwater to the Nordic Seas and Subpolar North Atlantic, thereby preconditioning European climate and deep water formation in the North Atlantic Ocean. Here we show that in 2018, the ice export through Fram Strait showed an unprecedented decline since the early 1990s.

Atmospheric deposition of polychlorinated biphenyls to seasonal surface snow at four glacier sites on Svalbard, 2013-2014.

During spring 2014 we collected annual surface snow from four glacial sites on Svalbard, an archipelago in the European Arctic. The sampling sites are 230 km apart from west to east, but are at varying elevations, affecting local atmospheric contaminant inputs. Samples were analyzed for 209 polychlorinated biphenyl (PCB) congeners.

Winter storms accelerate the demise of sea ice in the Atlantic sector of the Arctic Ocean.

A large retreat of sea-ice in the 'stormy' Atlantic Sector of the Arctic Ocean has become evident through a series of record minima for the winter maximum sea-ice extent since 2015. Results from the Norwegian young sea ICE (N-ICE2015) expedition, a five-month-long (Jan-Jun) drifting ice station in first and second year pack-ice north of Svalbard, showcase how sea-ice in this region is frequently affected by passing winter storms. Here we synthesise the interdisciplinary N-ICE2015 dataset, including independent observations of the atmosphere, snow, sea-ice, ocean, and ecosystem.

Younger Dryas ice margin retreat triggered by ocean surface warming in central-eastern Baffin Bay.

The transition from the last ice age to the present-day interglacial was interrupted by the Younger Dryas (YD) cold period. While many studies exist on this climate event, only few include high-resolution marine records that span the YD. In order to better understand the interactions between ocean, atmosphere and ice sheet stability during the YD, more high-resolution proxy records from the Arctic, located proximal to ice sheet outlet glaciers, are required.

Deposition history of polychlorinated biphenyls to the Lomonosovfonna Glacier, Svalbard: a 209 congener analysis.

A 37 m deep ice core representing 1957-2009 and snow from 2009 to 2010 were collected on the Lomonosovfonna glacier, Svalbard (78.82° N; 17.43° E) and analyzed for 209 polychlorinated biphenyl (PCB) congeners using high-resolution mass spectrometry.