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2018 vs 2019 Glimpses of two different environmental states

The Nansen Legacy conducted field surveys in the northern Barents Sea in August 2018 and August 2019. In 2018, the Barents Sea was virtually ice free, and sea ice work was first possible 400km north of Svalbard. In 2019, sea ice was encountered about 600km south. Preliminary results from the two field campaigns were discussed during a webinar in June. Here are some glimpses from the webinar showing differences between 2018 and 2019:

Sea ice

Dmitry Divine (NPI) showed first data suggesting that the sea ice in the Barents Sea formed and thawed differently in 2018 and 2019. For both years, sea ice formation was delayed compared to the 2006-2019 mean, but the formation process was extra delayed in 2018. This may have led to relative thin ice in 2018, which melted extraordinary rapidly in early May, leading to a virtually ice-free Barents Sea by the end of July 2018. In contrast, the sea ice cover extent in spring and summer 2019 was well above the 2006-2019 mean. Data from EM-surveys will give more information on possible differences in ice thicknesses in 2018 and 2019.

Hydrography

Sigrid Lind (NPI) showed first data suggesting that the hydrography of the Barents Sea was distinctively different in 2018 and 2019. In 2018, the Barents Sea had the highest water temperature and salinity on record, and the water column was only weakly stratified. In 2019, the ocean state of the Barents Sea appeared to have recovered from the record high water temperatures and low salinities in 2018, i.e. water temperatures had decreased in 2019 at the same time as the water had become fresher. The freshening was most likely the result of substantial melting of sea ice imported from the Arctic. The sea ice melting also led to a stronger stratification of the water column of the Barents Sea in 2019 compared to 2018.

Nutrients

Elizabeth Jones (IMR) presented first data on nutrient concentrations. The data showed lower concentrations of nitrate, silicate and dissolved inorganic carbon in August 2018 compared to August 2019. This suggests higher biological production during the ice-free conditions in 2018 compared to 2019. A thin layer of low dissolved inorganic carbon concentrations at the surface in 2019, may have been the result of sea ice melt.

[Title picture (c) Christian Morel / christianmorel.net]
Created By
Lena Seuthe
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