Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

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Chapter 2 · Status of the natural and human environments

Susanne Backe

Susanne Backe

Figure 2.5 Mosaic of a Palsa mire (left), demonstrating a collapsing pals (right).

Sea whereas cold fresher Arctic Water dominates the surface layer in the northern sectors. Atlantic Water that travels north along the west coast of Svalbard (theWest Spitsbergen Current) influences ice cover in the region (Ivanov et al., 2012); inducing open water areas at very high latitudes, even in winter, in places such asWhalers Bay.The boundary between the twomain water masses (Arcticwater andAtlanticwater) is delineated by the Polar Front.There is also a coastal current running along themainland shores carrying relatively warm and fresh water eastward. See Chapter 4 for further details. Sea ice is one of the most important drivers of the Barents Sea system (see Chapter 4). The flow and interactions of the Atlantic Current in the south and the Arctic currents in the north have a significant impact on the distribution and extent of sea ice in the Barents Sea (e.g.Vinje, 2001; Årthun et al., 2012). Most of the sea ice in the Barents Sea is formed locally (Vinje and Kvambekk, 1991; Vinje, 2001) but a significant amount is imported from adjacent regions of theArctic Basin through the straits between Svalbard and Novaya Zemlya (e.g. Pavlov and Pavlova, 2008; Kwok, 2009). Arctic sea ice also makes its way south along the east Greenland coast via southward flowing currents in Fram Strait.The Barents Sea ice cover has a strong seasonal variability.The spring melt stabilizes the upper water layers and is associated with a ‘spring’ plankton bloom that has traditionally followed the receding ice edge northward into the northern Barents Sea (Sakshaug and Skjoldal, 1989). A significant part of the southern Barents Sea is ice-free throughout the year.The decline in sea-ice volume and extent in the Arctic Ocean is widely documented (e.g. Parkinson and Cavalieri, 2008; Comiso, 2012) and many studies have shown that the most dramatic changes have taken place in the Russian sector of the Barents Sea. (e.g.Overland andWang, 2007; Pavlov and Pavlova, 2008; Rodrigues, 2008; Smedsrud et al., 2013). An ecologically-focused study of seasonal changes in sea ice is provided by Laidre et al. (2015). This showed the Barents Sea region to have experienced four times the average rate of change in terms of seasonal sea-ice coverage compared to the Arctic in general, with a reduction of 20+ weeks in just the last few decades; these changes have already had impacts on the region’s biota ( Figure 2.6 ). See Chapter 4 for more detail on sea-ice dynamics.

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Figure 2.6 Temporal patterns in ocean temperature, sea-ice extent, zooplankton biomass and fish biomass in the Barents Sea. Ocean temperature (50–200 m in the AtlanticWater in the Vardø-North section in August–September), September sea-ice extent, August–September zooplankton biomass (wet weight), and August–September pelagic fish biomass (capelin, polar cod, herring) and demersal fish biomass (cod, haddock).

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