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Fig. 6. Number of observations (a); and primary production, mg C m per day (b) in the Arctic Seas as a whole (Greenland, Norwegian, Barents, Kara, Laptev, East Siberian, and Chukchi).

Fig. 6. Number of observations (a); and primary production, mg C m per day (b) in the Arctic Seas as a whole (Greenland, Norwegian, Barents, Kara, Laptev, East Siberian, and Chukchi).

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The trends of the average values of the primary production in the test areas were estimated exclusively using the actual data of the satellite surveys with no designation of zero values to the winter phase of photosynthesis and to the periods of data gaps caused by continuous cloudiness.

The trend of average value of primary production (mg C/m2 per day) is negative for the Arctic Seas as a whole (Fig. 6). Negative values are observed for the Greenland, Norwegian and Chukchi seas (Table 3). For other seas there are no perceptible tendencies of primary production change. On the contrary total production of phytoplankton (t C per day) has positive trend for all seas (Fig. 7; Table 3). The difference in the trends of the daily total primary production and its average values in the test areas may be explained by the decrease in the ice covered areas and the gradual increase in the vegetation period caused by the climate warming. Thus total primary production grows but its average value can decrease because of involving northern parts of the sea characterized by small value of primary production.

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