Calanus Glacialis Photo: Norwegian Polar Institute

Mesozooplankton biomasses

Mesozooplankton play a key role in the Barents Sea ecosystem by transferring energy from primary producers to animals higher in the food web. Geographic distribution patterns of total mesozooplankton biomass show similarities over time, although some inter-annual variability is apparent. Challenges in covering the same area each year are inherent in such large-scale monitoring programs, and inter-annual variation in ice-cover is one of several reasons for this. This implies that estimates of average zooplankton biomasses for different years might not be directly comparable.

In 2017, relatively high biomass (> 10 g m-2) was observed in the Bear Island Trench (southwestern region), north of Svalbard/Spitsbergen; south of Franz Josef Land, and in large parts of the easterly survey-region including the South-eastern Basin. Relatively low biomass (< 3 g m-2) was observed: in the westernmost area bordering the Norwegian Sea; in regions both south and east of Svalbard/Spitsbergen, and in the south-eastern corner of the survey area (Fig. 3.3.1). Relative to 2016, the most notable difference in 2017 was enhanced biomass in easterly parts of the Barents Sea. However, a large area just north of the Kola Peninsula was not covered in 2016, which complicates comparison.

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