Distinct Seasonal Primary Production Patterns In The Sub-Polar Gyre And Surrounding Seas

by Sabrina Heerema | Published: 12-Jan-22 | Last updated: 12-Jan-22 | Tags : | category:

Research carried out by ECOTIP scientists Katherine Richardson and Jørgen Bendtsen published on December 9th 2021 in Frontiers in Marine Science demonstrates that there are distinct seasonal primary production patterns in the waters between Greenland and Norway.

It was well known that primary production in the sub-polar region is important for carbon uptake in the ocean,  but how the different water masses contribute to primary production occurring had not yet been described. Furthermore, a detailed understanding of the seasonal patterns in primary production in different water masses of the region was lacking.

In this research, the primary production for six regions between 60 – 70°N in the northern North Atlantic (between Greenland and Norway) was analysed in relation to light, photosynthetic parameters and mixed layer depth, using two primary production models: the vertically generalized production model (VGPM) is driven by satellite data and the vertically integrated primary production (VPP) model is driven by nutrient climatology.

Three important messages for the ECOTIP project emerge from the research. Firstly, although the spring bloom is a conspicuous feature in the annual distribution patterns of phytoplankton, it does not appear to produce a dominant signal in the annual distribution of primary production in any of the water masses included in the study. Secondly, the study suggests that a more shallow surface mixed layer southwest of Iceland during the winter will likely lead to an increase in primary production here. This conclusion is in contrast to global climate models that suggest that a change in the mixed layer depth here will lead to a decrease in primary production. Finally, the study suggests that a reduction of sea-ice along the East Greenland shelf would likely lead to an increase in the primary production occurring in that region. As primary production causes a significant drawdown of surface CO2 and thereby enhances ocean carbon uptake in the area (Takahashi et al., 2002) changes in primary production in this region may, ultimately, affect global greenhouse gas concentrations.