Interannual variability in Nordic seas primary production

Abstract

Abstract Skogen, M. D., Budgell, W. P., and Rey, F. 2007. Interannual variability in Nordic seas primary production. – ICES Journal of Marine Science, 64: 889–898. Phytoplankton represents the primary trophic level in marine pelagic ecosystems, through which most biological material produced by photosynthesis is further channelled through the foodweb via grazing by zooplankton. Therefore, the level and variability of primary production is believed to be an important factor for fish recruitment and growth. The Nordic seas are important feeding areas for large and important commercial fish stocks, but because of a scarcity of measurements, only few estimates of primary production exist. Additionally, primary production is highly variable because of the wide variations in light, temperature, and nutrient supply at a specific time and location. Here, primary production in the Nordic seas is studied using a coupled 3D physical, chemical, and biological ocean model, revealing large variations in primary production in space and time. The model gives a mean annual production of 73 gC m−2 y−1 and a 20% variation in phytoplankton biomass between the years of highest and lowest production. The interannual variability is linked to the North Atlantic Oscillation, sea ice, and the transport of water into the Nordic seas. The strong control of phytoplankton production by the physics suggests a possible mechanism for how climate can be an important driver for the availability of biological material in foodwebs.