Climate change and carbon flux in the Barents Sea: 3-D simulations of ice-distribution, primary production and vertical export of particulate organic carbon (scientific paper)

摘要

A 3-dimensional model is described that simulates current fields, ice-distribution, hydrography, primary production and vertical export of phytoplankton carbon in the Barents Sea. The model uses input data from meteorological stations and data from Det Norske Meterologiske Institutt (MI) hindcast database. From initial fields of temperature and salinity, changes in the hydrography as a result of transport, fresh-water supply from land, cooling/heating and melting/freezing of ice is simulated. A warm year (1984) and a cold year (1981) were selected in order to investigate how the climate may effect primary production and vertical flux. The annual production of phytoplankton is in particular dependent on the ice distribution during spring. When the ice melts, strong vertical stability is created which reduces the vertical transport of nutrients compared to conditions where thermal heating alone creates stability. A maximal extent of ice-distribution gives thus rise to a maximum area of strong stratification after the ice-melt. Comparing the cold and warm year simulated here, primary production was up to 400% higher in the ice-free area during the warm year. The total annual primary production for the whole Barents Sea increased about 30% during the warm year. Even greater variations were discovered for the vertical flux of carbon.