Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean ...

• Main Authors: Nissen, Cara, Vogt, Meike
• Format: Text
• Language: English
• Published: ETH Zurich 2020
• Subjects: Southern Ocean
• Online Access: https://dx.doi.org/10.3929/ethz-b-000398131; http://hdl.handle.net/20.500.11850/398131

The high-latitude Southern Ocean phytoplankton community is shaped by the competition between Phaeocystis and silicifying diatoms, with the relative abundance of these two groups controlling primary and export production, the production of dimethylsulfide, the ratio of silicic acid and nitrate available in the water column, and the structure of the food web. Here, we investigate this competition using a regional physical-biogeochemical-ecological model (ROMS-BEC) configured at eddy-permitting resolution for the Southern Ocean south of 35° S. We extended ROMS-BEC by an explicit parameterization of Phaeocystis colonies, so that the model, together with the previous addition of an explicit coccolithophore type, now includes all biogeochemically relevant Southern Ocean phytoplankton types. We find that Phaeocystis contribute 46 % and 40 % to annual NPP and POC export south of 60° S, respectively, making them an important contributor to high-latitude carbon cycling. In our simulation, the relative importance of ... : Biogeosciences Discussions ...