Fanny Monteiro (Bristol) Modelling diversity of marine phytoplankton (BCCS seminar Tuesday, 20/3/2012).
Phytoplankton play an important part of oceanic storage of carbon, they live near the ocean top, absorb carbon, die and sometimes sink to the depth where the carbon is sequestered. They come in diverse types, some with shells, shells of silica or calcium, some that can fix nitrogen. Originally modelling was done in a top down way, with different species examined in the lab and added to a simulation, now, a range of random artificial plankton are created with different efficiency and resource limitation trade-offs, grown in the simulated world oceans and then matched to known populations. This seems to work well, here it was used to examine distributions of nitrogen fixing plankton, the model is consistent with the limited experimental data, and predicts that unicellular nitrogen fixing plankton are more common and more significant than previously believed: the larger, colony based nitrogen fixing plankton are more common where there is more iron in the water, near deserts, and this is where data is more available. The distribution of nitrogen fixing plankton is explained by nitrogen availability, where it is available, usually because of up welling from the depths, they are out competed by other plankton species.