Restructuring of genomic provinces of surface ocean plankton under climate change

The impact of climate change on diversity, functioning and biogeography of marine plankton is a major unresolved scientific issue. Here, niche theory is applied on plankton metagenomes sampled during the Tara Oceans expedition to derive pan-ocean geographical structuring in climatic provinces for 6 size fractions, from viruses to meso-zooplankton. Assuming a high warming scenario (RCP8.5), the identified tropical provinces would expand and temperate provinces would shrink. Poleward shifts are projected for 96% of provinces in five major basins leading to their reorganization over ~50% of the surface ocean south of 60 degree north, of which 3% correspond to novel assemblages of provinces. Sea surface temperature is identified as the main driver and accounts only for ~51 % of the changes followed by phosphate (11%) and salinity (10.3%). These results demonstrate the potential of integration of genomics with physico-chemical data for higher scale modeling and understanding of ocean ecosystems.