Changes in functional composition and gene expression in eukaryotic plankton at the Atlantic-Arctic Polar front

Abstract

Planktonic communities are shaped by ocean currents and participate in multiple global biogeochemical cycles. Unraveling how the functions of communities respond to strong environmental gradients will improve our understanding of the interactions between climate change and marine ecosystems. Here, we investigate changes in functions and gene expression of eukaryotic plankton transiting between the North Atlantic Ocean (NAO) in winter and the Arctic Ocean (AO) in spring/summer using metatranscriptomes and metagenomes from Tara Oceans. In Arctic communities, functions involved in maintaining the protein pool and translation machinery appear to be more active. Four major phylogenetically distant algal groups are abundant in both basins and show similar strategies at transcriptional level, including increased expression of some functions related to cold acclimation. These results shade lights on gene expression strategies shared by cosmopolitan phototrophs of widely separated lineages.