Arctic and Atlantic Ocean Surface Transcriptome or Gene expression. marine metagenome

Global warming has led to a significant reduction of sea-ice coverage in the Arctic Ocean over the last 50 years with consequences for the earth system as a whole. Of special interest are marine eukaryotic phytoplankton communities, which are the basis of the entire Arctic food web supporting large stocks of fish, contributing significantly to carbon cycling and emission of climate active trace gases (e.g. Dimethylsulfide, DMS). Ice extent and its interannual variability in the marginal ice zone have a strong influence on Arctic phytoplankton productivity. It is expected that many sea-ice phytoplankton species won't be able to adapt because the predicted environmental changes will occur on a time scale too fast for evolutionary processes. Thus, it is more likely that species well adapted to the low-temperature Arctic environment (e.g. psychrophiles) will be replaced by intruders from lower-latitudes outside the Arctic Circle, a process that may already be underway. Despite the severity of current climate changes in the Arctic Ocean caused by global warming, there is a significant lack of fundamental data about phylogenetic and functional diversity in eukaryotic phytoplankton communities from Arctic seawater and sea ice. These data are urgently needed in addition to those from intruder communities to identify differences in phylogenomic metabolism of both groups, which will help to make predictions about changes in biogeochemical cycles of elements in a warmer and ice-free Arctic Ocean. We therefore propose to conduct the first targeted metagenomic and metatranscriptomic study of eukaryotic phytoplankton communities from inflowing North Atlantic currents to high Arctic sea ice covered water masses. A comparison between DNA and mRNA will enable us to identify whether a change in community composition is reflected in metabolism underpinning biology driven cycles of CO2 and other trace gases relevant for climate (e.g. DMS). All sequencing results will be analyzed in the context of environmental conditions (e.g. temperature, nutrients, CO2, DMS) that have shaped these communities. We aim to provide a comprehensive dataset to tackle the impact of global warming on Arctic sea-ice and phytoplankton communities with consequences for carbon and trace gas cycling in the Arctic Ocean.