Sea Ice is an ephemeral habitat that covers up to 13% of the earth’s surface. Sea ice contains a dense network of brine channels, ranging from cm - µm in width, that contain diverse microbial assemblages. In polar regions, sea ice algae (primarily diatoms) play an important role in the ecology of marine systems, particularly as a source of algal biomass for invertebrate grazers, seeding organisms for the post melt phytoplankton bloom, as producers of atmospherically active trace gases and f dissolved organic compounds (DOM).
Most diatoms produce extracellular polymeric substances (exopolymers or EPS) into the environment. These EPS form stalks and pads for attachment, capsules of mucilage surrounding cells, and in pennate (bilaterally symmetrical diatoms) are used in gliding motility. Preliminary work has found that much of the DOM present in sea ice may be in the form of EPS.
In this joint project, in association with David Thomas at Bangor University (Antarctic scene image provided by), we are investigating the role of EPS within the sea ice environment, particularly the seasonal and spatial distribution of EPS in sea ice, whether diatoms change the properties of their EPS as a response to changing conditions (extremes of temperature - down to –20oC, salinity (up to 300 ‰) and low light 5-10 µmol m-2 s-1) and does EPS confer advantages on diatoms and other microorganisms , such as cryoprotection, maintenance of a local microenvironment?
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