SS4.08 Life in Ice
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SS4.08 Life in Ice |
| Krembs, C UW, Polar Science Center, Seattle, USA, ckrembs@apl.washington.edu |
| Deming, J, W, UW, School of Oceanography, Seattle, USA, jdeming@u.washington.edu |
| Eicken, H UAF, Geophysical Institute, Fairbanks, USA, hajo.eicken@gi.alaska.edu |
| EXOPOLYMERIC SUBSTANCES, AN IMPORTANT COMPONENT OF MICROBIAL LIFE IN SEA ICE AT LOW TEMPERATURES. |
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| Microorganisms are important producers
of exopolymeric substances (EPS) which contain large portions of polysaccharides
and uronic acid. EPS are released as part of ecological strategies in mechanisms
of adhesion, stress responds, locomotion and structural components in terrestrial
and aquatic environments. The cumulative effect of EPS thereby often alters
the physical properties of the habitat. EPS constitute an assortment of large
molecules with high C/N ratios and of low nutritional value, which are metabolically
produced at low energetic cost. The porous interior of sea ice carries a significant
portion of organic material in the form of EPS, year round. To date, the
role of EPS in sea ice, however, remains unexplored. We demonstrate several
roles of EPS in the sea ice environment which include the preservation of
microbes at cold temperature, the interference of EPS with ice crystal growth
and the alteration of the brine inclusion network, increasing potential attachment
sites, habitat complexity and pore-space interconnectivity. While these effects
are ecologically beneficial at the microscopic scale, their cumulative effect
transcends to the macroscopic scale with noticeable consequences for sea-ice
physical properties. |