Microbial Colonization of Sea-ice with Consequences for Sea-ice Physical Properties
Christopher Krembs, a biological oceanographer, is an enthusiast of life in extreme environments and extraterrestrial microbial life. These interests led him to study the interactions of microbes with the physical processes of sea ice.
Christopher Krembs during field work off
the coast of Barrow, Alaska January 28, 2003
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Sea ice contains spaces filled with liquid brine. It is here where processes of crystal growth and microbial life interact in a sensitive thermodynamical equilibrium between solid matter, liquid and solutes. Some microbial organisms are capable of manipulating this equilibrium to their ecological advantage. Christopher's research involves detecting the microbes' manipulation of the sea ice micro- and macro properties.
Microscopic image of ice, brine
and algae inside sea ice at -10°C.
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Christopher and his colleagues Hajo Eicken and Jody Deming have investigated a large pool of organic carbon-rich microbial slime in Arctic sea ice near Barrow, Alaska. The slime consists of a wide range of organic molecules referred to as exopolymeric substances (EPS). EPS is an important component in organic particle formation, vertical particle flux and microbial biofilms.
EPS visualized inside brine using the stain Alcian blue and microscopic imaging techniques. EPS either occurs freely or in association with diatoms (right image).
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EPS can facilitate cryo-preservation and aid in the attachment of algae to sea ice. Cumulatively, EPS effects sea-ice salt segregation, micro-pore structure and sea ice mechanical stability.
Left: Microscopic images
of sea ice without (A) and with EPS (B).
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Right: Experimental sea ice containing EPS makes sea
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soft and pliable.
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Christopher Krembs and his colleagues Dale Winebrenner and Hajo Eicken have ongoing research in Arctic fast ice using in situ monitoring techniques, field and ice-tank experiments combined with laboratory tests. The results are anticipated to demonstrate the noticeable effect of EPS in natural sea ice.
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Transparent ice-tunnel in conjunction with experimental test fields allow a continuous non-invasive in situ observations of the dynamics of algal biomass in the ice.
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Experimental work in ice tanks investigating the effect of EPS on sea ice properties.
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Acknowledgement: Logistical support of BASC, Hajo Eicken, Jody Deming, Lew Shapiro, Richard Glenn, Matt Irinaga, Henry Gueco, Scott Oyagak and Perry Anashugak and financial support by the Office of Polar Programs, NSF.
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