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Sea ice algae, a major food source for herbivorous plankton and benthos in the eastern Bering Sea.

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funded by NSF through award 0732767

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sea ice algae

Sea ice algae, a major food source for herbivorous plankton and benthos in the eastern Bering Sea.

Rolf Gradinger, Katrin Iken, Bodil A Bluhm, School of Fisheries and Ocean Sciences, University of Alaska Fairbanks


Although sea ice is an inherent and sensitive habitat component of the Bering Sea ecosystem, investigations of the ice biota and production were not included in the major research efforts in this area over the last decades. In other Arctic and sub-Arctic areas sea ice primary production can contribute up to 25% to the overall yearly primary production. The scarce observations available from the Bering Sea indicate that ice algal production may be as high as 30% of the phytoplankton production; during times of ice cover, ice algal biomass can be nearly as high as integrated pelagic algal biomass.

 

The overarching hypothesis of this project was that sea ice algae are a major food source for pelagic and benthic herbivores in spring, specifically during periods of ice melt. In addressing this hypothesis, this project aimed at providing information on the spatial and temporal patterns of abundance, biomass, community composition and productivity of sea ice algae and phytoplankton just below the ice in relation to the physical and chemical environment. Environmental measurements included salinity, temperature, and nutrient concentrations in ice cores and under-ice water, as well as ice thickness, snow cover and light regime. Sedimenting material, stable isotope ratios (δ13C, δ15N) and algal community composition are used as three lines of evidence to follow the fate of ice algal production through the pelagic and into the benthic food web of the Bering Sea.

 

Field work conducted during different ice cover regimes in 2008 to 2010 were augmented with experimental work on pelagic and benthic herbivores, producing the first-ever stable isotope turnover rate measurements for any Bering Sea invertebrates. The combined data set allows for a refined interpretation of the relevance of the sea ice produced organic matter for the food web structure in the Bering Sea. The results of this research have started to be published in peer-reviewed articles.


The material presented on this web page is based upon work supported the National Science Foundation through award 0732767. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the funding bodies.

page modified 16-Feb-2013 For use of the pictures on the webpages of this NSF funded project request permission from Gradinger, Bluhm or Iken.