Sea ice microbial production supports Ross Sea benthic commu

Details of Research

TitleSea ice microbial production supports Ross Sea benthic communities: Influence of a small but stable subsidyAbstractDiversity in guilds of primary producers enhances temporal stability in provision of organic matter to consumers. In the Antarctic ecosystem, where temporal variability in phytoplankton production is high, sea ice contains a diatom and microbial community (SIMCO) that represents a pool of organic matter that is seasonally more consistent, although of relatively small magnitude. The fate of organic material produced by SIMCO in Antarctica is largely unknown but may represent an important link between sea ice dynamics and secondary production in nearshore food webs. We used whole tissue and compound-specific stable isotope analysis of consumers to test whether the sea ice microbial community is an important source of organic matter supporting nearshore communities in the Ross Sea. We found distinct gradients in Î´ 13C and Î´15N of SIMCO corresponding to differences in inorganic carbon and nitrogen acquisition among sites with different sea ice extent and persistence. Mass balance analysis of a suite of consumers demonstrated large fluxes of SIMCO into the nearshore food web, ranging from 5% to 100% of organic matter supplied to benthic species, and 0-10% of organic matter to upper water column or pelagic inhabitants. A Î´13C analysis of nine fatty acids including two key biomarkers for diatoms, eicosapentaenoic acid (EPA, 20:5Ï‰3), and docosahexaenoic acid (DHA, 22:6Ï‰3), confirmed these patterns. We observed clear patterns in Î´13C of fatty acids that are enriched in 13C for species that acquire a large fraction of their nutrition from SIMCO. These data demonstrate the key role of SIMCO in ecosystem functioning in Antarctica and strong linkages between sea ice extent and nearshore secondary productivity. While SIMCO provides a stabilizing subsidy of organic matter, changes to sea ice coverage associated with climate change would directly affect secondary production and stability of benthic food webs in Antarctica. â"' 2012 by the Ecological Society of America.AcknowledgementsWe thank G. Funnell, R. Van Hale, R. Alumbaugh, K.Hageman, L. Jack, K. Lavin, and R. Ghosh. Support was provided from Antarctica New Zealand, University of Otago,and the Marsden Fund. Collections were made under University of Otago Ethics Committee, Ministry of Agriculture and Forestry, and Antarctica New Zealand scientific research permits.

Other

TypeArticleCitationWing, S., McLeod, R., Leichter, J., Frew, R. and Lamare, M. (2012) Sea ice microbial production supports Ross Sea benthic communities: Influence of a small but stable subsidy. Ecology, 93(2): 314-323 doi:10.1890/11-0996.1 IdentifierWing2012Relevancerank5

Linked To

Author

Lamare, M.

Start typing here to find a location	Latitude	Longitude	Zoom	Actions

loading google map....

Save Cancel