Present address: College of Marine and Earth Studies, University of Delaware, Newark, DE 19711, USA.
Effect of environmental variables on eukaryotic microbial community structure of land-fast Arctic sea ice
Article first published online: 27 DEC 2009
© 2009 Society for Applied Microbiology and Blackwell Publishing Ltd
Volume 12, Issue 3, pages 797–809, March 2010
How to Cite
Eddie, B., Juhl, A., Krembs, C., Baysinger, C. and Neuer, S. (2010), Effect of environmental variables on eukaryotic microbial community structure of land-fast Arctic sea ice. Environmental Microbiology, 12: 797–809. doi: 10.1111/j.1462-2920.2009.02126.x
- Issue published online: 25 FEB 2010
- Article first published online: 27 DEC 2009
- Received 26 June, 2008; accepted 3 November, 2009
Sea ice microbial community structure affects carbon and nutrient cycling in polar seas, but its susceptibility to changing environmental conditions is not well understood. We studied the eukaryotic microbial community in sea ice cores recovered near Point Barrow, AK in May 2006 by documenting the composition of the community in relation to vertical depth within the cores, as well as light availability (mainly as variable snow cover) and nutrient concentrations. We applied a combination of epifluorescence microscopy, denaturing gradient gel electrophoresis and clone libraries of a section of the 18S rRNA gene in order to compare the community structure of the major eukaryotic microbial phylotypes in the ice. We find that the community composition of the sea ice is more affected by the depth horizon in the ice than by light availability, although there are significant differences in the abundance of some groups between light regimes. Epifluorescence microscopy shows a shift from predominantly heterotrophic life styles in the upper ice to autotrophy prevailing in the bottom ice. This is supported by the statistical analysis of the similarity between the samples based on the denaturing gradient gel electrophoresis banding patterns, which shows a clear difference between upper and lower ice sections with respect to phylotypes and their proportional abundance. Clone libraries constructed using diatom-specific primers confirm the high diversity of diatoms in the sea ice, and support the microscopic counts. Evidence of protistan grazing upon diatoms was also found in lower sections of the core, with implications for carbon and nutrient recycling in the ice.