SS2.06 Microbial Diversity in Time and Space
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
WellsLE, University of Washington, Seattle, USA, chimera1@ocean.washington.edu
Deming, J, W, University of Washington, Seattle, USA, deming@ocean.washington.edu
 
ENRICHMENT OF ARCHAEA IN NEPHELOID LAYERS OF THE NORTHWEST PASSAGE: A CLUE TO THEIR PHYSIOLOGICAL POTENTIAL AND BIOGEOCHEMICAL ROLE?
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Although a great deal of evidence now supports the numerical importance of Archaea in cold marine environments (ranging from the deep sea to high latitude oceans), little information is available about what these Archaea are doing. Using fluorescent in situ hybridization, we discovered that nepheloid layers in the Northwest Passage of the Canadian Archipelago were enriched in Archaea relative to non-nepheloid surface and deep waters during late summer (median Archaeal fraction of total cells: 5% in nepheloid layers, 0.4% in surface waters and 0.7% in deep waters). Based on the Archaeal enrichment in nepheloid layers, their significant positive correlations with particle concentration (r=0.76, p < 0.05) and particulate organic nitrogen (r=0.97, p < 0.001), their published correlation with nitrite, and the known importance of nitrification in turbidity maxima of river-influenced marine environments (such as this region of the Northwest Passage), we hypothesize that the Archaea may be nitrifiers or nitrosifiers. Bacteria-biased measurements of nitrification may therefore underestimate nitrogen cycling in vast areas of the global ocean.