Smith, D. C. Graduate School of Oceanography, dcsmith@gso.uri.edu
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BACTERIAL GROWTH AND ABUNDANCE IN BIOLOGICAL THIN-LAYERS
 
The fine-scale physical structure of marine ecosystems plays a critical role in governing the distribution and activities of microorganisms within the water column. Relatively high concentrations of phytoplankton can occur in thin-layers, which range from tens of centimeters to meters in thickness. While recent advances in instrumentation allow for the detection and sampling of these layers at the relevant spatial scales, little is known about the distribution and growth of bacteria within thin-layers. Bacterial abundance (epifluorescence microscopy) and growth rates (3H-leucine incorporation) were determined in thin-layers in the waters in Eastsound, WA, USA during June 1998. This shallow, temperate fjord was sampled at ~25 cm vertical resolution using a siphon system and at ~50 cm vertical resolution using 0.5 L Niskin bottles mounted on a free-falling rosette. Vertical profiles of bacterial growth showed microscale features consistent with the fluorescence profiles suggesting close bacteria-phytoplankton coupling at this scale with bacterial growth rates varying ~4-fold in the 10 - 20 m profiles. These data suggest that in situ growth of bacteria within thin-layers may modify water column optics via increased particle production and alteration of the dissolved organic matter field.
 
Day: Tuesday, Feb. 2
Time: 11:15 - 11:30am
Location: Hilton of Santa Fe
 
Code: SS05TU1115H