Smith, T. B.. Coastal Carolina University, tsmith@ccucs.coastal.edu
, . B.. ,

 
BACTERIVORY IN MIXOTROPHIC FLAGELLATES
 
Grazing experiments involving uptake of fluorescently labled bacteria (FLB) by nanoflagellates were performed from locations around the Hawaiian Islands with varying nutrient concentrations. It was hypothesized that the percentage of photosynthetic flagellates that consume bacteria is higher in environments with relatively low nutrient concentrations. Bacterivory by heterotrophic and mixotrophic flagellates was observed at all sites, and was highest in areas of higher nutrient concentrations (bays and harbors). Clearance rates of mixotrophic flagellates varied from 0.04 nl flag-1 h-1 in oligotrophic open ocean sites to 1.13 nl flag-1 h-1 in bays and harbors. Bacterivory was lower in oligotrophic sites,proving to be opposite to the initial hypothesis. This can be due to the relative sizes of pigmented flagellates, in both high and low nutrient environments which engage in bacterivory, and the possibility that nanoflagellates discriminate live and heat-killed bacteria for consumption. The proportion of mixotrophy was significantly low (clearance rates varied from 0.01 nl flag-1 h-1 in open ocean to 1.00 nl flag-1 h-1 in embayments) when Prymnesiophyceae flagellates were present; these cells were dominant in the systems and were not observed to graze on FLB. Ambient nutrient concentrations did not prove to be significantly related to the occurrence of mixotrophy.
 
Day: Wednesday, Feb. 3
Time: 09:15 - 09:30am
Location: Hilton of Santa Fe
 
Code: CS60WE0915H