Gibson, D. M.. Univ. of Georgia, Athens, GA/Skidaway Inst. of Oceanography, dgibson@skio.peachnet.edu
Paffenhofer, G. M.. Skidaway Institute of Oceanography, paffenhofer@skio.peachnet.edu

 
THE EFFECTS OF 4 DIFFERENT FOOD CONCENTRATIONS ON THE INGESTION RATES OF DOLIOLETTA GEGENBAURI (TUNICATA, THALIACEA)
 
The goal of this research is to enhance our knowledge of the contributions of doliolids to the planktonic community as consumers and secondary producers. The objectives are to quantify feeding, growth, and reproductive rates of Dolioletta gegenbauri at different food concentrations and temperatures in order to determine their impact as grazers throughout the water column. Although doliolids are abundant in numerous regions of the coastal ocean, and are considered to be major planktonic grazers, data on rates of feeding, growth, and reproduction are scarce. Laboratory experiments were conducted at 20 C quantifying removal of a 50:50 volumetric concentration of Thalassiosira weissflogii and Rhodomonas sp. at four different food concentrations of 18, 48, 140, and 360 ug C/l. Results from these experiments suggest that ingestion rates increase over a range of phytoplankton concentrations from 18 to 140 ug C/l, then decrease when abnormally high concentrations of 360 ug C/l are offered. However, the clearance rates are similar at concentrations from 18 to 48 ug C/l,and decrease as the food concentrations increase. These results suggest that doliolid feeding rates are a function of environmental food concentrations, and imply that they can be important consumers in neritic environments.
 
Day: Wednesday, Feb. 3
Time: 04:15 - 04:30pm
Location: Hilton of Santa Fe
 
Code: SS20WE0415H