SS2.05 Phylogenetic and Physiologic Successions in Aquatic Bacterial Communities
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
MatthewsPJ, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, pmatthew@mun.ca
Rivkin, R, B, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, rrivkin@mun.ca
 
EFFECT OF PRESERVATION AND STORAGE ON BACTERIAL ABUNDANCE AND CELL VOLUME
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Accurate estimates of microbial biomass are essential for models of carbon flux in the upper ocean. There are often delays of weeks-to-months between the collection and processing of seawater samples for bacterial abundance and biomass. These delays may in turn influence the accuracy of estimates of both number and size of cells. The effects of storage mode (preserved in suspension at 4 C or slides at –20C) and type of preservative (formalin, or gluteraldehyde) on the measurement of bacterial numbers and cell volume was determined during a 12-month time course. Bacterial numbers were determined by direct counts using Acridine Orange and DAPI, and volumes were estimated by image analysis. Results show a gradual decrease in cell numbers and increase in volume over the 12-month time course. These results suggest that delays in the processing of samples may lead to large errors in biomass estimates and consequently the characterization of microbial carbon dynamics.