Gasol, J. M.. Institut de Cičncies del Mar (CSIC), pepgasol@icm.csic.es
del Giorgio, P. M.. Horn-Point Lab., delgior@hpl.umces.edu
Peters, F. Institut de Cičncies del Mar (CSIC), cesc@icm.csic.es
Pedrós-Alió, C. Institut de Cičncies del Mar (CSIC), cpedros@icm.csic.es

 
BACTERIAL ASSEMBLAGE HETEROGENEITY ASSESSED BY FLOW CYTOMETRY AND NUCLEIC ACID STAINS: WHAT DO DIFFERENT SUBPOPULATIONS MEAN ?
 
Flow cytometry is increasingly being used in aquatic microbial ecology, particularly to determine microbe abundance. Different green-fluorescent dyes can be used to stain and count chemotrophic bacteria and different variations of this simple protocol are now being used in many laboratories. But the method provides additional information other than just abundance. Based on the green fluorescence emission per cell, it is usually possible to clearly differentiate at least two subpopulations in the bacterial assemblage. It has been suggested that these subpopulations represent bacteria with high and low DNA contents (or Type II and Type I bacteria). We analyzed data from several cruises in lakes, reservoirs and oceans, and from several mesocosm, bacterial dilution-growth and grazing experiments in an attempt to further characterize these subpopulations of bacteria that are evident in the flow cytometric analyses. We will discuss how fluorescence is related to bacterial size, how these data fit with that obtained with activity probes, and how the two bacterial subpopulations relate to the general activity of the assemblage.
 
Day: Monday, Feb. 1
Time: 03:45 - 04:00pm
Location: Sweeney Center
 
Code: SS41MO0345S