PRINCIPAL 



INVESTIGATOR(S) Stephen Giovannoni 



Department of Microbiology 

 Oregon State University 

 Corvallis, OR 97331 



PROJECT TITLE THE DYNAMICS OF CARBON EXCHANGE IN 



VERTICALLY STRATIFIED COASTAL 

 BACTERIOPLANKTON COMMUNITIES 



AMOUNT OF FUNDING FY 1994: $125 K 



SUMMARY OF GOALS 



Evidence suggests that bacterioplankton communities may be stratified, and that major 

 taxa in displaced communities can undergo downward shifts in growth rate. The overall goal of 

 this project is to determine whether vertical stratification in bacterioplankton communities affects 

 carbon transport. 



The short-range experimental goals of this project are: (1) to identify bacterial taxa 

 which are abundant in the OMP study area; (2) to determine whether these taxa are vertically 

 stratified; (3) to determine whether physical events which mix stratified communities cause 

 specific taxa to decline in growth rate or enter stationary phase. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



Current sampling methods limit bulk hybridization techniques to about 4 stations per 

 transect across the continental shelf in the OMP study region. Samples for vertical profiles are 

 collected at 10 meter intervals. About 10 liters of water are required per sample. Two hours are 

 needed for onboard processing of a vertical profile consisting of 4 - 7 samples. Vertical sampling 

 is not possible at every site in transects at this time. Hence, stations in the center of the study 

 region and on the edge of the continental shelf have been chosen for repetitive sampling. 



METHODS AND PLATFORMS 



Bacterioplankton samples are collected with Niskin bottles and standard filtration methods. 

 Total plankton nucleic acids are prepared at shore labs. Hybridization to radioactive 

 oligonucleotides complementary to ribosomal RNAs is used to measure the abundance of specific 



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