title: Flow cytometry assessment of bacterioplankton in tropical marine environments.
abstract: Flow cytometry was used to characterize bacterioplankton from two tropical environments in Brazil: the eutrophic Guanabara Bay and the oligotrophic southwest Atlantic Ocean. Bacterial abundance was evaluated by flow cytometry, and cells were stained with SYTO 13, allowing demonstration of differences in nucleic acid content. Bacterial production was also evaluated by means of 3H-leucine incorporation. Bacterial numbers were different for both sites. In Atlantic Ocean samples, we found a maximum of 5.50 x 10(5) cells ml(-1), and low nucleic acid content organisms predominated. In Guanabara Bay, bacterial numbers were one order of magnitude higher than in the ocean, and they varied from outer bay (1.01 x 10(6) cells ml(-1)) to inner bay (6.90 x 10(6) cells ml(-1)). Bacterial activity in ocean samples varied from 4.6 to 126 ng C l(-1) h(-1), while in the bay, mean values ranged from 1.95 microg C l(-1) h(-1) (outer bay) to 7.35 microg C l(-1) h(-1) (inner bay). Values found for both parameters are characteristic of different trophic situations. These results illustrate the utility of cytometric analyses of bacterioplankton populations in characterizing their large spatial and temporal scales of distribution in aquatic ecosystems.
authors: Department of Marine Biology, Institute of Biology, University of Brazil, Prédio do CCS, bloco A, sala A1-071-Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21944-970, Brazil.
authors: L
authors: L
authors: Andrade
authors: A M
authors: AM
authors: Gonzalez
authors: F V
authors: FV
authors: Araujo
authors: R
authors: R
authors: Paranhos
mesh_terms: D001267:Atlantic Ocean; D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism; D017753:Ecosystem; D005434:Flow Cytometry; D005456:Fluorescent Dyes / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D009930:Organic Chemicals; D010933:Plankton / Q000254:growth & development* / Q000378:metabolism; D012621:Seasons; D014329:Tropical Climate; D014871:Water Microbiology
chemical_list: D005456:Fluorescent Dyes; D009930:Organic Chemicals; C461159:SYTO 13; D007930:Leucine