Linking the physiologic and phylogenetic successions in free‐living bacterial communities along an estuarine salinity gradient

In this paper we assess whether the bacterial compositional succession that occurs along an estuarine salinity gradient is accompanied by changes in both community and single‐cell metabolic activity in the free‐living bacterioplankton. In addition, we explore whether up‐ and downstream estuarine communities, which are dominated by different phylogenetic groups, show distinct patterns in single‐cell activity and characteristics. We have characterized the physiological succession of the bacterioplankton along the salinity gradient in the Choptank River Estuary (Maryland), using a combination of indices of single‐cell activity, which include respiratory activity, membrane polarization and integrity, and DNA and RNA contents, combined with flow cytometry. We have also measured bacterioplankton community production, respiration, and growth efficiency along the estuary. Our data suggest that the sharp phylogenetic succession that occurs within the fresh to saltwater transition region is accompanied by profound metabolic changes both at the single‐cell and community levels and that the phylogenetic succession occurs together with measurable physiological stress. The different indices of single‐cell characteristics that we have used converge to suggest that within the fresh to saltwater transition zone, there is generalized decline in growth and possibly a loss of activity and even significant cell mortality. At the community level, these changes in singlecell physiology at the site of the phylogenetic succession appear to translate into a generalized decline in bacterial growth efficiency with a decrease in bacterial growth and production but an actual increase in bacterial carbon consumption. Our data also suggest that different phylogenetic groups may have intrinsically different levels of single‐cell activity or at least respond differently to the activity assays that we currently use.

[1]  T. Bouvier,et al.  Compositional changes in free‐living bacterial communities along a salinity gradient in two temperate estuaries , 2002 .

[2]  P. Servais,et al.  Are the actively respiring cells (CTC+) those responsible for bacterial production in aquatic environments? , 2001, FEMS microbiology ecology.

[3]  Philippe Lebaron,et al.  Does the High Nucleic Acid Content of Individual Bacterial Cells Allow Us To Discriminate between Active Cells and Inactive Cells in Aquatic Systems? , 2001, Applied and Environmental Microbiology.

[4]  P. Lebaron,et al.  Use of fluorescent probes to assess physiological functions of bacteria at single-cell level. , 2000, Microbes and infection.

[5]  P. Servais,et al.  Relationships among Bacterial Cell Size, Productivity, and Genetic Diversity in Aquatic Environments using Cell Sorting and Flow Cytometry , 2000, Microbial Ecology.

[6]  Josep M. Gasol,et al.  Using flow cytometry for counting natural planktonic bacteria and understanding the structure of planktonic bacterial communities , 2000 .

[7]  J. Pinhassi,et al.  Seasonal succession in marine bacterioplankton , 2000 .

[8]  Howard M. Shapiro,et al.  Multiparameter Flow Cytometric Analysis of Antibiotic Effects on Membrane Potential, Membrane Permeability, and Bacterial Counts of Staphylococcus aureus andMicrococcus luteus , 2000, Antimicrobial Agents and Chemotherapy.

[9]  M. Cottrell,et al.  Natural Assemblages of Marine Proteobacteria and Members of the Cytophaga-Flavobacter Cluster Consuming Low- and High-Molecular-Weight Dissolved Organic Matter , 2000, Applied and Environmental Microbiology.

[10]  S. Giovannoni,et al.  Evolution, diversity, and molecular ecology of marine prokaryotes , 2000 .

[11]  Odaa,et al.  Influence of growth rate and starvation on fluorescent in situ hybridization of Rhodopseudomonas palustris. , 2000, FEMS microbiology ecology.

[12]  J. Fuhrman,et al.  Significance of Size and Nucleic Acid Content Heterogeneity as Measured by Flow Cytometry in Natural Planktonic Bacteria , 1999, Applied and Environmental Microbiology.

[13]  E. Sherr,et al.  Estimating abundunce and single-cell characteristics of respiring bacteria via the redox dye CTC , 1999 .

[14]  R. Amann,et al.  Bacterioplankton Compositions of Lakes and Oceans: a First Comparison Based on Fluorescence In Situ Hybridization , 1999, Applied and Environmental Microbiology.

[15]  P. Servais,et al.  Flow cytometric discrimination of bacterial populations in seawater based on SYTO 13 staining of nucleic acids , 1999 .

[16]  P. Got,et al.  Viability and Virulence of Experimentally Stressed Nonculturable Salmonella typhimurium , 1999, Applied and Environmental Microbiology.

[17]  R. Desjardins,et al.  LIVE/DEAD BacLight : application of a new rapid staining method for direct enumeration of viable and total bacteria in drinking water. , 1999, Journal of microbiological methods.

[18]  J. Fuhrman,et al.  Microbial Desulfurization of a Crude Oil Middle-Distillate Fraction: Analysis of the Extent of Sulfur Removal and the Effect of Removal on Remaining Sulfur , 1999, Applied and Environmental Microbiology.

[19]  M. Sieracki,et al.  Flow Cytometric Analysis of 5-Cyano-2,3-Ditolyl Tetrazolium Chloride Activity of Marine Bacterioplankton in Dilution Cultures , 1999, Applied and Environmental Microbiology.

[20]  J. Fuhrman,et al.  Combined Microautoradiography–16S rRNA Probe Technique for Determination of Radioisotope Uptake by Specific Microbial Cell Types In Situ , 1999, Applied and Environmental Microbiology.

[21]  B. Karrasch,et al.  Is the CTC dye technique an adequate approach for estimating active bacterial cells , 1999 .

[22]  M R Barer,et al.  Bacterial viability and culturability. , 1999, Advances in microbial physiology.

[23]  J. Cole,et al.  BACTERIAL GROWTH EFFICIENCY IN NATURAL AQUATIC SYSTEMS , 1998 .

[24]  Erik M. Smith.  Coherence of microbial respiration rate and cell-specific bacterial activity in a coastal planktonic community , 1998 .

[25]  O. Decamp,et al.  Assessment of bacterioplankton viability by membrane integrity , 1998 .

[26]  P. Lebaron,et al.  Comparison of Blue Nucleic Acid Dyes for Flow Cytometric Enumeration of Bacteria in Aquatic Systems , 1998, Applied and Environmental Microbiology.

[27]  D. Gibson,et al.  Distinguishing between living and nonliving bacteria: Evaluation of the vital stain propidium iodide and its combined use with molecular probes in aquatic samples , 1998 .

[28]  Y. Prairie,et al.  Coupling Between Rates of Bacterial Production and the Abundance of Metabolically Active Bacteria in Lakes, Enumerated Using CTC Reduction and Flow Cytometry , 1997, Microbial Ecology.

[29]  N. Yamaguchi,et al.  Flow cytometric analysis of bacterial respiratory and enzymatic activity in the natural aquatic environment , 1997 .

[30]  S. Molin,et al.  Effects of stress treatments on the detection of Salmonella typhimurium by in situ hybridization. , 1997, International journal of food microbiology.

[31]  J. Fuhrman,et al.  Determination of Active Marine Bacterioplankton: a Comparison of Universal 16S rRNA Probes, Autoradiography, and Nucleoid Staining , 1997, Applied and environmental microbiology.

[32]  M. Troussellier,et al.  Succession of cellular states in a Salmonella typhimurium population during starvation in artificial seawater microcosms , 1997 .

[33]  G. G. Leppard,et al.  Relationship between the Intracellular Integrity and the Morphology of the Capsular Envelope in Attached and Free-Living Marine Bacteria , 1996, Applied and environmental microbiology.

[34]  Y. Prairie,et al.  Flow cytometric determination of bacterial abundance in lake plankton with the green nucleic acid stain SYTO 13 , 1996 .

[35]  L. Legendre,et al.  Bacterial activity during early winter mixing (Gulf of St. Lawrence, Canada) , 1996 .

[36]  William K. W. Li,et al.  DNA distributions in planktonic bacteria stained with TOTO or TO‐PRO , 1995 .

[37]  C. Duarte,et al.  Active versus inactive bacteria: size-dependence in a coastal marine plankton community , 1995 .

[38]  P. Giorgio,et al.  Increase in the proportion of metabolically active bacteria along gradients of enrichment in freshwater and marine plankton: implications for estimates of bacterial growth and production rates , 1995 .

[39]  R. Jepras,et al.  Development of a robust flow cytometric assay for determining numbers of viable bacteria , 1995, Applied and environmental microbiology.

[40]  J. Vives-Rego,et al.  Flow cytometric assessment of Escherichia coli and Salmonella typhimurium starvation-survival in seawater using rhodamine 123, propidium iodide, and oxonol , 1995, Applied and environmental microbiology.

[41]  K. Schleifer,et al.  Phylogenetic identification and in situ detection of individual microbial cells without cultivation. , 1995, Microbiological reviews.

[42]  L. Legendre,et al.  Assessment of salinity-related mortality of freshwater bacteria in the saint lawrence estuary , 1995, Applied and environmental microbiology.

[43]  R. Christen,et al.  Assessment of the state of activity of individual bacterial cells by hybridization with a ribosomal RNA targeted fluorescently labelled oligonucleotidic probe , 1994 .

[44]  B. Ward,et al.  Comparison of Nucleic Acid Hybridization and Fluorometry for Measurement of the Relationship between RNA/DNA Ratio and Growth Rate in a Marine Bacterium , 1993, Applied and environmental microbiology.

[45]  H. Ridgway,et al.  Use of a fluorescent redox probe for direct visualization of actively respiring bacteria , 1992, Applied and environmental microbiology.

[46]  David C. Smith,et al.  A simple, economical method for measuring bacterial protein synthesis rates in seawater using 3H-leucine , 1992 .

[47]  L. Ward,et al.  Seasonal distributions of suspended particulate material and dissolved nutrients in a coastal plain estuary , 1986 .