Biodiv Sci ›› 2011, Vol. 19 ›› Issue (6): 770-778.DOI: 10.3724/SP.J.1003.2011.09149

Special Issue: 中国的海洋生物多样性

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Bacterial community biodiversity in estuaries and its controlling factors: a case study in Chesapeake Bay

Jinjun Kan1*, Jun Sun2   

  1. 1 Stroud Water Research Center, 970 Spencer Road, Avondale, PA 19311, USA

    2 College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China
  • Received:2011-08-24 Revised:2011-11-30 Online:2011-11-20 Published:2011-12-19
  • Contact: Jinjun Kan
  • Supported by:

    Christina River Basin Critical Zone Observatory (CZO): Spatial and temporal integration of carbon and mineral fluxes: a whole watershed approach to quantifying anthropogenic modification of critical zone carbon sequestration (NSF 2010-2015)

Abstract: Estuaries are among the most productive and dynamic aquatic ecosystems on earth, due to the mixing of fresh and salt waters and significant recycling of nutrients and organic matters. Sitting in a transitional zone, bacterial communities in an estuary typically harbor representatives of both freshwater and marine groups: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Cyanobacteria (Synechococcus), Bacteroidetes, Actinobacteria, and Verrucomicrobia. In addition, estuaries such as Chesapeake Bay also contain their own unique bacterial signatures including the SAR11 group, Roseobacter, SAR86, and Actinobacteria subclades, suggesting the ecological adaptation of organisms endemic to the Bay or perhaps, to large temperate estuaries in general. Relative to spatial variations, remarkable seasonal shifts and recurring annual patterns were identified in Chesapeake Bay bacterial communities. Besides water residence time and bacterial growth rate, many other factors are potential driving forces for the microbial diversity and bacterial population dynamics we observed. Temporal variations in bacterial communities were best explained by change in chlorophyll a (Chl a) and water temperature, while other factors such as dissolved oxygen, ammonia, nitrite and nitrate, and viral abundance also appeared to contribute to seasonal succession. Recently, the applications applications of community-based genomics and postgenomics (transcriptomics and proteomics) have allowed us to study the comprehensive gene diversity and gene expression directly from natural microbial communities. We predict that further studies and analyses of these genes and proteins will deliver new discoveries regarding the composition and function of microbial communities in aquatic environments.