Microbial Ecology

, Volume 1, Issue 1, pp 191–218

The ecology of mercury-resistant bacteria in Chesapeake Bay

  • J. D. NelsonJr.
  • R. R. Colwell

DOI: 10.1007/BF02512389

Cite this article as:
Nelson, J.D. & Colwell, R.R. Microb Ecol (1974) 1: 191. doi:10.1007/BF02512389


Total ambient mercury concentrations and numbers of mercury resistant, aerobic heterotrophic bacteria at six locations in Chesapeake Bay were monitored over a 17 month period. Mercury resistance expressed as the proportion of the total, viable, aerobic, heterotrophic bacterial population reached a reproducible maximum in spring and was positively correlated with dissolved oxygen concentration and sediment mercury concentration and negatively correlated with water turbidity. A relationship between mercury resistance and metabolic capability for reduction of mercuric ion to the metallic state was established by surveying a number of HgCl2-resistant cultures. The reaction was also observed in microrganisms isolated by differential centrifugation of water and sediment samples. Mercuric ion exhibited an average half-life of 12.5 days in the presence of approximately 105 organisms/ml. Cultures resistant to 6 ppm of mercuric chloride and 3 ppm of phenylmercuric acetate (PMA) were classified into eight generic categories.Pseudomonas spp. were the most numerous of those bacteria capable of metabolizing both compounds; however, PMA was more toxic and was more selective forPseudomonas. The mercury-resistant generic distribution was distinct from that of the total bacterial generic distribution and differed significantly between water and sediment, positionally and seasonally. The proportion of nonglucose-utilizing mercury-resistantPsuedomonas spp. was found to be positively correlated with total bacterial mercury resistance. It is concluded from this study that numbers of mercury-resistant bacteria as established by plate count can serve as a valid index ofin situ Hg2+ metabolism.

Copyright information

© Springer-Verlag New York Inc. 1975

Authors and Affiliations

  • J. D. NelsonJr.
    • 1
  • R. R. Colwell
    • 1
  1. 1.Department of MicrobiologyUniversity of MarylandCollege Park
  2. 2.Biology DepartmentUniversity of BridgeportBridgeport