Spatial and temporal variation of phenanthrene-degrading bacteria in intertidal sediments.
Phenanthrene-degrading bacteria were isolated from a 1-m2 intertidal sediment site in Boston Harbor. Samples were taken six times over 2 years. A total of 432 bacteria were isolated and characterized by biochemical testing. When clustered on the basis of phenotypic characteristics, the isolates could be separated into 68 groups at a similarity level of approximately 70%. Several groups (a total of 200 isolates) corresponded to well-characterized species belonging the genera Vibrio and Pseudomonas. Only 51 of the 437 isolates (< 11.7% of the total) hybridized to a DNA probe that encodes the upper pathway of naphthalene and phenanthrene degradation in Pseudomonas putida NCIB 9816. A cluster analysis indicated that the species composition of the phenanthrene-degrading community changed significantly from sampling date to sampling date. At one sampling time, 12 6-mm-diameter core subsamples were taken within the 1-m2 site to determine the spatial variability of the degrading communities. An analysis of molecular variance, performed with the phenotypic characteristics, indicated that only 6% of the variation occurred among the 12 subsamples, suggesting that the subsamples were almost identical in composition. We concluded that the communities of phenanthrene-degrading bacteria in the sediments are very diverse, that the community structure undergoes significant change with time but does not vary significantly on a spatial scale of centimeters, and that the predominant genes that encode phenanthrene degradation in the communities are not well-characterized.
Berardesco
G
G
Environmental Sciences Program, University of Massachusetts at Boston 02125, USA.
Dyhrman
S
S
Gallagher
E
E
Shiaris
M P
MP
D019015:Geologic Sediments / Q000382:microbiology*; D010616:Phenanthrenes / Q000378:metabolism*; D010802:Phylogeny; D011549:Pseudomonas / Q000302:isolation & purification / Q000378:metabolism*; D014733:Vibrio / Q000302:isolation & purification / Q000378:metabolism*
D010616:Phenanthrenes; C031181:phenanthrene