Effects of deposition of heavy-metal-polluted harbor mud on microbial diversity and metal resistance in sandy marine sediments.
Deposition of dredged harbor sediments in relatively undisturbed ecosystems is often considered a viable option for confinement of pollutants and possible natural attenuation. This study investigated the effects of deposition of heavy-metal-polluted sludge on the microbial diversity of sandy sediments during 12 months of mesocosm incubation. Geochemical analyses showed an initial increase in pore-water metal concentrations, which subsided after 3 months of incubation. No influence of the deposited sediment was observed in denaturing gradient gel electrophoresis (DGGE) profiles of bacterial 16S rRNA genes, whereas a minor, transient impact on the archaeal community was revealed. Phylogenetic analyses of bacterial 16S rRNA clone libraries showed an abundance of members of the Flavobacteriaceae, the alpha- and gamma-Proteobacteria, in both the muddy and the sandy sediments. Despite the finding that some groups of clones were shared between the metal-impacted sandy sediment and the harbor control, comparative analyses showed that the two sediments were significantly different in community composition. Consequences of redeposition of metal-polluted sediment were primarily underlined with cultivation-dependent techniques. Toxicity tests showed that the percentage of Cd- and Cu-tolerant aerobic heterotrophs was highest among isolates from the sandy sediment with metal-polluted mud on top.
Toes
Ann-Charlotte M
AC
Department of Biotechnology, Delft University of Technology, Julianalaan 67, NL-2628, BC, Delft, The Netherlands.
Finke
Niko
N
Kuenen
J Gijs
JG
Muyzer
Gerard
G
D001420:Bacteria, Aerobic / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D019641:DNA, Archaeal / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004587:Electrophoresis, Agar Gel; D004785:Environmental Pollutants / Q000032:analysis / Q000633:toxicity; D014644:Genetic Variation; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D019216:Metals, Heavy / Q000032:analysis*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D019641:DNA, Archaeal; D004785:Environmental Pollutants; D019216:Metals, Heavy; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S