The Port of Houston and the Houston Ship Channel (HSC) are highly
industrialized areas along Galveston Bay, Texas. The HSC is highly polluted with a host
of persistent organic pollutants, including dioxins. The main objective of this study was
to determine the potential for in situ bioremediation in the HSC sediments. Our study
focused on the bacterial group Dehalococcoides, since it is the only known group to
reductively dechlorinate dioxins. Culture independent methods were used to determine
the presence or absence of Dehalococcoides in HSC sediments. Molecular methods
including PCR, cloning, restriction enzyme digest, and sequencing were used to
determine the diversity of Dehalococcoides as well as total bacterial diversity in HSC
sediments. The metabolically active members of the microbial community in HSC
sediments were also determined using the same molecular methods as described above.
Dehalococcoides was detected in every sediment core and at various depths
within each core. Depths ranged from 1cm (SG-6) to 30cm (11261). Dehalococcoides
diversity was centered on Dehalococcoides ethenogenes strain 195 and Dehalococcoides
sp. strain CBDB1. Overall bacterial diversity in HSC sediments was dominated by Proteobacteria, especially Deltaproteobacteria, and Chloroflexi, which include
Dehalococcoides. Total bacterial diversity at a wetlands control site was dominated by
Betaproteobacteria and Acidobacteria. Deltaproteobacteria and Chloroflexi were
determined to be the major metabolically active groups within the HSC sediments. These
findings indicate that the HSC sediments have great potential for successful in situ
bioremediation. These results also support the use of Dehalococcoides as a biological
proxy for dioxin contamination.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2796 |
| Date | 15 May 2009 |
| Creators | Hieke, Anne-Sophie Charlotte |
| Contributors | Brinkmeyer, Robin |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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