Polychaeta (Annelida) as biological assessment tools for monitoring marine ecosystem health

  • Matthew James Neave

    Student thesis: Doctor of Philosophy (PhD) - CDU


    The effects of marine pollution on polychaetes can be measured at the community level, at the level of individual organism or at a sub-organismal level. To examine community-level responses to pollution, the diversity and abundance of polychaetes were examined at sites impacted by an alumina refinery discharge and compared to reference sites. In the impacted areas, the polychaete assemblage was altered in two different benthic habitats and in hard-substrata habitats, and several polychaete indicator species were recorded. These indicator species will be useful for future impact assessments in this tropical coastal environment and may also be useful in other tropical coastal ecosystems.

    The effects of marine pollution on polychaetes were also examined at finer ecosystem scales, which required the comparison of individuals of the same species. To ensure that these comparisons were not compromised by the presence of cryptic species, the test polychaete, Ophelina cyprophila, was formally described. This species inhabited a copper- and zinc-polluted harbour and was used to examine changes in its associated bacterial assemblage and gene and protein expression. I examined changes in gene and protein expression in O. cyprophila using transcriptome sequencing, 2-dimensional protein gels and western blotting. Genes and proteins involved in respiration and detoxification were differentially regulated in the copper-impacted harbour. In addition, the copper chaperone, Atox1, was upregulated and may be a valuable and specific biomarker of copper contamination.

    I also used deep sequencing of 16S rRNA bacterial sequences associated with O. cyprophila and found changes at the impacted site, including increases in the abundance of bacteria from the order Alteromonadales. These changes in the bacteria associated with polychaetes could be a useful and novel indicator of metal pollution. In summary, polychaetes were excellent organisms for the detection of marine pollution in the Australian wet-dry tropics.
    Date of Award2011
    Original languageEnglish
    SupervisorKaren Gibb (Supervisor)

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