THESIS
2020
xv, 160 pages : illustrations (some color) ; 30 cm
Abstract
Exposure to emerging pollutants has put marine organisms living in the coastal environments at
risk. However, the ambient concentration of these emerging pollutants is poorly understood in
Hong Kong. This dissertation is the first to measure the ambient concentrations of fluoxetine in
Port Shelter, Hong Kong. With the measured concentration of fluoxetine in eastern Hong Kong
waters, I studied its impacts on larval marine invertebrates under environmentally-relevant
concentrations. This dissertation research is also the first of its kind to modify the protocol of
comet assay to reliably detect DNA strand break in larvae exposed to a stressor at
environmentally-relevant concentrations across various phyla. Very often, the adverse impacts of
ocean acidification (OA) or exposure to...[
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Exposure to emerging pollutants has put marine organisms living in the coastal environments at
risk. However, the ambient concentration of these emerging pollutants is poorly understood in
Hong Kong. This dissertation is the first to measure the ambient concentrations of fluoxetine in
Port Shelter, Hong Kong. With the measured concentration of fluoxetine in eastern Hong Kong
waters, I studied its impacts on larval marine invertebrates under environmentally-relevant
concentrations. This dissertation research is also the first of its kind to modify the protocol of
comet assay to reliably detect DNA strand break in larvae exposed to a stressor at
environmentally-relevant concentrations across various phyla. Very often, the adverse impacts of
ocean acidification (OA) or exposure to pharmaceuticals were studied alone. However, little is
known about the interactive effect between fluoxetine and OA, even when the bioavailability of
many pharmaceuticals is pH-dependent and/or the two stressors act upon similar physiological
pathways. Even if the interactive impacts on a single species were thoroughly understood, it is
still unclear how such observed impacts could be translated to other species. Here, I exposed
larval sea urchins Heliocidaris crassispina to the environmentally relevant concentration of
fluoxetine (10 and 100 ng L-
1) under present-day (pH 8.0) and future ocean conditions (pH 7.7).
Then, I took a comparative approach and exposed larval Styela plicata to a similar set of
conditions. The impacts of fluoxetine exposure on both species were modulated by OA. However,
the impacts on the early development of S. plicata were much subtler than that observed in H.
crassispina. This study's results highlight that future studies on ecological risks should consider
interactive effects and differences in life-history traits before concluding how the stressor(s) could
affect the population and community structures.
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