The potential impacts of exploratory drilling and aquaculture wastes on cold-water cnidarians with a focus on cold-water corals

Murray, Kathryn (2024) The potential impacts of exploratory drilling and aquaculture wastes on cold-water cnidarians with a focus on cold-water corals. Masters thesis, Memorial University of Newfoundland.

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Abstract

The study of anthropogenic impacts on benthic fauna, including cold-water corals (CWC), has increased in recent decades, but the state of knowledge fails to keep up with the rapid expansion of industry in the marine environment. Here, I aimed to experimentally probe the effects of two prominent marine industries, aquaculture and oil and gas exploration, on three representative benthic species. The first study explored the effects of finfish waste (feed and feces) on the soft coral Gersemia rubiformis and the sea anemone Aulactinia stella over 28 days. Results showed a potential difference in expansion behaviour in waste-exposed individuals compared to controls (no or inorganic sediment) for both species, as well as higher instances of pharynx eversion in A. stella. No change in lipid composition was detected as a result of waste sedimentation, although an increase in tracer fatty acids associated with salmon waste showed positive trends across treatments, especially in A. stella. The second study evaluated the effects of drilling muds from oil and gas exploration on the cup coral Flabellum (Ulocyathus) alabastrum. After 10 days of exposure to barite, bentonite, or a combination of the two, marked changes in behaviour (excessive polyp expansion) and mucus secretion were observed, along with a potentially higher density of stinging cells (nematocytes) in the combination treatment. An additional 10-day recovery period revealed a high recovery potential to the tested sedimentation rate (<6.3 mm). These findings contribute to the knowledge of potential impacts of marine industries on ecologically significant benthic animals like CWC and hopefully provide useful data towards their management and conservation.

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