Effects of environmental and anthropogenic influences on bacterial growth and community structure in Newfoundland coastal waters

• Main Author: Hemphill, Lindsey C.
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2015
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/9803/; https://research.library.mun.ca/9803/1/thesis.pdf

The release of petroleum hydrocarbons into coastal Newfoundland waters is an environmental and economic concern. Placentia and St. Mary’s Bays, Newfoundland have contrasting anthropogenic uses and environmental conditions, with greater shipping and traffic in the former site. Bacteria have a key role in marine food web transformations; and petroleum hydrocarbons have been reported to both stimulate and inhibit marine plankton. Here, we examine the influence of temperature and the addition of various combinations of petroleum hydrocarbons, inorganic nutrients and organic carbon, on bacterial growth and composition in Placentia and St. Mary’s Bays, Newfoundland. Organic carbon plus inorganic nutrients and elevated temperature generally increased bacterial growth while petroleum hydrocarbons did not influence growth in Placentia Bay and inhibited growth in St. Mary’s Bay. High-throughput metagenomics analysis examined the response of the bacterial community and showed that the relative abundance of known hydrocarbon degraders increased in the presence of petroleum hydrocarbons, with greater numbers in Placentia than St. Mary’s Bay following incubation. The bacterial community of Placentia Bay, where concentrations of petroleum hydrocarbons are higher, may be preconditioned to favour hydrocarbon degraders compared to St Mary’s Bay.