Resource-limited baterioplankton stimulated at mid salinities across the surface mixed layer of Lake Melville, Canada

• Main Author: Moore-Gibbons, Claire
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2018
• Subjects: Canada; Lake Melville; Churchill River
• Online Access: https://research.library.mun.ca/13826/; https://research.library.mun.ca/13826/1/thesis.pdf

This study investigates dissolved organic matter (DOM) and nutrient cycling by heterotrophic bacterioplankton along a salinity gradient in the surface waters of the Lake Melville estuary, Canada. Understanding estuarine processing of DOM is essential to better constrain the potential environmental impacts of natural and anthropogenic hydrological changes to the estuarine source waters. Here, bacterial biomass and chlorophyll concentrations were compared with modelled conservative mixing, and suggests stimulation of surface bacterioplankton and primary production at mid salinities. Multi-day nutrient incubations in the dark revealed resource limitation of bacterioplankton during September when the flow rates of Churchill River are low. Changes to chemical constituents and bacterioplankton biomass suggest that a riverine-dominated site was predominantly C- and P-limited while a marine-dominated site was predominantly C- and N-limited. Results suggest that riverine inputs’ control of microbial processes are relevant to future study of food webs in this boreal estuary.