Spatial and temporal variation in the population structures, carbon use and climate responses of heterotrophic microbial communities in coastal and offshore northwest Atlantic sites

• Main Author: Murphy, Ryan M. J. (Ryan Matthew John), 1982-
• Other Authors: Memorial University of Newfoundland. Dept. of Biology
• Format: Thesis
• Language: English
• Published: 2010
• Subjects: Marine microbiology > Atlantic Ocean; Northwest; Marine microbial ecology > Atlantic Ocean; Carbon cycle (Biogeochemistry) > Atlantic Ocean; Newfoundland studies; Northwest Atlantic; University of Newfoundland
• Online Access: http://collections.mun.ca/cdm/ref/collection/theses5/id/25311

Thesis (M.Sc.)--Memorial University of Newfoundland, 2011. Biology Bibliography: leaves 118-135. Heterotrophic marine micorbes were studied across spatial and temporal scales in the northwest Atlantic to investigate microbial communities' structural and functional responses to climate-relevant environmental forcings. Cellular abundance, morphometric, and 16S RNA-targetted Fluorescent In Situ Hybridization (FISH) analyses were used to examine variation in microbe-mediated carbon flow as it pertained to grazing pressure, temperature-shifts, and dissolved organic matter (DOM) availability. Significant spatial differences in growth and biomass production versus experimental manipulations indicate climate-driven physical changes in the upper ocean may influence future basin-scale patterns of the biogeochemical cycling of carbon. Seasonal variation of cell size and growth during grazer-exclusion experiments points to the increasing importance of inorganic nutrient limitation on plankton dynamics in a warming ocean. Analysis of grazing control on microbial communities relative to current and predicted ocean temperatures also suggests impacts of a warming ocean on spring phytoplankton bloom initiation and on carbon cycling in the upper ocean.