Project II.2.3h: Characterizing communities - Myrionecta rubra
Project Name: II.2.3h Characterizing communities - Myrionecta rubra
Project Leads: Lydie Herfort and Peter Zuber
Project Summary
Our goal is to describe the vertical and horizontal dynamic of M. rubra blooms in the Columbia river estuary and to characterize the impact of these blooms on the eukaryotic microbial and bacterial assemblages of the estuary.
Fit in program
Myrionecta rubra is a myxotrophic ciliate that ‘steals’ the chloroplasts and nucleus of its cryptophyte algae prey and as such is functionally a primary producer. Some of the highest rates of photosynthesis have been measured in M. rubra blooms. Given that the Columbia River estuary is characterized by low rates of primary production compared to the surrounding river and coastal ocean water, blooms of M. rubra are likely to be significant contributors to the total primary production of the estuary and thus have important biogeochemical impacts on the system. Since M. rubra blooms commonly occur in the estuary during late summer/early fall and because they correlate with important physical factors (e.g. low river flow, elevated temperature, water column stability), this important ciliate might serve as one of CMOP’s microbial sentinels. M. rubra is known to be prey to toxic dinoflagellates (Dinophysis) and its prolonged presence at elevated populations could foster a rise in levels of toxic marine microorganisms.
Outcomes
Surface water was collected in the estuary in and out of M. rubra bloom patches in August 2007 and October 2008. Microbial eukaryotic and bacterial assemblages were characterized by SSU rRNA sequence analyses (cloning), microscope cell counts, pigment analysis and bacterial production rates. A suite of physical and chemical parameters were also measured.
