Journal
MARINE ECOLOGY PROGRESS SERIES
Volume 372, Issue -, Pages 19-29Publisher
INTER-RESEARCH
DOI: 10.3354/meps07685
Keywords
Estuary; Turbidity; Light; Phytoplankton; Advection; Sulfur-stable isotopes
Categories
Funding
- Natural Sciences Research Council of Canada (NSERC)
- Fonds Quebecois de la Recherche sur la Nature et les Technologies (FQRNT)
- postgraduate NSERC and FQRNT fellowship
- Groupe de Recherche Interuniversitaire en Limnologie (GRIL)
Ask authors/readers for more resources
While estuarine turbidity maxima (ETM) are commonly known for their high biological productivity, the high abundances of primary producers in these light-limited environments have long been questioned. In the St. Lawrence River ETM, we pet-formed sampling cruises during August and October 2006 to test the hypothesis that advection of upstream algae is responsible for high phytoplankton biomass within the ETM. The ETM was situated at the freshwater end of the estuary, where salinity ranges from 0.06 to 1.10. This abrupt peak in turbidity (up to 89,9 and 49.5 nephelometer turbidity units [NTU] during August and October, respectively) coincides with peak chlorophyll a concentrations (54,8 and 22.9 mu g l(-1) during August and October, respectively); surface and depth concentrations were similar in the ETM and upstream, where the water column was vertically mixed. These biomasses represented an increase of > 1 order of magnitude compared to upstream and downstream sites, while no growth proximal factor such as light or nutrients could explain this pattern, Sulfur-stable isotopic ratios from planktonic algae in the ETM differed from those of local periphyton, but corresponded to those of attached algae grown upstream in freshwater. Phytoplankton community structures were similar throughout the salinity gradient, and the vast majority of identified algae corresponded to genera common to freshwater, ETM and downstream environments. This study provides evidence that the observed peak in phytoplankton biomass within the ETM is largely due to high inputs of phytoplankton from upstream freshwater, rather than to local growth.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available