Spatial distribution and seasonal variation of epiphytic cyanobacteria, filamentous algae and macrophytes in the St. Lawrence River

The epiphytic cyanobacterium Gloeotrichia pisum forms spherical colonies embedded in a gelatinous matrix that is attached to submerged aquatic vegetation. In surveys of two fluvial lakes of the St. Lawrence River conducted in 2006–2007, growth conditions and diazotrophic ability in conjunction with the biomass and condition of its supporting macrophyte, Vallisneria americana, were examined. G. pisum integrates complex, temporally variable water-quality characteristics that are dependent upon hydrology and water residence time, thus acting as an early warning indicator of incipient habitat degradation that may lead to cyanobacterial proliferation and low biomass of vascular macrophytes.

Supplemental Information

The St. Lawrence Action Plan (SLAP) 2011 to 2026 (see http://planstlaurent.qc.ca/en/home.html) is the latest Canada-Quebec Agreement on the St. Lawrence and builds on the four previous agreements implemented since 1988.

For more information on SLAP, please visit https://www.canada.ca/en/environment-climate-change/services/environmental-funding/ecosystem-initiatives/st-lawrence-action-plan.html