Abstract
Nuisance blue‐green algal (cyanobacterial) scums are a sign of advanced eutrophication in aquatic systems. Previous workers have concluded that scums arc a sign of cyanobacterial senescence, or uncontrollable buoyancy. Our studies, however, indicate that scum formation may represent a mechanism by which the cyanobactcria can dominate surface waters. The mechanism is based on a preference for CO2 over HCO3− and CO32− as a photosynthetic carbon source, particularly in poorly buffered (low total inorganic carbon) waters. On calm days, when surface waters are thermally stratified, supplies of free CO2 are depleted, resulting in an increase in ambient pH. In response to CO2 depletion, cyanobacteria form surface scums, enabling them to use CO2 at the air‐water interface. This also promotes optimal photosynthetic growth and N2 fixation while simultaneously shading underlying noncyanobacterial phytoplankton.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
