Hi all…despite the fact that it’s almost November, a cyanobacterial bloom generating microcystin recently occurred in a small lake near Waterloo. It is fitting then that a perspective “on the rise of toxic cyanobacteria” published earlier this year in the Canadian Journal of Fisheries and Aquatic Sciences is predicting cyanobacterial blooms are most likely to increase across the country, including the north. It’s a fairly easy read. I found it interesting that the author reports that “microcystin-LA is also encountered in Canadian waters and appears to exhibit greater persistence and bioaccumulation” (than MC-LR). Another point of interest is that the cyanobacterium previously known as Anabaena was reclassified in about 2009 to Dolichospermum. This won’t be of interest to most of you but if you are trying to look up information on a bloom in your water it might be important.
The terms algae and cyanobacteria are used somewhat interchangeably making it bit confusing (even in the title). To deal with this just recall that it is the cyanobacteria (and their blooms) that produce the cyanotoxins which are of concern to drinking water providers.
Bill
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Blooming algae: a Canadian perspective on the rise of toxic cyanobacteria
Frances R. Pick
Canadian Journal of Fisheries and Aquatic Sciences, 2016, 73(7): 1149-1158, 10.1139/cjfas-2015-0470
http://www.nrcresearchpress.com/doi/abs/10.1139/cjfas-2015-0470?utm_campaign=2016JulyEn&utm_medium=email&utm_source=NewsletterSubscribers#.V5EB-E1TGpp
Abstract
“Algal bloom reports are on the rise across Canada. While eutrophication is the main driver, other stressors of aquatic ecosystems, specifically climate change and food web alterations from the spread of invasive species and overfishing, are compounding factors acting in concert or independently. Current models can predict the average algal and cyanobacterial biomass concentrations across temperate lakes as a function of nutrients, but models to specifically predict harmful algal composition and toxicity are lacking. At the within-lake scale, where management occurs, strong year to year variations in cyanobacterial blooms remain challenging to explain, let alone predict. The most common cyanotoxins, the hepatotoxic microcystins, are chemically diverse with some variants more toxic than others and with greater propensity for persistence and bioaccumulation. These differences have been largely overlooked, as current guidelines have been based on microcystin-LR, considered the most common variant. Microcystin-LA is also encountered in Canadian waters and appears to exhibit greater persistence and bioaccumulation. With cyanobacterial blooms most likely to increase across the country, including the north, guidelines and policies for cyanotoxins in drinking and recreational waters as well as fish will need to be developed for the protection of ecosystem and human health. Ultimately, control of eutrophication is the most important option for managing toxic cyanobacterial blooms; nitrogen and phosphorus need to be considered as environmental contaminants, as both play a role in controlling the dominance of toxigenic cyanobacteria.”
