Quote:
Originally Posted by Ronbill
I checked the recent nutrient data and one basin of PCR is mesotrophic and the other is classified as eutrophic. More recently we (Alberta Environemnt) have began monitoring lakes and reservoirs including PCR for the microcystin toxin - a liver toxin produced by some species of large colonial cyanobacteria. It does show up in PCR (and Chain lakes res too), which leads me to conclude the dominance of cyanobacteria in PCR at least from July through September. For us to obtain microcystin levels in excess of 1 ug/L of lake water, high biomass of toxin-producing cyanobacteria is required.
I should also take this oportunity to dispell any other myths around toxic cyanos, namely: cyanobacteria exist in all aquatic ecosystems naturally and not all species grow exclusively in nutrient rich, shallow waters. There are some species that prefer mesotrophic (lower nutrient) systems and produce several types of toxin. Fortunately these species to not form bloms at the surface but rather congregate at deeper depths where light intensity is much reduced. These species grow and photosynthesize optimally in low light. Coincidentally, these species are also responsible for turning some lakes/reservoirs red immediately following ice during spring. Don't drink that water.  |
It does make sense. PCR is one of the greenest lakes that I have ever seen in mid summer. It gets so green that visibility is often only approximately 3-4 feet. Not kidding. my buddy had dropped a brand new rod I bought for him in the lake and we made him attempt to dive for it (approx 24 feet deep. We knew there was no way he would get it but we wanted to laugh at him while he tried.)when he was hanging onto the boat, the water was so discoloured that you could only see the top of his legs; couldnt see his knees or feet. I made note of that as I would never want to dive into that water myself.