For the second time this summer we’re seeing evidence of a major blue-green algae bloom. Since it’s late in the season nobody has really noticed the murky water this time around, but this morning there is green scum floating on the surface of the lake, mostly visible around the edges where it is piling up against the shore. I’ve posted a few pictures. I wondered if we’d be seeing another bloom after David Hodsdon reported several weeks ago the TP (Total Phosphorus) reading of 0.023 mg/l from the 8/12/2013 water test. That much phosphorus usually indicates a bloom is on the way or underway. David had reported an algae bloom back in late July so I thought at the time the bloom winding down, but it is clear now that it the algae die-off in early August was just a temporary condition. You can check out the water quality monitoring data going back a couple of years on the Clary Lake Water Monitoring Data page.
Looking out my second story office window, the green scum is clearly visible as I write this. It even shows up on the webcam’s mediocre 640×480 pixel picture (which is actually running for a change).
It isn’t clear exactly why we’re experiencing these algae blooms or what we can do about them. I’m certain that they’re at least partly attributable to the low water conditions we’ve been experiencing for the past few years. With the lake down 50″ below the top of the dam, fully 1/2 the full volume of the lake is missing. There are likely other causes that need to be investigated.
UPDATED 10 October: Upon seeing the green stuff, David Hodsdon asked me to take him out to do a secchi disk reading this afternoon. It was 2.1 meters where 2.0 is the cutoff for technical algae bloom. Given the dead algae on the surface, it’s safe to say that the bloom which started back in late July, with a short respite in late August, is still with us. This is the most severe and longest lasting bloom I think we’ve ever had.
As the day wore on, the green scum continued to accumulate along the south shore and I took a few more pictures including the one at left when I was heading out in my boat to go pick up David Hodsdon. There are more pictures in the Fall 2013 album.