All of the people who monitor our lake’s water quality are doing a great service. The monitors take water samples and record data on a weekly basis. Because this data gathering has been going on for decades, we can see changes to our lake and have data to back up claims of these changes.
On Labor Day, Teresa and Don Kretchmer visited Fullers Deep and Governors Deep. This is one of the years when all of the oxygen is essentially gone below 10-11 meters (35 feet). Besides being tough on fish that like the cold water at the bottom of the lake, there is always the risk that phosphorus can be released from sediments when oxygen concentrations are low. We collected both surface layer (0-10m, 0-31 ft) and deep phosphorus samples (20 m, 62 feet) to evaluate that possibility. The good news is that when I have done this in the past (in years with no oxygen) there has been no evidence that large amounts of phosphorus are being released.
A much better view of these profiles can be seen by clicking on this link. Wentworth Profiles 9-2017
Don has just purchased a cyanobacteria monitoring kit and microscope with a camera and took some pictures of the “little guys” in the water. These are pictures of some of the residents of our Fullers Deep. Both the Gloeotrichia and Anabaena (now called Dolichospermum) are cyanobacteria but both were present in very low, non-worrisome concentrations on Monday. Gloeotrichia are the little fuzz balls you can see with the naked eye.
There are lots of other algae and small critters living in the lake and these are important because they are eaten fish that many people enjoy catching and eating. One little beastie is Asterionella which is a diatom (family of algae) and just looks neat.
The others are zooplankton (they eat the algae and get eaten by the fish). The Calanoid copepod is red because of carotenoid pigments (think carrots).
Don is having fun with his new microscope camera and will be getting us other pictures in the future.
The photos and the data make water quality a lot less abstract, don’t they?