You will recall that in 2014-15 the Long Lake Stewardship Committee, concerned about the number of cyanobacteria or blue-green algae blooms occurring in our lake, commissioned a Lake Capacity Study by Dr. Gertrud Nürnberg of Freshwater Research. Lake Capacity studies are helpful for planning how to protect the environmental, recreational, economic and property value of a lake and can predict the impact of shoreline development on water quality. These studies help determine the carrying capacity of a lake in terms of the maximum allowable total phosphorus (TP) concentration. Phosphorus as you are aware, stimulates the growth of many aquatic organisms.
The data from this study indicated that Long Lake is “at capacity” with respect to the phosphorus loading criteria of the Ministry of the Environment & Climate Change (MOECC). It became clear that we must take steps to help reduce the amount of phosphorus entering Long Lake. This study “Water Quality and Capacity for Long Lake, City of Greater Sudbury," was presented at our May 2016 AGM by Dr. Nürnberg and is also posted on our LLS website and Facebook page.
Recently Dr. Nürnberg sent the Long Lake Stewardship Committee an additional report on our lake that was a joint project with the MOECC, and which has been published in a journal, Science of the Total Environment 626:412-422. This new study, “Reduced Phosphorus retention by anoxic bottom sediments after the remediation of an industrial acidified lake area: Indications from P, Al, and Fe sediment fractions” can be accessed at:
https://authors.elsevier.com/a/1WazcB8ccgW8m [P = Phosphorous, Al = Aluminum, Fe = Iron]
Gertrud states that "the essence is that the sediment qualities have changed and now indicate the possibility of less phosphorus retention which can easily lead to increased bluegreen (cyanobacteria) and their blooms, especially considering climate change". Phosphorous is leaving the sediment to move into the water column. This sediment work substantiates the conclusions of her first report.
The Long Lake Stewardship Committee is seeking further scientific interpretation of the study. Our layman’s interpretation so far is that results were what was expected in a lake in an industrialized/mining area that is recovering from acid rain. This would suggest the findings have ramifications for many lakes in the Sudbury area. This study provides more evidence that increased phosphorous levels can be linked to a deterioration of water quality, an increase in the growth of Eurasian Water Milfoil, and more importantly, increased cyanobacteria blooms.
HOW DO WE REDUCE PHOSPHOROUS ENTERING OUR LAKE?
· Regular septic system maintenance
· Enforcement of rigorous building codes and inspections
· Creating shoreline buffers
· Elimination of chemical fertilizers
Stewardship is a shared responsibility. Let’s all do our part!
The LLSC will continue to inform and educate, and collaborate with the Municipality and Ministries to positively influence the ecological health and sustainability of Long Lake.
Scott, Mary, Sandi, Richard, Forbes, Susan, Lori, Bill