LAURENTIAN RESEARCH FINDS DEVELOPMENT LINKED TO ALGAE BLOOMS 

Evidence of blue-green algae blooms is strongest in most populated bays in Long Lake 

SUDBURY, ON (JULY 8, 2015) – Research by aquatic biologists at Laurentian University indicates that over-development along parts of the shoreline of Sudbury’s Long Lake is a likely factor in recurrent blooms of blue-green algae.  

Dr. Charles Ramcharan
Associate Professor
School of the Environment and Department of Biology
Laurentian University, cramcharan@laurentian.ca 

My student, Mathiew Dykstra, and I developed a new method of measuring long-term nutrient levels in lakes.  Nutrients like phosphorus are associated with the inflow of fertilizers, sediment and sewage that enter lakes through drainage basins, and these high nutrient levels are typically seen in lakes with frequent blue-green algal blooms. 

  Across Ontario there is an increasing trend where we are seeing localized blooms, even in lakes that have relatively low average levels of nutrients.  Sudbury’s Long Lake is a case in point, with a few persistent trouble spots in an otherwise healthy lake. 

We used a new method of detecting nutrient inputs in a study of lakeshore algae called diatoms last summer.  Our work showed that across most of the bays on Long Lake, phosphorus levels were low.  In two isolated areas, however, the level of nutrients was found to be siginificantly higher.  Both of those bays experience regular algal blooms, and both are highly developed, with year-round homes on lakefront properties.   

This new method allows us to more accurately detect variations in phosphorus within a single body of water, and reinforces the finding that human activity and improper shoreline management are primary factors in repeated blue-green algae blooms.  

Known to scientists as cyanobacteria, blue-green algae are present in almost all lakes in Canada.  They usually multiply in the summer months, feeding on nutrients, carbon dioxide and light, and can form a thick, soupy layer on the water’s surface.  They can also be submerged and flourish for many weeks before they are detected from shore.  Algal blooms are a nuisance and can be dangerous, as they can foul drinking water supplies with cyanobacterial toxins.  

Our Laurentian University research suggests that blue-green algal blooms can be minimized through better shoreline management, including more stringent inspections of septic beds and other sources of nutrient inputs. Enhancing shoreline vegetation with reeds, rushes, and other aquatic plants that act as water filters are certainly effective ways of reducing blooms in these high-density areas of our shorelines.  

We seek to continue our work beyond this pilot study with a follow-up project that involves a diversity of Sudbury lakes and a better way to quantify housing density along lake shorelines.