Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 246 | 2016 lake StewardS newSletter The incidence of cyanobacteria—commonly referred to as blue-green algae—blooms in our lakes is currently on the rise in Ontario, and across the globe. Not all blooms are blue-green algae; however, information collected by the Ontario Ministry of the Environment and Climate Change (MOECC) algal identification and bloom tracking service illustrates that the total number of reported algal blooms have increased across the province since 1994 (Fig. 1). Within this trend, a significant increase in cyanobacteria blooms is evident, with over 50 bloom events reported in 2015, compared to 1 in 1994. Cyanobacteria are of particular interest to the public health and land managers because they pose a direct and immediate threat to water quality by producing a variety of toxic compounds, increasing turbidity, reducing the availability of oxygen for animals in bottom waters, and altering food webs. Factors affecting Blooms Within lakes, cyanobacteria can occur naturally in low numbers, but under certain conditions their numbers can increase dramatically, leading to blooms. A wide variety of factors are linked to the formation of blooms, but the most significant ones are increased nutrient input to lakes, and a number of specific meteorological conditions such as high water temperature, low rainfall/precipitation and reduced wind speeds. Consequently, blooms typically develop in shallow, sheltered bays and during the summer or fall when these meteorological conditions are most likely to occur. In Ontario, extensive research involving the MOECC and partners such as the Canadian Water Network has been done to advance our knowledge of cyanobacteria blooms and to move toward predicting their occurrence. Figure 1: Total number of algal bloom events reported to MOECC from 1994 to 2015, with breakdown by dominant algal group. Blue denotes reports of cyanobacteria. The category “other” refers to a range of algal classes for which blooms were only occasionally reported including diatoms, xanthophytes, dinoflagellates, cryptophytes, and euglenophytes. (unpublished data, courtesy MOECC) Predicting algal Blooms by Dr. Anurani Persaud Aquatic Ecosystems Science Specialist, MNRF Southern Region Advisory Team Here is some additional information from the website of our member group, the Three Mile Lake Association (http://www.3milelake.ca/faqs.htm): In 2005 Mother Nature created the perfect storm for a Blue/Green Algae bloom, and it happened here and elsewhere in Muskoka. The community response was amazing. Actions to protect the lake and the surrounding watershed were implemented by agencies, residents and the Three Mile Lake Association. Since then, the lake has been safe for swimming and the wildlife habitat has not been jeopardized. Cottagers need only follow the “Do’s and Don’ts” [see website, above]… to assist in keeping the lake in a safe, “clean” and enjoyable state. A First-hand Account Figure 2: Algal bloom in Three Mile Lake (image courtesy MOECC)