Most people who were at the lake between September 15th and 26th, may have heard about or actually noticed the formation of blue green algae blooms at the lake. We heard random reports that people saw what they thought was "gold-coloured pollen" floating on the water during this time period. These were very likely blooms.
On September 15th a few residents along the Lake Louisa North road reported significant pea soup coloured blooms in the water near the shore. The blooms continued throughout that very warm weekend there, as well as in Echo Bay and around Hope’s Island. They seemed to peak on Monday, September 18th when Claire Ropeleski took these photos on the north side of the lake where in some areas the pea soup colour reached as far as 20 feet out from the shore.
That same day the MRC, via the municipality of Wentworth, officially warned residents by email that there was a cyanobacterial bloom going on in Lake Louisa and to take appropriate precautions. This notice has been posted separately on the LLPOA website. It was also posted by Claire on the LLPOA Facebook page.
The blooms became much less dense as of Wednesday, September 20th, however significant algal activity continued along these shorelines for days, looking like green-gold striations composed of dandruff-sized green dots accumulating both along the shoreline and in deeper waters.
Our observations were that the small dandruff-sized, or cream-of-wheat sized particles would appear in the water in the morning, increasing in number as the day progressed, and clumping together in string-like groupings, or striations.
The green colour became more obvious as the clumps grew in size. The real opaque pea soup coloured areas in the water seemed to appear in the mid to late afternoon. They would dissipate in the evening as the temperature dropped. These striations or elongated clumps were also seen around Hope's Island and in some parts of the Club Bay. They were likely elsewhere, too, but the entire lake was not being monitored.
Less dense blooms continued to appear sporadically through the very warm weekend of September 23-24 along some shorelines in the Club Bay, Montgomery Bay, and around Hope's Island as well. Annick Valentine of Wentworth Township still found blooms, although nowhere near as dense as during the previous week, along Lake Louisa North on September 26.
Sampling was done according to government lab protocol and sent to Quebec City for analysis. We have not heard the results of this sampling yet. LLPOA and others are presently awaiting lab test results. We wonder whether the fact that the bloom which was finally sampled will yield the same results as a sampling of the thick pea soup-like bloom would have had it been taken the previous week. Knowing the type of cyanobacteria would give us information on the type and potential intensity of the toxins it is likely to produce.
We see that a major problem in this case is that the township had no protocol or sampling kits in place to deal with a big bloom like this. In the past, smaller blue green algae blooms have been reported from time to time. This was the most extensive bloom that we at the LLPOA remember.
According to an Environment Canada article, to which a link is provided below, cyanobacteria is not technically algae even though it is called blue green algae. It is a type of bacteria which uses chlorophyll and is a natural organism that lives in lakes like ours. The problem arises when it becomes too abundant. Then blooms can occur. A by-product of blooms can be toxins which make the water dangerous to drink and to swim in.
Here is a link to the article on cyanobacteria from the Environment Canada website:
Cyanobacteria thrive on nutrients such as phosphate. Blooms are more likely in warm water. You may remember how unusually warm those September days were, with mid-day temperatures reaching 30 Celsius a few times. As Melanie Laniel, a biologist from the Centre Régionale de l’Environnement des Laurentides said in a recent e mail to the LLPOA:
, j’ai été informé des récents blooms de cyanobactéries au lac Louisa. Je crois qu’avec tous les bouleversements météo que nous vivons, ce genre d’événement exceptionnel sera malheureusement de plus et plus fréquent dans les années à venir. D’où l’importance d’adopter de bonnes pratiques en bordure du lac Louisa afin de renforcer sa protection.
(I was informed of recent cyanobacteria blooms at Lake Louisa. I believe that with all the unusual weather we are experiencing, this type of exceptional event will unfortunately become more and more frequent in the years to come. It underlines the importance of adopting the best practices around the edge of Lake Louisa to bolster its protection,)
Protection, as far as lake residents can give it, means to restrict nutrients that encourage aquatic plant growth from entering the lake by the usual means the LLPOA recommends:
- Make sure your septic system is up to date and in good working order.
- Use environmentally friendly and phosphate free cleaning and personal care products.
- Protect the plants and trees along your shoreline so that their roots can filter out nutrients from erosion and run off. Do not cut grass or any other vegetation in the protected Shoreline Band.
- Treat our precious, fragile lake as gently as you can.
Claire Ropeleski and Mary-Anne Armstrong