2017-07-27 - July Water Report & Observations

This spring we had very clear water (over 11.6 m) and a Cladophora bloom. Cladophora is a nuisance algae that can form large “cloud like” masses that are a lime green colour on lake bottoms. These “clouds” will break away and float to the surface and drift to shore. You probably noticed them floating around. If you pick them up you will notice that they are made of fine hair-like structures. It is a type of filamentous algae that causes odour problems along the Great Lakes where the large mats are driven up on shore and decay. Last week the Cladophora stopped growing and started to disappear. The very back lakes are virtually free of it and the other lakes are starting to clear. This is an algae that prefers cooler water so as our lake warms, it will stop growing and organisms that live along a natural shoreline will feed on the algae cleaning it all up.

I have noticed some B-G algae the last few weeks. B-G algae is visible after a calm night and will drift into small coves and protected areas as the wind picks up and moves it toward shore. It is nowhere near the amounts that we had last year and forms a slight film on the water. I would recommend that you check your area before having a pet drink from the lake, especially in the morning following a calm night when the B-G algae can float to the surface and then get concentrated as it is blown towards a shoreline.

Last week I observed a film of B-G algae in the early morning and within 10 minutes the wind came up and it disappeared and mixed in the water column. This was a thin film and not a thicker scum. Remember B-G algae are present in all lakes. Only when the amounts get out of control and toxins are released does it becomes a health hazard.

Presently we have a small amount of B-G algae with water clarity of 6.2 m. The clarity is very good for this time of the year, especially after the amount of rain this summer and the torrential down pour of last week.

I have just returned from a tour of Lake Rosalind and they are enjoying the same conditions as we are at Marl Lake. Their back lakes are very clear with no signs of Cladophora. There were some tiny films of B-G algae present (like in our lake) but you had to look for it in tiny protected bays out of the wind and currents.

Where do we go from here? We will do toxin tests if conditions deteriorate (thick scums and poor water clarity). Last year at this time we had water clarity 3X worse with scums visible daily.

The problem, as I see it, is the Zebra Mussels which are still very present in our lake. They filter out all the good algae and plankton making the water very clear in the spring. This clear water allows the sunlight to reach deeper and algae like Cladophora can blanket the bottom. The Zebra mussels do not eat the species of B-G algae that is in our lake so there is no competition for space or food from the other algae and the B-G algae thrive. The droppings from the Zebra Mussels increase types of soluble phosphates that the B-G algae can use to grow...the perfect storm!

Rick Kalte