MWC Algae Monitoring Program

Muskoka Watershed Council developed the Algae Monitoring Program to collect information on the distribution, abundance and seasonal cycles of a) all phytoplankton combined, and b) blue-green algae in particular, across Muskoka area lakes so that, over time, it may be possible to identify conditions favoring algae, detect trends in phytoplankton abundance, and provide management advice.

Modelled from a  Cyanobacteria Monitoring Collaborative  program carried out in New England, MWC's Algae Monitoring Program harnesses the efforts of dedicated citizen scientists who currently monitor water quality across Muskoka in order to build a richer database of information on local algal populations.

A pilot project was undertaken in 2019 in collaboration with four selected lake associations to:

• Plan and pilot methods for fluorometric analysis of phytoplankton for future use by lake associations interested in adding this to current water quality monitoring;
• Undertake explicit evaluations to ground-truth methods used;
• Develop information materials and a presentation on algae for delivery to lake associations and others; and
• Communicate these efforts to other lake associations across Muskoka during the year.

Sampling occurred on a bi-weekly (14 day) schedule from June until mid-October. On each sampling week, samples were collected from all sites on the lake between 10:00 am and 2:00 pm within the same three day period (i.e. Mon-Tues-Wed, Fri-Sat-Sun, etc). This flexibility in date allowed for weather and other commitments by the volunteers.

An offshore and nearshore site was selected for each lake and were sampled on each sampling occasion. The offshore site was the centre of the deepest basin of the lake (and corresponded to the District of Muskoka's sampling site in that lake, if there was one). The nearshore site was selected by the lake association. Each site was assigned a unique Site Code by MWC.

Unless otherwise specified, once collected, samples were kept in a closed container on ice until brought to shore, and then they were frozen and stored in a freezer until delivered to the team doing the fluorometry.

Over the course of the sampling season, some minor adjustments were made to the composite sampler and the protocol for analyzing the water samples. These changes will be incorporated into the next version of the Protocol Manual.

Overall, the 2019 Pilot Project was a success. Only minor issues were found with the equipment and the procedure for analyzing the samples and these were quickly addressed. It is recommended that the pilot project proceed for a second year (2021) on the same set of lakes and with the same volunteers, with the following changes:

• Volunteers drop their samples off at one location instead of staff driving to each lake and collecting them. To implement this, a central location with a freezer needs to be found.

• Eliminate sample collection using the Integrated Tube sampler. Analysis of the data collected in 2019 indicates that the 2xSecchi and IT methods provide equivalent water samples for analysis, and the 2xSecchi method is easier to use in most situations. An alternate protocol for sampling shallow water sites will need to be developed and included in the Protocol Manual.

• All samples collected, including the triplicate samples, will have three sub-samples analyzed using fluorometry and the results for each sample will be reported as the mean of the three sub-samples.

• The Algae Sub-committee should investigate the possibility of including more opportunistic sampling during times when blooms seem most likely to occur for implementation during the 2021 pilot project. The data obtained from Three Mile Lake showed that a blue-green bloom would show up conspicuously in PC fluorometry results. More interesting will be to see if fluorometric data can anticipate a bloom by several days, but more frequent sampling seems infeasible as a routine procedure.

The Algae Sub-committee will continue to seek funding to implement the Algae Monitoring Program broadly across Muskoka based on the results of the 2-year pilot project. As part of the plan for broader implementation, MWC will investigate the potential for each lake association or group of associations to have their own fluorometer to conduct their own analyses. The data would then be submitted to MWC for inclusion in the database.