Thursday, August 14, 2008

Monitoring water quality

Benthic macroinvertebrates

This week, we did the annual collection of benthic macroinvertebrates. They are animals found on the bottom of a water body that are large enough to be seen with the naked eye and lack a backbone and internal skeleton. They are relatively sedentary and widespread, with varying tolerances to changes in water and sediment quality.

As in previous years, we were joined by members of Citizens Environment Watch, an organization which provides education, equipment and support for community-based environmental monitoring and stewardship. The monitoring procedure that CEW developed enable volunteers to sample stream habitats for benthic macroinvertebrates. The procedure includes necessary information to collect, process and identify benthic macroinvertebrates found in southern Ontario watersheds.

Collecting samples in one of the Riverdale ponds

The sampling is performed using a D-net (so-called because it's in the shape of a D) which is placed firmly against the stream bottom. Afterwards, the D-net is emptied into a sieve over a bucket or large tray and stewards use squeeze bottles and water from the stream to rinse the net. Once this is done, it's time to look for the bugs and try to find them. Unfortunately, at Riverdale, there is so much mud that it's very difficult to see anything. We managed to find a few, including isopoda (sow bugs) which have a tolerance value of 8 or high tolerance to poor conditions.

We should soon have the results of our experiment and I will post them as soon as they come.

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