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Summer Benthic Invertebrate Sampling the Grand River

I like to think that the work I did this summer was interpreting a narrative. A narrative told by the environment and the organisms that live in it. Sometimes nature has a way of expressing itself to us, we as humans just have to pay attention.

Benthic invertebrates include a wide diversity of aquatic organisms including insects, arachnids, crustaceans, mollusks, and annelids. All these organisms remain on the bottom of a waterbody or burrow into the sediment.

This diversity comes with a variety of life history traits that enable certain groups to thrive in certain aquatic environments, but also perish in others. By being aware of these life history traits and associating them with specific invertebrate groups, we can assess the general health of a given water body.

These invertebrates are at the bottom of any aquatic food web, making them a vital food source for larger aquatic organisms. This makes them a vital necessity to any thriving ecosystem.

In a 2005 paper, Ian Martin, the Vice President of the Friends of the Grand River, sampled the Grand River to assess its water quality. Furthermore, the Friends of the Grand expressed concern regarding the fertility of the stocked trout of the Grand River. As a result, in the Summer of 2022, the Prosser lab sampled the Upper Grand River for benthic invertebrates to continue the research of Ian Martin and to observe the potential changes in the benthic communities since Ian Martins’ paper was published.

A Part of the Prosser Crew sampling at a Fergus site.

In June and August of 2022, the Prosser lab sampled multiple sites along the Upper Grand River, ranging from Bellwood Dam to West Montrose Bridge. At each site, the CABIN protocol was used to collect samples and take river measurements. The benthic invertebrates were collected through kick netting and stored in formalin to be brought back to the lab.

Kick net sampling below Bellwood Dam.

In the lab, the collected invertebrates were identified at the family taxonomic level. By doing so, we could use the Family Biotic Index (FBI) to get a general sense of the water quality of a site. By using the CABIN protocol, 300 specimens were identified at each kick we sampled from each site. This led to the identification of over 30 000 specimens. Furthermore, other metrics of diversity were calculated such as Species Richness, Shannon diversity, Simpson diversity, EPT% and Chironomid %. These calculated values were then run through R for further analysis.

While a lot of the hands-on work was done in the field, collecting insects from multiple sites. Majority of the work was done in lab in the tallies of insects in a notebook or in the lines of code in R.

Some examples of thefamilies that were identified. In order from top left to bottom right: perlidae (Plecoptera), talitridae (Amphipoda), philopotamidae (Trichoptera), heptageniidae (Ephemeroptera), labial mask (Odonata), perlidae (Plecoptera).

The next step is to compare our findings with Ian’s raw data to be able to get an accurate representation of the change in the Grand River over these 20 years. From there we can see the state of the Grand Water quality to further understand why stocked trout are not making it to maturity.

--Kiran Suarez Sharma

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