Photo Karen Graham.
Trent University student Mariah Shaw and her Professor Kaitlyn Fleming examine samples of small invertebrates collected at Baxter Creek in early November.
Early last month, Trent University Mariah Shaw and her supervising Professor Kaitlyn Fleming spent a Sunday afternoon investigating the microscopic wildlife in Baxter Creek known as “benthics”.
This project is Mariah’s major research paper for her fourth year in Environmental Science and was initiated by the Baxter Creek Watershed Alliance (BCWA) through Trent University’s Community-based Research Centre.
Benthics are water- based insects without backbones that are large enough to be visible to the naked eye. Some of the larger species in this category are blackflies, dragonflies and mayflies. They live at the bottom of a sea or fresh water source, living between the spaces between sediment particles. They consume minute organic and inorganic particles from the sediment surface or from within it, providing a valuable service to their host environment by accelerating the decomposition of minute organic particles in the water, recycling nutrients and providing food to creatures that are higher up the food chain.
These creatures are very sensitive to changes in their environment, including water temperature, depth, pH, salinity, availability of organic matter and the composition of the sediment in which they live. As a result, the type and abundance of these creatures are considered to be indicators of the environmental health of their host water system.
Mariah stirred up the creek bottom to flush out and collect these small invertebrates which live at the bottom of their aquatic hosts, hunkered down in the spaces between sediment particles. Samples were collected using a net with 500 microgram mesh and continued until at least 50 creatures were collected. These samples would be subject to further examination at a university lab. Sometimes it can take hours to collect this number of creatures, but it took less than 15 minutes to accumulate this sample volume at the sample site at the foot of Bank St. South. This is the sample site closest to the treatment plant’s discharge pipe.
Benthic monitoring is often conducted to measure the impact of human activity on local waterways in areas with significant human interference such as the Alberta oil sands. Because they are so dependent on their environment, the size, health and diversity of benthic communities is considered a biological indicator of the health of their water environment. The higher and more diverse the population of benthic organisms detected, the better.
Mariah’s research report won’t be available until next spring. A high volume of mayflies were found in the samples taken that day, which is a very good sign: this creature is considered to be quite sensitive to pollution, so an abundance of them is an indicator of good environmental conditions. Preliminary observations suggest that Baxter Creek is doing well.
This study was the brain child of the late David Webster, a founding member of the BCWA who hoped it would be instrumental in orchestrating scientific research in the local watershed. This is the first of a multi-year survey. Next season the sampling will focus on green infrastructure such as residential stormwater ponds. Results of this research will also be integrated with surveys conducted by other organizations including the Otonabee Region Conservation Authority and will be added to public data catalogues for future research. Members hope the results will help establish a baseline indication of the watershed’s health as they work to develop plans to build Baxter Creek’s health and resiliency. KG
