Over the past few weeks in my science honours class we have been studying water quality and invertebrates. First, we learned about invertebrates and how they related to the quality of the water they live in. Then we walked to the Coquitlam River and the Oxbow pond that is behind our school. We searched for the different invertebrates that were living in those two study environments and then made inferences about how they could tell us what the quality of the water was. These are some results from our field studies and how the water quality and life in the two study sites compare.
To test the water quality, we measured the water temperature, air temperature, and pH for both the river and pond. Then we used measurements previously taken by other students who were doing a similar unit. Some examples of those measurements were the turbidity, nitrates, phosphates and dissolved oxygen. The water quality is based on all of these parameters, so we combined all the measurements to find a total water quality index.
For the Coquitlam river study site, we calculated that the water quality index was 82.26 out of 100. That says that the water quality is good and supports a high diversity of life. For the Oxbow pond study site, the water quality index that we found was 74.14 out of 100, which says that the pond also has good quality water, but slightly less than the river.
At the Coquitlam river, we held a net under the water and scrubbed river rocks inside a 1-foot square in front of the net. That way, any living thing attached to the rock would flow into the net and we could study it close-up. My group found a cranefly larva, a dragonfly nymph, and two mayfly larvae. The class found a total of sixteen mayfly larvae, one caddisfly larva, two snails, two stonefly nymphs, a water mite, a crane fly larva, two dragonfly nymphs and a spider.
At the Oxbow pond behind Riverside, we brushed the net along the edge of the water and the bushes surrounding it, to try and catch living things in different areas of the water. Our group did the testing, but we couldn’t find any life in the Oxbow pond. I think this was because the water was very murky and so it was hard to see things moving. The class however found many different living things. As a class we found four dragonfly nymphs, three aquatic sow bugs, four different fish, three dragonfly larvae, two spiders, a dragonfly suborder, an alderfly and a water mite.
These sample results compare in a few different ways. Both study sites had many living things that we found, but we found more life in the Coquitlam river. This could have just been the way our testing went that specific day, but it could also mean that life is more abundant in the river than the pond. Also, there were dragonfly nymphs, spiders, and water mites found in both study sites. The other living things that we found were each in only one of the two locations. So the life was quite diverse between the two sites.
These different invertebrates come from three different categories that can indicate the quality of the water they are found in.
The living things found in the river were generally from category one, indicating good quality water. They can only live in good water so that means that the river must be fairly good quality or else those invertebrates wouldn’t survive. Eighteen out of twenty-three invertebrates we found in the river were from this category, which is the majority of them. Three invertebrates were from category two, which can tolerate some pollution but can also be in good quality water. Two invertebrates found were from category three and can tolerate any water quality.
Most of the living things found in the pond were from category two. The invertebrates in category two can be in good quality water but can also tolerate fair quality water. One invertebrate that we found in the pond was the water mite, which is from category three. The water mite can tolerate any quality of water. Since we didn’t find any invertebrates from category one in the pond, and found most from category two, this could mean that the water quality is fair, but not the best.
After gathering all this information, I believe that the water quality in the river is generally really good, and therefore supports a high number of living things. The majority of the invertebrates found in the river indicate good water quality, which is another reason why I think the water quality is good.
I believe that the water quality in the pond is fair, but not as good as the river. This is because the invertebrates found in the pond were mostly from category two, which can tolerate some pollution. Since no invertebrates found in the pond were form category one, I think this is a clear sign that the water quality isn’t the best.
In conclusion, I really enjoyed studying this topic in science class because it was interesting and hands-on. I think it is way more fun to learn in a way when you get to actually do the learning yourself instead of being told the information. It is also fun to be outside and do something you wouldn’t normally do in school.
I learned a lot during this unit. I didn’t know very much about invertebrates and I thought it was very cool that they can actually tell us about water quality in a certain location. I learned that there are many factors in determining water quality and each one is very unique and specific. I also learned that there are tons of living things in nature even when you don’t see them at first. Most importantly, I learned that you can complete field science experiments right in our neighbourhood!
If we were to do this again, I would like to study the invertebrates that we found a little bit more. We could take more of them back to the classroom to look at them under the microscopes. I think this activity would have been more meaningful if we had more people wearing chest waders in the water. I understand that we only have a certain amount for the class, but I think we should have gone to the study sites more than once so that everyone understood what it was like to wear the chest waders and test for invertebrates.
Overall, I really enjoyed learning hands-on during this project and being in nature during science class!
All pictures taken by group members in science 9 honours.