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Benthic Macroinvertebrates
For our last test, we determined the amount and types of species of benthic macroinvertebrates present in the water. Benthic macroinvertebrates are bottom dwelling organisms, which means they live in, crawl upon, or attach themselves to the bottom of bodies of water. They can be seen with unaided eye. They are important because certain species present in the water can help determine the water quality or pollution. They serve as indicator organisms since they are sensitive to physical and chemical changes in their habitat. These organisms have a hard time escaping pollution since they are so small and have lived in their habitat for over a year. There are different tolerant and intolerant species that can be used to determine the quality of the water because if one can identify an intolerant species in a river, this means the water quality must be good in order for the organism to live there.
Benthic macroinvertebrates are present naturally in certain rivers and streams where the water quality is tolerable for them. They choose their own habitats based on the original conditions of them and if the area can help them thrive. Water temperature patterns, velocity of water flow, substrates, and energy relationships are all factors that affect these organisms and where they reside. They need to be able to tolerate certain conditions. Humans have impacted benthic macroinvertebrates because if there is an area where pollution and waste is added, some organisms will die or try to migrate to a different area of the river. Pollution that affects these organisms arise again from waste, fertilizer, or fossil fuels. These can all disrupt certain species that serve as indicators or cause others to thrive.
When testing the water in the Chicago River, we found a total of 12 different species of benthic macroinvertebrates present. However, certain species are put into different categories because some of them serve as indicator species for good quality water. These categories are based on the intolerances that organisms have based on water quality and their environment. Intolerant organisms are a good sign in water because they show that the water is in good enough condition for them to thrive. We added up how many species were in each category and then multiplied them to get a certain number to determine the weighting factor of each group. We added each of these groups up and got a total number of 35. This number gives us a rating of excellent water quality based on benthic macroinvertebrates. This reveals that in terms of indicator species, our water served as a great, thriving home from them since it was sustainable for their lives.
We got the results we did because the water we tested had to be a safe environment for these organisms. There is a large amount of DO and little chemicals that could hurt these organisms. Therefore, intolerable species were able to thrive in the area of water that we tested. They were not affected by other changes that were happening in the water.
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