62 untreated sewage and industrial wastes were often directly dumped into the river, contaminating the sediments in many areas and polluting the water.10 For example, during the 1950s through 1960s, the pulp/paper mills routinely used PCBs, which are highly carcinogenic compounds, in their operations, ultimately contaminating the river.11 Specific consequences of these actions include polluted runoff, invasive species, lost wetlands, and overall contamination of the river. In principle, both the construction/presence of the dams in the Fox River as well as the urbanization of the surrounding area have caused water pollution and habitat destruction in the river, greatly damaging the mussels’ ability to reproduce, live in their natural habitat, and resulting in their declining population. Mussels take an essential role in the ecosystem of the Fox River, where as filter feeders, they use a siphon to filter bacteria and plankton out of the water column into their gill chambers for consumption, and then they expel back out filtered water into the waterbody.12 A single adult mussel can filter up to 15 gallons of water per day, which clarifies the Fox River from excess phosphorus and nitrogen levels, algae, harmful pollutants, and small particulate matter. In addition, algae causes low dissolved oxygen levels that harm fish and other aquatic life, which indicates that algae blooms are seen as a major water quality problem for the Fox River.13 Mussels regulate the plankton population in the Fox River, maintaining the balance of the ecosystem and food chain, and they clarify/make the river look cleaner as a part of the natural abiotic/biotic interaction process. As a 10 “Green Bay & Fox,” Wisconsin’s Great Lakes Areas of Concern, accessed December 13, 2022, https://fyi.extension.wisc.edu/aocs/fox-river-greenbay/#:~:text=Before%20the%201970s%2C%20untreated%20sewage. 11 US EPA, OSRTI, “FOX RIVER NRDA/PCB RELEASES,” Epa.gov, 2019, https://cumulis.epa.gov/supercpad/SiteProfiles/index.cfm?fuseaction=second.cleanup&id=0507723. 12 Isabella Newingham, “Hidden within the Substrate Is an At-Risk Group of Species,” Outdoor Illinois Journal, May 2, 2022, https://outdoor.wildlifeillinois.org/articles/hidden-within-the-substrate-is-an-at-risk-group-of-species. 13 Arthur Malm, “The Fox’s Filtering Freshwater Mussels.”
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