Ecological status of a retired mine lake in a protected dune ecosystem

• Published in: Inland waters 2024-06, Vol.14, p.1-13
• Main Authors: Sheets, Katy, Hassett, Michael C., Orzechowski, Rachel M., Steinman, Alan D.
• Format: Article
• Language: English
• ISSN: 2044-2041; 2044-205X
• DOI: 10.1080/20442041.2024.2330858

Ottawa Sands Lake is a retired mine lake located in a protected dune ecosystem adjacent to Lake Michigan in western Michigan, USA. Development activities are planned for the lake and surrounding land, potentially threatening the lake’s ecological health. We conducted a baseline study of water quality and macroinvertebrates, combined with exclusion cage experiments, to examine the role of predation. Our results indicated the lake’s littoral zone had good water quality with low phosphorus (mean soluble reactive phosphorus [SRP] < 5 µg/L; mean total phosphorus [TP] < 10 µg/L) and nitrogen (mean nitrate [NO3-N] = 38–190 µg/L; mean ammonia [NH3-N] = 8–19 µg/L, excluding deep hole) concentrations, high dissolved oxygen (>9.5 mg/L, excluding deep hole), and low chlorophyll a (< 12 µg/L, except for 1 sampling date) concentrations. The macroinvertebrate community was dominated by 9 families, with Chironomidae the most abundant. Three environmental factors—specific conductivity, total dissolved solids, and ammonia—were significantly related, albeit weakly, to macroinvertebrate community structure. The exclusion cages did not result in a statistically significant difference in macroinvertebrate community structure, although high variance may have masked differences. Overall, Ottawa Sands Lake is a high-quality system, but development plans, including the installation of a paved trail around the lake and the implementation of a nonmotorized boating program, may result in changes. The baseline conditions outlined in this work will allow lake managers to assess the impact of development activity and add to the limited database regarding the limnology of retired mine lakes around the globe.