|Title||Trophic status of southeastern Lake Michigan based on the Chironomidae (Diptera)|
|Publication Type||Journal Article|
|Year of Publication||1985|
|Authors||Winnell MH, White DS|
|Journal||Journal of Great Lakes Research|
Chironomids and oligochaetes were identified from a total of 2.432 samples collected at depths < 42 m over a 9-year period in southeastern Lake Michigan. Each of 13 chironomid taxa was assigned a trophic indicator status based on density trends among samples characterized by oligochaete trophic indices in the ranges <0.50 (Type 0), 0.50-1.50 (Type 1), and > 1.50 (Type 2). A trophic index based on the chironomid fauna was generated for year, depth intervals, and combinations of years and depths. When averaged over all years, the trophic index at the 8- to 24-m depth interval was 1.26, indicating mesotrophic conditions in this portion of the littoral and sublittoral of southeastern Lake Michigan. Similarly, at depths > 28 m the trophic index value was 0.41, suggesting oligotrophic conditions in the profundal. No annual trophic status trends were evident.