Pontoporeia Distribution Along the Keweenaw Shore of Lake Superior Affected by Copper Tailings

Document Type

Article

Publication Date

1979

Department

Department of Biological Sciences

Abstract

The sediment and benthic macroinvertebrates of a 540 km2 area of Lake Superior were examined. The amphipod Pontoporeia hoyi was by far the most abundant animal collected. A 42 km2 area devoid of P. hoyi was found near where 50 million tons of copper tailings containing metallic copper in concentrations averaging 3750 mg/kg had been dumped between 1895 and 1968. In the no-amphipod region sediment copper ranged from 395 to 1310 mg/kg, while elsewhere mean levels were 14 to 298 mg/kg. The study area was divided into five transects which had maximum densities of P. hoyi ranging from 470 to 4480/m2. The depth of maximum density ranged from 40-45 to 60-65 m. Maximum density was associated with a mean grain size of φ 3.5-4.0 and elevated levels of total volatile solids, nitrogen, phosphorus, and chemical oxygen demand. Copper and dark color, characteristics of the copper tailings, showed significant negative correlations with P. hoyi density.

Publication Title

Journal of Great Lakes Research

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