Distribution of Photosynthetic Pigments in Nearshore Sediments of Lake Michigan

Abstract

To characterize nearshore detrital deposits and to identify potential input sources, photosynthetic pigments were examined in sediment cores taken from three stations in nearshore Lake Michigan between May and October 1979. Two stations were located at 11 m and one was at 23-m depth. At the 11-m stations, total pigment concentrations in the upper 0–1 cm layer were greatest in May and then declined, while seasonal changes at the 23-m station were not apparent. A high proportion of the spring influx of pigment at the 11-m depth was undegraded, indicating freshly settled material from the water column as a likely source. Sediment chlorophyll concentrations in the spring were as high as 212 μg/g, but typical summer values were 1–7 μ/g. Although these pelagic inputs are temporary, strong links exist between this material and benthic invertebrate distributions.