|Title||Notes on the vertical distribution of organisms in the profundal sediments of Douglas Lake, Michigan|
|Publication Type||Journal Article|
|Year of Publication||1953|
|Journal||The American Midlands Naturalist|
Ninety vertical core samples were taken from the profundal sediments of Douglas Lake, Michigan, during August, 1950. Cores were sectioned at intervals and the animals present in each stratum were recorded. Eight microbenthic forms were identified, more species occurring in upper profundal depths than in deeper regions. Encysted Cyclops bicuspidatus thomasi penetrated deeper in the sediments than other microscopic species, being present more than 16 cm below the ooze surface. One hundred and six macrobenthic organisms, representing at least five species, were present in the samples. Ninety-three percent of these were found in the upper 14 cm of the bottom deposits, with the 1-2 cm level containing more individuals than any other single stratum. The deepest penetration (Limnodrilus sp.) was the 20-24 cm stratum.