Chemical characteristics of south-central Lake Huron

Water samples were collected for chemical analysis during eight cruises of the U.S. Bureau of Commercial Fisheries M/V CISCO in south-central Lake Huron in June-October 1956. Temperature, pH, conductivity, and the concentrations of Na+, K+, Ca++, C1-, SO4-, SiO2, and dissolved oxygen were determined for 233 samples from stations at the mouth of Saginaw Bay and along a transect from Harbor Beach, Michigan, to Goderich, Ontario. The chemical compostion, with the exception of silica, did not vary with season or depth. Water flowing into the lake from Saginaw Bay sometimes caused marked increases in the concentration of chemicals in surface samples at certain stations. Prevailing currents determined the location of these areas of higher salt concentration.