Hopkins Marine Station Student Paper

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(full paper is archived in the Miller Library)

Title: Diurnal oxygen and nutrient level variations around a primary sewage outfall, Monterey Bay, California
Student Author(s): Blencowe, Craig
Faculty Advisor(s): Lee, Welton
Pages: 36
Location: Final Papers Biology 175H
Date: June 1970
Keywords: sewage pollution
Abstract: 1) The area of Monterey Bay near the Monterey City Outfall Line was investigated for relationships between dissolved oxygen and nutrient levels and changes in bieogeochemical cycles during a day-night study period. 2) It was found that neither oxygen levels decreased enough nor did hydrogen sulfide levels increase enough to pose immediate toxicity to fish life during the period of study. 3) Levels of hydrogen sulfide, oxygen, and to a lesser extent, nitrite, are dependent upon a day-night cycle. Phosphate seems to be dependent to a greater extent upon the volume of effluent being released from the outfall. Nitrate shows no obvious correlation with either factor. 4) Phosphate is found in greatest quantities at the surface. Hydrogen sulfide and nitrite are found in slightly increased levels towards the bottom depths. Nitrate does not show any obvious gradient with depth. 5) Stability of phosphate seems to make it a better indicator of effluent flow direction and rate than the other nutrients studied. 6) Using phosphate as an indicator, it is suggested that much of the effluent of the Monterey City Outfall is flowing southward and pooling in a dead water area near the Monterey Wharf number 2, enriching the area considerably.