Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Wildlife Management


Concentrations and loads of nutrients transported through the Lake Poinsett system were monitored from April 1, 1970 to April 1, 1971. An annual 2.07x 10~ m3 surface discharge into Lake Poinsett transported 1.66 x 104 kg (PO4) phosphorus, 1.28 x 104 kg nitrate nitrogen, and 3.90 x 104 kg organic carbon. The Big Sioux River-Dry Lake system contributed 63% of the phosphorus, 45% of the nitrate nitrogen, and 43% of the organic carbon load. The remaining portion entered Lake Poinsett from the Lake Albert drainage. Of the annual load of nutrients transported into Lake Poinsett, 33% of the nitrate nitrogen load, 40% of the organic card load, and 70% of the phosphorus load was retained by the lake or lost by ways other than water discharge. Average annual phosphorus concentrations decreased through the system from 1.9 mg/l (PO4) in the Big Sioux River of 0.22 mg/l (PO4) in Lake Poinsett. Soluble inorganic phosphorus constituted 71% of the total phosphorus which entered Lake Poinsett and comprised 50% of the phosphorus in the lake. The average annual concentration of nitrate nitrogen in Lake Poinsett was 0.52 mg/l. Average annual organic carbon concentrations increased through the system from 12.27 mg/l in the Big Sioux River to 18.40 mg/l in Lake Poinsett. Nutrient concentrations in Lake Poinsett, relative to the needs of aquatic plants in the lake, are in a state of super-saturation. The advanced degree of eutrophication in Lake Poinsett is ascribable to the large annual nutrient load entering and retained by the lake.

Library of Congress Subject Headings

Marine ecology -- South Dakota -- Lake Poinsett
Lake Poinsett (S.D.)


Includes bibliographical references (pages 61-62)



Number of Pages



South Dakota State University


No Copyright - Non-Commercial Use Only