A Review of Research on the Limnology of West Blue Lake, Manitoba

Abstract

An interdisciplinary research program on the West Blue Lake ecosystem is reviewed. The composition, seasonal occurrence, abundance, and primary productivity of the phytoplankton are reported. In spring "net" phytoplankton diversity and abundance were highest with diatoms predominating. In summer Anabaena spiroides and Aphanizomenon flos aquae were a major component. During winter both cell numbers and species diversity declined. Cyclotella bodanica became dominant. Average summer phytoplankton primary productivity approximated 320 mg C m−2 day−1 in both 1971 and 1972. Average daily estimates (exclusive of zooplankton) of organic carbon in the euphotic zone during summer periods in 1971 and 1972 were, respectively, 5 and 8 g C m−2.Kinetic parameters for the bacterial uptake of 11 dissolved organic substrates are reported. Values Vmax ranged from 0.003 mg C m−3 h−1 for formic acid to 0.115 mg C m−3 h−1 for lactic acid; turnover times from 8 h for malic acid to 950 h for glycolic acid, and (Km + S) values from 0.288 mg C m−3 for malic acid to 47.883 mg C m−3 for glucose. A relation between Vmax values and plated bacterial counts is described for six organic acids. Evidence for proliferation and adaptation of bacteria in sample bottles is presented and the absence of photoheterotrophy described. Potential bacterial production during the summer of 1972 ranged from 18.24 mg C m−2 day−1 to 67.44 mg C m−2 day−1. The relationship between this production and temperature (Q10 = 3.129) is described. "Filtration effect," as a source of error, in measuring glucose uptake is probably an artifact.Generally, Cyclops bicuspidatus was more abundant than Diaptomus siciloides. Both were relatively scarce in summer. Daphnia pulicaria were usually most abundant in spring and early summer, and persisted at low levels during winter. Largest animals (over 2.0 mm long) with high relative caloric content [Formula: see text] predominated in fall, winter, and early spring when reproduction was minimal. No fish species reside permanently in the pelagic zone of West Blue Lake, but age 0 fry of Perca flavescens inhabited the epilimnion during July and early August and fed almost exclusively on D. pulicaria. In contrast, age I and older perch consumed a variety of, principally, littoral organisms. Walleye, Stizostedion vitreum vitreum, over 25 cm in length put on most of their annual growth in length and weight during the summer, when maximum production also occurred. Perch fry and larger perch were an important food for walleyes.