Seasonal succession, standing crop and determinants of primary productivity of the phytoplankton of Ministik Lake, Alberta, Canada

Abstract

Ministik Lake (longitude I13°oi' ; latitude 53°21), a well-mixed, shallow (mean depth 1 .83 m), eutrophic lake is characterized by eutrophic chlorococcalean and cyanophycean phytoplankton associations, and little change in standing crop size with increasing depth. Standing crops and primary productivity are low during the winter but pronounced spring and late summer/early autumn maxima occur . Mean yearly areal standing crop (SB) and primary productivity (IA) were 199 .2 mg m 2 chlorophyll a and 319.5 mg C hr' m_' respectively . Annual productivity was estimated at 1399,6 g C m-2 yr' . The mean increase in the extinction coefficient (e) per unit increase in standing crop (B) was 0 .03 In units m -' . High non-algal light attenuation (eq) occurred averaging 46% which prevented the ratio BE from attaining more than 74.2% of the theoretical maximum except once when selfshading occurred . Insignificant relationships existed between B (mg M-3 chlorophyll a) and Amax (mg C hr-1 m_), 1A and XB and Y .A and B . Close correlations existed between XA and A max / e and 1A and Io (W m-) . The depth of the euphotic zone (z e.) varied between o .6 and 2 .0 m; the average relationship between z,,, and a was z e1 = 3 .78/ c , and the mean standing crop in the euphotic zone represented 58 .3% of the theoretical maximum. The high e g values made the model of Talling (i957) inapplicable to this lake. The Q,o value for the lake was 1 .20.Omax (mg C chlorophyll a' hf`) was closely related to both temperature and irradiance, and depressed by high pH values . Growth of the cyanophycean algae was correlated with temperature, chlorophycean algae with phosphate-phosphorus and temperature and the diatoms with dissolved silica and phosphate-phosphorus, but only in the case of Chaetoceros elmorii did any nutrient appear limiting . Indirect evidence that free CO2 limited photosynthetic rates is provided by the 0-:pH relationship.Dr. W. Junk b.v . Publishers -The Hague, The Netherlands

Phytoplankton Periodicity in a Eutrophic Coastal Water of the Baltic Sea

“…Two non-N2-fixing filamentous Cyanobacteria, Lyngbya contorta and Oscillatoria limnetica, were present throughout the year. This was already found in other waters for Lyngbya contorta (HICKMAN 1978(HICKMAN , 1979.…”

“…In the Darss-Zingst bodden waters the Chlorophyceae are present all year Gust as in other lakes: HICKMAN 1978HICKMAN , 1979aHICKMAN , 1979, indicating a high ecological flexibility. Normally the peak of their biomass is measured in May or June, when light intensity and pH have their maxima but temperature has not reached its maximum yet.…”

Oscillaxanthin and myxoxanthophyll in two cores from Lake Wabamun, Alberta, Canada

“…This shift suggests that the lake was most eutrophic between 7000 and 3800 years BP, and that diatoms comprised only a minor component of the phytoplankton, with blue-green algae being overwhelmingly dominant. Similar conditions are found in some eutrophic Alberta lakes today, (Hickman, 1979a(Hickman, , 1979b(Hickman, , 1979cJenkerson & Hickman, 1984).…”

“…Blue-green algae often dominate, while diatoms comprise a minor component of the phytoplankton assemblage (Hickman, 1979a(Hickman, , 1979b(Hickman, , 1979cJenkerson & Hickman, 1984). Although, blue-green algae are not found as microfossils in the lake sediments, they can be detected by the quantitative measurement of carotenoid pigments specific to this algal group.…”

Ecology of Cyprinus carpio var. specularis (Physico-Chemical Conditions of the Habitat)

“…In the river Atrai, the minimum values of transparency are found in the monsoon and post monsoon months like June to September due to strong current of water which washed away huge silt in water including many other suspended matters. Lakshminarayana (1965) and Hickman (1979) also made such type of observation.…”