Planktonic Primary Production in the Offshore Waters of Dreissenid-infested Lake Erie in 1997

Assessing the application of SeaWiFS ocean color algorithms to Lake Erie

“…Statistics of the full field-collected and of the collocated datasets are summarized in Table 2. In both datasets, the mean and standard deviation of the chlorophyll a concentrations decreased from west to east, in agreement with trends observed in previous studies of chlorophyll a (Makarewiczl et al, 1999;Ostrom et al, 2005;Smith et al, 2005). Table 1 Algorithms used to estimate chlorophyll a concentration (C) or chlorophyll a + phaeophytic concentration [C + P] in μg/L from observations of remote sensing reflectance (R rsnnn ) or normalized water-leaving radiance (L wnnnn ) at wavelengths nnn nm.…”

“…These variations in depth and stratification, as well as variations in nutrient loading, resulted in the shallow western basin being the most biologically productive part of the lake prior to the introduction of the zebra mussel Dresissena polymorpha (Makarewicz, 1993). Since then, biological productivity has decreased in the western basin and seasonal variations in the relative productivity of the three basins have been observed (Frost and Culver, 2001;Makarewiczl et al, 1999), though near-surface chlorophyll a concentrations continue to be highest in the western basin (Ostrom et al, 2005;Smith et al, 2005). Toxic algal blooms, which contribute to variations in CPAs, have been documented most commonly in the western basin of the lake (Budd et al, 2001;Vincent et al, 2004), and are expected to become more wide-spread in the future (Conroy et al, 2007).…”

Surficial sediment phosphorus fractions along a biogeochemical gradient in Nyanza (Winam) Gulf, northeastern Lake Victoria and their possible role in phosphorus recycling and internal loading

“…Williams et al (1976) reported TP concentrations ranging from 188 to 2,863 mg/kg in both offshore and highly eutrophied inshore stations in Lake Erie. OP concentrations in Lake Victoria (250 to 500 mg/kg) were higher than values Williams et al reported for Lake Erie (0-286 mg/kg), consistent with higher phytoplankton biomass in Lake Victoria compared to Lake Erie Table 2 Sedimentary carbon (C), nitrogen (N) and phosphorus (P) concentrations and molar ratios of P to N and C and C Values in the parenthesis are the standard deviations (6.9-21.1 and 3.9-5.3 lg Chl a/l, respectively; Gikuma- Njuru et al 2006;Smith et al 2005) and the much higher TP concentrations in Lake Victoria. Lake Victoria is unique among the African and world great lakes due to its high nutrient concentrations, relatively shallow depth and associated high algal productivity and biomass (Hecky and Bugenyi 1992;Bootsma and Hecky 1993;Hecky 2000).…”

In situ-measured primary production in Lake Superior

“…2D). Studies on Lake Erie have measured 155-169 g C m − 2 (summertime, Smith et al, 2005) and 320-370 g C m − 2 (annual, Fitzpatrick et al 2007). These are higher than the 93.7 g C m − 2 reported here for Lake Superior for the entire year.…”