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Microbial nutrient limitation in prairie saline lakes with high sulfate concentration
Author(s) -
Waker Marley J.,
Robarts Richard D.
Publication year - 1995
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1995.40.3.0566
Subject(s) - nutrient , salinity , environmental chemistry , phosphorus , phytoplankton , chlorophyll a , sulfate , zoology , biology , chemistry , ecology , botany , organic chemistry
Most of the lakes on the Canadian prairies are saline (>3 g liter −1 salt). Sulfate ions are relatively more abundant in these lakes than anywhere else in the world. Studies indicate that some of these lakes do not conform to empirical models which link chlorophyll a to spring total phosphorus concentration. A suite of tests, including nutrient enrichment bioassays, sestonic and protein to carbohydrate ratios, alkaline phosphatase activity, and 32 P‐turnover times were used to test microbial nutrient limitation in three prairie saline lakes. Although the concentration of soluble reactive P (SRP) was high (9–31 µ g liter −1 ) in two of the lakes, little was available for microbial growth. Bacteria were responsible for 84 and 53% of the 32 P uptake in these two lakes. Production of high levels of alkaline phosphatase by the phytoplankton in one lake appears to keep their intracellular stores of P replete and PN : PP ratios in the P‐sufficient range. Striking differences were noted when our data from saline lakes were compared to data from freshwater lakes. Our saline lakes were P‐deficient at SRP concentrations <31 µ g liter −1 , while freshwater lakes were P‐deficient at SRP concentrations <1 µ g liter −1 . High concentrations of dissolved organic C, pH, and ionic composition in saline lakes appear to play a role in the availability of P.