AME 33:19-28 (2003)  -  doi:10.3354/ame033019

Sestonic bacterial nutrient limitation in a northern temperate river and the impact of pulp-mill effluents

Mohamed N. Mohamed1,2,*, Richard D. Robarts1

1National Water Research Institute, Saskatoon, Saskatchewan S7N 3H5, Canada
2Present address: Dept. of Biology, University of Waterloo, 200 University Ave. W., Waterloo, Ontario N2L 3G1, Canada

ABSTRACT: Bacterial growth limitation and the effect of pulp-mill effluents (pme) on sestonic bacteria were studied in a northern temperate river (the Fraser River, British Columbia, Canada). Nutrient addition experiments demonstrated that sestonic bacterial growth was potentially limited by p. Experiments were done by adding n, p, or organic carbon to 2 l microcosms of river water. The addition of p (singly, and in combination with N and C) increased bacterial production (rate of 3H-thymidine incorporation) and activity (14C-glucose uptake), while the addition of n or organic carbon did not. The inflow of PME into the Fraser River increased bacterial abundance, activity, and production in 2 ways. First, p in the pme increased native bacterial abundance and processes, and second, pme provided a source of active bacteria to the river.

KEY WORDS: Bacteria · River · Phosphorus · Limitation · Pulp mill · Nutrient · Effluent · Sewage

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