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Communication at the NABS Annual meeting, Keystone, 2000
(54) CORRELATES OF WATER CLARITY FOR ASSESSING DEGRADATION OF A LARGE LACUSTRINE WETLAND IN CENTRAL CANADA.
L.G. Goldsborough1 and D.A. Wrubleski2. 1Department of Botany, University of Manitoba, Winnipeg, MB, Canada R3T 2N2, 2IWWR, Ducks Unlimited Canada, Stonewall, MB, Canada R0C 2Z0
Delta Marsh is one of several marshes bordering large lakes in southern Manitoba that have become turbid over the past three decades. This fundamental shift from a former clear state is primarily due to the imposition of stable water levels and proliferation of carp. The resulting biotic and abiotic changes in the water column have lead to a dramatic decline in waterfowl use. In 1998 and 1999, we analyzed biweekly water samples from 44 sites throughout the marsh for a full suite of water chemistry and clarity parameters to provide a baseline for future studies, and to assess the magnitude of change as compared to corresponding data from the early 1970s. Most of the sites were situated in open, wind-swept bays that were very turbid (> 20 NTU) with few or no submersed macrophytes. Water clarity (suspended solids, light extinction rate) was inversely correlated with planktonic algal biomass, indicating that algae was a major contributor to high turbidity. The few remaining isolated ponds around the marsh periphery were typically much clearer (< 5 NTU) and contained profuse submersed macrophytes.
Presented at 5:00 PM on Monday, May 29, 2000 in Wetlands and Lentic Ecology II
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