Interannual and long-term changes in the trophic state of a multibasin lake: Effects of morphology, climate, winter aeration, and beaver activity

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Little St. Germain Lake (LSG), a relatively pristine multibasin lake in Wisconsin, USA, was examined to determine how morphologic (internal), climatic (external), anthropogenic (winter aeration), and natural (beaver activity) factors affect the trophic state (phosphorus, P; chlorophyll, CHL; and Secchi depth, SD) of each of its basins. Basins intercepting the main flow and external P sources had highest P and CHL and shallowest SD. Internal loading in shallow, polymictic basins caused P and CHL to increase and SD to decrease as summer progressed. Winter aeration used to eliminate winterkill increased summer internal P loading and decreased water quality, while reductions in upstream beaver impoundments had little effect on water quality. Variations in air temperature and precipitation affected each basin differently. Warmer air temperatures increased productivity throughout the lake and decreased clarity in less eutrophic basins. Increased precipitation increased P in the basins intercepting the main flow but had little effect on the isolated deep West Bay. These relations are used to project effects of future climatic changes on LSG and other temperate lakes.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Interannual and long-term changes in the trophic state of a multibasin lake: Effects of morphology, climate, winter aeration, and beaver activity
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2015-0249
Volume 73
Year Published 2016
Language English
Publisher National Research Council Canada
Publisher location Ottawa
Contributing office(s) Wisconsin Water Science Center
Description 16 p.
First page 445
Last page 460
Country United States
State Wisconsin
Other Geospatial St. Germain Lake
Online Only (Y/N) N
Additional Online Files (Y/N) N