Title

The Effects of Road Salt Influx on the Geochemical Cycling of Woods Lake, Kalamazoo, Michigan

Date of Award

6-2012

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. Carla Koretsky

Second Advisor

Dr. Mohamed Sultan

Third Advisor

Dr. Alan Kehew

Access Setting

Masters Thesis-Campus Only

Restricted to Campus until

6-15-2032

Abstract

Recent studies suggest that the influx of saline runoff from seasonal applications of road deicing salts may lead to the formation of persistent density gradients in urban lakes, due to the elevation of lake salinity Allowed to develop, an increase in bottom water density has the potential to change physical mixing cycles and thus nutrient/chemical partitioning within freshwater lakes. To date, very few studies have focused on salinity-based density stratification as an avenue for study Therefore, the goal of this study is to examine the influence of road salt influx on the geochemical cycling of Woods Lake, a small, kettle lake in urban Kalamazoo, MI. Water samples were collected approximately twice a month for a period of 15 months at the point of maximum depth (~13 m) and analyzed for temperature, pH, conductivity, and dissolved oxygen (DO), Fe2+, total alkalinity, ΣNH4+, ΣP043-, ΣH2S, Mn2+, CI-, SO42-, Mg, Ca, K, and Na. Analyses of reduced solutes and DO show that Woods Lake displays persistent redox stratification and bottom water anoxia throughout the entire sampling period. Conductivity, CI-, and calculated density profiles indicate the presence of a pycnocline that persists year-round between ~8 and 10 m. These data imply persistent density/chemical stratification, presumably due to nutrient and road salt inputs, and that both fall and spring turnover events never fully reach completion. This is likely a widespread condition in temperate, urban lakes, one that will surely change the fundamental biogeochemical cycling of nutrients within these systems, leading to widespread destruction of aquatic habitat and loss of biodiversity.

Comments

This thesis is unavailable because permission has not been granted by the author. A print copy is available at the WMU Waldo Library in the General Stacks at call number: TD 9999.S534

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