Date Approved

2015

Date Posted

12-9-2015

Degree Type

Open Access Senior Honors Thesis

Department or School

Biology

First Advisor

Kristi Judd

Abstract

Temperate lakes typically turnover twice annually; however, certain factors can reduce the possibility of turnover. One of these factors may be the addition of road salt to the watershed. Road salt increases the density of water, increasing the energy needed to turnover a lake. Reduced turnover can have major effects on the nutrient dynamics of the lake. In this study, I examined seven small, deep lakes in Southeast Michigan to determine if turnover was affected by salinity. The purpose of this study was to determine whether these turnover events in TSL have changed since 2009 and how common incomplete spring turnover was in other small, deep lakes. I measured the amount of dissolved oxygen, temperature and conductivity and calculated the stability of each lake. I also measured nutrient concentrations and Chi a to determine whether nutrient cycling was affected. One lake, Third Sister Lake (TSL),demonstrated reduced turnover from repeated years of salt inputs.

The results of this study indicate that incomplete spring turnover occurred in two lakes: Third Sister Lake and Pickerel Lake, although excessive salt accumulation only occurred in TSL,suggesting that other factors may have caused this same phenomenon in Pickerel Lake. I found that these two lakes were also the most stable. In TSL,phosphorus was trapped in the hypolimnion during the summer and Chl was highest in the metalimion. However, we did not see these patterns in Pickerel Lake. Lower nutrient and oxygen availability creates unfavorable conditions for the wildlife of each lake. Other lakes, such as Pickerel Lake, that experienced decreased turnover should be monitored as they could follow the same fate as TSL if ever salt were presented into that particular watershed.

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