Comparative lake survey: Andrus Lake.

Abstract

Andrus Lake located in Chippewa County, Michigan was studied on July 11, 1992 by the UMBS Limnology calss as part of a comparative lake survey. Low nutrient levels and low pH render Andrus an oligotrophic, acid lake. It has not always been classified as an acidic lake, however. It is only within the past 20 years that pH levels have substantially dropped. Atmospheric deposition is thought to be largely responsible for this drop in pH. Clear water and deep light penetration allow the bottom sediments to be seen, thus giving the water the appearance of being brown. The watershed is small (143.9 hectares) and contains sandy, nutrient poor soils (EPA survey, 1984). The principle source of water input into Andrus Lake is through groundwater seepage as it is landlocked with no inlets or outlets (EPA survey, 1984). The principle objective of this study is to present an analysis of the data collected in order to confirm that Andrus Lake is indeed an oligotrophic acid lake as records indicate. Furthermore, this survey is intended as an aid in understanding the characteristics of different types of lakes, and thus to serve as a future comparative reference of Andrus Lake.