The affects of powerboat activity on the algal richness of Lake Charlevoix.

Abstract

My family has had a home on Lake Charlevoix since before I was born. My great-grandfather made a living fishing on Lake Michigan, and kept his homeport in Charlevoix. So naturally, when it came time for me to do a research project on freshwater algae, I turned to the lake I've grown up on. In the last ten years, I have watched the amount of powerboat activity on Lake Charlevoix rise significantly, eventually getting to the point where I avoid the lake completely on summer weekends due to overcrowding. I began to wonder how I could design a fairly simple experiment to see how this activity effects the algal population. The experiment design I settled on was to collect samples from two different sites on the lake. The goal was to find two sites that were as close to being identical as I could find, with the only significant difference being the amount of powerboat activity. I settled on one site at the end of Oyster Bay, on the north shore of the lake. This site is actually a nature preserve, and the entire bay is a no wake zone, meaning that any boats that do enter the bay are moving very slowly when they do. My second site is located in the south arm of Lake Charlevoix, which is a long and narrow stretch of the lake on the south shore. This site is a favorite for water-skiing, tubing, and other powerboat activities because it is protected from the wind. A map showing the locations of the two collecting sites is included at the end of this report. Each site has a large patch of Scirpus, which starts at the shore and runs out into the lake. Both Scirpus patches were large, comprising about fifty yards squared of space. I collected several samples from each site and examined them for algal richness based on the number of different genera of algae present. I also collected water samples for a chemical analysis of nutrients in the water at each site. The goal of the chemical analysis was to show that my two sites were quite similar in regards to nutrient supply. I expected to find greater algal richness in the low traffic site. My hypothesis was that the frequent disturbances caused by all of the powerboat wakes would cause a scouring effect that limited the genera of algae that would grow in the high traffic site to those which somehow directly attached themselves to the substrate.