Introduction:

Skaneateles Lake is experiencing eutrophication due to excessive levels of nitrogen and phosphorus introduced into the water through local agricultural run-off. Eutrophication results in hypoxia, or the growth of dense plant life in aquatic environments,
which leads to the death of fish and marine animals. Skaneateles Lake is part of the Finger Lakes region in New York State, an area with significant agricultural endeavors, including commercial farms surrounding the lake. The lake is a watershed, and it serves as the primary source of drinking water for the City of Syracuse. It is a glacial lake, and the second cleanest lake in the US. It measures 17 miles long, averages 3/4 miles wide, and is 315 feet deep at the deepest point. It is a crucial environmental site that needs protection as it serves as a community water source but is also open for recreational use.

In July 2023, I submitted a plan to the Skaneateles Lake Association (SLA) to prepare a Geographic Information System (GIS) map of Skaneateles Lake. I have collected and compiled dissolved oxygen data points to create a baseline GIS to better understand eutrophication in the lake. My initial scope was to establish a base or raster map of the lake and provide a GIS file to which additional data can be appended over time by SLA volunteer scientists. My hypothesis is that oxygen depletion occurs in the lake at points nearest to areas of increased agricultural activity. By correlating eutrophication and agricultural runoff, we can target efforts to bring the local use of fertilizers in agriculture under better control. I hope to change the perceptions and behaviors of consumers, farmers, and regulators. We can easily farm, manufacture, and landscape more sustainably, and I believe that measuring our "Nitrogen
Footprint" is a first step in making this change.

Objective:

Through this initiative, I have: (i) established a baseline GIS map of the lake basin that the SLA can use to aggregate data over time, (ii) acquired dissolved oxygen samples from various points on the lake, (iii) plotted these data measurements in a GIS environment, and (iv) supported my hypothesis that oxygen depletion occurs in the lake at points adjacent to areas of
increased agricultural activity. The initial scope of this research was to establish a base or raster map of the lake and provide a GIS file to which additional data can be appended over time. The value of the GIS file is that it will be a central resource for aggregating data collected by SLA volunteer scientists.

Methods and Results:

During the summer of 2023, I created a GIS map of Skaneateles Lake. Initial data points included farm locations and some historic algal bloom location data. With this information in hand, I used a personal watercraft to collect and measure the dissolved oxygen (DO) levels in water samples taken from the lake at various locations, including both near and far from areas of agricultural activity. These data were collected on three occasions, including once after a heavy rain and once in overcast conditions. On the first date, I was able to measure DO levels at 56 points around the perimeter of the Lake. On the second occasion I was only able to collect 49 samples as my equipment failed, however the data remains accurate. I layered the DO levels into the GIS mapping environment. My materials included a Milwaukee MW600 LED Economy Portable Dissolved Oxygen Meter with 2 Point Manual Calibration, lake water samples, and a GIS file.

Preliminary Conclusions:

The data collection and GIS plots reveal a correlation between dissolved oxygen levels and agricultural activity, indicating that the presence of algal blooms aligns with farm locations which contribute to detrimental nutrient run-off into the lake.