Executive Summary
Comparative Nutrient Data for Two Locations on the Marstons Mills River

Barnstable High School
Jessica Jackson

On October 30, 2007, we deployed water samplers at two locations along the Marstons Mills River: River Road and Hyrdo Dam/Route 28. We programmed a Sigma at each location to take a water sample each hour for 24 hours, to determine the amount of dissolved nutrients in the water in the course of one day. When compared to the discharge at each site, we found that the Hydro Dam location moved nearly 117 000 000 liters of water, 10 000 grams of phosphorus, and 25 000 grams of nitrogen-nitrate each day. Only a short distance upstream, the River Road location discharged under 7 000 000 liters of water, 500 grams of phosphorus, and 2000 grams of nitrogen-nitrate.

Along with the Sigma, we floated a MiniSonde Hydrolab at each site to measure and record hourly temperature, dissolved oxygen, dissolved oxygen saturation, pH and specific conductivity. The data showed temperature to be equal at both sites, but the Hydro Dam has a more constant pH—which is also closest to neutral—and greater dissolved oxygen at any hour.

We suspect the River Road site’s proximity to cranberry bogs and leeching fields has impacted our results. Furthermore, the Hydro Dam location is just downstream from a large pond, a likely nutrient sink.

Please see the PowerPoint Presentation for details.