“Monty” the buoy in hyper-eutrophic Shelburne Pond, Vermont, USA: the first year

Shelburne Pond is a 182-ha, shallow, hyper-eutrophic system in the Lake Champlain watershed. The pond is prone to annual cyanobacteria blooms and periodic summer fish kills. A custom buoy was built and then deployed in April 2015 to enhance research and teaching at the pond and to engage in global research through GLEON. The system includes a thermistor chain, sensors to measure dissolved oxygen (DO; near-surface and near-bottom), chlorophyll and phycocy an in fluorescence, pH, conductivity, and a suite of standard weather metrics. We report on the insights and challenges encountered during the first-year deployment. For example, the sensors captured the polymictic nature of the pond, showing a tight coupling between thermal stratification and near-bottom oxygen depletion driven by wind. Pond conditions, however, corroded our pH and near-bottom temperature sensors, the latter necessitating a switch to HOBO temperature loggers. Maintaining near-bottom temperature and DO observations with our suspended chain was, at times, hampered by changing water levels and a very soft-sediment bottom. Considerations for 2016 include deploying temperature and DO sensors from the lake bottom instead of the surface, epoxied temperature sensors to prevent corrosion, additional DO sensors to better profile the water column, and an onshore rain gauge to measure precipitation.