This data release presents data that were collected as part of a larger effort to assess factors that regulate metabolism in global lakes, via an international collaboration with the Global Lake Ecological Observatory Network (GLEON). From May to August 2019, dissolved oxygen and light penetration were measured throughout the water-depth profile of two small inland wetlands at Cottonwood Lake Study Area in North Dakota, USA. Water temperature and wind data also were collected, and recent water column chemistry (carbon, phosphorus, nitrogen) data from the summer of 2016 were compiled. Data from this collaborative study will be used to calculate gross primary production, and investigate how lake metabolism varies with lake size, light availability, and carbon and nutrient concentrations.