Year-round metabolism data from Lakes Simcoe (Ontario, 2010-2011), Diefenbaker, Blackstrap, and Broderick (Saskatchewan, 2013-2014), Canada.

This year-round limnology dataset is from four dimictic Canadian water bodies: three mesotrophic reservoirs in southern Saskatchewan (SK; Blackstrap, Broderick, Diefenbaker) and one oligo-mesotrophic large lake in southern Ontario (Lake Simcoe). Physical, chemical, and biological parameters were measured during the open-water and ice-covered seasons in 2010–2011 (Lake Simcoe) and the SK reservoirs in 2013–2014. Two stations were sampled on Blackstrap reservoir, one on Broderick reservoir, three on Diefenbaker reservoir, and seventeen on Lake Simcoe. Sampling was conducted from a boat during the open-water season and during winter, we accessed the same stations by snowmobile and sampled through holes in the ice. Epilimnetic or surface water was collected for parameters listed below, and δ18O-O2 (oxygen) stable isotope samples were collected from one to 4 depths per station, depending on water column depth and lake thermal structure that day. Parameters reported included photosynthetically active radiation, vertical attenuation coefficient, mean daily mixed layer irradiance, total phosphorus, total dissolved phosphorus, dissolved reactive phosphorus, total dissolved nitrogen, particulate nitrogen, ammonium, nitrate, chlorophyll a, particulate organic carbon, and phytoplankton biovolumes. Photosynthesis irradiance (P-E) parameters were measured including the light saturation parameter, maximum relative electron transport rate through PSII, and the light limited slope of the P-E curve. We also measured areal net productivity, areal gross productivity, and areal respiration via three different methods including fluorometry via a Water-PAM fluorometer, O2 concentrations and δ18O-O2 values, and light-dark bottle experiments measuring changes in O2 concentrations.