Phosphorus Content of Belwood Reservoir Sediment Core

On February 14, 2018, four sediment cores were obtained from Belwood Lake, an approximately 7-km2 reservoir in the upper Grand River Watershed that was created in 1941 as a result of dam construction.Of these four, one core, , 8.7 cm internal diameter and 47 cm long, was selected for sediment core dating and laboratory analysis. Cores were collected using a Glew hammer-driven gravity corer fitted with a lucite tube and were subsequently transported to the lab, where they were sectioned at 0.5-cm intervals. Sediment samples were sealed in plastic bags and refrigerated at 4℃ until undergoing further analysis. One of the four cores collected (47 cm long), was selected for sediment core dating and laboratory analysis. In the laboratory, sequential loss-on-ignition (LOI) analysis was performed using ~0.5-g subsamples of wet sediment from each core slice, as described previously, to obtain the organic matter and carbonate content. The sediment P content of core slices was determined by IC-OES (Thermo Scientific iCAP 6300) after digestion with potassium persulfate-sulfuric acid . A sediment core chronology was developed based on gamma ray spectrometric determination of 210Pb activity at contiguous 0.5-cm intervals, using previously described methods.