Field investigation.xlsx

In Lake Dianshan, the DIN concentration decreased gradually from May and reached the lowest value of 0.18 mg/L in August, and after that, the DIN value re-rose to a high level. Concurrently, the carbohydrate content of Microcystis biomass exhibited an opposite trend and showed a peak value of 24.3% in August. A strong negative correlation (R=-0.892, p<0.05, n=6) was found between the DIN concentration in the lake and the carbohydrate content. Similarly, the data on spatial variability of DIN concentration and carbohydrate content of Microcystis in August also suggest opposite trend. The correlation coefficient between the DIN concentration and the carbohydrate content was also negative (R= -0.748, p<0.05, n= 10). The results shown the temporal and spatial distribution of the DIN concentration in the lake and the carbohydrate content of Microcystis and provided field evidence for a strong negative correlation between them for the first time.