5. Conclusions
Significant seasonal biological responses to physical processes were observed in the central YS (Fig. 9). During winter, nutrient-rich water was observed coincidently with the occurrence of the YSWC (Fig. 4). Prasinophytes were abundant and the main contributors of Chl b in the YSWC water. The mechanism/process of the spring bloom was very complex and unique. However, the YSWC was suggested to be one of the important players. A very strong spatial heterogeneity was observed in the physical, chemical and biological parameters in the central YS during the YSCWM occurrence (Figs. 2, 7 and Table 2). A low Chl a biomass (0.2 mg m − 3 ) and a low contribution of diatoms to the total Chl a biomass (30%), with a high contribution of cyanobacteria (36%), were observed in the central YS in August when the YSCWM prevailed, and a high contribution of chrysophytes (38%) was observed in October when it was decaying. All these results were considered as the characteristic physical – chemical – biological response of the ecosystem in the central YS.