A hypothesis was formulated to explain the possible cause of water bloom occurring inLake Qiandaohu in 1998 and 1999. We tested this hypothesis with a 3-year in situ fieldstudy. The results showed that the reconstruct...A hypothesis was formulated to explain the possible cause of water bloom occurring inLake Qiandaohu in 1998 and 1999. We tested this hypothesis with a 3-year in situ fieldstudy. The results showed that the reconstruction of the silver carp and bighead carppopulations, without other measures of nutrient control, could prevent the recurrence ofalgal bloom in the lake successfully. This result could serve as an evidence to thesuggested hypothesis for water blooming: The drastic decline of the filter feedingsilver carp and bighead carp in the lake, rather than the nutrients overloading, wasmainly responsible for the algal bloom. According to this study, we suggest a generalhypothesis to the ecological mechanism of algal blooming: The insufficient grazing fromthe phytoplanktivores (top-down control) to the algal reproduction from nutrientsavailable (bottom-up effect) is the radical cause of water blooming, while conventionally,it is primarily attributed to the enrichment of nutrients. Besides, this study showedthat stocking silver carp and bighead carp in lakes could improve water quality, whichis also contrary to the conventional opinion. Finally, this study provided a cost-effective and practicable approach to control water bloom for the large-sized reservoirs,especially when water blooming occurred locally. A net-enclosed aquaculture zone (NEAZ)can be established in the nutrients-exposure area of the waters and stocked with the twocarps, water bloom could be controlled and prevented.展开更多
This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phospho...This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP). Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multivariate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.展开更多
基金supported by the Nationa1 Natural Science Foundation of China(30028018).
文摘A hypothesis was formulated to explain the possible cause of water bloom occurring inLake Qiandaohu in 1998 and 1999. We tested this hypothesis with a 3-year in situ fieldstudy. The results showed that the reconstruction of the silver carp and bighead carppopulations, without other measures of nutrient control, could prevent the recurrence ofalgal bloom in the lake successfully. This result could serve as an evidence to thesuggested hypothesis for water blooming: The drastic decline of the filter feedingsilver carp and bighead carp in the lake, rather than the nutrients overloading, wasmainly responsible for the algal bloom. According to this study, we suggest a generalhypothesis to the ecological mechanism of algal blooming: The insufficient grazing fromthe phytoplanktivores (top-down control) to the algal reproduction from nutrientsavailable (bottom-up effect) is the radical cause of water blooming, while conventionally,it is primarily attributed to the enrichment of nutrients. Besides, this study showedthat stocking silver carp and bighead carp in lakes could improve water quality, whichis also contrary to the conventional opinion. Finally, this study provided a cost-effective and practicable approach to control water bloom for the large-sized reservoirs,especially when water blooming occurred locally. A net-enclosed aquaculture zone (NEAZ)can be established in the nutrients-exposure area of the waters and stocked with the twocarps, water bloom could be controlled and prevented.
基金Project supported by the National Natural Science Foundation of China (No. 69673044) the Environmental Protection Bureau of Hangzhou (No. 9901), China
文摘This research considers the mathematical relationship between concentration of Chla and seven environmental factors, i.e. Lake water temperature (T), Secci-depth (SD), pH, DO, CODMn, Total Nitrogen (TN), Total Phosphorus (TP). Stepwise linear regression of 1997 to 1999 monitoring data at each sampling point of Qiandaohu Lake yielded the multivariate regression models presented in this paper. The concentration of Chla as simulation for the year 2000 by the regression model was similar to the observed value. The suggested mathematical relationship could be used to predict changes in the lakewater environment at any point in time. The results showed that SD, TP and pH were the most significant factors affecting Chla concentration.
