There is an urgent need to develop efficient evaluation tools that use easily measured variables to make rapid and timely eutrophication assessments, which are important for marine health management, and to implement ...There is an urgent need to develop efficient evaluation tools that use easily measured variables to make rapid and timely eutrophication assessments, which are important for marine health management, and to implement eutrophication monitoring programs. In this study, an approach for rapidly assessing the eutrophication status of coastal waters with three easily measured parameters （turbidity, chlorophyll a and dissolved oxygen） was developed by the grid search （GS） optimized support vector machine （SVM）, with trophic index TRIX classification results as the reference. With the optimized penalty parameter C=64 and the kernel parameter y=l, the classification accuracy rates reached 89.3% for the training data, 88.3% for the cross-validation, and 88.5% for the validation dataset. Because the developed approach only used three easy-to-measure variables, its application could facilitate the rapid assessment of the eutrophication status of coastal waters, resulting in potential cost savings in marine monitoring programs and assisting in the provision of timely advice for marine management.展开更多
To realize potential cost savings in coastal monitoring programs and provide timely advice for marine management, there is an urgent need for efficient evaluation tools based on easily measured variables for the rapid...To realize potential cost savings in coastal monitoring programs and provide timely advice for marine management, there is an urgent need for efficient evaluation tools based on easily measured variables for the rapid and timely assessment of estuarine and offshore eutrophication. In this study, using parallel factor analysis(PARAFAC), principal component analysis(PCA), and discriminant function analysis(DFA) with the trophic index(TRIX) for reference, we developed an approach for rapidly assessing the eutrophication status of coastal waters using easy-to-measure parameters, including chromophoric dissolved organic matter(CDOM), fluorescence excitation–emission matrices, CDOM UV-Vis absorbance, and other water-quality parameters(turbidity, chlorophyll a, and dissolved oxygen). First, we decomposed CDOM excitation-emission matrices(EEMs) by PARAFAC to identify three components. Then, we applied PCA to simplify the complexity of the relationships between the water-quality parameters. Finally, we used the PCA score values as independent variables in DFA to develop a eutrophication assessment model. The developed model yielded classification accuracy rates of 97.1%, 80.5%, 90.3%, and 89.1% for good, moderate, and poor water qualities, and for the overall data sets, respectively. Our results suggest that these easy-to-measure parameters could be used to develop a simple approach for rapid in-situ assessment and monitoring of the eutrophication of estuarine and offshore areas.展开更多
The concentrations of phosphate （PO43 ）, ammonium, nitrite, nitrate, silicate, dissolved organic nitrogen （DON）, dissolved or- ganic phosphorus （DOP）, particulate phosphorus （PP） and particulate nitrogen （PN...The concentrations of phosphate （PO43 ）, ammonium, nitrite, nitrate, silicate, dissolved organic nitrogen （DON）, dissolved or- ganic phosphorus （DOP）, particulate phosphorus （PP） and particulate nitrogen （PN） along the salinity gradient were measured in the Changjiang Estuary in April 2007. The behavior of nutrient species along the continuum from the freshwater to the coastal zone is discussed. In the mixing zone between the riverine and marine waters, nitrate and phosphate behave non-conservatively, while silicate behaves conservatively. Nutrient import was quantified from the fiver load. Nutrient export to the sea was quantified from fiver discharge and from the salinity-nutrient gradient in the outer estuary. Using these data, a nitrogen and phosphorus budget was made. The internal estuarine fluxes played an important role in the nutrient estuarine fluxes, which accounted for approximately 41% of the nitrogen flux and 45% of the phosphorus flux. The mixing experiments in the laboratory generally reproduced well the inorganic process affecting nutrient dynamics in the Changjiang Estuary, indi- cating that the primary P and N transformation processes were phosphate and nitrate desorption along the salinity gradient.展开更多
基金Supported by the National Key Research and Development Program(No.2016YFC1402101)the National Natural Science Foundation of China(No.41376106)the Natural Science Foundation of Shandong Province(No.ZR2013DM017)
文摘There is an urgent need to develop efficient evaluation tools that use easily measured variables to make rapid and timely eutrophication assessments, which are important for marine health management, and to implement eutrophication monitoring programs. In this study, an approach for rapidly assessing the eutrophication status of coastal waters with three easily measured parameters （turbidity, chlorophyll a and dissolved oxygen） was developed by the grid search （GS） optimized support vector machine （SVM）, with trophic index TRIX classification results as the reference. With the optimized penalty parameter C=64 and the kernel parameter y=l, the classification accuracy rates reached 89.3% for the training data, 88.3% for the cross-validation, and 88.5% for the validation dataset. Because the developed approach only used three easy-to-measure variables, its application could facilitate the rapid assessment of the eutrophication status of coastal waters, resulting in potential cost savings in marine monitoring programs and assisting in the provision of timely advice for marine management.
基金the National Natural Science Foundation of China (No. 41376106)the Shandong Provincial Natural Science Foundation of China (No. ZR2013DM017)
文摘To realize potential cost savings in coastal monitoring programs and provide timely advice for marine management, there is an urgent need for efficient evaluation tools based on easily measured variables for the rapid and timely assessment of estuarine and offshore eutrophication. In this study, using parallel factor analysis(PARAFAC), principal component analysis(PCA), and discriminant function analysis(DFA) with the trophic index(TRIX) for reference, we developed an approach for rapidly assessing the eutrophication status of coastal waters using easy-to-measure parameters, including chromophoric dissolved organic matter(CDOM), fluorescence excitation–emission matrices, CDOM UV-Vis absorbance, and other water-quality parameters(turbidity, chlorophyll a, and dissolved oxygen). First, we decomposed CDOM excitation-emission matrices(EEMs) by PARAFAC to identify three components. Then, we applied PCA to simplify the complexity of the relationships between the water-quality parameters. Finally, we used the PCA score values as independent variables in DFA to develop a eutrophication assessment model. The developed model yielded classification accuracy rates of 97.1%, 80.5%, 90.3%, and 89.1% for good, moderate, and poor water qualities, and for the overall data sets, respectively. Our results suggest that these easy-to-measure parameters could be used to develop a simple approach for rapid in-situ assessment and monitoring of the eutrophication of estuarine and offshore areas.
基金supported by the National Basic Research Program of China(2011CB403602)National Natural Science Foundation of China(41276070,40920164004)National Natural Science Foundation for Creative Research Groups(41221004)
文摘The concentrations of phosphate （PO43 ）, ammonium, nitrite, nitrate, silicate, dissolved organic nitrogen （DON）, dissolved or- ganic phosphorus （DOP）, particulate phosphorus （PP） and particulate nitrogen （PN） along the salinity gradient were measured in the Changjiang Estuary in April 2007. The behavior of nutrient species along the continuum from the freshwater to the coastal zone is discussed. In the mixing zone between the riverine and marine waters, nitrate and phosphate behave non-conservatively, while silicate behaves conservatively. Nutrient import was quantified from the fiver load. Nutrient export to the sea was quantified from fiver discharge and from the salinity-nutrient gradient in the outer estuary. Using these data, a nitrogen and phosphorus budget was made. The internal estuarine fluxes played an important role in the nutrient estuarine fluxes, which accounted for approximately 41% of the nitrogen flux and 45% of the phosphorus flux. The mixing experiments in the laboratory generally reproduced well the inorganic process affecting nutrient dynamics in the Changjiang Estuary, indi- cating that the primary P and N transformation processes were phosphate and nitrate desorption along the salinity gradient.
