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River-estuary-coast continuum: Biogeochemistry and ecological response to increasing human and climatic changes – Editorial overview
Estuarine, Coastal and Shelf Science 166 (2015) 144e145
Contents lists available at ScienceDirect
Estuarine, Coastal and Shelf Science journal homepage: www.elsevier.com/locate/ecss
River-estuary-coast continuum: Biogeochemistry and ecological response to increasing human and climatic changes e Editorial overview
The World Summit on Sustainable Development (WSSD) 2002 highlighted the integrated management from hilltops to oceans. The multidisciplinary and ecosystem approach has become a fundamental tool of developing realistic, ecologically sound, and cost-effective management strategies for river-estuary-coast systems. These systems have been suffering both anthropogenic and climatic perturbations, including population growth, land use/ cover change, temperature and precipitation for some time. During the transport from river to estuary to coast, terrestrial constituents experience a series of biogeochemical and ecological processes. The aim of this issue is therefore to synthesize our knowledge of biogeochemical and ecological processes occurring across the river-estuary-coast continuum. China's coasts have experienced rapid population growth, economic development and urbanization, accompanied by increasing water pollution and climate events. This special issue highlights the biogeochemical and ecological responses of coastal waters to river and subterranean inputs, as well as upwelling. Li et al. (2015) state that the Jiulong river plume in summer (wet season) can transport particles directly into the Taiwan Strait. Even as a small river plume, it can alter and enhance inner-shelf suspended particle transport either along-strait or cross-strait. Wang et al. (2015) model the long term trend of riverine nutrient export to and the DIN:DIP ratio in the Changjiang Basin using the GlobalNEWs model; and confirm that anthropogenic nutrient inputs have influenced Chl-a concentrations as well as the bottom DO level in the estuary. The observed Chl-a concentration increased by 146% while bottom seawater DO concentration decreased by 24.6% from 1992 to 2010, which was negatively related to the river DIN:DIP ratio. Yang et al. (2015) report that groundwater discharge provides an important source of dissolved organic matter to estuarine and coastal waters. They examine the concentration, chemical composition and bioavailability of DOM in two subterranean estuaries of southwest Taiwan with contrasting degrees of pollution and find that the DOC and fluorescent components are nonconservative (addition or removal) and very dynamic in both subterranean estuaries, although groundwater DOM may have a low bioavailability. Hu et al. (2015) observe an interesting phenomenon of low nutrient and high Chl-a in the southern Taiwan Strait that was influenced by a coastal upwelling system. Favored by proper temperature, N:P ratio and illumination, the phytoplankton grows rapidly and consumes most of the nutrients during the movement of the upwelled water in the surface sea current. Global climate change is likely to increase the number, duration and intensity of tropical/subtropical cyclones and accompanying http://dx.doi.org/10.1016/j.ecss.2015.10.036 0272-7714/© 2015 Published by Elsevier Ltd.
heavy storms. Chen et al. (2015) examine the effects of major storms on river phosphorus (P) export from an agricultural river (in SE China). Extreme storms exhibit broad fluctuation in P concentration, flux and composition. River water dissolved reactive phosphorus and dissolved organic phosphorous (DOP) have a different supply source and transport mechanism. Storms result in a 3.4e16-fold increase in P loads (with more DOP) to the estuary. These results are important in predicting the ecosystem response of estuarine and coastal regions to storm events. In subtropical regions, nitrogen export from the watershed is closely associated with precipitation and runoff (Liu et al., 2015). Another study by Zhai et al. (2015) suggests that the seawater carbonate system is dynamic during and after a summer flood, and that shallow-water aragonite undersaturation occurs in the China coast owing to respiration and dilution. However, aragonite undersaturated water disappears a week after the flood period. From a management perspective, it is critical to capture various spatial and temporal scales in the export of nutrients and other pollutants from watershed to river and then coastal waters. Huang et al. (2015) analyzed the watershed streamflow variability response to climate change and human activities by using the ecohydrologic and environmental flow component. Liu et al. (2015) develop a watershed-reservoir coupled model, a useful tool for understanding N retention by a reservoir and downriver transport at annual, monthly and daily scales. The reservoir serves mainly as a sink on an annual scale, but it may become a source in the dry season. Typically, coastal and estuary waters receive pollutant loading from diffuse sources. To mitigate eutrophication and improve water quality in an efficient way, quantifying the source at the sub-basin scale is essential to help decision makers to prioritize pollution management strategies, as demonstrated in a case study in Quanzhou Bay by Zhao et al. (2015). Increasing river nutrient input degrades water quality and threatens the ecological health of aquatic ecosystems, requiring decision makers to control landbased sources of nutrient pollution. Kong et al. (2015) present a systematic framework and models to estimate the minimum cost solutions of nutrient reduction at county level within the Jiulong River watershed. Given the spatial heterogeneity of the emission sources and their relative contribution to the water quality of the targeted water-body, such optimization of cost-effective measures is necessary and will achieve the long-term goals of sustainability in these coastal regions. In summary, this issue provides an important demonstration towards understanding the biogeochemistry and ecological responses to increasing human and climatic changes along the
H. Hong et al. / Estuarine, Coastal and Shelf Science 166 (2015) 144e145
river-estuary-coast continuum. It is apparent that local human activities and global climate change have exerted combined effects on the export of sediments, nutrients and pollutants from land to water. These studies address interdisciplinary studies including land management, estuarine chemistry, coastal oceanography and ecology. Coupled models linking biogeochemistry, ecology and social-economics can assist in decision making. However, it is still a challenge to quantify the major biogeochemical and ecological processes regulating the interactions that exist between and within river-estuary-coastal aquatic ecosystems. More research focusing on the river-estuary interface as well as the estuary-coast interface are needed to improve our understanding and better support management schemes within an integrated watershed-coast framework. Long-term collaborative monitoring and modeling of environmental dynamics are essential for developing realistic, ecologically sound, and cost-effective management strategies for the whole river-estuary-coastal system. We'd highly appreciated Dr Tom Bianchi as the chief editor for his thoughtful comments and suggestions throughout the whole process of the SI, and also the patience and coordination of Ms Java Pavithra and You Jun, at the editorial office of ECSS, and of Elsevier during the preparation of these manuscripts. We thank our international colleagues who served as our reviewers and guest editors and provided many stimulating and thoughtful comments on these manuscripts. We'd also like to thank Dr John Hodgkiss for kind assistances in English and grammar checking. Special thank goes to Ms Shuiying Huang for her coordination and assistances, and for Mr Qinbiao Ni for polishing the cover photo. The generous and sustained financial support provided by the Ministry of education, the Natural Science Foundation of China, Fujian Provincial Government and the State Key Laboratory of Marine Environmental Science for studying the Jiulong River-estuarycoast system during the past twenty years is much appreciated. References Chen, N., Wu, Y., Chen, Z., Hong, H., 2015. Phosphorus export during storm events from a human perturbed watershed, southeast China: implications for coastal ecology. Estuar. Coast. Shelf Sci. 166, 178e188.
145
Hu, J., Lan, W., Huang, B., Chiang, K., Hong, H., 2015. Low nutrient and high chlorophyll a coastal upwelling system e a case study in the southern Taiwan Strait. Estuar. Coast. Shelf Sci. 166, 170e177. Kong, H., Lin, H., Peng, B., Chen, N., Lin, C., Fielding, S., 2015. Modelling the costeffective solutions of nitrogen reduction in Jiulong River Watershed, China. Estuar. Coast. Shelf Sci. 166, 218e229. Li, Y., Chen, Y., Ruan, M., Chen, J., 2015. The Jiulong River plume as cross-strait exporter and along-strait barrier for suspended sediment: evidence from the endmember analysis of in-situ particle size. Estuar. Coast. Shelf Sci. 166, 146e152. Liu, M., Chen, X., Yao, H., Chen, Y., 2015. A coupled modeling approach to evaluate nitrogen retention within the Shanmei Reservoir watershed, China. Estuar. Coast. Shelf Sci. 166, 189e198. Wang, J., Yan, W., Chen, N., Li, X., Liu, L., 2015. Modeled long-term changes of DIN: DIP ratio in the Changjiang River in relation to Chl-a and DO concentrations in adjacent estuary. Estuar. Coast. Shelf Sci. 166, 153e160. Yang, L., Chen, C.-T.A., Hong, H., Chang, Y.-C., Lui, H.-K., 2015. Mixing behavior and bioavailability of dissolved organic matter in two contrasting subterranean estuaries as revealed by fluorescence spectroscopy and parallel factor analysis. Estuar. Coast. Shelf Sci. 166, 161e169. Zhai, W., Zang, K., Huo, C., Zheng, N., Xu, X., 2015. Occurrence of aragonite corrosive water in the North Yellow Sea, near the Yalu River estuary, during a summer flood. Estuar. Coast. Shelf Sci. 166, 199e208. Zhang, Z., Huang, J., Huang, Y., Hong, H., 2015. Streamflow Variability Response to Climate Change and Cascade Dams Development in a Coastal China Watershed. Estuar. Coast. Shelf Sci 166, 209e217. Zhao, W.L., Yang, S.Y., Wang, J., Xiao, J.M., Lu, X.X., Lin, J., Huang, P., Cai, M.G., 2015. Load estimation and assessment of land-based pollution for Quanzhou Bay and their relevance to the Total Quantity Control of Pollutants Discharged into the Sea (TQCPS) Program in China. Estuar. Coast. Shelf Sci. 166, 230e239.
Huasheng Hong*, Nengwang Chen State Key Laboratory of Marine Environmental Science, Xiamen University, PR China Coastal and Ocean Management Institute, College of the Environment and Ecology, Xiamen University, PR China Deli Wang State Key Laboratory of Marine Environmental Science, Xiamen University, PR China E-mail address: [email protected]. *
Corresponding author. State Key Laboratory of Marine Environmental Science, Xiamen University, PR China. E-mail addresses: [email protected] (H. Hong), [email protected] (N. Chen).
Contents lists available at ScienceDirect
Estuarine, Coastal and Shelf Science journal homepage: www.elsevier.com/locate/ecss
River-estuary-coast continuum: Biogeochemistry and ecological response to increasing human and climatic changes e Editorial overview
The World Summit on Sustainable Development (WSSD) 2002 highlighted the integrated management from hilltops to oceans. The multidisciplinary and ecosystem approach has become a fundamental tool of developing realistic, ecologically sound, and cost-effective management strategies for river-estuary-coast systems. These systems have been suffering both anthropogenic and climatic perturbations, including population growth, land use/ cover change, temperature and precipitation for some time. During the transport from river to estuary to coast, terrestrial constituents experience a series of biogeochemical and ecological processes. The aim of this issue is therefore to synthesize our knowledge of biogeochemical and ecological processes occurring across the river-estuary-coast continuum. China's coasts have experienced rapid population growth, economic development and urbanization, accompanied by increasing water pollution and climate events. This special issue highlights the biogeochemical and ecological responses of coastal waters to river and subterranean inputs, as well as upwelling. Li et al. (2015) state that the Jiulong river plume in summer (wet season) can transport particles directly into the Taiwan Strait. Even as a small river plume, it can alter and enhance inner-shelf suspended particle transport either along-strait or cross-strait. Wang et al. (2015) model the long term trend of riverine nutrient export to and the DIN:DIP ratio in the Changjiang Basin using the GlobalNEWs model; and confirm that anthropogenic nutrient inputs have influenced Chl-a concentrations as well as the bottom DO level in the estuary. The observed Chl-a concentration increased by 146% while bottom seawater DO concentration decreased by 24.6% from 1992 to 2010, which was negatively related to the river DIN:DIP ratio. Yang et al. (2015) report that groundwater discharge provides an important source of dissolved organic matter to estuarine and coastal waters. They examine the concentration, chemical composition and bioavailability of DOM in two subterranean estuaries of southwest Taiwan with contrasting degrees of pollution and find that the DOC and fluorescent components are nonconservative (addition or removal) and very dynamic in both subterranean estuaries, although groundwater DOM may have a low bioavailability. Hu et al. (2015) observe an interesting phenomenon of low nutrient and high Chl-a in the southern Taiwan Strait that was influenced by a coastal upwelling system. Favored by proper temperature, N:P ratio and illumination, the phytoplankton grows rapidly and consumes most of the nutrients during the movement of the upwelled water in the surface sea current. Global climate change is likely to increase the number, duration and intensity of tropical/subtropical cyclones and accompanying http://dx.doi.org/10.1016/j.ecss.2015.10.036 0272-7714/© 2015 Published by Elsevier Ltd.
heavy storms. Chen et al. (2015) examine the effects of major storms on river phosphorus (P) export from an agricultural river (in SE China). Extreme storms exhibit broad fluctuation in P concentration, flux and composition. River water dissolved reactive phosphorus and dissolved organic phosphorous (DOP) have a different supply source and transport mechanism. Storms result in a 3.4e16-fold increase in P loads (with more DOP) to the estuary. These results are important in predicting the ecosystem response of estuarine and coastal regions to storm events. In subtropical regions, nitrogen export from the watershed is closely associated with precipitation and runoff (Liu et al., 2015). Another study by Zhai et al. (2015) suggests that the seawater carbonate system is dynamic during and after a summer flood, and that shallow-water aragonite undersaturation occurs in the China coast owing to respiration and dilution. However, aragonite undersaturated water disappears a week after the flood period. From a management perspective, it is critical to capture various spatial and temporal scales in the export of nutrients and other pollutants from watershed to river and then coastal waters. Huang et al. (2015) analyzed the watershed streamflow variability response to climate change and human activities by using the ecohydrologic and environmental flow component. Liu et al. (2015) develop a watershed-reservoir coupled model, a useful tool for understanding N retention by a reservoir and downriver transport at annual, monthly and daily scales. The reservoir serves mainly as a sink on an annual scale, but it may become a source in the dry season. Typically, coastal and estuary waters receive pollutant loading from diffuse sources. To mitigate eutrophication and improve water quality in an efficient way, quantifying the source at the sub-basin scale is essential to help decision makers to prioritize pollution management strategies, as demonstrated in a case study in Quanzhou Bay by Zhao et al. (2015). Increasing river nutrient input degrades water quality and threatens the ecological health of aquatic ecosystems, requiring decision makers to control landbased sources of nutrient pollution. Kong et al. (2015) present a systematic framework and models to estimate the minimum cost solutions of nutrient reduction at county level within the Jiulong River watershed. Given the spatial heterogeneity of the emission sources and their relative contribution to the water quality of the targeted water-body, such optimization of cost-effective measures is necessary and will achieve the long-term goals of sustainability in these coastal regions. In summary, this issue provides an important demonstration towards understanding the biogeochemistry and ecological responses to increasing human and climatic changes along the
H. Hong et al. / Estuarine, Coastal and Shelf Science 166 (2015) 144e145
river-estuary-coast continuum. It is apparent that local human activities and global climate change have exerted combined effects on the export of sediments, nutrients and pollutants from land to water. These studies address interdisciplinary studies including land management, estuarine chemistry, coastal oceanography and ecology. Coupled models linking biogeochemistry, ecology and social-economics can assist in decision making. However, it is still a challenge to quantify the major biogeochemical and ecological processes regulating the interactions that exist between and within river-estuary-coastal aquatic ecosystems. More research focusing on the river-estuary interface as well as the estuary-coast interface are needed to improve our understanding and better support management schemes within an integrated watershed-coast framework. Long-term collaborative monitoring and modeling of environmental dynamics are essential for developing realistic, ecologically sound, and cost-effective management strategies for the whole river-estuary-coastal system. We'd highly appreciated Dr Tom Bianchi as the chief editor for his thoughtful comments and suggestions throughout the whole process of the SI, and also the patience and coordination of Ms Java Pavithra and You Jun, at the editorial office of ECSS, and of Elsevier during the preparation of these manuscripts. We thank our international colleagues who served as our reviewers and guest editors and provided many stimulating and thoughtful comments on these manuscripts. We'd also like to thank Dr John Hodgkiss for kind assistances in English and grammar checking. Special thank goes to Ms Shuiying Huang for her coordination and assistances, and for Mr Qinbiao Ni for polishing the cover photo. The generous and sustained financial support provided by the Ministry of education, the Natural Science Foundation of China, Fujian Provincial Government and the State Key Laboratory of Marine Environmental Science for studying the Jiulong River-estuarycoast system during the past twenty years is much appreciated. References Chen, N., Wu, Y., Chen, Z., Hong, H., 2015. Phosphorus export during storm events from a human perturbed watershed, southeast China: implications for coastal ecology. Estuar. Coast. Shelf Sci. 166, 178e188.
145
Hu, J., Lan, W., Huang, B., Chiang, K., Hong, H., 2015. Low nutrient and high chlorophyll a coastal upwelling system e a case study in the southern Taiwan Strait. Estuar. Coast. Shelf Sci. 166, 170e177. Kong, H., Lin, H., Peng, B., Chen, N., Lin, C., Fielding, S., 2015. Modelling the costeffective solutions of nitrogen reduction in Jiulong River Watershed, China. Estuar. Coast. Shelf Sci. 166, 218e229. Li, Y., Chen, Y., Ruan, M., Chen, J., 2015. The Jiulong River plume as cross-strait exporter and along-strait barrier for suspended sediment: evidence from the endmember analysis of in-situ particle size. Estuar. Coast. Shelf Sci. 166, 146e152. Liu, M., Chen, X., Yao, H., Chen, Y., 2015. A coupled modeling approach to evaluate nitrogen retention within the Shanmei Reservoir watershed, China. Estuar. Coast. Shelf Sci. 166, 189e198. Wang, J., Yan, W., Chen, N., Li, X., Liu, L., 2015. Modeled long-term changes of DIN: DIP ratio in the Changjiang River in relation to Chl-a and DO concentrations in adjacent estuary. Estuar. Coast. Shelf Sci. 166, 153e160. Yang, L., Chen, C.-T.A., Hong, H., Chang, Y.-C., Lui, H.-K., 2015. Mixing behavior and bioavailability of dissolved organic matter in two contrasting subterranean estuaries as revealed by fluorescence spectroscopy and parallel factor analysis. Estuar. Coast. Shelf Sci. 166, 161e169. Zhai, W., Zang, K., Huo, C., Zheng, N., Xu, X., 2015. Occurrence of aragonite corrosive water in the North Yellow Sea, near the Yalu River estuary, during a summer flood. Estuar. Coast. Shelf Sci. 166, 199e208. Zhang, Z., Huang, J., Huang, Y., Hong, H., 2015. Streamflow Variability Response to Climate Change and Cascade Dams Development in a Coastal China Watershed. Estuar. Coast. Shelf Sci 166, 209e217. Zhao, W.L., Yang, S.Y., Wang, J., Xiao, J.M., Lu, X.X., Lin, J., Huang, P., Cai, M.G., 2015. Load estimation and assessment of land-based pollution for Quanzhou Bay and their relevance to the Total Quantity Control of Pollutants Discharged into the Sea (TQCPS) Program in China. Estuar. Coast. Shelf Sci. 166, 230e239.
Huasheng Hong*, Nengwang Chen State Key Laboratory of Marine Environmental Science, Xiamen University, PR China Coastal and Ocean Management Institute, College of the Environment and Ecology, Xiamen University, PR China Deli Wang State Key Laboratory of Marine Environmental Science, Xiamen University, PR China E-mail address: [email protected]. *
Corresponding author. State Key Laboratory of Marine Environmental Science, Xiamen University, PR China. E-mail addresses: [email protected] (H. Hong), [email protected] (N. Chen).