Lu Jing, Newham Michael, Chuang Ann, Burton Joanne, Faggotter Stephen, Garzon-Garcia Alexandra, Hayton Joshua B, Carroll Anthony R, Burford Michele A
Australian Rivers Institute, Logan Campus, Griffith University, 68 University Dr, Meadowbrook, Queensland, 4131, Australia.
Department of Environment, Tourism, Science and Innovation, GPO Box 2454, Brisbane, Queensland, 4001, Australia.
J Environ Manage. 2025 Jun 25;390:126289. doi: 10.1016/j.jenvman.2025.126289.
Water quality trading between point and diffuse sources aims to improve waterway health and achieve sustainable management goals for aquatic ecosystems. However, methods are needed to quantitatively compare their ecosystem impacts. Our study used a key measure of ecosystem health, dissolved oxygen (DO) demand, to identify and compare the nutrient and organic carbon parameters in different nutrient sources that have the greatest impact on DO demand. Three nutrient sources, i.e., simulated soil erosion runoff (soil slurries), sewage treatment plant (STP) and aquaculture effluent, were compared in incubations measuring DO demand in estuarine water. For soil slurries, dissolved organic carbon (DOC) concentration was most highly correlated with DO demand (R = 0.52). For STPs, a combination of total nitrogen (TN), phosphate, and ratios of TN: total phosphorus and DOC: ammonium were most correlated with DO demand (R = 0.5). The combination of chlorophyll-a concentrations and DOC: total dissolved nitrogen explained most of the DO demand for aquaculture treatments (R = 0.80). Chemical characterization revealed that soil slurries contained organic compounds that were more bioavailable, i.e., glucose and fatty acids, than STP (small organic acids) and aquaculture effluents (lipophilic compounds). DOC bioreactivity (mg DO mg DOC d) of the three sources correlated with C:N ratios and N:P ratios, suggesting that microbes in the estuarine water were organic carbon and nutrient limited. Therefore, to ensure equitable environmental impacts from trading between different sources, both organic carbon and nutrient parameters from sources, and the nutrient characteristics of the receiving water environment need to be considered.
点源与面源之间的水质交易旨在改善水道健康状况并实现水生生态系统的可持续管理目标。然而，需要一些方法来定量比较它们对生态系统的影响。我们的研究使用了生态系统健康的一项关键指标——溶解氧（DO）需求，来识别和比较不同营养源中对DO需求影响最大的营养物质和有机碳参数。在测量河口水中DO需求的培养实验中，比较了三种营养源，即模拟土壤侵蚀径流（土壤泥浆）、污水处理厂（STP）和水产养殖废水。对于土壤泥浆，溶解有机碳（DOC）浓度与DO需求的相关性最高（R = 0.52）。对于污水处理厂，总氮（TN）、磷酸盐以及TN:总磷和DOC:铵的比例组合与DO需求的相关性最高（R = 0.5）。叶绿素-a浓度与DOC:总溶解氮的组合解释了水产养殖处理中大部分的DO需求（R = 0.80）。化学特征表明，土壤泥浆所含的有机化合物，即葡萄糖和脂肪酸，比污水处理厂（小有机酸）和水产养殖废水（亲脂性化合物）的生物可利用性更高。三种来源的DOC生物反应性（mg DO mg DOC d）与C:N比和N:P比相关，这表明河口水中的微生物受到有机碳和营养物质的限制。因此，为确保不同来源之间交易产生的环境影响公平合理，需要考虑来源中的有机碳和营养参数以及受纳水环境的营养特征。
