多重人为压力下莱州湾生态环境的演变趋势和调控原理

The deterioration of water quality and ecological system in Laizhou Bay is still serious and difficult to solve. This is mainly due to the conjunctive effect and cumulative effect of multi-pressures during the urbanization process or human activities, such as the waste water discharge and land reclamation. It is difficult to be explained by both the existing theoretical research results and the existing environmental control mechanisms. Therefore, to focus on the impacts of urbanization and human activities on the sea water quality and ecological processes in Laizhou Bay and its control mechanism, a number of major scientific issues are request to answer: (1) what is the environmental impact and the cumulative effect on hydrodynamics and sedimentation dynamics in Laizhou Bay due to the large-scale reclamation? (2) what is the response and control mechanism of typical plankton community in Laizhou Bay to various-form and high-intensity terrestrial nutrients? (3) under the conjunction of above two effects, how to regulate human activities and further to repair the damaged ecological environment? .Based on the research on dynamical environment evolution in Laizhou Bay, this project aims to explain the effects of large-scale reclamation and high-intensity land-based emissions on the single and complex effects of the Bay’s ecological environment, especially the long-term and cumulative effects in order to provide support for marine environmental improvement and the restoration of ecological functions. Through the interdisciplinary integration, this project also aims to develop an land-sea co-ordinate eco-dynamic model to predict the evolution trend of the ecological environment in this region, to put forward strategies to meet the needs of comprehensive management on the ecosystem based on the anthropogenetic pressure control, ecological system regulation and ecological function restoration, and finally to provide scientific support for the sustained and healthy development of the economic, social and ecological environment of the Laizhou Bay.

莱州湾环境质量持续恶化，生态灾害问题层出不穷，这主要是由于城市化过程中多重人为压力的复合效应与累积效应所导致。现有理论研究成果难以阐明，现有环境调控机制也难以支撑。因此，聚焦莱州湾生态环境演变，亟需全面系统深入回答若干重大科学问题：（1）莱州湾大规模围填海对海湾水文动力环境与沉积动力环境的影响过程与累积效应是什么？（2）莱州湾典型浮游生物群落对多形态高强度陆源营养物质的响应及其控制机制是什么？（3）上述作用叠加下，如何对人类活动进行调控以修复受损的生态环境？.本项目拟通过对莱州湾动力环境演变过程的研究，阐释大规模围填海和高强度陆源排污对海湾生态环境的复合影响，尤其是具有长期性和累积性的影响；通过多学科交叉集成，发展海陆统筹的莱州湾生态系统动力模型，预测莱州湾生态环境演变趋势，提出应对策略，满足基于生态系统水平的海湾综合管理需求，为莱州湾地区经济、社会及生态环境持续健康发展提供重要支撑。

项目通过莱州湾四季多学科现场调查，结合数值模拟技术，对1960和2016年典型时期岸线、水深和黄河入海物质变化，阐释大规模围填海和高强度陆源排污对海湾生态环境的复合影响。结果表明老黄河口附近的无潮点向东南偏移，造成莱州湾M2振幅减小幅度为5~20cm；从渤海湾南部流入莱州湾的环流显著增强，黄河入海泥沙、DIN更多地输送至莱州湾；2016年莱州湾春、夏、秋、冬水体半交换周期分别为101d、71d、109d和39d，1960年则分别为85d、53d、106d和39d。研究发现莱州湾冬季大风过程是水交换的主要机制，风和波浪作用有利于增强水交换能力（风90.7%、波浪6.2%）。夏季斜压效应下，风和波浪均对水交换起到明显的削弱作用（风23.1%、波浪19.0%）。. 项目通过全藻或除藻的现场培养实验基础上，建立了莱州湾生态动力学模型，模拟再现了近40年莱州湾浮游植物优势种变化。通过研究不同氮营养盐组成对莱州湾典型浮游植物优势种群生长的影响，发现莱州湾硅藻优势种群角毛藻净生长速率低于甲藻优势种群膝沟藻，结果造成随着陆源NO3-N比例总体上不断提高，浮游植物优势藻种组成逐步由以硅藻为主向硅藻和甲藻联合为主转变，揭示并阐明了莱州湾浮游植物优势种群演替机制，并对2021年黄河“秋汛”的影响进行了系统评估。在此基础上，系统研究了莱州湾陆源污染物排放与海域水质响应关系，为科学划分陆域排污主体的责任提供依据，也为陆源污染物精准化减排提供技术支撑。.围绕莱州湾水动力、水质及生物群落等因素，结合海洋环境和社会价值因素，识别和量化影响莱州湾生态系统健康的40项因子，构建以“驱动力-压力-状态-影响-响应”的莱州湾生态系统健康评价指标体系，选取1980-2019年进行评价，结果表明莱州湾生态系统健康整体呈现先波动下降后持续上升的趋势，最高值出现在1985年（指数为0.6370），最低值出现在2005年（0.3813）。在此基础上，将基于生态系统的管理拓展应用到生态修复理论、技术和政策评估，并对陆海统筹机制实现路径和政策存在问题进行深入剖析，提出了相关管理对策和建议。