未来黄东海生态环境变化情景预测

发布时间：2018-06-05 14:28

本文选题：营养盐浓度 + 群落结构　；参考：《中国海洋大学》2015年硕士论文

【摘要】：黄东海是我国经济社会发展的重要支持系统之一,过去几十年黄东海生态系统的结构发生了剧烈变化,对海洋生态系统的健康产生了深刻影响。黄东海生态环境的变化受到气候变化和人类活动的双力驱动,随着全球变暖和人类活动影响的加剧,海洋生态环境所面临的压力骤增。本文的主要目标是利用一个三维物理-生物耦合模型预测未来黄东海生态环境,利用IPCC报告中耦合模式给出的未来气候预测降尺度驱动区域海洋水动力模型和生态模型,并结合未来河流营养盐载荷特征,预测未来黄东海生态环境对气候变化、河流营养盐排放变化的响应。本文选取FGOALS模式在RCP4.5情景下对未来气候的预测作为大气强迫,结合GlobalNEWS模型在两个极端情景下的未来河流营养盐载荷,得到未来黄东海营养盐浓度、营养盐结构、初级生产和浮游植物群落组成。结果表明,未来两个情景下,河口邻近海区、苏北浅滩及黄海中部无机氮(DIN)、无机磷(DIP)营养盐浓度将显著增加,硅酸盐(SIL)浓度在黄海有所增加,海区富营养化加剧。GO情景下,河流无机氮载荷增幅较大,各海区磷限制更加显著；AM情景下,由于河流无机磷载荷增幅较大,海区氮磷比有所下降。由于未来氮、磷营养盐升高,黄海中部及东海北部初级生产力升高,黄海冷水团西侧锋面及长江口外海区增幅最大,AM情景初级生产力高于GO。未来硅酸盐浓度变化较小,黄海硅藻生物量没有明显变化,而氮、磷营养盐增长,导致甲藻生物量升高,硅甲藻比下降,硅成为一个重要的限制因子；长江口邻近海区由于受长江营养盐的补充,硅酸盐未被完全消耗,硅、甲藻生物量均升高,群落结构变化不大。通过敏感性实验对各海区未来水动力变化、河流载荷变化的相对贡献进行评估：相对于水动力环境改变,河流氮、磷营养盐排放的增长是未来氮、磷营养盐浓度增加的主要原因：河流硅酸盐载荷不变,硅酸盐浓度受外来海区输运影响,另外,硅藻、生物硅通过水平对流扩散并在局地矿化也使硅酸盐分布改变,水动力环境改变对于硅酸盐浓度变化的贡献较大。营养盐收支分析表明,未来对流输运有助于黄海营养盐浓度增加,由于河流氮、磷营养盐排放增长,夏季生物量升高碎屑沉降在底层矿化使得层化季节黄海冷水团底部营养盐浓度增长;长江口邻近海区营养盐浓度增长主要受冲淡水羽流影响。未来各海区生物量升高,生物过程增强加大对营养盐的消耗。由于未来黑潮等开边界流量、营养盐浓度变化未知,本研究仅考虑了上边界大气动力-热力强迫和河流营养盐载荷的未来情景,初步完成了海洋生态环境情景预测的尝试。获得更精确的未来河流载荷数据,可改善生态预测的准确性。
[Abstract]:The Yellow and East China Sea is one of the important supporting systems for the economic and social development of our country. The structure of the ecosystem of the East China Sea has changed dramatically in the past few decades, which has had a profound impact on the health of the marine ecosystem. The changes of ecological environment in the East and Yellow Sea are driven by climate change and human activities. With the increase of global warming and the impact of human activities, the pressure on the marine ecological environment increases sharply. The main objective of this paper is to use a three-dimensional physical-biological coupling model to predict the ecological environment of the future East China Sea, and to use the coupling model in the IPCC report to predict the downscale driving regional hydrodynamic model and ecological model of the future climate. Combined with the characteristics of future river nutrient load, the response of ecological environment of the future East China Sea to climate change and river nutrient discharge change is predicted. In this paper, the prediction of future climate by FGOALS model under RCP4.5 scenario is selected as atmospheric forcing, and the nutrient concentration and structure of the future East and Yellow Sea are obtained by combining the future river nutrient load of GlobalNEWS model in two extreme scenarios. Primary production and phytoplankton community composition. The results showed that the nutrient concentrations of inorganic nitrogen (DINN) and inorganic phosphorus (DIPs) in the estuarine adjacent area, the shoal of Subei and the middle of the Yellow Sea would increase significantly, the concentration of silicate sil) in the Yellow Sea would increase, and the eutrophication of the sea area would increase under the .go scenario. The increase of inorganic nitrogen load in rivers was larger, and the phosphorus limitation in each sea area was more obvious. Under AM scenario, the ratio of nitrogen and phosphorus in the sea area was decreased due to the larger increase of inorganic phosphorus load in rivers. Due to the increase of nitrogen and phosphorus nutrients in the future, primary productivity increased in the central part of Huang Hai and in the northern part of the East China Sea. The primary productivity of AM scenario in the western front of Huang Hai cold water mass and in the offshore area of the Yangtze River Estuary was higher than that in Go. In the future, the concentration of silicate changed little, but the biomass of Huang Hai diatoms did not change obviously, but nitrogen and phosphorus nutrients increased, which led to the increase of biomass and the decrease of the ratio of diatoms to algae. Silicon became an important limiting factor. Due to the supplement of nutrients from the Yangtze River, silicate was not completely consumed in the adjacent area of the Yangtze River Estuary, and the biomass of silicon and Pyrolima increased, and the community structure changed little. The relative contribution of hydrodynamic changes and river load changes in each sea area is evaluated by sensitivity experiments: compared with the hydrodynamic environment change, the increase of river nitrogen and phosphorus nutrient discharge is the future nitrogen. The main reasons for the increase of phosphorus nutrient concentration are as follows: the load of silicate in rivers remains unchanged, and the concentration of silicate is affected by the transport in the foreign sea area. In addition, the distribution of silicate is also changed by the horizontal convection diffusion of diatoms and biological silicon and local mineralization. The change of hydrodynamic environment contributes greatly to the change of silicate concentration. The analysis of nutrient budget shows that the convective transport in the future will contribute to the increase of nutrient concentration in the Yellow Sea, and the increase of nutrient discharge due to nitrogen and phosphorus in the river. Biomass rise in summer and clastic sedimentation in the bottom mineralize the nutrient concentration at the bottom of the Huang Hai cold water mass in stratified season and the nutrient concentration in the adjacent area of the Changjiang Estuary is mainly affected by the flushing fresh water plume. In the future, the biomass of each sea area will increase, and the biological process will increase the consumption of nutrients. Due to the future Kuroshio open boundary flow and the unknown change of nutrient concentration, this study only considered the future scenarios of upper boundary atmospheric dynamic-thermal forcing and river nutrient load, and preliminarily completed the prediction of marine ecological environment scenarios. More accurate future river load data can improve the accuracy of ecological prediction.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X145

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