Study On Coastal Wetland Development And Protection,and A Survey Of Coastal Wetland In Pearl River Estuary

The wetland is an extremely important ecological system which forms by amphibious mutual effect, is one of three major ecosystems including the forest and the ocean on the world. Meanwhile, due to possessing important environmental resources and physical resources, the exploitation and utilization of wetland has become a focus issue on global environment protection. Coastal wetlands lies in the crisscross zone between continents and oceans, and affected by that, which is very sensitive to the environment-the edge areas. Additionally, coastal wetlands are the most densely populated and economically developed regions, under the pressure of population growth, economic development and environmental change.China has 18000 kilometers long coastline, and it holds abundant types of wetland.. As the development of Chinese economic, Coastal wetlands has gained a lot of momentum in resource utilization including. Simultaneously, blind transformation reclamation of coastal wetlands has caused a rapid decline, and become important influencing factors for the sustainable development of coastal economy. Pearl River Estuary is the river mouth place that gathering economic activities, human activities and spontaneous changes, its wetland environment is also significantly worse. Thus, in order to explore countermeasures on on utilizing comprehensively and protecting coastal wetlands, this article analyzed the development and application on coastal wetlands and existing state of affairs of Pearl River Estuary.Using literature data collected analysis and field survey, this study systematically arranged the literature on the development and utilization of coastal wetlands in China. Based on the previous studies, the water quality and sediment samples collected from the Pearl River estuary are obtained periodically by the continuous fixed point,several testing indexes including nutrients, dissolved oxygen and Potential Of Hydrogen surveyed(p H) were investigated.1)The area of the wetland in the whole is about 38.48 million hectares. Coastal wetlands is 5.94 million hectares, distributed mainly over eleven provinces(including Shandong, Jiangsu, Guangdong, Liaoning, Hebei, Zhejiang, Guangxi, Fujian, Shanghai, Hainan, Tianjin), Hong Kong, Macao and Taiwan. The main utilization of coastal wetlands is salt evaporation pond, mariculture, sea reclamation and protection zone, which cover 21.7% 5%、21% and 73% of the whole coastal wetlands respectively. In available mariculture, Guangdong is largest(835,670 hectares), followed by Liaoning(725,840 hectares) and Shandong(512,126 hectares). Actually, actual mariculture area of Guangdong is 203,410 hectares that is not yet fully developed. In recent years, to meet the social and economic development, the reclamation project have further developed in the construction of harbors and airports. In 2012, totally 1607 harbors being over 10 thousand tonnes harbors being over 10 thousand tonnes totaled 1607, up 25 year-on-year, all which is over 50 thousand tonnes.2)Since 2010, a slowing in water quality improvement has occurred in Pearl River estuary, turning unhealthy into sub-health. However, in 2014, amounts of the pollutants has registered an increase compared to the corresponding period last year. Among that, COD had risen by 626,620 tons; ammonia nitrogen content had risen by 7,697 tons; nitrate nitrogen content had risen by 195,194 tons; Total phosphorus content had risen by 4,698 tons. From April 2012 to April 2013,nine monitoring sites of water quality were investigated. Sediment in Pearl River Estuary is in very good shape, without heavy metal pollution(copper, lead, zinc and cadmium). Dissolved oxygen content of sea surface water had meet the first class-national standard for seawater quality, and that of bottom seawater had meet the second class-national standard. The pH value of seawater had meet the third or fourth class-national standard. In addition, the eutrophication level and the inorganic nitrogen pollution degree are relatively severe, inorganic nitrogen content of each monitoring site was 4.64- 8.3 times than the four class-national standard of seawater quality. Of that, nitrate content is largest, possessing 1.17-6.35 times than the national standard of eutrophication, which is the main reason for severer inorganic nitrogen pollution. During the period of monitoring, both ammonium salt in surface seawater and cadmium concentration in sediment have been a major change in different time. Ammonium Salt content form 87.5% monitoring sites have exceeded the second class-national standard. But in September 2012, 87.5% monitoring sites was better, only possessing 0.16-0.21 times than the national standard. From September 2012 to April 2014, cadmium concentration in sediment have been declined significantly, a drop of 60%-100% in April 2014. These results demonstrated that Pearl River Estuary is mainly affected by inorganic nitrogen pollution threat.