Research On Marine Ecological Carrying Capacity

With the rapid development of marine economy, both marine resource over-exploitation and coastal water pollution are obvious gradually. Furthermore, the development of ocean exploitation and marine economy will been annually intensified in the future. Therefore, the conflict between the limited carrying capacity and the increasing marine exploitation activities is becoming more and more prominent. In this situation, it is high time to study the marine ecological carrying capacity(MECC) in order to ensure the sustainable development of marine economy. By introducing the connotation and characteristic of MECC, the system dynamic(SD) model, state-space evaluation model and multi-objective programming(MOP) model were established in this paper, which can provide the scientific proof and decision support for ocean development and management. The main contents and research results are as follows:1.The connotation, charter and influencing factors of MECC were analyzed, which includes the sustainable supply capacity of marine resources, pollution receiving capacity of ecological environment, human supporting ability and ecological elastic capability. The marine ecological carrying capacity was influenced by natural factors, human factors and subjective factors.2.The SD model, state-space evaluation model and MOP model of MECC were established. The SD model contained four sub-modules, which were population submodule, economy submodule, marine environmental pollution submodule and marine resources submodule. A set of assessment indicator system, including pressure indicators, support indicators and regional exchange indicators, was established in evaluation model. Meanwhile, taking ecological carrying capacity, population and total output value of marine industry as the objective function, and considering the constraints of marine environment carrying capacity and marine resouces, the study have tried to set up MOP model. 3.The MECC of Qingdao was evaluated by state-space evaluation model. The results show that the MECC fluctuated from 1998 to 2007, and the marine ecosystem was overloading. The main reason for this is that system stress is too large. From 1998 to 2003 the economic development was the dominant stress, but environmental pollution and resource use turn into a major stress from 2004 to 2007. The system support ability slightly heightened, which caused by the increase of human support ability.4.According to the evluation results, it is found that, too high pressure and a slow development of low support ability are the major problem of MECC in Qingdao. The principal limiting factors are pollutant emission and surplus environmental carrying capacity of Jiaozhou Bay. So, we should start from regulation demand and supply to carry out ecological regulation, and the two limiting factors can be regarded as the objects of regulation control.5.The SD model was used to simulate the change tendency of population, economy and marine environmental pollution in Qingdao. The simulation results revealed that the population showed an increasing trend, and the simulation results lower than the value of planning. The GDP performed exponential growth, and the proportion of tertiary industry promoted steady. The industrial wastewater discharge per ten thousand RMB production value decreased yearly, while the total diacharege of main pollutants increased gradually. In the total sewage, the domestic dewage occupied a larger proportion, at 2010, 2015 and 2020, the value were 64.8%, 66.91% and 71.9%, respectively. COD, ammonia nitrogen and active phosphate load has increased year by year, whose load are 39541 t.a-1, 8237 t.a-1 and 329 t.a-1, respectively, in 2020. In 2007, the nitrogen pollution load from different sources was in the order of precipitation source(PS)>agricultural non-point source(ANPS)>domestic wastewater(DW)>industrial wastewater(IW)>tourism wasterwater(TW), while phosphorus pollution load was ANPS>DW>IW>PS>TW.6.The SD model also used to forecast the MECC, combining with the relevant planning in Qingdao. Two scenarios were developed based on the main problems facing the MECC in Qingdao from 2008 to 2020. Scenarioâ… represents ecosystem changes under the present module, whereas scenarioâ…¡reflects ecosystem changes under improved development, including the decrease of pollutant emission, and the promotion of human support ability. The effects of these two scenarios on the marine ecosystem were modeled. The results indicates that the carrying status of marine ecosyetem will significantly be improved under two scenarios compared with the period of 1998 to 2007. Under scenarioâ… , the carrying status of marine ecosyetem will be worsening in the coming thirteen years, which will be over-loading in the period of 13th five-year plan. Under scenarioâ…¡, the carrying status of marine ecosyetem in Qingdao will be improved gradually, which turn into over-loaded from loaded. Furthermore, the paper also qualitativly analysed the change tendency of MECC under the recently released government policy, which is named"Protection Along the Bay, Development Around the Bay"for Qingdao. We find that the carrying status of marine ecosyetem in Qingdao will be improved better when the policy is implemented. The implement of the policy, not only release the ecosystem preesure, but also enhance the support ability and regional exchange capacity.At the end, the research work is summarized and a perspective on the future research is made.