Study On Assessment Of Ocean Ecosystem Damage Caused By Oil Spill

The ocean, an important environment for human's existence and development, has been providing massive materials and services. However, the frequently occurred oil spill has seriously damaged the ocean ecosystem, and brought tremendous economic losses to human beings. Thus it has become a commonly concerned topic all around the world to assess ocean ecosystem damage caused by oil spill. In China, not having efficient ecosystem damage assessment technique brings about frequent compensation difficulties and disputes in oil spill accidents. Therefore, to set up a series of scientific, reasonable and practical assessment indicator system and procedure of ecosystem damage caused by oil spill will help theoretically and practically to improve China's ecosystem damage assessment technique of oil spill. Intending to solve problems and overcome shortcomings in current oil spill damage assessment, the present dissertation studies the content and methods of ecosystem damage assessment caused by oil spill. The results and conclusion covers the following aspects:1. Defining the content of ecosystem damage assessmentIntending to solve the problem of unclear assessment content and insufficient legal sanction in ecosystem damage assessment, based on ocean ecosystem service theory and theory on ecosystem damage caused by oil spill, the author defines the ecosystem damage as ecosystem service damage and divides the assessment content into three parts:the value loss of marine ecosystem service from being damaged to restoring its normal condition (the value loss of ecosystem service); the expenditure from restoring the damaged ecosystem service to the original condition (recovery expense); the expenditure to conduct ecosystem damage assessment (damage assessment expense). Combining related laws and judicial practice of oil spill compensation, the dissertation clarifies that the ecosystem damage caused by oil spill has been partially compensated in judicial practice; the compensation type shall not only be environmental damage but also the property damage, economic losses and preventive measures. The dissertation differentiates ecosystem service damage from currently existing assessment mode of environmental damage, natural resources damage, environmental capacity damage etc. Therefore the defined ecosystem damage assessment accords with related scientific theories and compensation laws.2. Determining the method of ecosystem damage assessmentAiming at overcoming the uncertainty and lack of validity in current ecosystem damage assessment method, based on theory of oil spill damage and ecosystem recovery, consulting the National Resource Damage Assessment method (NRDA) of the United States and Habitat Equivalence Analysis (HEA), the dissertation tries to assess ecosystem damage through five steps:determining damage, determining recovery, quantification of damage, calculation of recovery and assessment expenditure, and determining compensation. The respective service value loss in ecosystem is indicated as integral function of original value, damaged area, damaged extent, recovery velocity and damage time. Based on ecosystem value assessment theory and according to their respective value character in ecosystem service, the dissertation selects appropriate assessment method to assess its damage, which can make a reasonable and efficient computation to ecosystem damage and realize the refinement and improvement of ecosystem damage assessment.A set of indicator system of marine ecosystem damage assessment is built by combining newly defined assessment content and method, which is significant theoretically and practically to the development of oil spill damage assessment technique.3. Constructing assessment procedure of ecosystem damage assessmentIntending to solve problems in marine ecosystem damage assessment, such as comparatively low efficiency and not emphasizing ecosystem recovery, the dissertation centers around the established ecological damage assessment indicators, optimizes every procedure from the occurrence of oil spill to the submission of compensation amounts on the basis of consulting the research results in China and NRDA and HEA in United States, making the ecological damage assessment and recovery an integrity. The numerical simulation as a primary assessment technique has been adopted to construct ecological damage assessment procedure. The assessment procedure is based on data collection and on site investigation of the accident, covers four modules of temporal and spatial recurrence of oil spill, determination of damaged objects and degree, establishment of ecosystem recovery plan and assessment of ecosystem value. These four modules is coherent and compact, pay attention to the role of ecosystem recovery in damage assessment. The procedure is concise and clear, which is easy to operate and can enhance the speed and efficiency of oil spill damage compensation assessment.4. The empirical study of oil spill ecosystem damage assessmentBased on the established assessment indicator system and procedure, the dissertation conducts an empirical study of ecosystem damage in Jiaozhou Bay caused by potential oil spill accident. The results indicate that the ecosystem service damage type vary for the oil spill accidents of the similar scale in the same spot, because the environment conditions differ; In the same oil spill accident, the damage extent, degree, time and recovery speed of the respective service type also vary; The determination of ecosystem damage type, damage situation and recovery effect shall be made by investigation and analysis according to accident conditions and sea area feature. The empirical study shows that the ecosystem damage assessment indicators and procedure constructed in this dissertation is feasible, which can assess the ecosystem damage made by oil spill pollution effectively. Meanwhile, the research result can also provide quantificational technique support to the ecosystem damage assessment caused by oil spill, offer technical guidance to the improvement of marine ecosystem protection and emergency plan of Jiaozhou Bay.