Ecological risk assessment for the ecosystem of the Caspian shelf on the basis of modeling

Abstract

Based on ecoscreening models, results of dynamic (ecosystem) modeling and field observations, environmental risk assessments for the Northern Caspian ecosystem were calculated. The proposed method is effective in assessing the risk from the combined action of natural, anthropogenic, and invasive factors in the development of oil resources in offshore waters. Calculations of ecological risk and the acceptable probability of impact for the ecosystem were carried out for three frequency ranges of anthropogenic impacts such as "technical system accidents" during the spring phytoplankton outbreak, taking into account the natural and low illumination of the Northern Caspian water area. The results obtained for spring and summer-autumn maxima of phytoplankton biomass of various durations revealed ranges of practically safe, with a probability of acceptable impact from 80 to 100%, ecosystem conditions, and extremely dangerous, with a probability of acceptable impact less than 5%. The results obtained showed that conclusions about ecosystem vulnerability in conditions of intense anthropogenic pressure are not trivial and that it is necessary first to calculate the environmental risk and then evaluate the acceptable probability of impact. The proposed approach is important for overcoming difficulties in the practical harmonization of environmental and economic requirements for the safe development of shelf resources.