The Impacts Of Offshore Oil Exploration And Development On Macrobenthos Community

With the growing of economic and social development, human demand forenergy is increasing. Rich offshore oil resources is still in the early stages ofexploration and exploitation. In the land of oil resources increasingly tense situation,people set their sights on offshore oil exploration and development. With increasingoffshore oil exploration and development efforts, the pollution problems caused by itssurrounding waters get growing concern. Various pollutants discharged will changethe status of quality of the surrounding waters and sediment, which directly orindirectly affect the macrobenthos living in them. Macrobenthos is not only animportant part of the marine ecosystem food chain, play an important role in nutrientcycling and energy flow of marine food webs, but also biological evaluation of waterquality indicator organisms. Through the community structure of investigation,analysis of macrobenthos communities and its changes in the composition can be usedto evaluate the quality of the environment. At present, the domestic researches payless attention on offshore drilling platform pollution, and there is no research focusedon impact of the whole work process of drilling platform.September, November and December in2011, respectively, in different stages ofthe drilling platform: the exploration front stage, the exploration phase and oil phaseof the drilling platform around15stations and three control stations carried the water,sediment and benthos survey, combined with PRIMER, SPSS software for pollutionof the waters surrounding the rig’s water sediment, benthic community structure anddistribution were analyzed to explore the impact of oil exploration and developmentdrilling platform near the waters of the benthic community for future referencemonitor rig.The result of research shows：3voyage were identified201kinds of benthic organisms. Groups include:annelids, echinoderms, arthropods, mollusks, cnidarians, esculenta animals. In various groups in order polychaete annelid door for up to reach114kinds, accounting for56.16%of the total number of species; followed arthropod crustaceans56kinds,27.58%of the total number of species; molluscs15species, accounting for7.39%;nine kinds of echinoderms, accounting for4.43%;4kinds of animal Nemertinea,accounting for1.97%;4kinds of other groups, accounting for1.97percent.Investigation of sea area dominant species alternated obviously. In theexploration of voyage and exploration during the voyage, the dominant species of thetop ten, Polychaeta accounted for70%; in the process of exploitation of voyage, thedominant species of the top ten kinds of Mollusca and Crustacean significantlyincreased.Changes voyage waters surrounding the rig total macrobenthos abundance is:before the voyage of exploration (3601.33ind./m2)> mining process voyage(1946.67ind./m2)> exploration process voyage (1474.11ind./m2); voyage ofexploration changes in biomass pre-voyage (6.65g/m2)> mining process voyage(6.26g/m2)> exploration process voyage (4.07g/m2).Voyage diversity index changesThe analysis3cruises four typical stations of ABC curve shows the formervoyage of exploration, drilling platforms adjacent waters of the large benthiccommunities basically undisturbed; voyage of exploration process, from drillingplatforms closer to the center of large benthic biomes being moderate disturbance, andslightly away from the platform location of large benthic communities undisturbed;mining process voyage, macrobenthic communities near drilling platform basicallyundisturbed, only moderately affected individual stations disturbance.The results of CLUSTER and MDS showed voyage of exploration process, therig can be divided into two communities adjacent waters: Pollution communities andundisturbed communities, SIMPER analysis showed that the similarity between thetwo communities was68.64%of non-aroused among communities the main types ofdifferences include Brittlestar a1, to be subject to special worms, a polychaete,tumbler insects, original, bivalves, such as a, ANOSIM test showed that thedifferences between the two communities significantly. Mining process voyage, drilling platforms adjacent waters can be divided into two communities: Communitiesand the main types of pollution undisturbed communities, SIMPER analysis showedthat the similarity between the two communities was54.83%Non-caused differencesbetween the communities, including red bright cherry clams, sea kind of a tail, redthorn tip worms, former footed, detailed white cherry clams, worms and other exoticjuvenile teeth, ANOSIM test showed that the differences between the twocommunities significantly.Analysis of BIOENV and BVSTEP show voyage of exploration process, waterquality and sediment pollution of Pb content and community structure ofmacrobenthos maximum correlation, the correlation coefficient (Spearman) was0.374;contaminated mining process voyage, sediment conditions and large benthiccommunity structure maximum correlation, the correlation coefficient (Spearman)was0.404.In summary, the petroleum exploration and development of offshore drillingplatform near the sea benthic communities produce large moderate interference. Withexploration activities，benthic communities have transformed gradually to two distinctboundaries benthic communities.