Damage assessment of Baghjan oil field blowout on terrestrial and aquatic ecosystems near Dibru Saikhowa Biosphere Reserve, Assam India

Abstract

Ecosystems can be severely damaged by oil field blowouts. There is growing need to improve and enhance use of advance scientific tools and techniques for monitoring, mapping, and estimating the impact of oil spills on the terrestrial and aquatic ecosystems. It is also required to estimate the extent of spills to develop effective remediation plans, that ensures improved monitoring systems in place to spot early leakages. The Baghjan oil field blowout in Assam, India, adjacent to the Maguri-Motapung Wetland and the Dibru-Saikhowa National Park, substantially affected the health of nearby terrestrial and aquatic ecosystems. To assess the impact of the oil spill on the vegetation, we used Normalized Difference Vegetation Index and Case2Regional.CoastColour algorithm data to assess the pre and post blowout conditions. Results reflected to 41% increase in senescing vegetation followed by 25% increase in chlorophyll-a, and 35% of the total suspended matter (TSM) during the initial months. During the blowout period total TSM exceeded 175 kg/m3, which was observed to be exceptionally high for the wetland ecosystem. Areas cleared of vegetation after the oil spill were reported to have various levels of re-vegetation in the later year, according to change detection conducted for the two dates. Present study reflects the necessity of using high spatial resolution studies to map precise locations where the oil from the spill entered and later also to evaluate the impact of blowout on the vegetation. Study observed post-blowout changes in plant growth and survival which could be monitored to check ecosystem recovery after a year of oil spill.