Abstract

Sundarbans mangrove ecosystem, the world largest mangrove forest in Bangladesh, is one of the most productive and biologically diverse wetlands in the world. This unique coastal tropical forest is among the most threatened habitats on earth. Its importance lies in its floristic composition, resource and economic value and precious wildlife reserve. It is a habitat of some 40,000 wildlife species including endangered royal Bengal tigers, rare freshwater dolphins, and crocodiles. It is a nursing and breeding ground of over 340 fish species and 250 bird species and many others.

This paper critically examines the present status of the Sundarbans and assesses the potential threat of oil and gas exploration. Every aspect of the exploration and development of oil and gas is analyzed and the magnitude of the impact quantified. In addition detailed guidelines and mitigation plans that will minimize potential impacts are addressed. A case study is done in the Sundarbans mangrove and it shows that by undertaking proper protection and mitigation measures, oil and gas operations can be developed by preserving ecological quality and protecting wildlife. Since there is limited research that focuses on environmentally sensitive areas, this work can serve as a basis for understanding the potential effects and required remediation of oil and gas in an environmentally sensitive ecosystem.

The findings of this case study are applicable in any environmentally sensitive area. This work is not intended for use in deciding whether or not to allow oil and gas development in the Sundarbans but rather, to aid in the identification of potential problems, to increase the manager's awareness of the implications of development, and to provide information that may facilitate minimization of harmful effects.

Introduction

Mangrove ecosystems are one of the most productive and biodiverse wetlands on earth. However, these unique coastal tropical forests are among the most threatened habitats in the world [1]. Due to commercial exploration they may be disappearing more quickly than the island tropical rainforest, and so far, with little public notice [1, 2].

The Sundarbans is the largest single-tract mangrove ecosystem in the world with an area of about 10,000 square kilometers [3]. It contains a large variety of genera and species of plants, wildlife and astonishing biodiversity [4]. It stretches across two countries Bangladesh and India, over the northern part of the Bay of Bengal (see Figures 1 and 2). Due to its great significance the Sundarbans was declared a World Heritage Site and Biosphere Reserve. However, the future of the Sundarbans remains uncertain due to logging, human settlement and other numerous exploitation activities [4].

In order to improve a struggling economy, the Bangladesh government has been looking into using the oil and gas resources in the country. After the recent discovery of huge amount of proven gas reserves in the country, Bangladesh got attention by many multinational oil companies. It is considered that the future of the oil and gas is brighter and its reserves are placed at 15.3 trillion cubic feet (TCF), while the US Geological Survey estimates that Bangladesh contains additional 32.1 TCF "undiscovered reserves" [5]. The most terrestrial and offshore areas of Bangladesh have been divided into twenty three blocks and are gradually being leased to multinational oil and gas companies.

The Bangladeshi government recently completed the initial signing of a production sharing contract with two multinational oil giants to begin oil and gas exploration in block number five within the Sundarbans. The companies plan to conduct seismic and aerial surveys. In Bangladesh, the gas and oil exploration business is in its infancy and, therefore, environmental impacts have not yet been felt. However, the impact of hydrocarbon pollution has been clearly reported in many other parts of the world [6, 7, 8, 9]. Oil and gas exploration might pose a new and, for the most part, unknown threat to the Sundarbans ecosystem.

There has been a very limited amount of research done so far to determine the effects of oil and gas exploration in mangroves ecosystems except for the preliminary work of [6, 7].

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