The first record of active methane (cold) seep ecosystem associated with shallow methane hydrate from the Indian EEZ
Here we report the discovery of cold-seep ecosystem and shallow methane hydrates (2–3 mbsf) associated with methane gas flares in the water column from the Indian EEZ for the first time. The seep-sites are located in the Krishna–Godavari (K–G) basin at water depths of 900–1800 m and are characterized by gas flares in the water-column images. The occurrence of methane gas hydrates at very shallow depths (2–3 mbsf) at some of the seep-sites is attributed to high methane flux and conducive P–T conditions, necessary for the stability of methane hydrate. Chemosymbiont bearing Bivalves (Vesicomidae, Mytilidae, Thyasiridae and Solemyidae families); Polychaetes (Siboglinidae family) and Gastropods (Provannidae family) are also identified from seep-sites.
KeywordsCold seep gas flares methane hydrate methane and hydrogen sulfide gases chemosymbiont
We acknowledge the Director, CSIR–NIO and Secretary, MoES for supporting the gas hydrate program; National Gas Hydrate Program (NGHP) for scientific discussion, and background geology and ONGC for additional sites. Support from CSIR–NIO’s ship cell management team (Miliketan S Kerkar, M Kallathian, Kuldeep Kumar, Buddhadas Patole), Survey team (A W Gavin and S S Gaonker) and ship crew are sincerely acknowledged. Sincere thanks, Dr V V S S Sarma, Dr F Badesab and Dr M Rama Krishna for material support. Thanks to Mandar Nanajkar, Dr Ravail Singh, Mr Govardhan Sahu for useful discussion. This is CSIR–NIO contribution no. 6320.
- Choudhuri M, Guha D, Dutta A, Sinha S and Sinha N 2011 Spatiotemporal variations and kinematics of shale mobility in the Krishna–Godavari Basin, India. Shale tectonics; AAPG Memoir 93 91–109.Google Scholar
- Collett T S, Riedel M, Cochran J R, Boswell R, Kumar P and Sathe A V 2008 Indian continental margin gas hydrate prospects: Results of the Indian National Gas Hydrate Program (NGHP) expedition 01; In: Proc. 6th Int. Conf. Gas Hydrates, Vancouver.Google Scholar
- Decker C, Zorn N, Le Bruchec J, Caprais J-C, Potier N, Leize-Wagner E, Lallier F H, Olu K and Andersen A C 2017 Can the hemoglobin characteristics of vesicomyid clam species influence their distribution in deep-sea sulfide-rich sediments? A case study in the Angola Basin; Deep-Sea Res. Part II: Topical Studies in Oceanography 142 219–232.CrossRefGoogle Scholar
- Le Bris N, Arnaud-Haond S, Beaulieu S, Cordes E, Hilario A, Rogers A, van de Gaever S and Watanabe H 2016 Hydrothermal vents and cold seeps; In: First Global Integrated Marine Assessment (ed.) United Nations, Cambridge University Press, pp. 853–862.Google Scholar
- Levin L 2005 Ecology of cold seep sediments: Interactions of fauna with flow, chemistry and microbes; In: Oceanography and Marine Biology: An annual review (eds) Gibson R N, Atkinson R J A and Gordon J D M, 43 1–46 (Taylor and Francis).Google Scholar
- Rao G N 1993 Geology and hydrocarbon prospects of East Coast sedimentary basins of India with special reference to Krishna Godavari basin; Geol. Soc. India 41 444–454.Google Scholar
- Rao G N and Mani K 1993 A study on generation of abnormal pressures in Krishna Godavari basin, India; Ind. J. Petrol. Geol. 2 20–30.Google Scholar
- Sibuet M and Olu-Le Roy K 2002 Cold seep communities on continental margins: Structure and quantitative distribution relative to geological and fluid venting patterns; In: Ocean margin systems, Springer, pp. 235–251.Google Scholar
- Sloan E D Jr 1990 Clathrate Hydrates of Natural Gases; Marcel Dekker Inc., New York, 641p.Google Scholar
- Southward A J and Newman W A 1998 Ectosymbiosis between filamentous sulphur bacteria and a stalked barnacle (Scalpellomorpha, Neolepadinae) from the Lau Back Arc Basin, Tonga; Cah. Bio. Mar. 39 259–262.Google Scholar
- Zande J M and Carney R S 2001 Population size structure and feeding biology of Bathynerita naticoidea Clarke 1989 (Gastropoda: Neritacea) from Gulf of Mexico hydrocarbon seeps, Gulf of Mexico; Science 19 107–118.Google Scholar
- Zal F, Leize E, Oros D R, Hourdez S, Van Dorsselaer A and Childress J J 2000 Haemoglobin structure and biochemical characteristics of the sulphide-binding component from the deep-sea clam Calyptogena magnifica; Cahiers de Biologie Marine 41 413–424.Google Scholar