Benthos response following petroleum exploration in the southern Caspian Sea: Relating effects of nonaqueous drilling fluid, water depth, and dissolved oxygen

MARINE POLLUTION BULLETIN

卷:110

Article

Tait, R. D.¹  Maxon, C. L.²  Parr, T. D.³  Newton, F. C., III² 

[1] Exxon Mobil Corp, 22777 Springwoods Village Pkwy, Spring, TX 77389 USA

[2] Maxon Consulting, 2546 San Clemente Terrace, San Diego, CA 92122 USA

[3] Terry Parr Environm Consulting Serv, 7924 Grape Strea, La Mesa, CA 91924 USA

关键词: Hypoxia;    Benthic macrofauna;    Nonaqueous drilling fluid (NADF);    Linear alpha olefin (LAO);    Caspian Sea;    Drill cuttings;   

DOI  :  10.1016/j.marpolbul.2016.02.079

来源: Elsevier

【 摘 要 】

The effects of linear alpha olefin (LAO) nonaqueous drilling fluid on benthic macrofauna were assessed over a six year period at a southern Caspian Sea petroleum exploration site. A wide-ranging, pre-drilling survey identified a relatively diverse shelf-depth macrofauna numerically dominated by amphipods, cumaceans, and gastropods that transitioned to a less diverse assemblage dominated by hypoxia-tolerant annelid worms and motile ostracods with increasing depth. After drilling, a similar transition in macrofauna assemblage was observed with increasing concentration of LAO proximate to the shelf-depth well site. Post-drilling results were consistent with a hypothesis of hypoxia from microbial degradation of LAO, supported by the presence of bacterial mats and lack of oxygen penetration in surface sediment. Chemical and biological recoveries at >= 200 m distance from the well site were evident 33 months after drilling ceased. Our findings show the importance of monitoring recovery over time and understanding macrofauna community structure prior to drilling. (C) 2016 The Authors. Published by Elsevier Ltd.

【 授权许可】

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