Oil And Gas: Exploration, Production and Transport

The exploration and production of oil and gas is wide-spread in coastal areas and has well-defined environmental effects (e.g. Clark, 1997; GESAMP, 1993). For example, the release of refinery effluent to intertidal mudflats will result in anoxic sediments, a degraded infaunal community and changes to predator-prey relationships through a possible decrease in the palatability of prey (Elliott & Griffiths, 1988).

Oil-spills resulting from tanker accidents can cause large-scale deterioration of communities in intertidal and shallow subtidal sedimentary systems (e.g. Majeed, 1987). Oil covering intertidal muds prevents oxygen transport to the substratum and produces anoxia resulting in the death of infauna whereas tidal-pulsing will push an oil into intertidal sands. In both biotopes, the changes will favour the development of opportunistic communities. Oil pushed into coarse sands will destabilise the sediment and produce an oxygen demand where oxygen is available but little degradation at depth where aeration does not occur.

Subtidal sandbanks will be less at risk from oil spills unless dispersants are used in clean-up operations or if wave action allows sediment mobility and thus oil to be incorporated into the sediments. In nearshore and sedimentary areas of oil and gas exploration, such as Morecambe Bay, the release of drill cuttings will cause deterioration of the sediments and the fauna. Seismic testing for oil and gas exploration can affect fish spawning areas on coarse substrata (IECS, 1993).

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