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In-Situ Environmental Impact - Detailed Description Research Area In-Situ Environmental Impact Reference 2.1 Title Faunal Colonisation of Cuttings Piles Objectives To review existing information on patterns of species colonisation of drill cuttings piles and to relate these to models of benthic succession. Background Historic discharges of oily drill cuttings have an initial smothering effect on seabed fauna, coupled with initial or secondary toxicity. As cuttings weather and hydrocarbons are biodegraded the cuttings are colonised by a range of opportunistic and sulphide tolerant species. Some of these species appear to promote biodegradation and the timing and constraints on species succession are important aspects in how long cuttings piles will last. Likely longevity of cuttings piles is a key consideration in decisions about leaving piles in situ or their partial or complete removal. Existing Information Only limited information is available because the vast majority of seabed surveys around offshore platforms did not include sampling of the cuttings pile. Information available is primarily in the form of unpublished reports and ROV inspection videos. Scope Review existing information on faunal colonisation of cuttings material (field and experimental observations) Relate species and patterns found to other information on recovery from defaunation and natural and anthropogenic sources of hydrocarbon and other organic enrichment Project forward to estimate the rate of faunal succession on cuttings. Deliverables Detailed report summarising and reviewing what is currently known about faunal colonisation of cuttings piles and how this relates to other examples of benthic smothering and organic enrichment. Schedule Requirements The work is important to identify natural faunal colonisation processes at drill cuttings sites. To take advantage of the 1999 weather window, the draft report is required within 3 months of contract award.