Ecological monitoring is discussed in terms of minimum requirements for high confidence in detection and subsequent determination of the cumulative effects of low-level discharges from oil and gas drilling, development, and production operations in offshore and adjacent coastal ecosystems. Comparisons are made of (1) the use of ecological baselines established in undisturbed areas prior to drilling, and (2) comparisons of similar ecosystems, one experiencing drilling and production and the other undisturbed. Requirements for rapid synthesis, interpretation, and display of ecological data imposed by minimum monitoring systems are defined.
On discute du contrôle écologique permettant de déceler d'une façon sure et de déterminer les effets cumulatifs de fuites survenues au cours du forage ou de la production de gaz ou de pétrole, sur les écosystèmes marins ou côtiers adjacents. On compare deux méthodes comportant:
l'utilisation des données de base écologiques, provenant d'une zone non perturbée; avant le forage
la confrontation d'écosystèmes similaires, l'un observé sur place, en cours de forage et de production, et l'autre non perturbé.
On décrit les moyens de synthèse, d'interprétation et de présentation des données écologiques, nécessaires à I'établissement d'un système de contrôle minimal et à son utilisation.
Biological monitoring is discussed in this paper only as it relates to the detection of those ecological changes which could be associated with the cumulative effects of persistent low-level discharges or physical disturbances directly related to offshore oil and gas drilling, production and pipelining. Acute or transient phenomena which might occur, for example, from a major oil spill are not considered since post-spill procedures are now reasonably well established and accepted.
The methods and rationale described have resulted from (1) the Offshore Ecology Investigation (OEI) and (2) a subsequent independent appraisal of the OE1 data and conclusions by environmental scientists, not originally involved, using recently developed computer-assisted methods for analysis of ecological data and information synthesis and display. The OE1 is described briefly herein because the OE1 data base was used to develop the biological monitoring methods described and because of the relevance of the OE1 results to offshore oil and gas development. 2. THE OE1 AND ITS SUBSEQUENT INDEPENDENT EVALUATION The OE1 was a multidisciplinary field study conducted in the coastal and offshore oil and gas product