Responses of Macrobenthos Colonizing Estuarine Sediments Contaminated with Drilling Mud Containing Diesel Oil

摘要

Boxes filled with clean sand or clean sand with a 2-cm overlay of mixtures of sand with barite or drilling mud were placed in Santa Rosa Sound, Florida to determine the effects of a used lime drilling-mud on field-colonized macrobenthic communities. Effect of the drilling mud on community structure was greater than that of its barite component after colonization for 8 weeks. Barite causes changes in texture of the sediment and thereby recruitment. The average numbers of animals and species in boxes containing 1:10 and 1:3 mixtures of mud to sand were significantly less than those in control boxes and most of the barite/sand mixtures. The Shannon-Weaver index of diversity, Simpson's index of dominance, and the Bray-Curtis dissimilarity index differed only for 1:3 mud/sand communities. Toxic effects of the lime drilling mud were attributed to a diesel fuel oil component.