Meiofauna dispersal near natural petroleum seeps in the Santa Barbara channel: A recolonization experiment

Studies on the response of fauna to natural disturbances indicate that disturbance events may be important in structuring marine benthic communities. Benthic populations in the Santa Barbara Channel off Isla Vista, California are regularly subjected to natural disturbances by chronic petroleum seepage in the area. It has been suggested that these populations show enhanced dispersal abilities when compared to populations that are not disturbance-adapted. Our study compared the rate of meiofaunal colonization into azoic sediment trays buried at an oil seep site with a nearby comparison site free of fresh oil. At the comparison site, for all taxa examined, meiofaunal abundances in the colonization trays did not reach ambient (surrounding sediments) levels at any time during the 23-h experiment. At the seep site, meiofaunal abundances in the trays reached ambient levels in 6 to 23 h, depending on taxa. Thus, the rate ofmeiofaunal colonization was faster at the seep site than at the comparison site. Enhanced susceptibility to passive transport or active water column entry by some species was most likely responsible for the enhanced colonization rate at the seep site.