Succession of hydrocarbon seep communities associated with the long-lived foundation species Lamellibrachia luymesi

Abstract

The vestimentiferan tubeworm Lamellibrachia luymesi lives for over 250 yr and forms aggregations of hundreds to thousands of individuals at hydrocarbon seep sites in the Gulf of Mexico. A succession model has been proposed where changes in the abiotic environment within tubeworm aggregations lead to shifts in the associated community structure. Here, we test this model using new data from communities associated with 13 tubeworm aggregations. We quantify the temporal scale of succession by using a population-growth model to estimate aggregation age. In older tubeworm aggregations, biomass, density, and number of species m -2 tube surface area decline. In addition, pri- mary producer, primary consumer, and endemic species comprise a smaller proportion of the tube- worm-associated community in old aggregations. These changes in the associated community are at- tributed to lower epibenthic sulfide concentrations in older aggregations. A number of species' densities show strong correlations to sulfide concentration, and similarity between communities is best explained by a combination of aggregation age and sulfide concentration. Together, these data demonstrate the role of hydrogen sulfide in this seep habitat and the effect that the hypothesized reduction of epibenthic sulfide concentration by L. luymesi would have on the associated community.