Benthic foraminifera living in Gulf of Mexico bathyal and abyssal sediments: Community analysis and comparison to metazoan meiofaunal biomass and density

Benthic foraminiferal biomass, density, and species composition were determined at 10 sites in the Gulf of Mexico. During June 2001 and 2002, sediment samples were collected with a GoMex box corer. A 7.5-cm diameter subcore was taken from a box core collected at each site and sliced into 1-cm or 2-cm sections to a depth of 2 or 3 cm; the > 63-mu m fraction was examined shipboard for benthic foraminifera. Individual foraminifers were extracted for adenosine triphosphate (ATP) using a luciferin-luciferase assay, which indicated the total ATP content per specimen; that data was converted to organic carbon. Foraminiferal biomass and density varied substantially (similar to 2-53 mg C m(-2): similar to 3600-44,500 individuals m-2, respectively) and inconsistently with water depth: although two similar to 1000-m deep sites were geographically separated by only similar to 75km, the foraminiferal biomass at one site was relatively low (similar to 9 mg C m(-2)) while the other site had the highest foraminiferal biomass (similar to 53 mg C m(-2)). Although most samples from Sigsbee Plain (>3000m) had low biomass, one Sigsbee site had >20mg foraminiferal C m(-2). The foraminiferal Community from all sites (i.e. bathyal and abyssal locales) was dominated by agglutinated, rather than calcareous or tectinous, species. Foraminiferal density never exceeded that of metazoan meiofauna at any site. Foraminiferal biomass, however, exceeded metazoan meiofaunal biomass at 5 of the 10 sites, indicating that foraminifera constitute a major component of the Gulf's deep-water meiofaunal biomass. (C) 2008 Elsevier Ltd. All rights reserved.