Evaluation of the relationship between biomass of living (stained) benthic foraminifera and particulate organic matter vertical flux in an oligotrophic region, Campos Basin, southeastern Brazilian continental margin

Abstract This study investigates the relationship between the vertical flux of particulate organic matter (POM) and the biomass of living benthic foraminifera in a region at the continental slope of the Campos Basin (between 400 and 3000 m). Vertical POM fluxes to the seafloor were modeled as a function of remote sensing chlorophyll-a concentration, sea surface temperature, and derived products such as primary production rates and estimates of dominant phytoplankton size. Measurements of biovolume predicted the biomass of benthic foraminifera. The mean calculated vertical POM fluxes (24.2 ± 17.3 mgCm−2.day−1) were consistent with observations from other oligotrophic environments and correlated positively with the total organic carbon (TOC) content in the sediments. The total biomass of benthic foraminifera, and the biomasses of 14 individual foraminifera species also showed significant correlations with the estimated vertical POM fluxes. The spatial distribution of these fluxes, sediment carbon, and foraminifera biomass in Campos Basin depicted the expected decrease with local depth but our data suggested that the foraminifera communities were influenced by mesoscale eddies associated with the Brazil Current System.