Assemblage Comparisons of Living Benthic Foraminifera at Bathyal Sites Oiled and Un-Oiled by the Deepwater Horizon Blowout in the Northeastern Gulf of Mexico
type: CreativeWork
description: Live benthic foraminiferal assemblages were studied at contaminated and uncontaminated bathyal sites around the wellhead of the Deepwater Horizon oil spill. Samples collected in October of 2010 and 2011 and summer of 2012 were divided into uncontaminated (GIP 12, 21, K, and 25 and Obs0), moderately oiled (GIP 16 and 17) and heavily oiled groups (GIP 15), in which the TPAH concentrations ranged from 29 to 7,553 ng/g in 2010. Metric multidimensional scaling (MDS) and cluster analyses were conducted to compare all surface samples. Additionally, the heavily oiled site (GIP 15) and an uncontaminated site (GIP 25) were studied downcore to assess the impact on the foraminiferal depth of habitation (DOH). A total of 284 species from 6 suborders have been identified in the ≥ 45-μm size fraction. Three pseudo-replicates at Obs0 had more similarity in species distribution and diversity than any other site. The MDS and cluster analyses show that the surface assemblages are within a single biofacies except for two sites (GIP 21 and K). The assemblages from the heavily oiled and un-oiled cores were distinctly different. In 2010, the standing stock was nearly two times greater at the heavily oiled site, but the DOH was half the depth of the un-oiled site. In 2011, the standing stock of the two sites was similar, but the DOH remained shallower at the oiled site. The trends in density, DOH, standing stock, diversity, and abundance of an opportunistic species (Bulimina aculeata) at the heavily oiled site appear consistent with hypertrophy.
abstract: Live benthic foraminiferal assemblages were studied at contaminated and uncontaminated bathyal sites around the wellhead of the Deepwater Horizon oil spill. Samples collected in October of 2010 and 2011 and summer of 2012 were divided into uncontaminated (GIP 12, 21, K, and 25 and Obs0), moderately oiled (GIP 16 and 17) and heavily oiled groups (GIP 15), in which the TPAH concentrations ranged from 29 to 7,553 ng/g in 2010. Metric multidimensional scaling (MDS) and cluster analyses were conducted to compare all surface samples. Additionally, the heavily oiled site (GIP 15) and an uncontaminated site (GIP 25) were studied downcore to assess the impact on the foraminiferal depth of habitation (DOH). A total of 284 species from 6 suborders have been identified in the ≥ 45-μm size fraction. Three pseudo-replicates at Obs0 had more similarity in species distribution and diversity than any other site. The MDS and cluster analyses show that the surface assemblages are within a single biofacies except for two sites (GIP 21 and K). The assemblages from the heavily oiled and un-oiled cores were distinctly different. In 2010, the standing stock was nearly two times greater at the heavily oiled site, but the DOH was half the depth of the un-oiled site. In 2011, the standing stock of the two sites was similar, but the DOH remained shallower at the oiled site. The trends in density, DOH, standing stock, diversity, and abundance of an opportunistic species (Bulimina aculeata) at the heavily oiled site appear consistent with hypertrophy.
author: Cruz, Valerie Joanna
keywords: foraminifera, Deepwater Horizon oil spill, bathyal, Gulf of Mexico
date published: 2014-08-01T07:00:00Z
date modified: 2026-07-24T05:44:27Z
provider: University of Southern Mississippi
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Southern Mississippi