A Decline in Benthic Foraminifera following the Deepwater Horizon Event in the Northeastern Gulf of Mexico

Authors

Patrick Schwing, University of South FloridaFollow
Isabel Romero, University of South FloridaFollow
Gregg R. Brooks, Eckerd College
David Hastings, Eckerd College
Rebekka A. Larson, University of South Florida
David Hollander, University of South FloridaFollow

Document Type

Article

Publication Date

3-18-2015

Digital Object Identifier (DOI)

https://doi.org/10.1371/journal.pone.0120565

Abstract

Sediment cores were collected from three sites (1000–1200 m water depth) in the northeastern Gulf of Mexico from December 2010 to June 2011 to assess changes in benthic foraminiferal density related to the Deepwater Horizon (DWH) event (April-July 2010, 1500 m water depth). Short-lived radioisotope geochronologies (²¹⁰Pb, ²³⁴Th), organic geochemical assessments, and redox metal concentrations were determined to relate changes in sediment accumulation rate, contamination, and redox conditions with benthic foraminiferal density. Cores collected in December 2010 indicated a decline in density (80–93%). This decline was characterized by a decrease in benthic foraminiferal density and benthic foraminiferal accumulation rate (BFAR) in the surface 10 mm relative to the down-core mean in all benthic foraminifera, including the dominant genera (Bulimina spp., Uvigerina spp., and Cibicidoides spp.). Cores collected in February 2011 documented a site-specific response. There was evidence of a recovery in the benthic foraminiferal density and BFAR at the site closest to the wellhead (45 NM, NE). However, the site farther afield (60 NM, NE) recorded a continued decline in benthic foraminiferal density and BFAR down to near-zero values. This decline in benthic foraminiferal density occurred simultaneously with abrupt increases in sedimentary accumulation rates, polycyclic aromatic hydrocarbon (PAH) concentrations, and changes in redox conditions. Persistent reducing conditions (as many as 10 months after the event) in the surface of these core records were a possible cause of the decline. Another possible cause was the increase (2–3 times background) in PAH’s, which are known to cause benthic foraminifera mortality and inhibit reproduction. Records of benthic foraminiferal density coupled with short-lived radionuclide geochronology and organic geochemistry were effective in quantifying the benthic response and will continue to be a valuable tool in determining the long-term effects of the DWH event on a larger spatial scale.

Comments

Table 1 appears incorrectly in the published article. Please see the correct Table 1 in supplementary material or here.

Rights Information

This work is licensed under a Creative Commons Attribution 4.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

PLoS ONE, v. 10, issue 3, art. e0120565

Scholar Commons Citation

Schwing, Patrick; Romero, Isabel; Brooks, Gregg R.; Hastings, David; Larson, Rebekka A.; and Hollander, David, "A Decline in Benthic Foraminifera following the Deepwater Horizon Event in the Northeastern Gulf of Mexico" (2015). C-IMAGE Publications. 21.
https://digitalcommons.usf.edu/cimage_pubs/21