374
© Springer Nature Switzerland AG 2020
S. A. Murawski et al. (eds.), Deep Oil Spills,
https://doi.org/10.1007/978-3-030-11605-7_23
Chapter 23
Impact and Resilience of Benthic
Foraminifera in the Aftermath
of the Deepwater Horizon and Ixtoc 1 Oil
Spills
Patrick T. Schwing and Maria Luisa Machain-Castillo
Abstract Benthic foraminifera, which are single-celled protists that primarily produce calcite shells, have been commonly used as bioindicators of anthropogenic and
natural perturbations. Numerous surveys of benthic foraminifera conducted in the
Gulf of Mexico (GoM) prior to any major oils spills allow for a fair assessment of
impact, response, and resilience during and following the Deepwater Horizon (DHW)
oil spill in the northern GoM (2010) and Ixtoc 1 oil spill in the southern (1979–1980).
Initially, in the aftermath of DWH, there was an 80–93% decrease in benthic foraminifera density and a 30–40% decrease in species richness and heterogeneity in the
northern GoM. From 2010 to 2012, there was a continuous depletion in benthic foraminifera calcite stable carbon isotopes related to increased deposition of petroleum
carbon (PC). This depletion has subsequently been preserved in the sedimentary
record. Following this period of impact, benthic foraminifera density and diversity
reached a resilient state of equilibrium from 2013 to 2015, suggesting that the rate of
resilience for the benthic habitat is on the order of 3 years following an event like the
DWH. Secondly, the sedimentary records of benthic foraminifera were used to assess
the impact, resilience, and subsequent preservation of the Ixtoc oil spill. A noticeable
decrease in benthic foraminifera density as well as a depletion in the stable carbon
isotopes of benthic foraminifera calcite occurred in the sedimentary interval corresponding to 1979–1980. These results have implications for determining the longterm preservation of oil spills, assessing PC mineralization and burial, and contributing
to overall oil spill budgets. Overall, benthic foraminifera have proven to be valuable
indicators of impact, response, and resilience of the benthos and can provide useful
information concerning benthic habitat suitability following oil spills in the future.
P. T. Schwing (*)
University of South Florida, College of Marine Science, St. Petersburg, FL, USA
e-mail: pschwing@mail.usf.edu
M. L. Machain-Castillo
Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología,
Mexico City, Mexico
e-mail: machain@cmarl.unam.mx
© Springer Nature Switzerland AG 2020
S. A. Murawski et al. (eds.), Deep Oil Spills,
https://doi.org/10.1007/978-3-030-11605-7_23
Chapter 23
Impact and Resilience of Benthic
Foraminifera in the Aftermath
of the Deepwater Horizon and Ixtoc 1 Oil
Spills
Patrick T. Schwing and Maria Luisa Machain-Castillo
Abstract Benthic foraminifera, which are single-celled protists that primarily produce calcite shells, have been commonly used as bioindicators of anthropogenic and
natural perturbations. Numerous surveys of benthic foraminifera conducted in the
Gulf of Mexico (GoM) prior to any major oils spills allow for a fair assessment of
impact, response, and resilience during and following the Deepwater Horizon (DHW)
oil spill in the northern GoM (2010) and Ixtoc 1 oil spill in the southern (1979–1980).
Initially, in the aftermath of DWH, there was an 80–93% decrease in benthic foraminifera density and a 30–40% decrease in species richness and heterogeneity in the
northern GoM. From 2010 to 2012, there was a continuous depletion in benthic foraminifera calcite stable carbon isotopes related to increased deposition of petroleum
carbon (PC). This depletion has subsequently been preserved in the sedimentary
record. Following this period of impact, benthic foraminifera density and diversity
reached a resilient state of equilibrium from 2013 to 2015, suggesting that the rate of
resilience for the benthic habitat is on the order of 3 years following an event like the
DWH. Secondly, the sedimentary records of benthic foraminifera were used to assess
the impact, resilience, and subsequent preservation of the Ixtoc oil spill. A noticeable
decrease in benthic foraminifera density as well as a depletion in the stable carbon
isotopes of benthic foraminifera calcite occurred in the sedimentary interval corresponding to 1979–1980. These results have implications for determining the longterm preservation of oil spills, assessing PC mineralization and burial, and contributing
to overall oil spill budgets. Overall, benthic foraminifera have proven to be valuable
indicators of impact, response, and resilience of the benthos and can provide useful
information concerning benthic habitat suitability following oil spills in the future.
P. T. Schwing (*)
University of South Florida, College of Marine Science, St. Petersburg, FL, USA
e-mail: pschwing@mail.usf.edu
M. L. Machain-Castillo
Universidad Nacional Autónoma de México, Instituto de Ciencias del Mar y Limnología,
Mexico City, Mexico
e-mail: machain@cmarl.unam.mx