312
© Springer Nature Switzerland AG 2020
S. A. Murawski et al. (eds.), Deep Oil Spills,
https://doi.org/10.1007/978-3-030-11605-7_19
Chapter 19
Molecular Legacy of the 1979 Ixtoc 1 Oil
Spill in Deep-Sea Sediments
of the Southern Gulf of Mexico
Sara A. Lincoln, Jagoš R. Radović, Adolfo Gracia, Aprami Jaggi,
Thomas B. P. Oldenburg, Stephen R. Larter, and Katherine H. Freeman
Abstract The 2010 Deepwater Horizon blowout in the northern Gulf of Mexico
(GoM) was the first major oil spill to impact the deep sea. This lack of precedent
creates challenges for predicting the long-term fate of spilled oil constituents in the
deep GoM. Depletion of oil residues in oxygenated seafloor sediments is thought to
be relatively rapid, but as impacted horizons are buried by sediments and oxygen is
depleted, biodegradation rates are likely to decrease. The sedimentary record of the
1979 Ixtoc 1 oil spill (southern GoM), the second largest marine oil spill to date,
affords a window for forecasting the fate of constituents of spilled oil in the northern
GoM over multi-decadal time scales.
This chapter summarizes evidence for the persistence of traces of Ixtoc 1 oil in
sediments underlying deep (>500 m) waters of the southern GoM over ~4 decades.
Recognizing the complex hydrocarbon background of the region, which is
impacted by natural and anthropogenic sources of petroleum, we focused on metrics
with the greatest potential for assessing Ixtoc 1 input. Ratios of polycyclic aromatic
hydrocarbons, sulfur heterocycles, and petroleum biomarkers, and molecular compound classes revealed by Fourier transform ion cyclotron resonance-mass spectrometry provide evidence that recalcitrant signatures of Ixtoc 1 oil can still be
detected in Bay of Campeche sediments, although they are heavily overprinted by
the regional hydrocarbon background. We discuss the spatial heterogeneity of
S. A. Lincoln (*) · K. H. Freeman
The Pennsylvania State University, Department of Geosciences, University Park, PA, USA
e-mail: slincoln@psu.edu; khf4@psu.edu
J. R. Radović · A. Jaggi · T. B. P. Oldenburg · S. R. Larter
University of Calgary, PRG, Department of Geoscience, Calgary, AB, Canada
e-mail: jagos.radovic@ucalgary.ca; aprami.jaggi@ucalgary.ca; toldenbu@ucalgary.ca;
slarter@ucalgary.ca
A. Gracia
Universidad Nacional Autónoma de México, Instituto Ciencias del Mar y Limnología
Apartado, Mexico City, DF, Mexico
e-mail: gracia@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_19
Chapter 19
Molecular Legacy of the 1979 Ixtoc 1 Oil
Spill in Deep-Sea Sediments
of the Southern Gulf of Mexico
Sara A. Lincoln, Jagoš R. Radović, Adolfo Gracia, Aprami Jaggi,
Thomas B. P. Oldenburg, Stephen R. Larter, and Katherine H. Freeman
Abstract The 2010 Deepwater Horizon blowout in the northern Gulf of Mexico
(GoM) was the first major oil spill to impact the deep sea. This lack of precedent
creates challenges for predicting the long-term fate of spilled oil constituents in the
deep GoM. Depletion of oil residues in oxygenated seafloor sediments is thought to
be relatively rapid, but as impacted horizons are buried by sediments and oxygen is
depleted, biodegradation rates are likely to decrease. The sedimentary record of the
1979 Ixtoc 1 oil spill (southern GoM), the second largest marine oil spill to date,
affords a window for forecasting the fate of constituents of spilled oil in the northern
GoM over multi-decadal time scales.
This chapter summarizes evidence for the persistence of traces of Ixtoc 1 oil in
sediments underlying deep (>500 m) waters of the southern GoM over ~4 decades.
Recognizing the complex hydrocarbon background of the region, which is
impacted by natural and anthropogenic sources of petroleum, we focused on metrics
with the greatest potential for assessing Ixtoc 1 input. Ratios of polycyclic aromatic
hydrocarbons, sulfur heterocycles, and petroleum biomarkers, and molecular compound classes revealed by Fourier transform ion cyclotron resonance-mass spectrometry provide evidence that recalcitrant signatures of Ixtoc 1 oil can still be
detected in Bay of Campeche sediments, although they are heavily overprinted by
the regional hydrocarbon background. We discuss the spatial heterogeneity of
S. A. Lincoln (*) · K. H. Freeman
The Pennsylvania State University, Department of Geosciences, University Park, PA, USA
e-mail: slincoln@psu.edu; khf4@psu.edu
J. R. Radović · A. Jaggi · T. B. P. Oldenburg · S. R. Larter
University of Calgary, PRG, Department of Geoscience, Calgary, AB, Canada
e-mail: jagos.radovic@ucalgary.ca; aprami.jaggi@ucalgary.ca; toldenbu@ucalgary.ca;
slarter@ucalgary.ca
A. Gracia
Universidad Nacional Autónoma de México, Instituto Ciencias del Mar y Limnología
Apartado, Mexico City, DF, Mexico
e-mail: gracia@unam.mx