383
Following the depletions in δ
13
C CaCO3 assessed in the IL in the IXN750 and
IXW750 records from the southern GoM, it took approximately 4–5 years for benthic foraminiferal δ
13
C CaCO3 to return to the mean value for the entire record, signifying a return to a carbon source/flux similar to that prior to Ixtoc 1. This is consistent
with the DWH records in the northern GoM which took 4 years (Schwing et al.
2018a).
23.4 Implications
23.4.1 Establishment of Baselines in Advance of Next Spill
Indices of benthic foraminifera diversity are robust proxies of benthic impacts,
response, and ecosystem resilience and useful for establishing benthic resilience
rates following oil spills. Metrics of benthic ecosystem resilience are essential for
establishing current baselines (new normal) and providing context for quantitative
characterization of the severity of benthic impact and recovery following submarine
oil spills in the future.
23.4.2 Importance of Long-Term Time-Series Studies
These studies demonstrate the necessity of long-term time-series studies in the
aftermath of events like DWH and Ixtoc 1. Longer-term (decadal) time-series collections and measurements will not only provide ongoing baselines but also provide
context for seasonal, annual, and decadal changes to benthic communities. The variability and extent of natural (seasonal to decadal timescale) changes are essential to
extricate a quantitative assessment of impact and recovery following any human
perturbations such as oil spills.
23.4.3 Biomineralization and Preservation of Oil Events
(MOSSFA)
Benthic foraminifera and the stable carbon isotopes of their tests provide a distinctive tool to assess the spatial extent of MOSSFA on the seafloor following oil spill
events. Benthic foraminifera test carbon isotope composition is also likely a persistent recorder of marine oil snow sedimentation events (e.g., Ixtoc preservation). On
a longer timescale (hundreds to thousands of years), the alteration of stable carbon
isotope composition of benthic foraminifera during oil spills may have implications
for long-term burial and biomineralization of petroleum carbon considering the
23 Impact and Resilience of Benthic Foraminifera in the Aftermath of the Deepwater…
Following the depletions in δ
13
C CaCO3 assessed in the IL in the IXN750 and
IXW750 records from the southern GoM, it took approximately 4–5 years for benthic foraminiferal δ
13
C CaCO3 to return to the mean value for the entire record, signifying a return to a carbon source/flux similar to that prior to Ixtoc 1. This is consistent
with the DWH records in the northern GoM which took 4 years (Schwing et al.
2018a).
23.4 Implications
23.4.1 Establishment of Baselines in Advance of Next Spill
Indices of benthic foraminifera diversity are robust proxies of benthic impacts,
response, and ecosystem resilience and useful for establishing benthic resilience
rates following oil spills. Metrics of benthic ecosystem resilience are essential for
establishing current baselines (new normal) and providing context for quantitative
characterization of the severity of benthic impact and recovery following submarine
oil spills in the future.
23.4.2 Importance of Long-Term Time-Series Studies
These studies demonstrate the necessity of long-term time-series studies in the
aftermath of events like DWH and Ixtoc 1. Longer-term (decadal) time-series collections and measurements will not only provide ongoing baselines but also provide
context for seasonal, annual, and decadal changes to benthic communities. The variability and extent of natural (seasonal to decadal timescale) changes are essential to
extricate a quantitative assessment of impact and recovery following any human
perturbations such as oil spills.
23.4.3 Biomineralization and Preservation of Oil Events
(MOSSFA)
Benthic foraminifera and the stable carbon isotopes of their tests provide a distinctive tool to assess the spatial extent of MOSSFA on the seafloor following oil spill
events. Benthic foraminifera test carbon isotope composition is also likely a persistent recorder of marine oil snow sedimentation events (e.g., Ixtoc preservation). On
a longer timescale (hundreds to thousands of years), the alteration of stable carbon
isotope composition of benthic foraminifera during oil spills may have implications
for long-term burial and biomineralization of petroleum carbon considering the
23 Impact and Resilience of Benthic Foraminifera in the Aftermath of the Deepwater…