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impacts to the Gulf’s ecosystems (Lubchenco et al. 2012; McNutt et al. 2012b; Joye
et al. 2016). Effects of the DWH oil spill have been described in plankton (Almeda
et al. 2013, 2014), microbial communities (Bælum et al. 2012; Bik et al. 2012),
foraminifera (Schwing et al. 2015), benthic invertebrates (Montagna et al. 2013),
fish communities (Murawski et al. 2014; Tarnecki and Patterson 2015; Ainsworth
et al. 2018), dolphins (Venn-Watson et al. 2015; Schwacke et al. 2014), salt marshes
(Silliman et al. 2012), deep-water corals (White et al. 2012), and continental shelf
ecosystems (Murawski et al. 2016).
While DWH is perhaps the most well-studied oil spill to date, it is not the first
massive offshore spill to affect the Gulf of Mexico. On June 3, 1979, an explosion
occurred on the exploratory oil well Ixtoc 1 in Campeche Sound. The drilling rig
caught fire and sank, and the well spilled oil into the Gulf for nearly 10 months until
it was capped on March 23, 1980. Oil and gas were discharged as a jet plume from
the top of the well blowout preventer approximately 38 m below the surface and
14 m above the sea floor. Upwelling gas formed a large fire, 10 m in height and
25–30 m in diameter with occasional outburst up to 80 m, burning on the water
surface directly above the stack (Haegh and Rossemyr 1980). Turbulent flow conditions caused by the jet plume thoroughly mixed spilled oil, gas, and seawater, creating a three-phase emulsion. The emulsion raised to the surface where most of the
gas was burned (Jernelöv and Lindén 1981). During the first part of the blowout, the
emulsified oil formed a surface layer 1–4 cm thick, 0.7–5 km wide, and about 60 km
long (Jernelöv and Lindén 1981). Later reports describe an oil slick that varied in
thickness from 0.2 to 0.5 cm and extended between 2 km and up to 10 km downstream depending on wind and waves (Haegh and Rossemyr 1980; Ross et al. 1980).
At the end of the slick, windrows of very stable water-in-oil emulsion were formed
and stretched out to 40 km downstream. The windrows gradually broke up downstream and formed oil patches, some of which washed ashore along the western and
southern Gulf of Mexico, from Texas to Yucatan (Haegh and Rossemyr 1980).
Estimates of the total volume of oil spilled from Ixtoc 1 vary from 0.44 to 1.4 million metric tons (National Research Council 1985; Jernelöv and Lindén 1981).
Moreover, the rate of release varied during the 295 days of the spill (National
Research Council 1985; PCEESC 1980; OSIR 1980; Ross et al. 1979; Jernelöv and
Lindén 1981). Brooks et al. (1981) measured concentrations of volatile liquid
hydrocarbons (VLH) as high as 400 μg/L in the surface water near the Ixtoc 1 wellhead. Concentration of both VLH and low-molecular-weight hydrocarbons
(LMWH) in the water decreased by one, two, and three orders of magnitude at locations 6, 18, and 24 miles, respectively, downstream from the blowout site due to
dilution and evaporation (Brooks et al. 1981). A subsurface plume of oil droplets
suspended in the top 20 m of the water column extended 25 km away from the blowout. Subsurface concentrations of oil ranged from 10,600 μg/L within several hundred meters of the blowout to 5 μg/L at a distance of 40 km (Boehm and Flest 1982).
In comparison to DWH, assessments of Ixtoc 1 oil spill effects on the ecosystem
were limited (Soto et al. 2014). While initial observations suggested a decline in
zooplankton biomass (Guzmán del Próo et al. 1986) and changes to the composition
of shrimp trawling bycatch (Soto et al. 1981), no conclusive evidence has been
J. G. Ortega-Ortiz et al.
impacts to the Gulf’s ecosystems (Lubchenco et al. 2012; McNutt et al. 2012b; Joye
et al. 2016). Effects of the DWH oil spill have been described in plankton (Almeda
et al. 2013, 2014), microbial communities (Bælum et al. 2012; Bik et al. 2012),
foraminifera (Schwing et al. 2015), benthic invertebrates (Montagna et al. 2013),
fish communities (Murawski et al. 2014; Tarnecki and Patterson 2015; Ainsworth
et al. 2018), dolphins (Venn-Watson et al. 2015; Schwacke et al. 2014), salt marshes
(Silliman et al. 2012), deep-water corals (White et al. 2012), and continental shelf
ecosystems (Murawski et al. 2016).
While DWH is perhaps the most well-studied oil spill to date, it is not the first
massive offshore spill to affect the Gulf of Mexico. On June 3, 1979, an explosion
occurred on the exploratory oil well Ixtoc 1 in Campeche Sound. The drilling rig
caught fire and sank, and the well spilled oil into the Gulf for nearly 10 months until
it was capped on March 23, 1980. Oil and gas were discharged as a jet plume from
the top of the well blowout preventer approximately 38 m below the surface and
14 m above the sea floor. Upwelling gas formed a large fire, 10 m in height and
25–30 m in diameter with occasional outburst up to 80 m, burning on the water
surface directly above the stack (Haegh and Rossemyr 1980). Turbulent flow conditions caused by the jet plume thoroughly mixed spilled oil, gas, and seawater, creating a three-phase emulsion. The emulsion raised to the surface where most of the
gas was burned (Jernelöv and Lindén 1981). During the first part of the blowout, the
emulsified oil formed a surface layer 1–4 cm thick, 0.7–5 km wide, and about 60 km
long (Jernelöv and Lindén 1981). Later reports describe an oil slick that varied in
thickness from 0.2 to 0.5 cm and extended between 2 km and up to 10 km downstream depending on wind and waves (Haegh and Rossemyr 1980; Ross et al. 1980).
At the end of the slick, windrows of very stable water-in-oil emulsion were formed
and stretched out to 40 km downstream. The windrows gradually broke up downstream and formed oil patches, some of which washed ashore along the western and
southern Gulf of Mexico, from Texas to Yucatan (Haegh and Rossemyr 1980).
Estimates of the total volume of oil spilled from Ixtoc 1 vary from 0.44 to 1.4 million metric tons (National Research Council 1985; Jernelöv and Lindén 1981).
Moreover, the rate of release varied during the 295 days of the spill (National
Research Council 1985; PCEESC 1980; OSIR 1980; Ross et al. 1979; Jernelöv and
Lindén 1981). Brooks et al. (1981) measured concentrations of volatile liquid
hydrocarbons (VLH) as high as 400 μg/L in the surface water near the Ixtoc 1 wellhead. Concentration of both VLH and low-molecular-weight hydrocarbons
(LMWH) in the water decreased by one, two, and three orders of magnitude at locations 6, 18, and 24 miles, respectively, downstream from the blowout site due to
dilution and evaporation (Brooks et al. 1981). A subsurface plume of oil droplets
suspended in the top 20 m of the water column extended 25 km away from the blowout. Subsurface concentrations of oil ranged from 10,600 μg/L within several hundred meters of the blowout to 5 μg/L at a distance of 40 km (Boehm and Flest 1982).
In comparison to DWH, assessments of Ixtoc 1 oil spill effects on the ecosystem
were limited (Soto et al. 2014). While initial observations suggested a decline in
zooplankton biomass (Guzmán del Próo et al. 1986) and changes to the composition
of shrimp trawling bycatch (Soto et al. 1981), no conclusive evidence has been
J. G. Ortega-Ortiz et al.