443
contaminated by oil and that Kemp’s ridleys continued to forage in these areas after
the spill. Loggerhead foraging sites characterized through satellite tracking demonstrated an overlap with the oil spill footprint, with 32% of tracked individuals taking
up year-round residence in the northern GOM foraging habitats (Hart et al. 2014).
Stable isotope analysis confirmed that loggerheads returned to the oiled area and did
not change foraging patterns after the spill, increasing their risk of chronic exposure
to oil and dispersants (Vander Zanden et al. 2016).
Declines in reproductive parameters of loggerheads in the northern GOM were
reported (Lamont et al. 2012), although the decline could not be linked directly to
the DWH spill. Observed declines in nesting may have been partly due to reduced
prey availability and therefore an inhibited ability to allocate resources required for
nesting. Colder temperatures in 2010 may have delayed or reduced nesting activity
or suppressed the ability of turtles to reach breeding condition (Chaloupka et al.
2008; Lauritsen et al. 2017; Weishampel et al. 2010; Hawkes et al. 2007).
26.4.3 Response Activities
Surface skimming and burning of oil slicks during the DWH disaster response may
have impacted an unquantified number juvenile turtles living in Sargassum
(McDonald et al. 2017). Up to 23% of important Sargassum habitat was estimated
as lost as a result of oil exposure (Trustees 2016).
Response activities related to cleanup efforts, such as mechanical beach cleaning
of oiled sand with heavy machinery and the associated disturbance from noise and
artificial lighting, impacted sea turtle nesting habitats in the northern GOM (Michel
et al. 2013). Enhanced vessel activity and physical barriers (e.g., booms) in nearshore waters may have affected nesting activity as well (Lauritsen et al. 2017).
Loggerhead nesting densities in 2010 in northwest Florida were 43.7% lower than
expected based on previous data, and an estimated 250 loggerhead nests were lost
due to DWH response activities on nesting beaches (Lauritsen et al. 2017).
26.4.4 Dispersants
In addition to being exposed to oil, marine mammals and sea turtles were also
exposed to dispersants. Impacts of exposure to dispersants or dispersants in conjunction with oil are not well known, as there are few studies for marine mammals
and sea turtles. Since oil itself is generally toxic and can be lethal, dispersants may
improve short-term survival of marine megafauna by reducing formation of oil
slicks, decreasing the probability of heavy oiling, and accelerating the initial degradation of released oil (Neff 1990).
The ramifications of the unprecedented release of high volumes of dispersant
chemicals as part of the DWH spill response are widely unknown. Evidence for
26 Impacts of the Deepwater Horizon Oil Spill on Marine Mammals and Sea Turtles
contaminated by oil and that Kemp’s ridleys continued to forage in these areas after
the spill. Loggerhead foraging sites characterized through satellite tracking demonstrated an overlap with the oil spill footprint, with 32% of tracked individuals taking
up year-round residence in the northern GOM foraging habitats (Hart et al. 2014).
Stable isotope analysis confirmed that loggerheads returned to the oiled area and did
not change foraging patterns after the spill, increasing their risk of chronic exposure
to oil and dispersants (Vander Zanden et al. 2016).
Declines in reproductive parameters of loggerheads in the northern GOM were
reported (Lamont et al. 2012), although the decline could not be linked directly to
the DWH spill. Observed declines in nesting may have been partly due to reduced
prey availability and therefore an inhibited ability to allocate resources required for
nesting. Colder temperatures in 2010 may have delayed or reduced nesting activity
or suppressed the ability of turtles to reach breeding condition (Chaloupka et al.
2008; Lauritsen et al. 2017; Weishampel et al. 2010; Hawkes et al. 2007).
26.4.3 Response Activities
Surface skimming and burning of oil slicks during the DWH disaster response may
have impacted an unquantified number juvenile turtles living in Sargassum
(McDonald et al. 2017). Up to 23% of important Sargassum habitat was estimated
as lost as a result of oil exposure (Trustees 2016).
Response activities related to cleanup efforts, such as mechanical beach cleaning
of oiled sand with heavy machinery and the associated disturbance from noise and
artificial lighting, impacted sea turtle nesting habitats in the northern GOM (Michel
et al. 2013). Enhanced vessel activity and physical barriers (e.g., booms) in nearshore waters may have affected nesting activity as well (Lauritsen et al. 2017).
Loggerhead nesting densities in 2010 in northwest Florida were 43.7% lower than
expected based on previous data, and an estimated 250 loggerhead nests were lost
due to DWH response activities on nesting beaches (Lauritsen et al. 2017).
26.4.4 Dispersants
In addition to being exposed to oil, marine mammals and sea turtles were also
exposed to dispersants. Impacts of exposure to dispersants or dispersants in conjunction with oil are not well known, as there are few studies for marine mammals
and sea turtles. Since oil itself is generally toxic and can be lethal, dispersants may
improve short-term survival of marine megafauna by reducing formation of oil
slicks, decreasing the probability of heavy oiling, and accelerating the initial degradation of released oil (Neff 1990).
The ramifications of the unprecedented release of high volumes of dispersant
chemicals as part of the DWH spill response are widely unknown. Evidence for
26 Impacts of the Deepwater Horizon Oil Spill on Marine Mammals and Sea Turtles