The open-ocean Gulf of Mexico (GoM) was the most impacted habitat by the toxic mixture of hydrocarbons and dispersants released during the Deepwater horizon oil spill (DWHOS) in 2010. The DEEPEND consortium has been conducting continuous observations of deep-sea micronekton to determine the impact of the spill on the ecosystem. With respect to the exposure to contaminants, we focus on polycyclic aromatic hydrocarbons (PAHs), which are known for their mutagenic, genotoxic, and carcinogenic effects. We will present results from an eight year period after the spill for analysis of PAHs in deep-pelagic fishes, cephalopods, shrimps, and gelatinous zooplankton. Results showed a 10-fold increase in PAH concentration during 2010-2011 compared to pre-spill values, which then decreased over the following years for all taxonomic groups except cephalopods. We also found that PAHs were still present in elevated concentrations years after the DWHOS, but only in unhatched eggs, indicating a strong maternal transfer of contaminants. This evidence suggests a long-term bioaccumulation of contaminants in the ecosystem, potentially linked to declines in population levels of all taxa studied, which have dropped substantially by more than 50% since the spill. The tight trophic connections within the oceanic GoM also indicate that reductions  in abundance at intermediate levels could have a ripple effect throughout the entire system. Ongoing studies include connectivity between higher (e.g., tuna) and lower trophic levels as well as other contaminants (PCBs, pesticides, emerging contaminants). 

Primary Presenter: Isabel Romero, University of South Florida (isabelromero@usf.edu)

Authors:

Isabel Romero, Universitty of South Florida  (isabelromero@usf.edu)

T. Sutton,   ()

Z. Milligan,   ()

L. Rose-Mann,   ()

H. Bracken-Grissom,   ()

T. Frank,   ()

A. Cook,   ()

H. Judkins,   ()

K. Boswell,   ()

M. Woodstock,   ()

D. Hahn,   ()

M. Johnston,   ()

M. D’Elia,   ()

J. Moore,   ()

J. Quinlan,   ()

M. Vecchione,   ()

F. Parker,   ()