A Multidisciplinary Approach to Investigate Deep-Pelagic Ecosystem Dynamics in the Gulf of Mexico Following Deepwater Horizon

April Cook ,R J David Wells,Travis M Richards,Jose V Lopez,Mahmood S Shivji,Matthew W Johnston,Bradley Penta,Ron I Eytan,Jon A Moore,Isabel C Romero,Michael Vecchione,Chuanmin Hu,Chad Lembke,Sergio Derada,Cole G Easson,Andrea M Bernard,Kevin M Boswell,Marta D’Elia,Heather Judkins,Nina Pruzinsky ,Heather D Bracken‐Grissom ,Tamara M Frank ,Max Weber ,Jennifer J Quinlan ,Diana P English ,Rosanna Milligan ,Tracey Sutton

doi:10.3389/fmars.2020.548880

Abstract

The pelagic Gulf of Mexico (GoM) is a complex system of dynamic physical oceanography (western boundary current, mesoscale eddies), high biological diversity, and community integration via diel vertical migration and lateral advection. Humans also heavily utilize this system, including its deep-sea components, for resource extraction, shipping, tourism, and other commercial activity. This utilization has had impacts, some with disastrous consequences. The Deepwater Horizon oil spill (DWHOS) occurred at a depth of ∼1500 m (Macondo wellhead), creating a persistent and toxic mixture of hydrocarbons and dispersant in the deep-pelagic (water column below 200 m depth) habitat. In order to assess the impacts of the DWHOS on this habitat, two large-scale research programs, described herein, were designed and executed. These programs, ONSAP and DEEPEND, aimed to quantitatively characterize the oceanic ecosystem of the northern GoM and to establish a time-series with which natural and anthropogenic changes could be detected. The approach was multi-disciplinary in nature and included in situ sampling, acoustic sensing, water column profiling and sampling, satellite remote sensing, AUV sensing, numerical modeling, genetic sequencing, and biogeochemical analyses. The synergy of these methodologies has provided new and unprecedented perspectives of an oceanic ecosystem with respect to composition, connectivity, drivers, and variability.

Highlights

Of the ecotypes of the Gulf of Mexico (GoM) affected by the Deepwater Horizon oil spill (DWHOS), the open-ocean pelagic ecotype was by far the largest
We describe the sampling, sensing, and analysis methods of two major research programs, both aimed at characterizing effects, or potential effects, of the DWHOS on the epi, meso, and bathypelagic faunas of the northern GoM
The first program, ONSAP (Offshore Nekton Sampling and Analysis Program), was supported by the National Oceanic and Atmospheric Administration (NOAA) as part of the DWHOS Natural Resource Damage Assessment (NRDA) conducted in 2010–2015. This program encompassed in situ net sampling, water column profiling, and active acoustic sensing (Supplementary Tables 1,2) to address the question, “What could have been affected by the DWHOS in the deeppelagic GoM?” The dearth/lack of pre-DWHOS data and the needs of the NRDA process required this initial approach

Summary

Introduction

Of the ecotypes of the Gulf of Mexico (GoM) affected by the Deepwater Horizon oil spill (DWHOS), the open-ocean pelagic ecotype was by far the largest. This program encompassed in situ net sampling, water column profiling, and active acoustic sensing (Supplementary Tables 1,2) to address the question, “What could have been affected by the DWHOS in the deeppelagic GoM?” The dearth/lack of pre-DWHOS data and the needs of the NRDA process required this initial approach.

Results

Conclusion