Deep Sea to Coast Connectivity in the Eastern Gulf of Mexico (DEEP-C)

Principal Investigator
Eric P. Chassignet -- Florida State University, Center for Ocean-Atmospheric Prediction Studies

Abstract

The Deep-C Consortium is a long-term, interdisciplinary study of deep-sea-to-coast connectivity in the northeastern Gulf of Mexico. The study will investigate the environmental consequences of petroleum hydrocarbon release in the deep Gulf on living marine resources and ecosystem health. Deep-C will examine the geomorphologic, hydrologic, and biogeochemical settings that influence the distribution and fate of the oil and dispersants released during the Deepwater Horizon (DwH) accident, and use the resulting data for model studies that support improved responses to possible future incidents.

The dual pressures in the northeastern Gulf of Mexico of expanding oil exploration in the outer continental slope and burgeoning population growth along the coast increase the risk of catastrophic discharges of oil and gas, over-enrichment of nutrients, and habitat loss. The region is considered a hotspot of biological diversity and has the highest biological productivity in the Gulf of Mexico so it has tremendous economic value. The DwH accident revealed that oil exploration activities can cause oil spills that affect a substantial part of the Gulf, and that the confluence of petroleum hydrocarbon release and water quality deterioration can have synergistic and negative effects on seafloor and pelagic ecosystems. It also brought to light a profound lack of understanding of the consequences of petroleum hydrocarbon release to the deep and shallow Gulf ecosystems, a deficiency that impairs the effectiveness of disaster response and mitigation efforts. Specifically, processes controlling the spatial and temporal distributions of oil components and dispersants, and the pathways through which petroleum hydrocarbons and their decomposition products move through the ecosystem are poorly quantified. The overarching goals of the Deep-C project, therefore, are (1) to generate quantitative data on the physical, chemical, and biological systems of the northeastern Gulf of Mexico including regions affected by the DwH spill such as the De Soto Canyon and the Florida Panhandle Bight; and (2) to integrate these data in both earth system and food web models that will improve prediction of the path, fate, and consequences of crude oil and gas released from the northeastern deep Gulf through natural or anthropogenic causes. This structure will ultimately allow the forecasting of changes in ecosystem services.

The Deep-C project addresses Themes 1, 2, 3, and 4 of the Gulf of Mexico Research Initiative, embodying elements of physical transport under average and extreme (e.g., hurricanes, hypoxia) conditions, defining chemical proceses related to hydrocarbons originating from the oil spill and natural seepage, and describing the ecological interactions from microbial to benthic invertebrate and fish populations. Key questions relate to physical transport mechanisms, biogeochemical reactions, food web dynamics, and socioeconomic consequences. These include:

1. What are the magnitudes, directions, and spatial and temporal scales of hydrodyamic processes that transport particles and dissolved substances (including oil, gas nutrients, solutes, and organisms) from the deep Gulf to the Florida Panhandle shelf waters in the northeastern Gulf of Mexico? How are these influenced by canyon and shelf topography?

2. How does the transport of these particles and dissolved substances influence geochemical, biological, and demographic processes, including food web dynamics, across sea floor, pelagic, and near-shore ecosystems?

Integration of these data into earth system and food web models will allow simulations of oil spill scenarios, producing projections of changes in ecoysstem services that can support decision making and forecasting of potential socioeconomic outcomes.