Consortium for Simulation of Oil-Microbial Interactions in the Ocean (CSOMIO)
Grant
Overview
Overview
abstract
Since the Deepwater Horizon (DwH) oil spill, numerous research teams, many funded by GoMRI, have spent considerable resources developing modeling tools, collecting and analyzing measurements, and performing scientific studies to understand different aspects governing the eventual fate of the oil. This has resulted in more than 12,800 articles (including peer-reviewed and non-reviewed articles, listed in a Googletm Scholar search) referencing the spill. Together, these data have provided the basis for development of vastly improved modeling tools for tracking the distribution and chemical evolution of oil. But one area where our understanding remains quite limited is the role that microbes play in determining the eventual fate of oil and its impact on ecosystems, and how these processes depend on environmental conditions (hydrographic and biogeochemical properties of the water and circulation), hindering predictive capability. The overarching goal of this project is to synthesize recent model developments and results from field- and laboratory-based microbial studies in order to fundamentally advance understanding of how microbial biodegradation influences accumulation of petroleum in the water column and in marine sediments of the deep ocean and the shelf, and to investigate the impacts of potential future oil spills under different temperatures, oxygen levels, suspended particulate matter, transport, and bathymetric regimes, all of which would influence biodegradation. The outcomes of this study will provide a more comprehensive analysis of the fate of the Deepwater Horizon (DwH) oil spill than is currently available and improve the ability to forecast the fate of future oil spills. This directly addresses the Gulf of Mexico Research Initiative’s (GoMRI) Research Theme 2, “Chemical evolution and biological degradation of the petroleum/dispersant system and subsequent interaction with coastal, open-ocean, and deep-water ecosystems.” The DwH oil spill occurred in an area that encompasses a broad variety of oceanographic environments and ecosystems; where microbial activities are quite significant and diverse and where one expects the microbes to strongly influence biodegradation and accumulation of petroleum in the water column and marine sediments of the deep ocean. The DwH spill originated over the deep outer shelf where it could potentially have been transported seaward over the abyssal region of the Gulf of Mexico, or onto shelves of varying width and toward coasts with sandy shores or wetlands. One of the most important components of this area’s circulation, hydrography, and biogeochemistry is the Mississippi River. Among other things, the river supplies nutrients fueling productivity, fresh water that contributes to upper ocean stratification, and sediments that can interact with oil in the water column. Over the Texas-Louisiana shelf to the west, seawater properties (temperature, salinity, turbidity, and currents) are very different than what is found in the deeper location of DwH, and low oxygen (hypoxic) conditions occur each summer. While analysis of the DwH surface oil transport shows that a relatively small fraction of oil from the spill drifted over the Texas-Louisiana shelf, under different forcing regimes, a substantial quantity of the oil could have been advected over this shelf and deposited on the seafloor through sedimentation/flocculation. Additionally, microbial respiration of oil deposited on sediments when hypoxic conditions prevail can further exacerbate low oxygen conditions..........
