Summary:
We have been examining the effects of the Macondo well oil spill on chemical distributions in the vicinity of the wellhead and in the Mississippi Bight and western Mississippi Sound. Specifically, we have been examining distributions of dissolved organic matter, optical properties, nutrients, oxygen, metals, polycyclic aromatic hydrocarbons (PAH's), and methane. Our work to date has helped characterize deep submerged plumes associated with the well as well as surface contamination. This includes enrichment and fractionation of PAH's, depletion of nutrients and oxygen, enrichment of certain trace elements, and characteristic signatures in optical properties.
We have also examined the return to normal conditions following the stopping of the leak. For instance, subsurface methane concentrations in the vicinity of the wellhead were observed to be fairly normal this past October. This type of fundamental observational work is pertinent to other oil spill researchers who seek to understand ecosystem effects of the oil. Furthermore, it is vital to our own efforts to understand the chemical impact of the spill.
Our work has so far contributed to one peer-reviewed publication and a number of presentations. We expect a number of other publications to result from this work. This work has been performed collaboratively with various other investigators at USM, TAMU, UGA, LSU, NRL, and MSU. Despite this progress, we have a significant number of samples that remain to be analyzed from the various cruises that we have participated in.
Continued funding will allow us to better characterize chemical effects of the oil spill including distributions of Cu and Ni in subsurface plumes, flow of carbon isotope signatures into the dissolved inorganic carbon pool, examination of summer hypoxia in the Mississippi Bight, distribution of the redox-sensitive metals Fe and Mn in sediments near the wellhead, and allow us to examine our data and methods carefully for analytical artifacts. Furthermore, we intend to participate in other planned cruises in mid-2011 to further delineate the return to normal conditions using the same suite of chemical parameters in a complete time series from maximum impacts to absence of oil.