A recent study has confirmed that toxic compounds derived from oil that was released in the Deepwater Horizon spill that occurred in the Gulf of Mexico nearly two years ago has entered the ocean's food chain through microorganisms.

The study, funded by the National Science Foundation and led by a team of researchers from East Carolina University, the University of Maryland Center for Environmental Science, Oregon State University, Georgia Institute of Technology, and the U.S. Geological Survey, detected chemical compounds found in oil called hydrocarbons, some known to be carcinogenic, within the bodies of microscopic crustaceans called zooplankton.

Our research helped to determine a 'fingerprint' of the Deepwater Horizon spill--something that other researchers interested in the spill may be able to use, Dr. Siddhartha Mitra of East Carolina University said in a statement. Furthermore, our work demonstrated that zooplankton in the Northern Gulf of Mexico accumulated toxic compounds derived from the Macondo well.

Zooplankton form the base of the ocean's food web and are typically fed upon by fish larva and smaller crustaceans, said Dr. David Kimmel of East Carolina University. Whether or not these larger organisms have accumulated significant amounts of toxic compounds, or has entered the human food chain, has yet to be determined.

That is certainly one of the questions we would like to see answered with more research, said Dr. Mitra in a phone interview.

Another question the researchers would like to see answered is how long the oil compounds will remain in the zooplankton, but it requires sustained observation over a long period of time.

The zooplankton themselves, do not seem to have been negatively impacted in terms of population, said Dr. Mike Roman at the University of Maryland, though they serve as a conduit for energy and matter, including the toxic compounds, to move up the food chain.

The research team was funded to test its hypothesis about the presence of oil compounds in zooplankton, and the results of its study are viewed as something to build upon in determining the full ecological impact of the oil spill.

Dr. Roman said there needs to be long-term monitoring systems in place in the Gulf to examine various levels of the ecosystem and how they have been impacted by the spill.

Dr. Joseph Montoya at GIT plans to return to the Gulf in late May through June to study the impact of the carbon infusion into the ecosystem due to the spill, particularly how it interacts with another aquatic microorganism called phytoplankton, which he describes as the trees of the ocean as they produce oxygen, through photosynthesis. Approximately half of the oxygen in the Earth's atmosphere is produced in its oceans and phytoplankton are responsible for the majority of that production.

The zooplankton that the initial study examined graze on phytoplankton, and Dr. Montoya hopes to learn more about how the carbon compounds from the oil spill move up the food chain in his next field study.