Increasingly scientists are turning to computers to generate models of the ebbs and flows of a healthy ecosystem to understand how pollution such as an oil spill can alter natural processes. As part of its research mission, CONCORDE will produce a four-dimensional model of the coastal waters of the northern Gulf of Mexico most affected by freshwater from North American rivers as they empty into the sea.

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So what is a four-dimensional (4D) model anyway?

According to Jerry Wiggert, Associate Professor of Marine Science at the University of Southern Mississippi, that just means understanding the way three-dimensional water volume evolves through time. Wiggert, a specialist in numerical modeling, is interested in how all of the elements work together—how the water moves in response to winds and tides, how various aquatic nutrients are carried by these water motions, and how plankton respond to these nutrients—over a span of hours to days to weeks, or even longer.

Making a model of any marine system is quite an undertaking, and the intrusion of fresh river water into this area complicates matters even more. The freshwater is lighter than the sea water, so layers of different weight waters tend to form. The river water flows can also carry sediments into the system. With the addition of atmospheric conditions like winds and storms, the whole picture becomes a puzzle for scientists to make sense of.

Wiggert’s team will take up that challenge. Using the data collected by CONCORDE’s plankton and physical processes teams, Wiggert, Eileen Hofmann of Old Dominion University, Gregg Jacobs of the Naval Research Lab and Pat Fitzpatrick of Mississippi State University, will work together to create a model of this complex system from top to bottom, summer to winter, and everything in between.

Once scientists have a model of the ecosystem as it is intended to work, they can use it to see how the ecosystem could respond to an oil spill or another scenario such as a large river flood. For example, oil has been found on the sea floor just south of the Mississippi barrier islands following the Deepwater Horizon spill. As freshwater flows out from the rivers into the Gulf, it often pushes plumes of sediments as it goes. Scientists wondered if the sediment from incoming river water was stirred up by winds and perhaps combined with oil, weighing it down enough to sink to the bottom. This model will help researchers consider this possibility to see if the theory holds up.

Wiggert explains, “The model will set up what ‘normal’ looks like, then we can use it to play with various scenarios.” Ultimately the model will help future responders develop tables of guidance for dealing with a whole host of potential environmental problems, both natural and man-made.