environmental science
Keys to Life: Response Plans
For Threatened Ecosystems
By Joseph Schreder Image courtesy of Wikimedia Commons
W
hat if you knew the best way to respond to the stresses of your everyday life? Your life would be more successful and productive. The stakes are even higher for the environment. If we could develop the most advantageous response plan to things such as hurricanes, wildfires, and extensive pollution, the organisms that keep our planet rich with biodiversity would be protected. Food webs show the relationships of all organisms within an ecosystem and can display the consequences of changes to the environment. Currently, research is being done by Dr. F. Joel Fodrie of the University of North Carolina Institute of Marine Sciences to better understand these webs, which will allow scientists to formulate the optimal response to environmental stress. One of the most prominent examples of an environmental stressor in the United States was 2010’s Deepwater Horizon oil spill, in which 5 million barrels of crude oil leaked into the Gulf of Mexico. The 5 million barrels of oil spread to over 100 kilometers of shoreline, with the marshes of Louisiana absorbing the brunt of the damage. Dr. Fodrie studies coastal biological oceanography with a focus on both trophic interactions in estuarine communities and the connectivity of marine populations and ecosystems. He conducted a study of the food webs in the Gulf of Mexico, and how they were affected by the tragic Deepwater Horizon oil spill.1 Disastrous accidents like this rarely occur, so as a marine scientist, Fodrie was interested in the possible effects that oil would have on the salt marsh ecosystem.2 To better understand the implications of the spill on local ecosystems, Dr. Fodrie began the study by constructing a model of the salt marsh food web located on the coast of Louisiana with a focus on one of the most heavily polluted areas: the Barataria Bay region. A food web is essentially a series of interdependent food chains, so there are many
Figure 1. Oil Spill Area. Image courtesy of BBC News.
links between organisms. For the purposes of the study, links were only established if organisms were directly observed in a predator-prey relationship, whether observed on site, experimentally, or through analysis of stomach contents. Data from over 120 studies was analyzed to accurately represent the food web. Overall, the web has 52 organisms with a total of 376 links between them.3 To produce an accurate food web, Dr. Fodrie needed to understand which species were the most sensitive to oil. He determined this by analyzing 37 different studies that documented the impacts of the oil spill on the populations of the 52 species in the food web. These pieces of literature were either published papers or field-based studies relevant to the effects of oil on the organisms. The purpose of this analysis was to create a baseline of oil sensitivity to compare to the results gathered by Fodrie and his team. If no studies existed for a particular species, the team used data from the
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