The disastrous and tragic oil spill in the Gulf of Mexico might enhance the regions already environmentally threatening dead zone.
According to researchers who just happened to have been in the area when the British Petroleum Deepwater Horizon offshore drilling rig blew out and sank on April 20, the oil spill could worsen and expand the dead zone in the Gulf.
A dead zone is a hypoxic (low-oxygen) area of water that as a result of its low and sometimes non-existent levels of oxygen are unable to support life. One of the most well-known dead zones is in the Gulf of Mexico where runoff from the Mississippi River carries urban runoff and nitrogen-based fertilizers from the farmland farther up the river into the ocean.
“At the moment, we are seeing some indication that the oil spill is enhancing hypoxia,” said Michigan State University professor Nathaniel Ostrom. “It’s a good hint that we’re on the right track, and it’s just another insult to the ecosystem – people have been worried about the size of the hypoxic zone for many years.”
Ostrom and collaborator Zhanfei Liu from the University of Texas at Austin had been out at sea when the rig blew, and quickly landed federal support to expand their area of enquiry to include the oil spill area. Along with two undergraduate researchers, they collected water samples and will be conducting numerous tests on them over the next few weeks to determine the effect the oil spill will have on the dead zone.
The dead zones spring from algae blooms that are nourished by the runoff from the Mississippi River but quickly die and sink. They are then eaten by bacteria that consume more oxygen. While these bacteria might in fact be eating the oil itself they will be removing oxygen as they go, further increasing the dead zone.
On top of that, Ostrom believes that there are other effects the oil spill might be causing, including the possibility that the oil slick and chemical dispersants might be reducing the flow of oxygen from the atmosphere to the ocean, and the possibility that the slick might be reducing the sunlight reaching into the water to nourish the oxygen-producing marine plant life.
Source: Michigan State University
Image Source: NASA Goddard Photo and Video