The Gulf Oil Spill and Impacts on the Everglades Coastal Areas
(Caption: Oil-soaked Brown Pelican, AP Photo/Charlie Riedel.)
The state of Florida's territorial waters extend nine nautical miles off its west coast, and the state has the authority to manage, develop and lease oil and gas resources within these boundaries. Earlier this year, state lawmakers had entered into debate regarding a proposal to open up Florida's waters along this coast to offshore drilling for oil and gas.
In-depth analysis regarding the impact of these activities on the estuarine and marine environments -- particularly near-shore ecosystems that include Everglades coastal areas and its critical resources such as fishing, beaches and clean waters on which Florida depends -- has not been thoroughly vetted.
"For those who enjoy the recreational opportunities of the coastal Everglades, the proposal to open up the pristine coastal waters off the west coast of Florida to offshore drilling would be of great concern," said Stephen Davis, wetland ecologist, Everglades Foundation.
Drilling for oil and gas does not come without a cost to the environment, especially the areas surrounding these activities. The primary concern of the Everglades Foundation is the restoration and health of the greater Everglades ecosystem that reaches offshore to mangrove, seagrass and coral reef habitats.
"Impacts from oil spills would be most severe to the ecosystems that border the Everglades," said Davis. "The coastal Everglades contains the largest and most pristine tracts of mangrove forest, seagrass beds and coral reefs in the United States. These ecosystems are highly valued for recreation and for their ecosystem services which include shoreline protection, nutrient retention and support of biodiversity."
The Gulf oil spill has heightened concerns the Foundation has regarding the impacts of potential spills from oil and gas developments that may affect the near-shore and coastal ecosystems around the Everglades from the Ten Thousand Islands, through Florida Bay and around the Florida Keys and up the Atlantic coast.
This also includes the organisms such as manatees, dolphins and migratory fish that travel between the coastal Everglades and areas further offshore or are transported as larvae into near-shore coastal Everglades habitats as part of their life cycle.
As the Gulf oil spill has shown, the fate of the Everglades coastal regions are at the mercy of tidal currents, circulation patters and wind. "Even with the presence of the Loop Current and the Gulf Stream, it is difficult to predict with a high percentage of accuracy exactly how much oil could impact the mangrove areas, estuaries and coral reef habitats of the Everglades," warns Davis. "It has been more than 50 days since the Deepwater Horizon spill began spewing millions of gallons of crude oil into the Gulf. We can only hope that if the oil does reach sensitive areas of the Everglades ecosystem, that exposure to the sun would degrade the oil that could end up around the Florida Keys or Ten Thousand Islands. Even still, much of remains to be seen with what we might experience in terms of the degradation by-products or the excessive use of dispersants with recently confirmed underwater oil plumes."
Circulation and Hydrologic Drivers
Circulation in the Gulf is driven by two primary mechanisms: the Loop Current (part of the global ocean circulation structure) and wind-driven circulation. The Loop Current acts to entrain water from the near-shore areas along Florida's west coast. This loop is unstable, and tends to "break off" into huge gyres. Overall, the predominant effect would be to pull spills toward the Everglades and Keys in the areas from Tampa Bay south, but away from the Everglades from Tampa to Pensacola, roughly speaking. Wind-driven currents are highly variable. However, the predominant wet season winds are shoreward along the west coast of Florida. During the dry season, prevailing winds are from the north and west, which would also tend to push spills shoreward.
This does not even consider the impacts of hurricanes, which can both initiate spills and carry them further inshore, thus magnifying the impact. Hurricanes pose a growing threat to Gulf of Mexico oil production as larger, more complex, deepwater platforms produce the majority of hydrocarbons in the region. Hurricane frequency and intensity tend to follow 20-to 30-year cycles, and within that rhythm, scientists are forecasting an increased level of activity over the next decade-even though 2009 was a relatively inactive neo-tropical storm season.
Potential Impacts
The magnitude of a spill is related to the activity involved, the safety measures in place, and causes include equipment failure, personnel mistakes and extreme natural impacts. In highly developed waters such the northern Gulf of Mexico, "small" spills categorized as those that are less than 1,000 barrels or 42,000 gallons occur routinely. The environmental consequences of accidental episodes of this nature are especially severe and sometimes dramatic, when they happen near the shore or reach the shore.
Spills of oil or leakage of other compounds commonly used in the drilling and extraction process have direct impacts on water quality and can be lethal to the organisms within vicinity of the spill or leak. The sub-lethal effects of exposure to petroleum hydrocarbons and other associated substances involve impairment of feeding mechanisms, altered growth and development, reduced reproduction and recruitment and increased susceptibility to disease. In the marine environment, spills can be devastating to numerous species of mammals, birds, fish, and invertebrates. Depending on the location of the spill or the direction of currents that are steering the spill, these effects could harm species that are of commercial importance or ecological significance to the coastal Everglades-not to mention the potential for beach closures and subsequent local economic impacts.
At the same time, these ecosystems are highly susceptible to oil spills. Studies have shown that small spills can result in rapid die-off of mangrove vegetation resulting in slow recovery. Lethal effects of spills on seagrass are greatest under conditions of physiological stress or in shallow, intertidal seagrass flats-both of which are commonly found in Florida Bay. Lastly, coral reefs are particularly susceptible to chemical contamination, and oil spills are especially toxic to corals and the wide array of organisms that utilize the reef for structure and as a source of food. Recent research has also shown that compounds such as dispersants that are commonly used to mitigate spills are even more toxic to corals than the oil itself, thus eliminating the chance of mitigating a spill in reef-contaminated areas should one occur.
It is the position of the Everglades Foundation and its environmental partners, that in light of current developments related to the Gulf oil spill there is an even greater sense of urgency to advocate for Everglades restoration. "When events like the Gulf oil spill occurs, it becomes even more important to ensure that initiatives such as wetland ecosystem restoration move forward," said Kirk Fordham, CEO, Everglades Foundation. "An ecosystem such as the Everglades can be more resilient to natural and manmade impacts if it is healthier to begin with."
For more information on the Everglades Foundation's response to the Gulf oil spill, click here.
For Florida's latest Gulf oil spill news, visit:
http://www.dep.state.fl.us/deepwaterhorizon/
Looking for volunteer opportunities? Visit: Florida Volunteer opportunities.
For a Florida county-by-county account of spill activities, click here.
For satellite views of the spill, visit:
http://www.nasa.gov/topics/earth/features/oilspill/index.html
For beach conditions, click here.
