The Mississippi River drains over 24 million acres of watershed into the Gulf of Mexico through the state of Louisiana. The marshes, bayous, and wetlands created by this massive flow of freshwater form the basis of the Louisiana Wetlands and account for over 40% of the wetlands in the lower 48 United States. The entire area consists of nearly 7,000 square miles of wetlands composed of freshwater, saltwater, and in some areas a mixture of both. These wetlands have slight variations that make them unique with different wildlife. There are natural levees, bottom-land hardwoods, swamps, freshwater marshes, intermediate marshes, brackish marshes, and salt marshes.[1]

Louisiana Wetlands and the Mississippi Delta

Louisiana Wetlands and the Mississippi Delta

The wetlands of Louisiana are both valuable wildlife habitat and storm buffers against hurricanes. The plants and animals that live and migrate here are diverse. Marine life in the salt marshes include the Ribbed Mussel (Geukensia granosissima), Periwinkles (snails of the family Littorinidae), the Black Mangrove (Avicennia germinans), and Cord Grass (Spartina alterniflora).

Brackish marshes are salty, but have a lower salt concentration than the salt marshes. Seagrasses are common in these areas along with speckled trout, fiddler crabs, and blue crabs. Invertebrates, like crabs, living in these brackish marshes attract birds through out the year. Migratory birds from all over North America visit the wetlands to rest, feed, and gain energy for their long journeys. Wetlands play a vital role for these birds. This is why the health of the animals living here is so important. The damaging effects of oil and dispersants on the native animals will then affect the health of the birds. This impact will then continue through the food web both locally and wherever the affected birds migrate.

Ribbed Mussel

Ribbed Mussel

Birds that reach the Gulf of Mexico could face the dangers of the oil spill from direct contact with the oil or from eating contaminated animals in the area. Cornell University Lab of Ornithology has asked birdwatchers to report any evidence of these effects via their website, Data collected here is used to monitor the success rates of nesting birds and any affects that the oil spill might have on bird populations.

Oil has already encroached on Louisiana's wetlands.[2] For these areas, there are three factors that determine how damaging the affects will be on the inhabitants. According to Dr. James Cowan, Jr., Professor of Oceanography and Coastal Sciences at Louisiana State University, these three factors are: an animal’s mobility, their life cycle, and the effects of the oil spill on their habitat.[3] Animals such as oysters and mussels that attach to surfaces are effectively immobile, meaning that they cannot escape any oil entering their environment. Animals with short life cycles, such as some shrimp and crabs that only live for one year, are more vulnerable and could be wiped out if spawning levels are diminished even for a short time. Animals that live longer have greater potential to survive, even if one year of reproduction is unsuccessful. Finally, the effects of oil on habitats play an important role in survival rates. In the case of the Deepwater Horizon oil spill, both nursery habitats in the wetlands and adult habitats offshore have been affected.  For this reason, this oil spill could be devastating for the marine life of the Louisiana wetlands. This is also bad news for the fishing and shrimping industries that rely on these creatures. Dr. Kumar Mahadevan, President of Mote Marine Laboratory in Sarasota, Florida, points out that everyone “will be paying more for sea food and getting less.”

Oil Spill Mississippi Delta

Oil Spill Encroaching on the Mississippi Delta

Resources for Louisiana Wetlands

[1] Types of Wetlands

[2] NASA Images Show Oil's Invasion Along Louisiana Coast

[3] Scientific Research into Gulf Seafood Survival