The Gulf Coast region includes five U.S. states: Texas, Louisiana, Mississippi, Alabama, and Florida. They share more than 17,140 miles of shoreline along the Gulf of Mexico. The Gulf is the ninth largest body of water in the world (615,000 square miles). It is home to an abundance of wildlife, including 29 species of marine mammals, 5 species of sea turtles, 49 shark species, and over 1,000 species of fish.
The Gulf is an important migratory stopover for birds, with as many as 2.5 million birds landing in Louisiana to rest each night during annual migrations. The Gulf Coast contains 15.6 million acres of coastal wetlands. It supports the only extensive shallow coral reef in the continental U.S.
Much of the Gulf Coast economy is tied to its coast and wetlands. Coastal resources generate over $200 billion in economic activity annually in four main industries: fishing, shipping, tourism, and oil production.
The Gulf Coast region faces many environmental threats.
This includes loss of habitat, particularly wetlands, and nutrient runoff that has resulted in a large dead zone in the Gulf of Mexico. Oil and noise pollution are also problems.
Gulf Coast wetlands are being lost at an alarming rate.
The Gulf Coast is home to about half of the country’s saltwater wetlands and about 35% of its freshwater wetlands. These habitats provide a number of important ecosystem services, including flood control, wildlife habitat, and shoreline protection.
Almost all of the Gulf of Mexico’s wildlife rely on wetlands at some point in their lives. This includes commercial and recreational fish species, shrimp, and migratory and wading birds. Wetland areas are critical for maintaining the large fishing and tourism industries of the region.
Wetlands play several important roles. They:
Unfortunately, Gulf Coast wetlands are vanishing at an alarming rate. A 2013 report by the U.S. Fish and Wildlife Service noted that more wetlands were lost in the Gulf Coast than in any other
region. They were also being lost more rapidly.
The Mississippi River Delta is particularly vulnerable, having lost wetlands equal to the size of the state of Delaware in the past 80 years. In fact, coastal Louisiana loses an area of wetlands equal to the size of a football field every 100 minutes.
The Gulf of Mexico has the largest dead zone in the United States.
Excess nutrients, such as nitrogen and phosphorus, in waterbodies can create harmful algal blooms and dead zones, or areas where conditions make it impossible for aquatic life to survive. At 6,500 square miles in size, the Gulf of Mexico has the largest dead zone in the United States.
Fertilizer runoff and septic system effluent are two main contributors of nitrogen and phosphorous leading to dead zones. The excess nutrients they provide create large algal blooms. When the algae die, microbes decompose them. They use up oxygen in this process, and these areas eventually become hypoxic or oxygen-starved. The algal blooms can also block sunlight, killing aquatic plants.
Three restoration strategies that can restore and protect wetlands are:
Extensive levees in the lower and middle Mississippi River, as well as dams in the upper reaches, have cut off the natural sediment supply to the river delta. As a result, these areas become slowly submerged and lost. Rising sea levels are also having an impact. Altering river management to allow for the natural flooding of these areas would provide important sediment to rebuild these areas.
Living shorelines are strategies that stabilize the shoreline from erosion by mimicking natural conditions while also creating or maintaining habitat. They use natural materials such as stones, oyster shells, coir logs, or wood debris to mitigate wave energy and trap sediment. Living shorelines projects may replace a seawall or bulkhead with a natural beach, soft shore protection, salt marsh bordered by an oyster reef, or similar structure.
In many Gulf Coast areas, restoration also involves planting cord grass or other salt marsh plants. The vegetation helps dissipate wave energy and provides critical habitat. One study suggested that marshes protect shorelines from erosion better than bulkheads.
Beneficial reuse involves the application of dredge sediment to wetlands to raise their elevation. These “created” marshes are built higher than the surrounding natural mass to offset the sinking of the land over time.