Isaac’s Environmental Impact Will be Far-Reaching
Storm will exacerbate decline of already stressed wetlands along the Gulf Coast
Tropical storm Isaac has been pummeling the Gulf Coast ever since it made landfall on Tuesday, causing substantial damage along the way. So far it has flooded several New Orleans suburbs, knocked out power to some 650,000 homes and business across Louisiana, forced thousands of people to evacuate their homes and left several thousand more in need of rescue.
Photo courtesy NOOA
[From NBC at around 1 p.m. Pacific time:
“Up to 50,000 people in Louisiana's Tangipahoa Parish were ordered to evacuate Thursday morning when water from Tropical Storm Isaac threatened to overwhelm a dam across the state line in Mississippi.”]
The National Hurricane Center has warned that Isaac, which lost its hurricane status yesterday and is now moving northwest at 12 miles per hour, had not yet finished its dance of destruction. More heavy rainfall, “significant storm surges,” isolated tornadoes and flooding are in the offing as it slowly spins into the Midwest. The eye of the storm is expected move from Louisiana and into Arkansas tonight.
It will be a while before officials will be able to assess the full extent of the damage from Isaac, but already its impact is being felt nationwide as gas prices shot up yesterday. From the Huffington Post:
“Drivers are being hit with the biggest one-day jump in gasoline prices in 18 months just as the last heavy driving weekend of the summer approaches.
“As Hurricane Isaac swamps the nation's oil and gas hub along the Gulf Coast, it's delivering sharply higher pump prices to storm-battered residents of Louisiana and Mississippi – and also to unsuspecting drivers up north in Illinois, Indiana and Ohio.
“The national average price of a gallon of gas jumped almost five cents Wednesday to $3.80, the highest ever for this date. Prices are expected to continue to climb through Labor Day weekend, the end of the summer driving season.”
Well, that’s not the best news ahead of a long weekend, but on the bright side, if high gas prices keep more cars off the road for a while, that’s all the better for our environment.
I’ve been learning about some other long-term impacts of Isaac on the Gulf ecosystem that I find far more troubling. I spoke with ecologist Steve Apfelbaum, author of Restoring Ecological Health to Your Land, who says what Isaac is doing is it’s kicking up nutrient rich mud that has been deposited by the Mississippi river and pushing that mud into the coastal wetlands. A lot of the mud is very nutrient rich because of the remnants of fertilizers (nitrogen and phosphorous) that come down with the rivers, says Apfelbaum, who runs a restoration ecology consulting firm that has done quite a bit of research in the Gulf Coast.
Photo by Green Fire Productions
The mud deposits bury the wetlands and create an environment favorable for invasive plant species like giant reed grass or phragmites. This grass grows quickly to cover large areas of the impacted wetlands and forms large monocultures on the mud deposits that affect native plant and animal diversity.
One non-native animal that’s flourishing directly because of the proliferation of phragmites is the feral pig. The pigs mat up the grass stalks and live on them. This allows them to stick around in the wetlands all year round, which they were otherwise unable to do because the wetlands are too watery during part of the year. “In addition to eating the desirable native vegetation, the pigs are establishing large areas of bare soil and adding additional instability and stress on the Gulf ecosystem,” Apfelbaum says.
The freshwater marshes in the Mississippi delta are already in decline (disappearing at the alarming rate of 60 acres a day) because of rising sea level and human interference with coastal processes. Dams on the Mississippi block the flow of sediments that used to build new marshes. Instead, a fine, warm type of mud is coming down the river. This mud, which contains absorbed nutrients, gets past the dams and into the Gulf and is then pulled up by big hurricanes and storms like Isaac and blown into the wetlands, Apfelbaum says
So what we have now is a vicious cycle. While wetland decline occurs in some areas, wetland filling is occurring in other areas. And in places where the filling occurs, the invasive species problem is becoming a serious problem in the Gulf. Apfelbaum says this is just starting to be recognized as a problem.
As climate change induces more frequent storm events like Isaac, it will exacerbate the decline of the already stressed wetland systems along the Gulf Coast.
Why does this matter? Because not only does this threaten the Mississippi Delta’s biodiversity, but as the Union of Concerned Scientists says: “natural services performed by wetlands, such as retaining and purifying water, stabilizing sediments, and protecting coastal areas from storm surges, would be lost. These natural services are valued at millions of dollars.”
As extreme weather related disasters continue to scale up and increase in frequency, (such events cost the United States 646 lives and a record-breaking $52 billion in damage to property and infrastructure in 2011), it’s more crucial than ever to protect the natural systems that can safeguard us from such events.
Sadly, it looks like this is yet another battle that we are close to losing.