A Football Field an Hour
by Ian Markham -- February 16th, 2015
I spent this past weekend in and around the city of New Orleans where my girlfriend and brother had both converged for the Sustainable Seafood Summit (alas, too pricey an affair for me to attend as well). While much of the time was spent enjoying carnival season and the first few parades of Mardi Gras I also managed to get out to see some of the famous Bayous of Louisiana.
We visited Barataria preserve of the Jean Lafitte National Park and was astounded by the richness of the environment. The boardwalk wended its way through a complex mixture of habitats, my favorite of which pictured above being the bald cypress swamps. These amazing trees are adapted to living essentially permanently inundated and often in thick anoxic muds. Trees have to be able to exchange carbon dioxide and oxygen in their roots to survive, so bald cypress is thought to have evolved special “breathing roots” to sustain them in their challenging environment. The spiky stalagmite looking structures emerging from the water beside the board walks are known as “cypress knees” and are projections of the roots that shoot back out above the ground and the water for gas exchange.
The trees, however, are just the foundation and what I found most incredible about the swamp was just how much life could be thronging through it in the middle of winter. It seemed everywhere you looked in the dark water was a ripple or a wriggling from insects, tadpoles, fish, and unseen creatures.
Carolina Anoles scampered about the boardwalk and nearby vegetation basking, courting and hunting insects.
Garter snakes patrolled the cypress knees and low lying vegetation as well as occasionally venturing on to the boardwalk perhaps in search of Anoles.
We even found a water snake who on first encounter disappeared almost immediately into the dark waters but on return was basking cooperatively on some vegetation beside the boardwalk waiting to be photographed. I couldn’t believe it. In just a few short hours we had found dozens of anoles, 5 frogs of two different species, and 10 snakes of three different species! If that was the offering of Bayou critters provided mid-winter I can scarcely imagine spring or summer. I was thrilled by my introduction to this rich new ecosystem.
Before leaving, however, we paid a visit to the visitor center that proved to be rather sobering. According to the National Parks service’s placards nowhere on Earth is disappearing as fast as the Mississippi river Delta. These marshlands have persisted by the deposition of silt from the river and accumulation of vegetation keeping ahead of the erosive force of the ocean and hurricanes. But as humans have radically changed the hydrology of the delta with dams, levees, canals and jetties much of the sediment flows out into the gulf and into the abyss. On top of that subsidence from oil and gas exploration and salt water incursions from agricultural diversion further drown these marshlands. In the image below you can see in red the massive amount of land already lost and in yellow the startling amount predicted to be lost by 2050.
Apparently, Coastal Louisiana has lost an average of 34 square miles a year for the last 50 years. Between 1932 and 2000 it lost 1,900 square miles of coastal land. That is the equivalent of the entire coastline of California losing its first 2 miles! I think the figure that struck me most was that the rate of loss was the equivalent of every forty minutes a football field of land turning to open water.
The thought of these swamps disappearing struck me in a peculiar way. Working in environmental science you can get pretty calloused to hearing the perils of the world. At this point in my education I tend to just hear new frightening figures of the perils to my favorite familiar ecosystems and grimly bear it. This was my first encounter with the swamps of the South, and in some way I felt I’d made a new friend. It came as quite a shock to me to find out how quickly they are disappearing.
As I flew away looking down on the plumes of sediment disappearing from channelized rivers into the gulf, I thought about all the creatures that must disappear with these swamps. The cypress, the snakes, the frogs, the lizards. All the critters that had slithered or squirmed away and I might never see.
I realized I was determined to come back soon, lest the only gator I ever saw in Louisiana would remain this crooked-jawed behemoth trundling down Saint Charles Avenue: