I was already beginning to feel queasy when we the pilot banked our alarmingly tiny four-passenger airplane to the right over the Caernarvon Outfall Area to the east of the Mississippi River. A thousand feet below, the land slid by, a flat expanse of deep blue water splotched with patchy yellow-green vegetation.
My headset crackled, and Dr. Eugene Turner, marine biologist at Louisiana State University, piped onto our shared passenger communication line to tell me more about what I was seeing below.
The Caernarvon Outfall Area, I learned, is a fan of marshland that has been receiving water diverted from the Mississippi River since 1991. Hoping the measure would build land to restore the slowly sinking marsh, the structure was designed to re-direct the Mississippi’s water out over the marsh.
In 2011, Dr. Turner, along with two other scientists, published a study wherein he examined vegetation growth inside the Caernarvon Outfall area since it began receiving water from the Mississippi. The study itself examined more than twenty years-worth of data. The three researchers found that vegetation health had significantly decreased in the area after the diversion was opened (Kearney). Turner posited that large quantities of nutrient chemicals suspended in the Mississippi River--thanks to fertilizer and agricultural runoff from farms as far north as Minnesota—are to blame. These nutrients impair native plants’ ability to develop resilient, hurricane-strength root systems.
According to the study, excessive nitrogen spurred impressive initial upward growth, but inhibited the development of healthy root systems. “Fertilizers give you fruit, not roots,” said Turner. Without sturdy roots, new vegetation grown near river diversion sites washes easily away in the storm surge and high winds of a hurricane.
Dr. Turner explained, over the muted chop of rotors, that Hurricane Gutav decimated the area below. It ripped up whole mats of vegetation. In some cases, high winds rolled up these detached patches of turf into long tubes as easily as you’d roll up rug.
Our pilot swung the plane onto a more westerly course, and we left the outfall area behind. Despite how hard I’d worked to orient myself ahead of time to the planned flight route, now that we were up in the air, I felt dazed and disoriented. I struggled to integrate what I had just seen with what I’d read beforehand in Turner’s study—nutrients make the marshland sick. I scanned the landscape below. It was a clear day, and the sunlight reflected back up at me from the surface of the water. Indeed, even in what seemed to be densely vegetated areas of marshland, reflected sunlight betrayed the presence of water just below. Much of what appeared to be vibrant land area below, Dr. Turner informed me, were actually just floating islands of annual plants.
As the flight continued, I became more and more nauseous. About an hour in, as the plane executed a U-bend above the highly polluted town of Norco, Louisiana, I lost control of my gut and puked into a little plastic barf-bag tucked into the back seat-pocket before me. Dr. Turner looked apologetic.
I shrugged. “It must be all the chemicals,” I said.
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Works Cited:
Henkel, Theryn. "What can the Caernarvon Diversion and Bohemia Spillway teach us about coastal restoration?" RESTORE the Mississippi River Delta, Delta Dispatches, 23 Dec. 2014.
Kearney, Michael S, et al. “Freshwater River Diversions for Marsh Restoration in Louisiana:
Twenty‐Six Years of Changing Vegetative Cover and Marsh Area.” AGU100, Geophysical Research Letters, Aug. 2011, agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL047847.
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