Oil-threatened estuary is key to life in the gulf

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The sickening images of pelicans struggling in oil along Louisiana’s barrier islands only hint at what’s at stake if the slick forces its way into the state’s 3 ½ million acres of estuaries and marshes.

These bays and bayous are thrumming with life — they are far more biologically diverse than the Everglades — and serve as nursery and breeding ground for the gulf’s world famous shrimp, crab, oyster and fish. The wetlands system that fringes the coast is often called “Liquid Louisiana.”

Nearly everything that lives in the gulf is in some way connected to Barataria Bay, which is part of a coastal water system that regularly flushes with tides that mix salt water and fresh water. Pirates used the region’s uncounted cul-de-sacs as hideouts and bases from which to launch forays into the gulf and Caribbean. Today, commercial fishermen motor south from their docks in Lafitte and Barataria.

The prospect of oil penetrating that connection threatens a unique system of floating freshwater marsh already brought to its knees by hurricanes, thousands of canals cut for oil industry traffic, and the dikes, levees and channels that have altered the natural flow of the Mississippi River.

Oil first reached islands at the mouth of the bay May 20, and this week streamers of rust-colored mousse pushed past Grand Isle well into the inland waterway.

“It’s all tidal. We are connected to the gulf and therefore affected by storms in the gulf and, potentially, oil,” said David Muth, chief of planning and resource stewardship at Jean Lafitte National Historical Park and Preserve. Barataria Preserve is part of the park.

“This tragedy has already happened,” Muth said. He poured over colorful map containing hundreds of yellow points, each representing nesting colonies in the region, all in the path of the incoming oil. For example, a survey of site No. 83 revealed 400 pairs of brown pelicans, 8,500 pairs of royal terns, 30,000 pairs of sandwich terns and 200 pairs black skimmers.

“This is a soap opera and we’re just in Act 1 right now,” Muth said. “It’s going to go on and on and on.”

Earlier this week Muth toured Barataria Bay, checking on nesting birds and looking for signs of oil. He launched from Twin Canals into a bright green carpet of floating dots known as duckweed.

A solidly built New Orleans native, Muth steered the boat down broad avenues of water the color of weak ice tea, the result of naturally occurring tannins. Trailing his hand, he pointed out an oily residue on the surface. It was not crude oil from the Deepwater Horizon well, but vegetable oil that is the byproduct of the near-constant breakdown of organic compounds in the marsh.

These reedy redoubts are where the gulf’s marine life comes to be born and mature. “Much of the life in the Gulf of Mexico depends directly or indirectly on what comes out of the estuaries,” Muth said.

The value to the nation’s fisheries is well known.

If the region’s “natural capital” were treated as an economic asset, the present value of the Mississippi Delta would be between $330 billion and $1.3 trillion, according to a 2006 report by the Seattle-based group Earth Economics.

Muth, his green and brown National Parks Service cap set low on his forehead against a blistering sun, guided the boat past a small alligator, with part of its eyes and nostrils peeking above the water’s surface. At 4 feet long, the gator was likely 4 years old, Muth said. Three moorhen chicks waddled across the duckweed, effectively walking on water to their waiting mother.

The birds were standing on mats, known locally as “flotant.” All the vegetation in this floating estuarine freshwater marsh rest on top of the water’s surface, moving up and down with tides. The mat is so thick in some places that shrubs and trees grow on them.

The mats float above a bay floor that has beneath it 30,000 feet of deltaic sediment, the result of millions of years of deposits by the Mississippi River.

Muth paused, listening to a mournful lowing he couldn’t quite make out. Eventually he guessed the sound was the muted cry of a pig frog being swallowed slowly by an aquatic snake.

“What I love about this place is that it’s a system that is incredibly alive and diverse,” he said. “When I go to the beautiful places — to Yellowstone or to the Rocky Mountains or to the Everglades — what I’m really struck by is how lifeless it is. There aren’t that many creatures around at any given time. I’m used to being in a place where there are birds and frogs and turtles and snakes. This is an incredible place.”

The boat continued south across the expanse of Lake Salvador and its green spits of land, stranded islands of what was once connected land. The region has been ripped apart by storms and the constant cutting of canals for oil and gas operations; there are some 10,000 miles of canals in south Louisiana. Today there are a few threads of land to hold together. Boaters equipped with GPS programs are surprised by false alarms warning they are about to run into land where there is only open water. The programmers can’t keep up with the land loss.

The shoreline in the Barataria Preserve retreats 30 feet every year.

This thin tissue of remnant land eventually gave in to Barataria Bay, where a dozen shrimp boats were laying down booms, which trailed like a tangerine-colored tail.

The crews were busy trying to protect an island where marshy edges already had a black coating of oil. In the open water, strands of rusty orange mousse floated: oil that has been treated with dispersants. Muth observed a colony of nesting Forster’s terns.

“The sickening, helpless feeling around all this is the birds have to go on making a living with patches of oil moving through the system,” he said. “We just don’t know how many times can these birds take even a light oiling.”

Like most wetlands scientists, Muth cannot say for sure what the impact of oil will bring to this delta.

“Oil is a wild card,” he said. “This is an extremely adaptive place. When you throw in a completely unnatural event, like this mass of oil, we just don’t know.”