Saving wetlands | Science News for Students

Saving wetlands

In Louisiana and elsewhere, wetlands are disappearing, threatening plant and animal life.
Mar 29, 2005 — 12:00 am EST
bayou

A bayou, like this one in Louisiana, serves as a home for many species, ranging from bald cypress trees to a host of wetland-dependent animals, including ospreys, herons, and egrets, along with alligators and beavers.

U.S. Fish and Wildlife Service

There's water, and there's land. Somewhere in the middle, there are wetlands.

Not totally flooded by water, but not completely dry either, these in-between places rank among the richest ecosystems on Earth. Marshes, mangroves, bogs, swamps, bayous, prairie potholes, and other wetlands often have more plant and animal life than any lakes, rivers, grasslands, forests, or hillsides nearby.

Baby fish and shellfish thrive in the protected waters of shallow estuaries, where rivers meet the sea. Many types of migratory birds spend their winters in marshes or stop there to rest during their travels. Wetlands are full of salamanders, frogs, turtles, snakes, and alligators, as well as sea grasses and other specialized plants.

"They're really beautiful environments," says Denise Reed of the University of New Orleans. She studies landforms and the processes that made them.

Reed is determined to get people to care about wetlands—and not just because they're beautiful.

Wetlands also help preserve water quality. They protect land from getting battered by storms. And they fuel billions of dollars worth of recreation, fisheries, and other industries.

Disappearing marshes

Unfortunately, the world's wetlands are disappearing.

In the last few hundred years, more than half of the wetlands in the United States (excluding Alaska and Hawaii) have vanished, according to the National Wetlands Research Center. The center is part of the U.S. Geological Survey.

These wetlands in the Grand Cote National Wildlife Refuge in Louisiana include a crawfish pond bordered by smartweed. Such a mix of habitat supports a wide variety of species. Northern pintail ducks spend their winters here.

These wetlands in the Grand Cote National Wildlife Refuge in Louisiana include a crawfish pond bordered by smartweed. Such a mix of habitat supports a wide variety of species. Northern pintail ducks spend their winters here.

U.S. Fish and Wildlife Service

Louisiana's wetlands, in particular, are in need of help. Even though it's a fairly small state, Louisiana holds 30 percent of the nation's coastal marshes along its meandering coastline, especially where the Mississippi River drains into the Gulf of Mexico.

Yet, of all marshes that have disappeared in the U.S., 90 percent were in Louisiana, according to an organization known as America's Wetland. This group is dedicated to saving the Louisiana coast.

During the 20th century, 1.2 million acres of land were lost along the state's coast. Between 1990 and 2000, alone, the equivalent of a football field-sized area of wetland disappeared every 38 minutes.

These are more than just numbers. As wetlands vanish, fish and migrating birds lose critical habitat. Some of these species are already endangered.

Human lives are at stake, too. More than half of Louisiana's population lives along the water, and many of these people rely on fishing and shipping to survive.

"I think it's one of the biggest environmental issues there is," says Garret Graves. Graves grew up in Louisiana but now lives in Washington, D.C., where he works with Louisiana politicians to create laws that will help restore the area.

Vanishing mystery

Why Louisiana's wetlands have been disappearing has long puzzled researchers. Now, after several decades of research, some of the reasons are becoming clearer.

The culprit isn't normal erosion, which happens when waves gnaw away at the land. In this case, the marshes are falling apart from the inside out.

Walking through the wetlands used to be like slogging through a squishy field of wet hay. Now, invisible holes lie all over the place. People walking around in the marshes today can fall up to their knees in water without warning, Reed says. "It's like a Swiss cheese effect."

Sinking marshes in Louisiana create an intricate pattern where water and land meet.

Sinking marshes in Louisiana create an intricate pattern where water and land meet.

U.S. Fish and Wildlife Service

Why this is happening is a complicated question. There seem to be a number of factors involved, Reed says.

One is the Mississippi River. Water used to come down the Mississippi full of sediment and dirt, which piled up in the marshes and kept them sturdy. Flooding was part of the normal course of things, and the process helped distribute sediment.

Then, in the mid-1900s, oil companies discovered a huge quantity of oil and gas just off the coast of Louisiana. They built extensive networks of canals, called levees, to control the flow of the river, providing better access to Earth's natural resources. These efforts ended up changing the flooding cycle. Sediment couldn't spread through the marshes, and the wetlands grew weaker.

Next came development, which filled in marshes to build parking lots, shopping centers, and houses on top of the wetlands.

Large rat-like animals called nutrias are also causing problems. In a healthy marsh, the animals simply graze year after year without causing too much damage. When a marsh is stressed out, though, nutrias eat away at them.

Imported animals known as nutrias may be contributing to the decline of Louisiana's marshes.

Imported animals known as nutrias may be contributing to the decline of Louisiana's marshes.

John and Karen Hollingsworth, U.S. Fish and Wildlife Service

All these stresses add up. "There's no one factor you can point to and say, 'This is the culprit. Here's the smoking gun,'" Reed says. "There are many things going on that cause stress to wetlands. The wetlands could take any one or two of them. Once you get three or four on top of each other, though, the marsh just can't hang on anymore."

Trapping sediment

Now that scientists have a good idea of what's happening to the wetlands, the next challenge is to figure out how to fix the problem, Reed says.

In her research, she's trying to understand why some marshes have managed to survive, even as so many others have vanished.

"How do they keep their heads above water?" she asks. "Where do they get their sediment from? How do they build themselves up when the land is subsiding?"

For about 10 years, Reed has been scattering sediment traps made out of filter paper on the surface of marshes in Louisiana. She attaches the traps to the ground with aluminum wire. Then, she checks them every 2 weeks.

Traps made out of filter paper capture sediment in marshes.

Traps made out of filter paper capture sediment in marshes.

Denise Reed

The traps are clean when Reed puts them in and muddy when she comes back. With the data she collects, she can track when and how much sediment builds up over short periods of time and over the years. She also takes samples of the soil to study how plant roots might help hold a wetland together.

Among her results, Reed has found that hurricanes actually deposit a lot of sediment in salt-water marshes. "Everyone thinks 'Hurricanes, oh my God, they're so bad,'" Reed says. "It is bad for people. For marshes, it keeps them going."

Political action

Even as research continues to help scientists understand what wetlands need, understanding can go only so far, Graves says. The only way to truly reverse wetland destruction, he argues, is through politics.

It would cost $15 billion to cut slits in the earth and restore natural sediment flow patterns along the Louisiana coast, Graves says. That's money the state doesn't have. He wants the U.S. Congress to create new laws that would give Louisiana a big chunk of the profits that come from the oil and gas obtained off its coast.

The state could then put this money toward reconstructing the environment. Right now, the U.S. government officially owns these resources.

Despite 8 years of work on the issue, Graves hasn't seen much progress. His passion has grown with his frustration.

Student Cathy Cebul of Wooster, Ohio, examines shellfish specimens that she gathered during a recent JASON Expedition to explore Louisiana wetlands.

Student Cathy Cebul of Wooster, Ohio, examines shellfish specimens that she gathered during a recent JASON Expedition to explore Louisiana wetlands.

Copyright © 2005 Jason Foundation/Daniel J. Splaine

Scientists and politicians aren't the only ones who have grown passionate about Louisiana's wetlands. Kids have started to get involved, too.

Earlier this year, an educational program called the JASON Expedition gave middle school students a close look at wetland research in Louisiana.

Most of the students participated in the expedition through the Internet and live satellite broadcasts, but some actually got to dig in the mud and explore the science with their own hands.

By the end of the weeklong program, the most popular question from kids, Reed says, was, "What can I do?"

The answer, she says, depends on where you're from. You may not live in Louisiana or even near a coast. Chances are, though, Louisiana's problems hit closer to home than you might think.

Nearby wetlands

"Almost everyone has a wetlands nearby," Reed says. If you're looking for a science fair project idea, she suggests, go find out about your local wetlands.

"As you learn and understand it better, you might then see things you can do in terms of cleaning it up," she says. "Learning is part of doing something. Try to understand how it works."

 Students Rosalind Fennell (left) and Ambika Nath (right) and teacher Suzanne Ciccarelli (center) survey plant species in the swamp at Jean Lafitte National Historic Park, Barataria Preserve in Marrero, La., during a recent JASON Expedition to Louisiana wetlands.<br />
<p>

Students Rosalind Fennell (left) and Ambika Nath (right) and teacher Suzanne Ciccarelli (center) survey plant species in the swamp at Jean Lafitte National Historic Park, Barataria Preserve in Marrero, La., during a recent JASON Expedition to Louisiana wetlands.

Copyright © 2005 Jason Foundation/Daniel J. Splaine

Find out what sustains the wetlands in your area, why they're there, and what they give to your community. Think about the water that drains into them, where it comes from, and what you can do to keep it clean.

Using less water is something everyone can do, Reed says. This helps keep rivers and lakes full, which reduces the strain on wetlands. Paying attention to what goes down storm drains can protect them, too.

If you're really inspired, you can study to become a wetland ecologist. Wetlands are fascinating systems to study, Reed says, because they're always changing.

When the fish are jumping, the birds singing, and the marshes green, wetlandscapes can be beautiful. Even better, they're full of mud, and studying them requires hands-on slogging through squishy dirt and mud, Reed says. "Who doesn't like getting dirty?"

Whatever we do, it's important to do it soon, she adds. "This system could be in radically different shape in 10 years if we get moving," she says. "If we stay this way, it's still going to be in radically different shape, but in the wrong direction."


Going Deeper:

Additional Information

Questions about the Article

Word Find: Wetlands