July 1, 2008 Soil scientists spread material dredged from shipping channels over shore areas to help rebuild marsh areas. Wetlands along the shore protect the land from storm surges, create habitat for wildlife, and the plants that grow in them could sequester three to eight tons of carbon dioxide per acre every year.
- Carbon cycle
- Permian-Triassic extinction event
- Consensus of scientists regarding global warming
- Climate model
Our nations wetlands are disappearing at an alarming rate. But now, marshes are being restored to help save the planet.
Bill Giese has lived near wetlands his whole life, and year after year he's watched a once thriving marsh disappear. "We've lost over 8,000 acres of wetland vegetation," said Giese.
Increasing atmospheric carbon dioxide causes global warming, which causes rising sea levels that are then washing away wetlands. But tidal marshes are excellent at capturing carbon dioxide.
"Now, the beauty of a tidal marsh the decomposition is very slow, so most of the carbon that's fixed, or sequestered, stays. It doesn't get returned back to the atmosphere," Brian Needelman, Ph.D., soil scientist at the University of Maryland, told Ivanhoe.
Now, soil scientists are wading through soggy, murky marshes in a new project to help restore wetlands and help reduce carbon dioxide in the atmosphere. Dirt and sediment from the bottom of rivers and bays are pumped into washed-out marshes. New marsh grasses are planted, die and decompose in the water -- taking carbon dioxide down with them. A healthy marsh can collect three to eight tons of carbon dioxide per acre a year.
"What we do is take a soil sample each year and we try to tell how much more carbon is in the soil after each year, and it increases slowly from year to year," Dr. Needelman said.
Marshes are a vital habitat for wildlife; they improve water quality and prevent shoreline erosion. Restoring wetlands is essential for a healthy earth.
"If we want marshes as part of our ecosystem and part of our lives, then we need to restore them and we need to build new ones," said Dr. Needelman.
Helping to save the planet one marsh at a time.
THE CARBON CYCLE: The carbon cycle describes the movement of carbon, in its many forms, between the earth, atmosphere, oceans, and the animals, plants and bacteria that live there. For example, much of the carbon stored in trees and soils is released into the atmosphere when forests are cleared and cultivated. Sometimes this release happens very quickly, like when a forest fire burns. Sometimes it happens slowly, as dead plants decompose. When forests regrow on cleared land, trees draw carbon from the atmosphere and store it again in the plants and soil. If the global totals for photosynthesis (plants taking CO2 from the air and using it for energy, giving off oxygen) and respiration (animals taking in oxygen and using it to make energy, giving off CO2) are not equal, carbon accumulates, either on land or in the atmosphere. The rates of photosynthesis and respiration are not known, and they're not measured well enough, but there does appear to be an imbalance, known as the "missing sink" of carbon. Yet the carbon cycle must be a closed system, which means there is a fixed amount of carbon; we just don't know where the missing carbon is yet. Understanding why there is an imbalance, and where it occurs, is critical to combating the threat of global warming.
ABOUT GLOBAL WARMING: Global warming refers to an increase in the earth's average temperature -- which has risen about 1 degree F over the past 100 years. A warmer earth may lead to changes in rainfall patterns, and a rise in sea level, for example, as polar glaciers melt. Some of this rise is due to the greenhouse effect: certain gases in the atmosphere trap energy from the sun so that heat can't escape back into space. Without the greenhouse effect, the earth would be too cold for humans to survive, but if it becomes too strong, the earth could become much warmer than usual, causing problems for humans, plants and animals.
The American Geophysical Union and the American Waterworks Association contributed to the information contained in the TV portion of this report.