Bay Area marshes could help slow global warming

TWITCHELL ISLAND, Calif. (KGO) -- The Sacramento-San Joaquin Delta was once one of the lushest marshlands in the state. The peat-rich soil made it an ideal place for some of the state's first farms to pop up.

Today, scientists are hacking their way through thick brush to see if restoring these marshes is a way to reduce carbon dioxide in the air. CO2 is what scientists believe is responsible for global warming. Sensitive instruments here monitor this wetland as it breathes and absorbs carbon dioxide.

"We are at the stage now with unprecedented levels of carbon dioxide or CO2, based on fossil fuel combustion since the industrial revolution," said Dennis Baldocchi, an agricultural meteorologist at U.C. Berkeley. He says the Delta could hold clues on how we can reduce those carbon dioxide levels locally.

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Ariane Arias-Ortiz is a postdoc fellow from Barcelona looking for those answers.

"We are trying to measure how much organic carbon built up in the soil since restoration," said Arias-Ortiz.

A plot of marsh on Twitchell Island near Antioch was once farmland. It was restored back to marshlands by the California Department of Water Resources in 1997.

Arias-Ortiz and her team hike in and set up a ladder to take samples from the earth, hammering through decades of sediment to remove valuable evidence -- a timeline of the amount of carbon this marsh has absorbed since it was restored.

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"So the goal is to measure carbon sequestration rates in the soil," said Arias-Ortiz.

Carbon sequestration is the process of removing carbon dioxide from the atmosphere and storing it in the ground. According to a study published last year by another U.C. researcher, wetlands effectively sequestered carbon.

In her lab at U.C., Arias-Ortiz is building on that study, going deep into the marsh's past. She takes her samples from a freezer and then cuts them into 1 centimeter slices so she can analyze the amount a carbon that has been sequestered underground.

"We have 20 years of greenhouse gas exchange data, and I am also going to look at the soils and the carbon capture data, so I can integrate short time scales with longer time scales," said Arias-Ortiz.

In theory, scientists now believe that restoring more wetlands could result in less carbon dioxide.

"So we can bury carbon, very effectively, and we feel that restoring marshes in the Bay Area can be a very effective natural carbon solution to this greenhouse problem we are all facing," said Baldocchi.

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