SNAPSHOT: Wetlands Emissions

Wetlands can positively impact climate change by absorbing atmospheric carbon dioxide. But the wetlands that absorb sewage overflows from New York City may actually be increasing greenhouse gas emissions rather than mitigating them, according to a study published in Soil Science of America Journal by researchers at The Graduate Center, CUNY, and Queens College.

Wetlands surrounding the city receive large quantities of dissolved organic carbon and nitrogen from runoff, sewage overflow, and treated wastewater. “We wanted to test how saturation of these elements impacted greenhouse gas production,” said Professor Brian Brigham, the paper’s lead author.

A landscape of the wetlands

Researchers collected soil from three wetlands sites, then simulated what happens during sewage overflow events by adding acetate (a simple form of organic carbon) to one sample, and inorganic nitrogen to the others. Carbon dioxide and methane production was measured and compared to a control group of sample soils.

Methane production was 100 times higher and carbon dioxide production was twice as high in soil where carbon was added compared to the control group. The effect was not seen with the addition of inorganic nitrogen.

The research has implications for quantifying New York City’s impact on climate change.

SNAPSHOT is SUM’s new afternoon science brief.