Scientists surprised to learn Mexico mangroves have trapped carbon for millennia

Sept. 16 (UPI) -- According to new research, Mexican mangroves are playing a helpful role in fighting climate change because they have been trapping carbon for thousands of years.

Researchers from the University of California, Riverside and University of California, San Diego began the study because they wanted to understand how the mangroves absorb and release elements like nitrogen and carbon.

The team specifically studied marine mangroves off the coast of La Paz, Mexico, which is located in Baja California. What they found surprised them -- carbon that had been trapped in a layer of peat dating back at least 5,000 years.

"What's special about these mangrove sites isn't that they're the fastest at carbon storage, but that they have kept the carbon for so long," study co-author Emma Aronson said according to Phys.org.

"It is orders of magnitude more carbon storage than most other ecosystems in the region."

The researchers found that very little oxygen -- which is needed for fungi that break down carbon compounds -- penetrates to the deepest peat layer. That could explain why the mangroves have been able to keep carbon trapped for so long.

"Mangroves provide important ecosystem services, including storing carbon below-ground for millennia. Mangrove carbon storage relies in part on high primary productivity, but essential to the long-lived nature of this storage is the slow rate of microbial decomposition of peat," the study's authors wrote in their 17-page paper.

"This research area has taken on special urgency due to an alarming 2% global loss of mangrove area annually from 1980−2000."

The study teams concluded that future research into the metabolic activity of mangroves will lead to more "insight into mangrove element cycling, with the possibility of developing methods to manage these ecosystems to increase their carbon sink capacity."