Mangrove forests are among the most carbon-rich habitats on the planet. Most mangrove forests lay down peat. There are other important peat forests worldwide, but the microbial processes in those peat forests give off substantial amounts of methane, which is a greenhouse gas in its own right. The saline soils of the mangroves generally prevent this methane production. That gives us a huge extra carbon store in the soil. In other words, mangroves are natural carbon-scrubbers, taking CO2 out of the atmosphere and packing it away, for millennia or more, in their rich soils