Seasonality of CO2, CH4, and N2O Fluxes Reveal Seagrass Ecosystems as CO2 and N2O Sink Attenuating Carbon Climate Impacts

Seagrass meadows help fight climate change by absorbing and storing carbon dioxide (CO2) from the atmosphere. However, their full impact on climate change depends not just on CO2, but also on other potent greenhouse gases (GHGs) like methane (CH4) and nitrous oxide (N2O), which have been rarely measured together in these habitats. Our study provides the first comprehensive, year-round measurements of all three GHGs in a tropical seagrass meadow in China. We found that while the seagrass ecosystem released CH4 to atmosphere, it absorbed even greater amounts of CO2 and N2O. When combined, this means the overall effect of the seagrass meadow is to remove GHGs from the atmosphere, helping to slow climate warming. This research highlights that to truly understand and protect these valuable coastal ecosystems, scientists and policymakers must consider the balance of all major GHGs.