Evaluating the Recovery of Ecosystem Services in a Restored Seagrass Meadow: Greenhouse Gas Fluxes and Climate Mitigation Potential

Seagrass meadows are critical components of coastal ecosystems, playing a significant role in the global carbon cycle. These "Blue Carbon Ecosystems" (BCEs) are highly effective natural carbon sinks because they are highly productive, trap allochthonous carbon, and can store sequestered carbon for centuries to millennia in the sediment. Hence, they contribute to the long-term removal of atmospheric CO2 and prevent the remineralization of buried carbon via methanogenesis, thereby supporting climate regulation. This study evaluates the recovery of ecosystem services, specifically greenhouse gas (GHG) flux regulation, in a Zostera marina seagrass meadow that has undergone phased restoration since 2015.

By assessing the fluxes of methane (CH4) and carbon dioxide (CO2) across different restoration stages using a LICOR 7810 and an incubator chamber, we explore how the meadow's GHG emissions and carbon sequestration capacity change over time as the ecosystem recovers. Our findings show that, after 9 years of restoration, CH4 emissions decreased by 1.11-fold and CO2 net sequestration increased by 1.23-fold compared to the eroded meadow. While CO2 fluxes in the older restored meadow are 1.33 times higher than those in the original meadow, CH4 fluxes are 3 times higher, indicating a greater challenge in restoring ecosystem services related to methane flux. Despite this, GHG fluxes, especially methane emissions, decrease over time, suggesting that restored meadows are gradually recovering their capacity as carbon sinks. This study highlights the potential of phased restoration to enhance carbon sequestration and support long-term climate mitigation efforts.