Mangroves have the capacity to sequester organic carbon (Corg) in their sediments permanently. However, the carbon budget of mangroves is also affected by the total alkalinity (TA) budget. Principally, TA emitted from carbonate sediment dissolution is a perennial sink of atmospheric CO2. The assessment of the TA budget of mangrove carbonate sediments in the Red Sea revealed a large TA emission of 403 ± 17 mmol m−2 d−1, independent of light, seasons, or the presence of pneumatophores, compared to −36 ± 10 mmol m−2 d−1 in lagoon sediment. We estimate the TA emission from carbonate dissolution in Red Sea mangroves supported a CO2 uptake of 345 ± 15 gC m−2 yr−1, 23-fold the Corg burial rate of 15 gC m−2 yr−1. The focus on Corg burial in sediments may substantially underestimate the role of mangroves in CO2 removal. Quantifying the role of mangroves in climate change mitigation requires carbonate dissolution to be included in assessments.
|Original language||English (US)|
|Journal||Limnology And Oceanography Letters|
|State||Published - Oct 16 2020|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-19
Acknowledgements: We thank M. Predragovic, W. Rich IV, U. Langner, J. L. Curdia, R. Cadiz, and M. Ennasri for their help in the field and the lab. This research was supported by King Abdullah University of Science and Technology (KAUST) baseline funding to C.M.D. and the KAUST Circular Carbon Economy initiative.