A researcher collects a soil core from a marine coastal ecosystem dominated by the seagrass Posidonia oceanica.
A researcher collects a soil core from a marine coastal ecosystem dominated by the seagrass Posidonia oceanica. Data from such cores unveil how coastal vegetation like seagrass can capture and store atmospheric carbon for centuries at a time. Credit: Thanos Dailianis
Source: Journal of Geophysical Research: Biogeosciences

Coastal ecosystems capture large amounts of carbon from the atmosphere, sequestering it in soils for years. Estimates of how quickly this “blue carbon” accumulates influence climate predictions, but such values often suffer from uncertainties. Now Belshe et al. demonstrate how combining two computational modeling strategies could boost the accuracy of blue carbon estimates.

The new method builds on age-depth models, which are widely used to calculate blue carbon accumulation according to sedimentation rates gleaned from soil cores. To overcome limitations of the age-depth approach, which gives information only on the rate at which carbon accumulates, the researchers combined it with a “carbon pool” strategy. Carbon pool models—originally developed for inland settings—also estimate the age of carbon in a system and the time it remains in the system, which provides more detailed pictures of organic carbon dynamics within soils.

When applied to soil cores collected from a seagrass ecosystem in Spain’s Balearic Islands, the new two-model strategy outperformed an age-depth-only approach, reducing uncertainties in blue carbon accumulation estimates.

According to the authors, the two-model approach might also generate better estimates in other coastal ecosystems, such as tidal marsh and mangrove habitats. Moreover, it could enable identification of spatial and ecological patterns in blue carbon accumulation that inform estimates in locations where extensive core sampling has not been done.

The seagrass soils sampled in this study appear to store organic carbon for centuries at a time, underscoring the potential benefits of conserving coastal ecosystems in mitigating climate change. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2019JG005233, 2019)

—Sarah Stanley, Freelance Writer


Stanley, S. (2019), Improving estimates of coastal carbon sequestration, Eos, 100, https://doi.org/10.1029/2019EO136472. Published on 05 December 2019.

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