Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Biogeosciences
Seagrass meadows in coastal areas are significant global carbon sinks, exhibiting carbon accumulation rates close to other more recognized coastal ecosystems, such as mangroves and saltmarshes. Most of this carbon is stored primarily in the sediments. Although the degradation of these coastal ecosystems is positively linked with increased carbon dioxide emissions, few studies report carbon dioxide emission rates from seagrasses sediments after losing their vegetation cover.
In a controlled experiment with seagrass sediments collected at a closed Mediterranean bay, Roca et al.  show that emissions intensify with water agitation and increased temperature. Considering that water temperatures will likely increase in the Mediterranean Sea, these findings have direct implications for more accurate predictions of future emissions of organic carbon dioxide from coastal areas. The authors suggest that when healthy seagrass meadows lose their vegetation and sediments become exposed, the carbon that it had sequestered for one year could potentially be lost during a single summer season.
Citation: Roca, G., Palacios, J., Ruíz-Halpern, S., & Marbà, N. (2022). Experimental carbon emissions from degraded Mediterranean seagrass (Posidonia oceanica) meadows under current and future summer temperatures. Journal of Geophysical Research: Biogeosciences, 127, e2022JG006946. https://doi.org/10.1029/2022JG006946
—Jorge Villa, Associate Editor, Journal of Geophysical Research: Biogeosciences