Role of carbonate burial in Blue Carbon budgets.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30846688.
- Also identified by DOI 10.1038/s41467-019-08842-6 and PMC identifier 6405941.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Calcium carbonates (CaCO<sub>3</sub>) often accumulate in mangrove and seagrass sediments. As CaCO<sub>3</sub> production emits CO<sub>2</sub>, there is concern that this may partially offset the role of Blue Carbon ecosystems as CO<sub>2</sub> sinks through the burial of organic carbon (C<sub>org</sub>). A global collection of data on inorganic carbon burial rates (C<sub>inorg</sub>, 12% of CaCO<sub>3</sub> mass) revealed global rates of 0.8 TgC<sub>inorg</sub> yr<sup>-1</sup> and 15-62 TgC<sub>inorg</sub> yr<sup>-1</sup> in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO<sub>3</sub> burial may correspond to an offset of 30% of the net CO<sub>2</sub> sequestration. However, a mass balance assessment highlights that the C<sub>inorg</sub> burial is mainly supported by inputs from adjacent ecosystems rather than by local calcification, and that Blue Carbon ecosystems are sites of net CaCO<sub>3</sub> dissolution. Hence, CaCO<sub>3</sub> burial in Blue Carbon ecosystems contribute to seabed elevation and therefore buffers sea-level rise, without undermining their role as CO<sub>2</sub> sinks.