ABSTRACT
Seagrass meadows are commonly associated with carbonate-rich soils in the sub-tropics and tropics, where the functional traits of seagrasses and the ecosystem supported by seagrass meadows facilitate the growth of calcareous organisms that contribute to the accumulation of detrital carbonate particles in the soil. This chapter outlines processes in seagrass ecosystems that contribute to calcium carbonate (CaCO3) production and accumulation in the underlying soils and how the relative rates of the organic carbon and the CaCO3 cycles affect chemical changes in the water column that determine the direction of the air-sea carbon dioxide exchange. The biogenic production of CaCO3 in seagrass ecosystems generally leads to local CaCO3 deposition and accumulation of CaCO3 stocks. The accumulation rate of CaCO3 soils underlying seagrass meadows has rarely been directly measured, with most current estimates derived from calculated rates of epiphyte production or from soil stocks of CaCO3 and soil accumulation rate, or from the alkalinity anomaly method from benthic incubations and seawater transects.
