Blue carbon storage in Fijian seagrass meadows: First insights into carbon, nitrogen and phosphorus content from a tropical southwest Pacific Island.

Seagrasses provide vital ecosystem services which include the accumulation and storage of carbon and nutrients in sediments and biomass. Despite their importance in climate change mitigation and adaptation, seagrass ecosystems have been poorly studied, particularly in the Pacific. Therefore, the present study assessed variability in sedimentary and vegetative C, N and P storage in three monospecific seagrass meadows (Halophila ovalis , Halodule pinifolia and Halodule uninervis), reporting baseline data for the first time. Sediment C org stocks ranged from 31 to 47 Mg C ha⁻¹ and varied (p < 0.001) between seagrass meadows, unvegetated areas and locations. Comparison of N and P storage between vegetated meadows and unvegetated areas revealed differences (p < 0.05); implying seagrass meadows function as C, N and P sinks. Differences in species composition and environmental conditions, may play a key role in estimating C, N and P stocks, which are valuable data for conservation and monitoring of seagrass ecosystems. • C, N and P content was high for sediments and seagrass tissues. • C stocks were up to 2.5 times more in vegetated sediments. • C, N and P accumulation are dependent on seagrass species. [ABSTRACT FROM AUTHOR]