Thirty-five years of mangrove planting leads to measurable increases in blue carbon stocks in the Arabian Gulf

Context Sustained mangrove planting over 35 years at Mubarraz Island (United Arab Emirates) allowed examination of blue carbon stock increases over decadal timescales. Aims Investigate carbon storage in arid mangroves with implications for climate change mitigation and adaptation. Methods Measured differences in carbon stocks among 2-, 6-, 10-, 17- and 35-year-old mangrove plantations. Key results Total organic carbon content of upper 50-cm soil layers ranged from 51 to 159 Mg C ha−1 (mean: 99 ± 25 Mg C ha−1) being lower than the global average but typical of arid mangroves. Soil organic carbon content was highest in surface soil layers (upper 4 cm) of 17 and 35-year-old plantations. Mangrove biomass increased from 20 ± 30 Mg ha−1 in 2-year-old stands to 479 ± 64 Mg ha−1 in 35-year-old stands. Total carbon stocks in mangrove biomass (excluding soil) increased from 9 ± 12 Mg C ha−1 in 2-year-old plantations to 209 ± 31 Mg C ha−1 in 35-year-old plantations. Conclusions The 17.5 ha of planted mangroves represent a significant total blue carbon store of 1732 Mg C (39% in biomass, 61% in soil). Implications Mangrove planting can measurably contribute to coastal carbon storage even in arid regions.