Distribution of soil organic carbon in the mangrove forests along the southern Saudi Arabian Red Sea coast

Abstract

Climate change is an issue that has huge concerns worldwide. Carbon dioxide (CO2) emission is one of the important factors in global climate change. Carbon sequestration potential (CSP) of various terrestrial ecosystems, especially wetlands, play a role in manipulating the excessive increase of CO2 in the atmosphere. In the current investigation, we report on the efficiency of mangrove forests located in the southern Saudi Arabian Red Sea coast in carbon sequestration and establishment of a baseline data on soil organic carbon (SOC) pools for future studies on SOC dynamics. Sampling was carried out in three locations along the southern Saudi Arabian Red Sea coast. The sampled locations were classified into landward and seaward stands. In each of the sampling location, ten sampling sites were selected to assure representative samples to each of the landward and seaward stands. Three soil cores were taken in each sampling site and were pooled together into one composite core per sampling site. A total of 480 soil samples were collected. The mean distribution of soil bulk density in the landward and seaward stands increased significantly with depth reaching the maximum at a depth of 20–25 cm. SOC concentration in the landward stands declined significantly with depth from 35.8 g C kg−1 at depth 0–5 cm to 20.9 g C kg−1 at depth 20–25 cm. SOC concentration in the seaward stands declined significantly with depth from 35.7 g C kg−1 at depth 0–5 cm to 24.8 g C kg−1 at depth 20–25 cm. The carbon sequestration rate (CSR) ranged between 11.7 g C m−2 year−1 in the landward stands and 12.0 g C m−2 year−1 in the seaward stands. Based on the area of mangrove stands (292 km2) and CSR, the total CSP of mangroves in Saudi Arabia was 3.47 ± 0.05 Gg C year−1.