Potential Effect of Mangrove Ecosystem on Soil Carbon Sequestration and its Physico-Chemical Properties

The mangrove ecosystem is a natural wetland located in the Red Sea that extends 500 km on the Egyptian western coast. It has great potential to sequestrate soil organic carbon, reduce atmospheric CO2, and enhance soil hydro-physical properties. In this context, this research aims to characterise soil changes induced by mangrove growing. Both modelling and measurements herein were performed on five sampling areas at the Western Strand of the Red Sea (plus one control site - beach without plants). The locations (sites 1 and 2) of mangrove forest were in El-Gouna village with ages of 10 and 5 years, respectively, while (sites 3, 4, and 5) represent mangroves at Hurghada, Abu-Monquar Island, and Safaga, respectively. The mean values of measured soil organic carbon pool (SOCP) at the soil surface (0-90cm) revealed that the lowest values of the SOCP were at Hurghada with 8.81± 0.12 Mgha-1 and the highest values at Abu Monquar island with 59.75 ± 0.15 Mgha-1. At El Gouna 1, 2 and Safaga, the SOCP values were 14.48, 12.86, and 39.98 Mgha-1, respectively. In addition, the SOCP at the control site (beach without plants) was 6.62± 0.25 Mgha-1. Thus, the mangrove ecosystem has a great potential to sequestrate the soil's organic carbon and reduce atmospheric CO2. Soil bulk density (SBD) values varied at El-Gouna1, 2, and Hurghada from 1.63 to 1.75 g/cm³, while the lowest SBD values were observed at Abu-Monquar Island and Safaga with 1.31± 0.02, g/cm³ and 1.53 ± 0.05 g/cm³, respectively. SBD at the control site was 1.75± 0.05 g/cm³, which reflects the higher values. Morphological characteristics reveal that tree height results varied from 110-130 cm, 50-70 cm, 150-200 cm, 200-300 cm, and 200-270 cm for ElGouna1, ElGouna2, Hurghada, Abu-Manqar, and Safaga, respectively. Higher values of tree height, size index, and density are convenient, as are the lower values of SBD at Abu-Monquar and Safaga compared to other site locations. The soil-water HYDRUS-1D model revealed that the soil water storage capacity at Abu-Monquar was higher than the other samples. Thus, the joint use of modelling and measurements enabled deeper insight and a suitable characterisation of soil physicochemical changes induced by mangrove growth.