Geomorphology-Driven variations in mangrove carbon stocks and economic valuation across fringing, estuarine, and riverine ecosystems

Abstract

Mangrove ecosystems play a vital role in climate change mitigation by capturing and storing carbon, particularly in their soils. As essential coastal wetlands, they contribute significantly to blue carbon sequestration, helping to offset greenhouse gas emissions and mitigate global change. This study evaluates vegetation and soil carbon stocks, along with their economic valuation, across three distinct geomorphological settings: bordering mangroves in Nusa Lembongan, estuarine mangroves in Benoa Bay, and riverine mangroves in Estuary Perancak. Soil samples were analyzed for organic carbon, bulk density, and various physical and chemical properties, and carbon economic value was estimated using the World Bank’s proposed carbon tax rates. The results revealed significant differences (ρ < 0.05) in soil carbon stocks across the sites, with Estuary Perancak showing the highest values due to its riverine characteristics, while Nusa Lembongan had the lowest values, attributed to sandy soils and limited organic input. Vegetation carbon stocks did not differ significantly among the locations. The economic assessment highlighted a range of values, from 27,622 to 87,925 USD tonCO₂⁻¹ ha⁻¹, demonstrating the financial benefits of mangrove conservation and restoration. Strong positive correlations were observed between soil carbon storage and parameters such as canopy coverage, water content, and clay content, whereas bulk density and salinity were negatively correlated. These findings underscore the critical influence of geomorphology on carbon sequestration in both vegetation and soil, while highlighting the ecological and economic value of mangroves. The study provides valuable insights to support sustainable management and conservation strategies, contributing to global climate mitigation efforts and advancing Sustainable Development Goals (SDGs) 13, 14, and 15.