CO₂ Removal from Soil Organic Carbon (SOC)

Soil organic carbon (SOC) is an essential component of the carbon sequestration process in mangrove ecosystems. SOC is the carbon stored in the soil as a result of decaying organic matter, plant roots, and other biological processes that convert atmospheric CO₂ into stable organic compounds over time. This carbon storage occurs through the accumulation of organic material in the soil, contributing to long-term carbon sequestration. The calculation for annual CO₂ removal from SOC is:

The SOC Sequestration Rate varies across regions and ecosystem types. Default values for SOC sequestration in wetlands, including mangroves, are provided by the IPCC 2013 Wetlands Supplement. These default values are based on global data and represent general trends observed across different wetland and soil conditions. They are considered scientifically reliable and offer a useful baseline for calculating SOC sequestration when more specific site data is not available. However, as SOC sequestration is site-dependent, localized data should be used when available for greater accuracy.

This accurate estimation of soil organic carbon sequestration rates is critical for quantifying carbon storage in mangrove ecosystems. To achieve this:

• Tier 1 Approach: Default values from the IPCC Wetlands Supplement (Table 4.12) are used in the absence of site-specific data. These values provide a standardized starting point and ensure consistency in carbon accounting.
• Refined Approaches (Tier 2 or 3): When possible, project-specific measurements or species-specific values from peer-reviewed literature should be applied. For example, studies on mangrove species like Rhizophora mucronata may provide more accurate data on SOC sequestration rates that reflect local soil conditions and tidal influences.