Spatial and landscape-scale variability in global mangrove soil carbon estimates

Area of Science:

• Environmental Science
• Climate Science
• Ecology

Background:

• Mangrove ecosystems store significant carbon, playing a vital role in the global carbon cycle.
• Current global mangrove soil carbon estimates exhibit wide variations (2.26–10.2 Pg C), leading to substantial uncertainties.
• These uncertainties hinder effective policymaking and accurate climate change mitigation assessments.

Purpose of the Study:

• To compare five global mangrove soil carbon stock models.
• To identify factors contributing to spatial and landscape variability in mangrove soil carbon stocks.
• To generate a more accurate global estimate of mangrove soil carbon stocks.

Main Methods:

• Comparative analysis of five distinct global mangrove soil carbon stock models.
• Ensemble mean approach to synthesize model outputs for a unified estimate.
• Statistical analysis to identify significant drivers of spatial and landscape variability.

Main Results:

• A refined global soil carbon stock estimate of 4.13 ± 0.89 Pg C (to 1m depth) was generated using the ensemble mean.
• Significant spatial variability (P < 0.001) in carbon stocks was observed, particularly in Africa and Asia.
• High model-to-model standard deviation and limited data characterized variable regions, including specific geomorphic settings (terrigenous, deltaic, carbonate, open coasts) and microtidal sites.

Conclusions:

• The study provides a more robust global estimate for mangrove soil carbon stocks, reducing previous uncertainties.
• Understanding spatial and landscape variability is critical for accurate carbon accounting in mangroves.
• Findings will guide future research efforts to improve mangrove carbon stock assessments and inform climate mitigation strategies.