Exploring Soil Carbon and Nutrient Profiles in the Sundarbans Mangrove Forest of Bangladesh

Abstract

Mangroves are globally significant ecosystems known for their carbon storage and nutrient cycling capabilities. Sundarbans is the largest contiguous mangrove forest in the world and is located in the south-west of Bangladesh. This study examines the carbon and nutrient (nitrogen, phosphorus, potassium) dynamics in the soil profile of the Sundarbans, the largest mangrove forest, focusing on pioneer and non-pioneer stands. Soil samples (n=150) from 30 sites were analysed for organic carbon and nutrients at 0-100cm depths. Results showed no significant (p>0.05) variation in carbon and nutrients (nitrogen, Phosphorus and Potassium) concentration across soil layers and stands. Significant (p<0.05) relationships between nutrient stocks and increasing depth were observed. The statistical models for the stock of carbon, nitrogen, phosphorus, and potassium were y = 1.0859*X + 39.184, R² = 0.65; y = 1.5455*X0.0669, R2=0.58; y = 0.0386x + 1.0606; R² = 0.89; and y = 1.1992x + 17.332; R² = 0.97 respectively. Within the top 1 m of soil, total stocks of carbon, nitrogen, phosphorus, and potassium were estimated at 212.21t/ha, 8.25t/ha, 5.88t/ha, and 104.65t/ha, respectively. These findings underscore the Sundarbans’ role in carbon sequestration and nutrient cycling, which is vital for mitigating climate risks and sustaining ecosystem functions. The study highlights the need for comprehensive assessments beyond 1 m depth to capture total ecosystem carbon and nutrient stocks accurately.