Modeling of Nitrogen Sequestration in Coastal Marsh Soils

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Extensive field‐based data from two representative submerged upland tidal marsh soils in the Chesapeake Bay area were gathered to develop a predictive model for total N sequestration. The data covered the range in physiographic position and variation in marsh habitats. Sampling protocol and model validation assure the validity of the model, and placed 80% confidence, and 10% accuracy on the rate of total N sequestration and the predictive model. In coastal marsh ecosystems, total N sequestration continues to occur with time by accumulation in the organic horizons and sea‐level rise is the driving force. The predictive model was a two‐step linear function indicating accelerated sequestration of total N in the past two centuries. During the last 150 yr, the rate of total N sequestration averaged 4.2 ± 1.15 g m−2 yr−1, while over the last one or two millennia the rate of total N sequestration averaged 1.47 ± 0.3 g m−2 yr−1 In the next century, modeled prediction of total N sequestration in newly forming marshes averaged 20 ± 7.9 g m−2 yr−1 Present and long‐term rates of organic S and total N sequestration in coastal marsh ecosystems were comparable as well as their future predictions. Sequestration of total N in terrestrial closed systems and coastal marshes showed similar long‐term trends.