Soil Science Society of America journal. 2004 Sept-Oct, v. 68, no. 5, p. 1786-1795.
NALT Subjects:
coastal soils salt marsh soils carbon sequestration models upland soils forest soils agricultural soils mineral soils Maryland Chesapeake Bay
Other Subjects:
Dorchester County submerged upland tidal marsh soil
Issue Date:
Sep-2004
Abstract:
Two transects were established across submerging coastal landscapes in Dorchester County, Maryland. Extensive sampling protocol was performed along the submerging upland tidal marsh soils to model C sequestration. Coastal marsh soils are accreting vertically and migrating laterally over the low-lying forest soils to keep pace with sea-level rise. The predictive C sequestration model was a two-step linear function. Therefore, C sequestration will continue to occur by accumulation in the organic horizons and sea-level rise is the driving force. During the last 150 yr, the rate of C sequestration averaged 83.5 ± 23 g m-2 yr-1. Before the last few hundred years, the predicted long-term rate of C sequestration averaged 29.2 ± 5.35 g m-2 yr-1. Sampling protocol and model validation ascertain the validity of the model and placed 80% confidence and 10% accuracy on rates of C sequestration and the predictive model. The model indicated that coastal marsh soils have higher C storage capacity than upland forest soils, and soils in the Cumulic subgroup of Mollisols. In general, C storage in mineral soils tends to reach a steady-state condition, whereas C sequestration in coastal marsh soils is a continuous phenomenon. During the next century, future C sequestration in the newly formed coastal marsh soils averaged 400 ± 162 g m-2 yr-1. Modeling C sequestration in coastal marsh ecosystems indicated that C storage under positive accretionary balance acts as a negative feedback mechanism to global warming.
