Submitted to: Wetlands Carbon Cycling and Climate Change Annual Workshop
Publication Type: Abstract Only
Publication Acceptance Date: December 20, 2000
Publication Date: N/A
Recent modeling studies indicate that soil erosion and terrestrial sedimentation may establish ecosystem disequilibrium that promote carbon sequestration within the biosphere. Movement of upland eroded soil into wetland systems with high net primary productivity may represent the greatest increase in storage capacity potential for C. The capacity of wetland systems to capture sediments and build up areas of deposition has been documented as well as the ability of these ecosystems to store substantial amounts of C. The purpose of this study was to determine the rates of sediment deposition and C storage in a wetland site adjacent to a small first-order stream that drains an agricultural area. The soils of the site consist of a histosol buried by sediments from the agricultural area. Samples of deposited sediments in the riparian zone were collected in 5 cm increments. The concentration of Cs-137 was used to determine the 1964 and 1954 deposition layers. Agricultural activity in the watershed has caused increased sediment deposition to the wetland. The recent upland sediment is highly enriched in organic matter indicating that large amounts of organic C have been sequestered within this zone of sediment deposition. Rates of sequestration are much higher than rates that have occurred over the premodern history of the wetland. These data indicate the increased sedimentation rates in the wetland ecosystem are associated with increased carbon sequestration rates.