From email from the Natural Resource Ecology Laboratory (Laurie Richards):
Friday, October 28, 2011, 11:00 AM – 12 noon, Third Floor Conference Rooms A302-304, Natural and Environmental Sciences Building
Recent high-profile papers have highlighted the role that rivers play in the global carbon cycle. Of the terrestrial carbon delivered to rivers, less than half reaches the oceans. The remainder is returned to the atmosphere or sequestered in sediments. The balance among these outputs depends on how long carbon is retained in various storage sites along a river. Headwater rivers are particularly important in that they receive the majority of terrestrial carbon inputs from soil, vegetation, and fossil carbon in sedimentary bedrock. Despite recognizing the importance of riverine processes in the carbon cycle, many existing studies of carbon dynamics treat physical processes in rivers as a black box, focusing only on inputs and outputs rather than mechanisms within the river network. This talk uses the example of headwater rivers in Rocky Mountain National Park to examine the magnitude and spatial distribution of carbon stored in floodplain sediments, coarse organic material on the floodplain and in the stream, and living biomass on the floodplain. We partition river segments into distinct process domains as a function of their elevation and valley geometry.
We find that laterally unconfined valley segments above the Pleistocene glacial moraines store disproportionately large amounts of carbon relative to their percentage of the total river length. This has important management implications in that the biotic drivers that facilitate and maintain this carbon storage have been progressively lost over the past few decades.