Influence of Rhizosphere Iron on Carbon Cycling in a Wetland Environment
EMSL Project ID
47898
Abstract
About 20% of the earth's carbon resides in wetlands and another 20% of the organic carbon in sediment is associated to reactive iron phases, either existing in wetlands or elsewhere. This proposed EMSL project is a key part of a larger DOE-OS/BER project dealing with the impact of the root rhizosphere (and its associated organic root exudates, microbial communities, and iron mineralogy) on uranium mobility. The specific objective of this EMSL proposal is: 1) to characterize the changes in natural organic matter (NOM) composition in the rhizosphere and as a function of depth within root plaques (Fe oxyhydroxides coatings on roots formed under reducing conditions) using nano-DESI, 2) to define the Fe-oxide mineral composition along the Eh transect within the rhizosphere and plaque (Mossbauer, SEM-EDX, TEM-SAED, micro-XRD), and 3) to provide a 3-D map of plaques (X-ray computed tomography) to provide insight into the causes for various Fe oxyhydroxide and carbon accumulations (interior vs. exterior). This research will provide necessary insight in how plants create a very tight organic carbon cycle within wetlands through the formation and digenesis of Fe oxyhydroxides. Data from these studies will be leveraged against other related activities, including: long term (multiple years) uranium-greenhouse mesocosm experiments, PCR analyses, synchrotron X-ray microprobe mapping of uranium and iron, and field collection of root plaques. Together these experiments will provide a multi-disciplinary explanation of an extremely important component of the carbon and Fe cycles on a natural contaminant immobilization process that is rarely accounted for in risk calculations.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2013-10-01
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members