Spatiotemporal Controls on Organic Matter Availability and Decomposition Rates across Floodplain Sediments
EMSL Project ID
50285
Abstract
Although depositional environments such as floodplains are key regulators of ecosystem carbon storage and downstream metal loadings, they are not very well represented in earth system models. Importantly, the fate of organic matter (OM) and redox active metals such as iron are intimately linked, but highly variable. Alpine watersheds are particularly hydrodynamic systems, where spring snowmelt causes seasonal flooding of riparian sediments and promotes OM loss and metal export. What remains elusive are the controls on the fate of OM and associated metals in such biogeochemically and hydrologically dynamic floodplain sediments. To predict future C and metals exports from floodplain sediments in response to warming-induced perturbations of hydrological cycles, a better mechanistic understanding of the processes regulating OM-metal interactions is urgently needed.Herein we aim to decipher the interplay of metal-OM interactions and microbial metabolic constraints in controlling OM availability and decomposition over seasonal flooding cycles, and their feedback to metal mobility. We propose to examine spatiotemporal variations in the controls on OM availability, depolymerization and respiration within seasonally flooded sediments using EMSL's unique -omics capabilities (specifically: metabolomics, proteomics, lipidomics) in conjunction with Mossbauer spectroscopy. Our objective is to examine transformations of OM-mineral associations and variations in metabolic potential over a complete hydrological cycle across two meanders in the East River (CO) floodplain. The proposed work will leverage an active DOE-SBR grant, which provides complementary field data on hydrology, redox state, carbon fluxes and metal dynamics at high spatial and temporal resolution. Using this multifaceted approach, we will deduce spatial variations in OM availability and microbial metabolic function within floodplain sediments, and the resulting governance over greenhouse gas emissions and fate and transport of metals.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2018-10-01
End Date
2021-03-31
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members