Geobiology of Chemical Weathering: Spatially Explicit Characterization of the Inorganic Chemical Composition of Mycorrhizospheric Biofilms
EMSL Project ID
40111
Abstract
Rich literatures and recent advances across several fields have set the stage for process-based research into the biogeochemical agency of vascular plants -- in particular, how their physiologies drive Earth's 'weathering engine' to extract mineral matter from regolith to build soils, chemically denude the continents, and set the chemistry of the ocean / atmosphere on geologic timescales. Our overarching concept is that plant-driven weathering rates and mechanisms vary, depending on geologic setting and ecosystem phase. We focus here on primary-successional settings, where plants must extract nutrients from soils by chemical weathering. Our premise is that a key adaptation of many plants to these conditions is development of mycorrhizospheric biofilms, which attach the root system to mineral surfaces and micro-localize the biology, chemistry, and hydrology of weathering and nutrient uptake at the root system-mineral interface. Our central hypothesis is that varying degrees of nutrient limitation (need to extract base cations from mineral sources) influence biofilm development and weathering/uptake function. To address this hypothesis, we will use replicated ectomycorrhizal seedling systems in a growth experiment, and vary the availability of Ca and K in bulk soil water and primary minerals by manipulating irrigation solutions and initial mineral composition. Our specific aim is to evaluate the impact of base-cation (BC) limitation on the microbiology and chemistry of ectomycorrhizospheric biofilms at the root system-mineral interface. We expect to see that under BC limitation relative to controls, cation fluxes from minerals through biofilms will increase; biofilm pH will generally decrease; charge and cation selectivity of extra-cellular polymeric substances (EPS) will change; and these changes will drive increases in diffusion of Ca and K to hyphae and roots. Because these mycorrhizal biofilms are characteristically microns thick and tens of microns in areal extent, and because their natural state is hydrated by soil moisture, specialized microscopic facilities are needed for spatially explicit physical and chemical biofilm characterizations.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-06
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
(see Summary)
Shi Z, Z Balogh-Brunstad, MR Grant, JB Harsh, R Gill, L Thomashow, A Dohnalkova, D Stacks, M Letourneau, and CK Keller. 2014. "Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment." Plant and Soil. doi:10.1007/s11104-013-2016-2
Tian L, Z Shi, Y Lu, A Dohnalkova, Z Lin, and Z Dang. 2017. "Kinetics of Cation and Oxyanion Adsorption and Desorption on Ferrihydrite: Roles of Ferrihydrite Binding Sites and a Unified Model." Environmental Science & Technology 51(18):10605-10614. doi:10.1021/acs.est.7b03249