Coupling Solid-Aqueous-Gas Phases Of Carbon And Nitrogen Across Topographic Gradients And

Extreme Weather Events

Rodrigo VargasDepartment of Plant and Soil Sciences

University of Delaware

CoPI: Shreeram Inamdar Collaborators: Angelia Seyffeth, Jinjun Kan, Josep Barba

Students: Sandra Petrakis, Daniel Warner

Contact: rvargas@udel.edu

AFRI and NIWQP PD meetingOctober 12-13, 2016Washington, D.C.

Overall goal:

To understand how weather variability (especially extreme weather events) influences the key ecosystem processes of nutrient and soil GHG fluxes in ex-urban forests.

Approach:- In situ field measurements across topographic gradients- Experiment of extreme water pulses on soils- Automated measurements of multiple soil GHG

Motivation

Hurricane Matthew (2016)

Hurricane Sandy (2012)

(Dhillon and Inamdar 2013)

(Vargas 2012)

Conceptual diagram of how topographic position will influence GHG fluxes, soilwater content, C and N pools, and variance. The size of the symbol represents the relative magnitude of the variable

- In situ field measurements across topographic gradients

Fairhill State Park, MD

- In situ field measurements

CO2 (Emissions):• Soils => 64%• CWD => 8%• Stems => 28%

CH4 (Consumption):• Soils => 99%• CWD => 1%• Stems => -4%

(Werner et al. in review)

- In situ field measurements

(Werner et al. in review)

- In situ field measurements

2015 2015

Werner et al (in preparation)

- In situ field measurements

Werner et al (in preparation)

- Experiment of extreme water pulses on soils

Petrakis et al (in review)

Location Name Soil texture

Upslope Upland Forest Site 1 Sandy loam

Mid-slope Upland Forest Site 2 Loam

Wetland Wetland Loamy sand

Creek Creek Sand

244% for CO2 (Creek)>5x104 % for CH4 (Wetland) >5x104 % for N2O (Forest)

- Experiment of extreme water pulses on soils

Petrakis et al (in review)

Creek soil contributed the most to a 20-year global warming potential

Forest Site contributed the most to the 100-year GWP (53.7%) as a result of large N2O emissions.

Petrakis et al (in preparation)

- Automated measurements of multiple soil GHG

- Automated measurements of multiple soil GHG

Petrakis et al (in preparation)

- Concluding remarks