Postdoctoral Research Associate - Plant Ecophysiology & AI

We are seeking a Postdoctoral Research Associate to focus on AI-enabled plant ecophysiology to improve mechanistic understanding and predictions of ecosystem responses to environmental change. This position resides in the Ecosystem Processes Group in the Environmental Sciences Division at Oak Ridge National Laboratory (ORNL). The selected candidate will work with Dr. Jeffrey Warren and Dr. Lianhong Gu and collaborate with researchers in the ORNL Terrestrial Ecosystem Science (TES) Scientific Focus Area (SFA) to integrate experimental measurements and trait databases to assess ecosystem response to environmental forcing.

About the role

The primary research focus is AI-forward and experiment-driven. This position encourages leveraging AI/ML methods to assess plant physiological responses to current or imposed environmental conditions. Research may include:

• Leveraging laboratory, growth chamber, and field experimental data, and/or new measurements to quantify molecular to ecosystem-scale responses to warming, drought, and elevated CO₂ (e.g., gas exchange, fluorescence, hydraulics, respiration, water potential, thermal tolerance).
• Trait synthesis at scale (e.g., using trait databases TRY, FRED, LeafWeb, Sapfluxnet, PSInet) to translate trait variation into model parameter priors and functional constraints, and to explore parameter relationships with environmental conditions.
• Hybrid modeling that combines mechanistic ecophysiology with AI, such as:
  • Physics-informed machine learning and neural networks to investigate plant physiological/abiotic relationships.
  • Bayesian statistics and neural and Gaussian-process emulators for accelerating parameter estimation and uncertainty propagation.
  • Selective cross-scale evaluation using complementary ecosystem observations (e.g., experiments) to test how AI-informed analyses can contribute to ecosystem-scale simulations.

Responsibilities

• Conduct observational and manipulative ecophysiological research to quantify plant and ecosystem responses to abiotic stressors (e.g., heat and drought) and identify mechanistic resilience thresholds across the soil–plant–atmosphere continuum.
• Lead soil-plant-atmosphere hydraulics measurements at the Missouri flux tower site (MOFLUX), including plant hydraulics, rooting depth, canopy temperature, and other parameters for tree species that vary in sensitivity to drought. Scale water flux measurements to the site level for comparison with carbon/water exchange based on eddy flux measurements.
• Use AI/ML data integration, modeling, and trait databases to scale up ecophysiological mechanisms of ecosystem water and carbon flux from MOFLUX to broader region/ecotone/biome response to changes in seasonality of precipitation, temperature, and atmospheric constituents.
• Contribute to other AI/ML synthesis activities (e.g., neutron imaging, SPRUCE hydraulic/thermal thresholds and scaling).
• Produce and publish AI-ready datasets to the ESS-DIVE data archive and BER data lakehouse.
• Develop AI pipelines for experimental ecophysiology, including automated QC and uncertainty-aware learning from sparse/noisy measurements.
• Build hybrid mechanistic–AI models linking traits to photosynthesis, stomata, hydraulics, and respiration across experimental gradients.
• Benchmark and stress-test model improvements against experimental datasets (e.g., SPRUCE, MOFLUX, and related lab/field measurements), and publish open reproducible code and results.
• Deliver ORNL’s mission by aligning behaviors, priorities, and interactions with core values of Impact, Integrity, Teamwork, Safety, and Service. Promote equal opportunity by fostering a respectful workplace.

Requirements

• PhD (completed by start date) in plant ecophysiology, plant biology, ecology, Earth system science, or related field.
• Strong understanding of plant physiological processes (photosynthesis, stomata, hydraulics, respiration, plant–water relations).
• Demonstrated strength in quantitative methods and programming (e.g., Python or R; reproducible workflows; version control).
• Experience or interest in AI/ML application to ecophysiological research.

Qualifications

• Hands-on experience with lab/growth chamber and/or field experimental ecophysiology measurements.
• Experience applying ML/AI to biological or environmental data (e.g., transformer, state space models, multi-layer perceptrons, convolutional neural networks).
• Familiarity with trait databases (e.g., TRY, LeafWeb) and trait-based scaling.
• Excellent written and oral communication skills.
• Motivated self-starter with the ability to work independently and to participate creatively in collaborative teams across the laboratory.
• Ability to function well in a fast-paced research environment, set priorities to accomplish multiple tasks within deadlines, and adapt to ever-changing needs.

Special Requirements

Applicants cannot have received their Ph.D. more than five years prior to the date of application and must complete all degree requirements before starting their appointment. The appointment length will be up to 24 months with the potential for extension. Initial appointments and extensions are subject to performance and availability of funding. Names and contact information for three professional references are required.

For employment at ORNL, a Real ID-compliant form of identification will be required. All employees must also be able to obtain and maintain a federal Personal Identity Verification (PIV) card, which requires a favorable post-employment background investigation, including a declaration of illegal drug activities within the last year.

Foreign national candidates who have not resided in the U.S. for three consecutive years are not eligible for the PIV credential and instead will need to obtain a favorable Local Site Specific Only (LSSO) risk determination to maintain employment. Once the three-year residency requirement is met, a PIV credential will be required.

Benefits

• Prescription Drug Plan
• Dental Plan
• Vision Plan
• 401(k) Retirement Plan
• Contributory Pension Plan
• Life Insurance
• Disability Benefits
• Generous Vacation and Holidays
• Parental Leave
• Legal Insurance with Identity Theft Protection
• Employee Assistance Plan
• Flexible Spending Accounts
• Health Savings Accounts
• Wellness Programs
• Educational Assistance
• Relocation Assistance
• Employee Discounts
• On-site fitness, banking, and cafeteria facilities