Riley Leff

PhD Candidate, Biological Sciences

Washington, DC · [email protected] · Google Scholar

Education & Research Roles

PhD, Biological Sciences 2021 – Present
George Washington University, Washington, DC
  • Research Interests: Plant Ecophysiology, Climate Change, Hydraulics, Compression, Intelligence, Open Source
  • Research Advisor: Dr. Keryn Gedan
Research Associate 2019 - 2021
Pacific Northwest National Laboratory, Richland, WA
  • Studied Tree Mortality In Response To Drought And Sea Level Rise
  • Research Advisor: Dr. Nate McDowell
BSc, Biological Sciences 2015 – 2019
University of Chicago, Chicago, IL
  • Honors B.S. Thesis: Microbial Diversity and Function in the Phyllosphere
  • Research Advisor: Dr. Joy Bergelson

Software

Rust
Static typing, memory safety, performance-critical applications.
  • myco: a declarative, acausal programming language for scientific models. Link
  • ozzydb: a purely functional approach to version control for scientific data. Link
  • sdi12: no_std implementation of the SDI-12 protocol for embedded environmental sensors. The core runs anywhere with a GPIO, with adapters for RP2040, STM32, and ESP32. Link
  • riley web services: self-hosted suite powering rileyleff.com, including riley_auth (accounts and sign-in), riley_cms (Git-as-database content management), riley_leaderboards (versioned rankings with live updates), and riley_comments. Link
  • Floco: a library to enforce user-defined constraints on arbitrarily-sized floats directly within Rust's type system; an early inspiration for myco. Link
  • Dirgrab: CLI utility for injecting entire local projects into LLM context windows. Link
  • licor: Type-safe parser for LI-COR 6800 data with Python and R bindings. Link
Python
Prototyping, data analysis, AI/ML.
  • quadrat: causal ecosystem simulator for benchmarking ecological reasoning in LLM agents, with Docker-sandboxed agent evaluation. Code available on request.
  • rileyviewer: Browser-based plot viewer for matplotlib/seaborn, inspired by R's httpgd. Link
R
  • ezSperry: Wrapper package to call a stomatal optimization model from R. Link
JavaScript / TypeScript
  • Forest Royale: an educational 3D multiplayer game to communicate plant physiology concepts to students. Link
  • annopurr: WebGPU image annotation tool for scientific measurements with TIFF support. Link
  • rileaf2: PWA for measuring leaf area from images, designed for field use with the LI-COR 6800. Link
  • RiLeaf.ijm: ImageJ macro automating leaf area quantification. Link

Hardware

  • Sap flux logic board: open hardware for experimental heat-pulse sap flux sensors, built for a new method that solves for thermal parameters and probe positions conventional workflows assume; prototypes fabricated 2026. Link
  • SDI-12 converter board: interface hardware (designed in atopile) connecting SDI-12 environmental sensors to any microcontroller with a GPIO. Link
  • LI-6800 leaf clip: calibrated, 3D-printed leaf clip with a fiducial locator constellation and a companion offline phone app for in-chamber leaf area measurement.

Awards

Claude Campus Ambassador, Anthropic 2026
Hidden Science Competition Winner, Astera Institute 2026
Dean's Dissertation Completion Fellowship, GWU 2026
Organismal Systems Research Exchange Grant, University of Oxford 2025
NSF Graduate Research Fellowship, National Science Foundation April 2023
Harlan Graduate Research Fellowship, GWU Biology April 2021, 2022, 2024, 2026
Irish Endowment Fund, GWU Biology April 2023, 2024
Laboratory Mission Award Finalist, Pacific Northwest National Laboratory September 2020
Research Honors, UChicago Biological Sciences June 2019
Academic Honors, The University of Chicago June 2019
Excellence in Teaching Award, UChicago Biological Sciences June 2018
Ecology & Evolution Research Fellowship, UChicago Biological Sciences May 2018
Dean’s List, The University of Chicago 2016, 2017, 2018
The University Scholarship, The University of Chicago March 2015

Publications & Datasets

Citations: 361 · h-index: 9 · Google Scholar

Papers

  1. Biogeochemistry of upland to wetland soils, sediments, and surface waters across Mid-Atlantic and Great Lakes coastal interfaces Allison N. Myers-Pigg, Stephanie C. Pennington, Khadijah K. Homolka, Allison M. Lewis, Opal Otenburg, Kaizad F. Patel, Peter Regier, Madison Bowe, Maxim I. Boyanov, Nathan A. Conroy, Donnie J. Day, Cooper G. Norris, Edward J. O’Loughlin, Jesse Alan Roebuck, Lucie Stetten, Vanessa L. Bailey, Kenneth M. Kemner, Nicholas D. Ward, EXCHANGE Consortium, Silver Alford, Michael P. Back, Andy Baldwin, Jade Bolinger, Jacob A. Cianci-Gaskill, Matthew J. Cooper, Alex Demeo, Kyle Derby, Derek Detweiler, Suzanne Devres-Zimmerman, Erin Eberhard, Keryn Gedan, LeeAnn Haaf, Erin Johnson, Aliya Khan, Matthew L. Kirwan, Payton Kittaka, Erika Koontz, Adam Langley, Riley Leff, Scott Lerberg, Sairah Y. Malkin, Amy M. Marcarelli, Steven E. McMurray, Tyler Messerschmidt, Taylor C. Michael, Holly A. Michael, Elizabeth C. Minor, Brian Moye, Thomas J. Mozdzer, Scott Neubauer, Andrea Pain, Michael Philben, Evan Phillips, Dannielle Pratt, Lauren Sage, Daniel Sandborn, Stacy Smith, Alexander Smith, Samina Soin-Voshell, Bongkeun Song, Amanda Sprague-Getsy, Kari St. Laurent, Lorie Staver, Alice Stearns, Rebecca Swerida, Ethan J. Theuerkauf, Katherine Tully, Rodrigo Vargas, Elizabeth Watson, and Coreen Weilminster Scientific Data, 2023. doi:10.1038/s41597-023-02548-7
  2. Coastal inundation regime moderates the short-term effects of sediment and soil additions on seawater oxygen and greenhouse gas dynamics: a microcosm experiment Peter Regier, Nicholas D. Ward, Alex Izquierdo, Andrew H. Baldwin, Donnie Day, Julia McElhinny, Kaizad Patel, Rodrigo Vargas, Jianqiu Zheng, Exchange Consortium, and Allison Myers-Pigg Frontiers in Marine Science, 2023. doi:10.3389/fmars.2023.1308590
  3. Draft Genome Sequences of Three Bacterial Species from Aquatic Habitats near Washington, DC Riley T. Leff, Jonathan MacDougall, Christina Pavloudi, Lausanne Oliver, Kaitlynn Slattery, Guinevere Lissner, and Jimmy H. Saw Microbiology Resource Announcements, 2023. doi:10.1128/mra.01319-22
  4. Severe declines in hydraulic capacity and associated carbon starvation drive mortality in seawater exposed Sitka-spruce (Picea sitchensis) trees Wenzhi Wang, Peipei Zhang, Hongxia Zhang, Charlotte Grossiord, Stephanie C Pennington, Matthew J Norwood, Weibin Li, Alexandria L Pivovaroff, Laura Fernández-de-Uña, Riley Leff, Steven B Yabusaki, Scott Waichler, Vanessa L Bailey, Nicholas D Ward, and Nate G McDowell Environmental Research Communications, 2022. doi:10.1088/2515-7620/ac5f7d
  5. Plant genetic effects on microbial hubs impact host fitness in repeated field trials Benjamin Brachi, Daniele Filiault, Hannah Whitehurst, Paul Darme, Pierre Le Gars, Marine Le Mentec, Timothy C. Morton, Envel Kerdaffrec, Fernando Rabanal, Alison Anastasio, Mathew S. Box, Susan Duncan, Feng Huang, Riley Leff, Polina Novikova, Matthew Perisin, Takashi Tsuchimatsu, Roderick Woolley, Caroline Dean, Magnus Nordborg, Svante Holm, and Joy Bergelson Proceedings of the National Academy of Sciences, 2022. doi:10.1073/pnas.2201285119
  6. The influence of increasing atmospheric CO2, temperature, and vapor pressure deficit on seawater‐induced tree mortality Weibin Li, Nate G. McDowell, Hongxia Zhang, Wenzhi Wang, D. Scott Mackay, Riley Leff, Peipei Zhang, Nicholas D. Ward, Matt Norwood, Steve Yabusaki, Allison N. Myers‐Pigg, Stephanie C. Pennington, Alexandria L. Pivovaroff, Scott Waichler, Chonggang Xu, Ben Bond‐Lamberty, and Vanessa L. Bailey New Phytologist, 2022. doi:10.1111/nph.18275
  7. Declining carbohydrate content of Sitka-spruce treesdying from seawater exposure Peipei Zhang, Nate G McDowell, Xuhui Zhou, Wenzhi Wang, Riley T Leff, Alexandria L Pivovaroff, Hongxia Zhang, Pak S Chow, Nicholas D Ward, Julia Indivero, Steven B Yabusaki, Scott Waichler, and Vanessa L Bailey Plant Physiology, 2021. doi:10.1093/plphys/kiab002
  8. Hydraulic architecture explains species moisture dependency but not mortality rates across a tropical rainfall gradient Alexandria L. Pivovaroff, Brett T. Wolfe, Nate McDowell, Bradley Christoffersen, Stuart Davies, L. Turin Dickman, Charlotte Grossiord, Riley T. Leff, Alistair Rogers, Shawn P. Serbin, S. Joseph Wright, Jin Wu, Chonggang Xu, and Jeffrey Q. Chambers Biotropica, 2021. doi:10.1111/btp.12964
  9. Seawater exposure causes hydraulic damage in dying Sitka-spruce trees Hongxia Zhang, Xinrong Li, Wenzhi Wang, Alexandria L. Pivovaroff, Weibin Li, Peipei Zhang, Nicholas D. Ward, Allison Myers-Pigg, Henry D. Adams, Riley Leff, Anzhi Wang, Fenghui Yuan, Jiabing Wu, Steve Yabusaki, Scott Waichler, Vanessa L. Bailey, Dexin Guan, and Nate G. McDowell Plant Physiology, 2021. doi:10.1093/plphys/kiab295
  10. Changes in carbon and nitrogen metabolism during seawater-induced mortality of Picea sitchensis trees Weibin Li, Hongxia Zhang, Wenzhi Wang, Peipei Zhang, Nicholas D Ward, Matt Norwood, Allison Myers-Pigg, Chuanyan Zhao, Riley Leff, Steve Yabusaki, Scott Waichler, Vanessa L Bailey, and Nate G McDowell Tree Physiology, 2021. doi:10.1093/treephys/tpab073
  11. Stability of tropical forest tree carbon‐water relations in a rainfall exclusion treatment through shifts in effective water uptake depth Alexandria L. Pivovaroff, Nate G. McDowell, Tayana Barrozo Rodrigues, Tim Brodribb, Lucas A. Cernusak, Brendan Choat, Charlotte Grossiord, Yoko Ishida, Kolby J. Jardine, Susan Laurance, Riley Leff, Weibin Li, Michael Liddell, D. Scott Mackay, Heather Pacheco, Jennifer Peters, Israel J. Sampaio Filho, Daisy C. Souza, Wenzhi Wang, Peipei Zhang, and Jeff Chambers Global Change Biology, 2021. doi:10.1111/gcb.15869
  12. Tree growth, transpiration, and water-use efficiency between shoreline and upland red maple (Acer rubrum) trees in a coastal forest Wenzhi Wang, Nate G. McDowell, Stephanie Pennington, Charlotte Grossiord, Riley T Leff, Aditi Sengupta, Nicholas D. Ward, Uğur Uzay Sezen, Roy Rich, J. Patrick Megonigal, James C. Stegen, Ben Bond-Lamberty, and Vanessa Bailey Agricultural and Forest Meteorology, 2020. doi:10.1016/j.agrformet.2020.108163

Datasets

  1. EXCHANGE Campaign 1: A Community-Driven Baseline Characterization of Soils, Sediments, and Water Across Coastal Gradients Stephanie C. Pennington, Silver Alford, Michael P. Back, Vanessa Bailey, Andy Baldwin, Jade Bolinger, Madison Bowe, Maxim I. Boyanov, Jacob A. Cianci-Gaskill, Nathan A. Conroy, Matthew J. Cooper, Donnie Day, Alex Demeo, Kyle Derby, Derek Detweiler, Suzanne Devres-Zimmerman, Erin Eberhard, Keryn Gedan, LeeAnn Haaf, Khadijah K. Homolka, Erin Johnson, Kenneth M. Kemner, Aliya Khan, Matthew Kirwan, Payton Kittaka, Erika Koontz, Adam Langley, Riley Leff, Scott Lerberg, Allison M. Lewis, Sairah Malkin, Amy M. Marcarelli, Steven E. McMurray, Tyler Messerschmidt, Taylor C. Michael, Holly A. Michael, Elizabeth C. Minor, Brian Moye, Thomas J. Mozdzer, Scott Neubauer, Cooper G. Norris, Edward J. O'Loughlin, Opal Otenburg, Andrea Pain, Kaizad F. Patel, Michael Philben, Evan Phillips, Dannielle Pratt, Peter Regier, Jesse Alan Roebuck Jr., Lauren Sage, Daniel Sandborn, Stacy Smith, Alex Smith, Samina Soin-Voshell, Bongkeun Song, Amanda Sprague-Getsy, Kari St. Laurent, Lorie Staver, Alice Stearns, Lucie Stetten, Rebecca Swerida, Ethan J. Theuerkauf, Katherine Tully, Rodrigo Vargas, Nicholas D. Ward, Elizabeth Watson, Coreen Weilminster, and Allison N. Myers-Pigg Environmental System Science Data Infrastructure for a Virtual Ecosystem, 2023. doi:10.15485/1960313
  2. Leaf gas exchange (BNL-PNNL collaboration), San Lorenzo, Panama, 2020 Julien Lamour, Kenneth Davidson, Kim Ely, Alexandria Pivovaroff, Nate McDowell, Riley Leff, Alistair Rogers, and Shawn Serbin Next-Generation Ecosystem Experiments Tropics; Brookhaven National Laboratory; Pacific Northwest National Laboratory, 2022. doi:10.15486/NGT/1897199
  3. Functional trait data for 11 canopy tree species in the control and drought treatments at AU-DRO (2018-2019) Alexandria Pivovaroff, Nate McDowell, Tayana Barrozo, Timothy Brodribb, Lucas Cernusak, Charlotte Grossiord, Yoko Ishida, Kolby Jardine, Susan Laurance, Riley Leff, Weibin Li, Heather Pacheco, Israel Sampaio, Daisy Souza, Wenzhi Wang, and Peipei Zhang Next-Generation Ecosystem Experiments Tropics; Pacific Northwest National Laboratory, 2021. doi:10.15486/NGT/1810164

Presentations

Talks

We Fixed Sap Flux 2026
UVA Coastal Research Center Seminar
What Do The Trees Know? 2026
George Mason University Computational Social Sciences Seminar
What Scientists Need To Know About AI 2025
GWU Biology Department Seminar
Foliar Water Uptake Keeps Dying Trees Alive 2025
Ecological Society of America Annual Meeting
Tree Mortality In Response To Seawater Inundation 2023
George Washington University Seminar Series
Predicting Tree Function and Mortality in a Changing Tropical Environment 2020
American Geophysical Union Fall Meeting
Microbial Diversity and Function in the Phyllosphere 2019
University of Chicago Honors Research Symposium

Posters

Foliar Water Uptake Keeps Dying Trees Alive In A Coastal Forest 2024
VCR LTER All-Hands Meeting
Reverse sap flow in coastal forest in response to saltwater flooding 2024
New Phytologist Next-Gen Scientists
Hydraulic Stress Limits Pinus taeda Range In A Mid-Atlantic Coastal Forest 2024
SALT Conference
Sap Flux: Updates After 3 Years Of Monitoring Across The Delmarva 2024
Critical Zone Network All-Hands Meeting
Seawater Inundation Impacts On Pine Hydraulic Regime 2024
Delaware Wetlands Conference
A Novel Quantitative Method To Improve Sap Flux Measurements 2023
George Washington University Harlan Symposium
Wireless Sensor Networks For Automated Field Data Collection 2023
VCR LTER All-Hands Meeting & Critical Zone Network Meeting
Seawater Intrusion Disrupts Sap Flux Dynamics In A Coastal Forest 2022
George Washington University Harlan Symposium
Seawater Inundation Induces Reverse Sap Flux In Coastal Forest 2022
Virginia Coastal Reserve LTER NSF Mid-Term Review
Predicting Tree Function and Mortality in a Changing Tropical Environment 2020
American Geophysical Union Fall Meeting
Microbial Diversity and Function in the Phyllosphere 2019
University of Chicago Honors Research Symposium

Teaching

Instructor, Setting Up Your Dev Machine For The Agent Era (Seminar) 2026
UVA Coastal Research Center
Teaching Assistant, Conservation Biology 2026
George Washington University
Instructor, Intro To Python (Summer Seminar Series) 2023
George Washington University
Instructor, Intro To R (Summer Seminar Series) 2023
George Washington University
Instructor, Intro To Ecology (Summer Seminar Series) 2022
George Washington University
Teaching Assistant, Conservation Biology 2022
George Washington University
Lab Instructor, Introductory Microbiology 2021
George Washington University
Interim Instructor (7th Grade) 2020
Twin Rivers Charter Academy, Yuba City, CA
Lab Instructor, Core Biology 2017 - 2019
University of Chicago
Instructor / Mentor, Neighborhood Schools Program (5th Grade) 2016 - 2017
University of Chicago Outreach, Chicago, IL
Corps Member / Tutor, Jumpstart (Pre-K Literacy) 2015 - 2016
University of Chicago Community Service Center, Chicago, IL

Outreach & Engagement

Reverse sap flow in coastal forest in response to saltwater flooding 2024
Presentation at GWU Earth Day Symposium
What Do The Trees Know? 2024
Activity at Virginia Coastal Reserve LTER 'Day In The Lab'
Trees As Strategists 2025
Presentation at GWU Earth Day Symposium
Trees As Strategists 2025
Activity at GWU Biology Graduate Student Council Science Fair
Forest Royale 2025
Online Educational Game
A 3D multiplayer plant physiology strategy game designed to teach students about complex tradeoffs in plant-environment interactions.

Mentorship

Acadia Conboy (Undergraduate, James Madison University) 2026
Detailed photosynthetic characterization of Phragmites australis across a salinity gradient.
Presented her work at two research symposia.
Shay Cihlar (Undergraduate, UC Davis) 2025– 2025
Measurement and analysis of pressure-volume curves across salinity gradients
Presented his work at two research symposia.
Sehrin Hossain (Undergraduate, George Washington University) 2025– Present
Automated image segmentation pipeline to analyze wood traits
Won Luther Rice Fellowship, presented her work as a poster at a research symposium.
Ellyn Kinkel (Undergraduate, George Washington University) 2024– Present
Analyzing non-structural carbohydrate storage in salt-stressed coastal forests.
Won Harlan Undergraduate Fellowship, presented her work as a poster at a research symposium.
Kaeden Rippon (Undergraduate, University of Virginia) 2024
Detected foliar water uptake in pine saplings.
Presented his work as a talk at a research symposium.
Noa Shapiro-Tamir (REU Student, Oberlin College) 2023
Measured leaf decomposition rates across a salinity gradient.
Presented her work as a talk at a research symposium.
Maggie Connolly (Undergraduate, George Washington University) 2022
Studying plant hydraulic responses to elevated salinity.
Presented her work as a talk and poster at a research symposium.
Aaron Mendez (High School Student, GWU School Without Walls) 2022
Analyzing non-structural carbohydrate levels in Phragmites australis for AP Research project.
Presented his work, now a student at SUNY.
Aidan Brown (Master's Student (former undergraduate mentee), George Washington University) 2022– 2025
Training deep learning model to detect and analyze tree canopy structures from drone images.
Won GWU Harlan Fellowship, Critical Zone Network Fellowship (2x), Accepted to GWU 5-Year BS/MS Program In Biology.
James Abend (High School Student, Tri Cities, WA) 2019
Processed samples for non-structural carbohydrate analysis.
Dakota DeRoos (High School Student, Tri Cities, WA) 2019
Processed samples for non-structural carbohydrate analysis.