STEPS research is organized by Themes, length-scale groupings in which researchers pursue closely related research questions, promote interactions on highly associated research activities, and drive overall forward momentum.

Image illustrating scales


Theme 1 (Materials Scale) generates new fundamental knowledge about phosphorus capture at atomic and molecular scales using discovery-driven approaches (i.e., biological inspiration, chemical analytics). Integrated with Materials Informatics (MI), Theme 1 accelerates the development of novel capabilities to promote the facile transformation of organic and inorganic phosphorus and enable the efficient capture and recovery of phosphate.

Theme 2 (Human-Technology Scale) implements materials and technologies from Theme 1 in both aqueous suspensions (e.g., surface water and wastewater) and the plant-soil-microbial system by using laboratory, greenhouse, and field-scale techniques. Theme 2 applies state-of-the-art scientific approaches including nanoscale spectroscopic characterization of phosphate speciation in soils, novel sensor development to improve tracking of phosphorus in soils, genome-wide approaches for selecting and engineering crop systems with enhanced phosphorus utilization, and development of next-generation, plant-responsive fertilizers.

Theme 3 (Regional and Global Scale) identifies intervention portfolios (e.g., innovative technologies, best management practices) that enable the realization of the 25-in-25 vision and are resilient to socio-economic, policy, and environmental change, using integrated modeling at global, regional, and local scales and social network analysis. Theme 2 data about the flow and management of phosphorus as a function of space and time (e.g., through urban, aquatic, and agricultural systems) guide research prioritization in Themes 1 and 2.

A Convergence Informatics (CI) research initiative provides data-science-driven guidance for the design of novel and effective materials, technologies, and strategies for phosphorus capture, decomposition, and modification to realize the opportunities presented by Theme integration. CI builds upon an MI-based approach in which process-structure-properties-performance relations are designed by analyzing large materials data sets with machine learning algorithms.

The STEPS convergence research strategy, drawing from the fields of Science of Team Science as well as Integration and Implementation Science, utilizes evidence-based approaches to assimilate emerging knowledge and co-refine research questions through strategically designed interactions and processes. Convergence research strategies create efficiencies at integrating research across 17 orders of magnitude in length scale. Convergence boundary objects (data, phosphorus flow diagrams, and language mapping) serve as tangible and conceptual anchors, linking specific research contributions across STEPS disciplines and length scales and allowing the researchers to contextualize individual contributions to a highly complex problem. An example of one of these, a phosphorus flow diagram, is shown below. Specific geographical sites or Triple-Bottom-Line Scenarios that represent urban, agricultural, and aquatic systems provide technological constraints, potential impact scenarios, and connection to unique types of stakeholders in phosphorus sustainability.

Flow diagram inspired by an earlier version published by Cordell and White, Annu. Rev. Environ. Resour. 2014. 39:161–88. Numbers alongside arrows represent million metric tons of phosphorus per year.


Theme 1

1.1 Chemical and Biological Transformations of Non-Reactive Phosphorus

Project PI: Brooke Mayer

Co-PIs: Doug Call, Paul Westerhoff


1.2 Standardizing & Advancing Phosphorus Analytics

Project PI: Paul Westerhoff

Co-PIs: Jacob Jones, Doug Call


1.3 Bio-Inspired Phosphorus Removal and Recovery

Project PI: Brooke Mayer

Co-PIs: Yara Yingling, Eric McLamore


1.4 High-Throughput Screening of Phosphate Adsorption in Polymer Brushes

Project PI: Jan Genzer

Co-PIs: Marty Lail, Sherine Obare, Yara Yingling


1.5 Metal Cations for Phosphorus Recovery

Project PI: Chris Muhich

Co-PIs: Jacob Jones, Detlef Knappe, Paul Westerhoff


1.6 Biomimetic Phosphate Sorbents via Chemical Modification of 2D Materials

Project PI: Wei Gao


Theme 2

2.1 Human Urine as Boundary Object for Advancing Phosphorus Recovery

Project PI: Treavor Boyer

Co-PIs: Doug Call, Anna-Maria Marshall


2.2 Characterizing Phosphorus After Anaerobic Treatment of High-Strength Organic Waste Streams

Project PI: Bruce Rittmann

Co-PIs: Sherine Obare, Doug Call, Joshua Boltz


2.3 Developing Phosphite as a Sustainable, Next Generation Fertilizer

Project PI: Owen Duckworth

Co-PIs: Doug Call, Chris Muhich


2.4 Understanding of the genetic mechanisms involved in the regulation of plant phosphorus use efficiency

Project PI: Rubén Rellán Álvarez

Co-PI: Ross Sozzani


2.5 Controlling and Utilizing Legacy Phosphorus in Soils

Project PI: Luke Gatiboni

Co-PIs: Jango Bhadha, Owen Duckworth


2.6 Exploring stimulus-response nanobrush materials for phosphorus sensing

Project PI: Eric McLamore

Co-PIs: Sherine Obare, Jango Bhadha


Theme 3

3.1 National Phosphorus Budget and Mapping Phase I

Project PI: Dan Obenour

Co-PIs: Natalie Nelson, Owen Duckworth, Paul Westerhoff, Rebecca Muenich


3.2 Establishing Baseline Data and Tools for Simulating Phosphorus Flows at the TBLs

Project PI: Natalie Nelson

Co-PIs: Elise Morrison, Rebecca Muenich, Sandra Guzman


3.3 Evaluating Stakeholder Perceptions, Needs, and Networks in STEPS Research

Project PI: Khara Grieger

Co-PI: Anna-Maria Marshall


3.4 Adoption and Diffusion of Innovation: Case Studies of STEPS Technologies

Project PI: Anna-Maria Marshall

Co-PIs: Khara Grieger


3.5 Systems Modeling, Decision Support, and Roadmapping to Achieve 25-in-25

Project PI: Justin Baker

Co-PIs: Jordan Kern, Rebecca Muenich, Cary Strickland


Convergence Informatics & Other Research

4.1 Convergence Informatics I: Gathering and Fusing Data

Project PI: Yara Yingling

Co-PIs: Rada Chirkova, Cranos Williams


4.2 Convergence Science Education Research

Project PI: Gail Jones


4.3 Developing Technical and Convergence Educational Resources

Project PI: John Classen