Promoting Advanced Analytical Tools in Science for Food Security By USDA NC1187 Multi-state group1 Synopsis Many ecosystems are becoming increasingly stressed, and resources needed for agriculture, such as fertilizers and water, are becoming more costly to access and process. To produce enough food for the increasing population, we must get more food from already strained soil and water resources. One of the most promising ways to make significant technological breakthroughs in is fundamental research on biological, physical, and chemical processes occurring in natural and managed ecosystems (Sposito, Reginato et al. 1992, Huang, Sparks et al. 1998, Augustine and Lane 2014)2,3. Historically, basic research has played critical roles in propelling agricultural revolutions, including the Haber-Bosch process responsible for producing nitrogen fertilizer needed to grow crops, and plant genetics and breeding that led to increased crop yields and disease resistance (Green Revolution). Breakthroughs are fueled by basic research. Thus, to meet future demands for food, energy and water, and maintain ecosystem services, it is imperative that we train more applied scientists to utilize cutting- edge molecular and microscopic tools in agricultural related research. Goal Most agricultural research is focused on applied trials to provide short-term solutions. However, long- term solutions requires basic research focusing on understanding fundamentals of processes governing innovations in food, energy and water science. To address the modern challenges of food production, and decrease use of water and energy resources, we propose that the NSF innovations in food, energy and water sciences (INFEWS) program create funding opportunities that promote the following objectives: Objective 1: Train soil and water scientist to use advanced molecular and microscopic tools. Objective 2: Adapt sample preparation methods used in pure systems for advanced molecular and microscopic analysis of soil-plant-water systems so that fundamental information on these complex systems can be discovered. Objective 3: Create more funding opportunities for scientists to study fundamental processes controlling managed and natural ecosystem processes. Justification Fate and availability of plant nutrients and environmental toxins depends on reactions with particles with diameters of tens of micrometers or less (, clays, microbes, nanoparticles) contained in a very complex mixtures within . Because of this complexity, it is often difficult to gain a mechanistic understanding of processes governing the retention and mobility of chemicals. Mechanistic understanding of chemical reactions in soils that control nutrient and contaminant mobility and bioaccessibility requires using advanced spectroscopic and microscopic instruments. The situation may be likened to the current ability to characterize microbial communities in natural systems by the analysis of genetic material. Without the application of molecular tools, we will not have the required knowledge to advance agricultural systems to minimize inputs while optimizing production and economy. A common thread that runs through much environmental research is the importance of understanding processes that operate on different spatial and temporal scales. The technical feasibility of applying advanced analytical methods to a wide range of sample sizes and chemical compositions is amply

1 USDA NC1187 Multi-state group: The Chemical and Physical Nature of Particulate Matter Affecting Air, Water and Promoting Advanced Analytical Tools in for Food Security

supported by the current scientific literature. The utilization of a combination of techniques to accomplish full characterization of natural systems and to relate these properties to behavior in complex systems has become increasingly important and successful. Significant advances in technologies related to spatially resolved microscopic and spectroscopic molecular characterization methods have resulted from advances in optics, focusing devices, and detectors; and because of greater availability of high brilliance synchrotron facilities world-wide (Fenter, Rivers et al. 2002, Kelley, Hesterberg et al. 2008, Lombi and Susini 2009, Singh and Grafe 2010), such as the Advanced Photon Source (APS), the Advanced Light Source (ALS), Stanford Synchrotron Radiation Lightsource (SSRL), the National Synchrotron Light Source II (NSLS-II) and others around the world. At these facilities, spatially resolved synchrotron-based X-ray fluorescence (XRF), X-ray absorption fine structure (XAFS) spectroscopy are providing microscopic and molecular level information on soil systems not previously available using other techniques. While there exists a variety of micro-analytical techniques that have long been used in these disciplines, synchrotron-based spatially resolved XRF, XANES, scanning tunneling X-ray microscopy (STXM), EXAFS spectroscopy, and X-ray diffraction (XRD) are emerging as important methods that complement characterization by traditional techniques. Advanced analytical techniques are also at available at national labs, such as the Environmental Molecular Science laboratory (EMSL) is a national scientific user facility at the Pacific Northwest National Laboratory that has a number of instruments useful for the studying soils and sediments. Specialized instrument facilities, funded by the National Science Foundation and located at universities around the country, also have instruments that can assist in meeting the basic research needs of the INFEWS. Opportunities for Advanced Methods to be used in Food, Energy and Water Research Chemical speciation in soils Chemical speciation determines the bioavailability of nutrients and contaminants in soils, and can be measured using spectroscopic methods such as X-ray spectroscopy, Fourier transform infrared spectroscopy (FTIR), XRD, and nuclear magnetic spectroscopy (NMR). These methods are considered to be macro-spectroscopic, and are generally applied to bulk soil samples. The results, therefore, represent a combination of all the chemical species in the sample, and do not allow insight into the spatial association of chemical species at a scale smaller than the sample volume. This limitation is a concern for analysis of chemical speciation in soils, which have spatially discreet features that vary on the scale of sub-micron soil colloids, to micron and millimeter-sized aggregates. Microscopic analysis methods such as scanning electron microscopy (SEM) or X-ray computed tomography (X-ray CT) are useful for analyzing the distribution of physical features and elements in soils. Needed for determining and scaling-up soil to water flow, and other hydrological processes in soils, as well as landscape-level processes. Peth, Chenu et al. (2014) recently combined synchrotron-based X-ray CT and a chemical tracer to create three dimensional maps of SOM distribution in soil aggregates and determine fine-scale spatial associations of SOM with and soil pores. With careful validation of tracers, X-ray CT has the potential for being a very powerful method for imaging soil components in heterogeneous systems. To gain the most insight into specific reaction processes and species in soils, advanced micro- spectroscopic tools that can probe soil chemicals in spatially discreet zones are required. Techniques such as nano-secondary ion mass spectroscopy (NanoSIMS) (Behrens, Kappler et al. 2012) and microscopically focused XAFS (µ-XAFS) (Manceau, Marcus et al. 2002) have been used to investigate soil chemical speciation. Microscopically focused spectroscopy can map and measure speciation in soil samples at resolutions of 0.05-5 µm; a good size for analyzing soil microaggregates and particles.

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X-ray micro-spectroscopic studies have been done on soil to investigate speciation and behavior of metals and metalloids in the environment (Tokunaga, Sutton et al. 1998, Strawn, Doner et al. 2002, Manceau, Marcus et al. 2004, McNear, Chaney et al. 2007). New advances in low energy X-ray microprobe methods, such as STXM (scanning tunneling X-ray microscopy), allow for measurement of the distribution of SOM species in microaggregates (Wan, Tyliszczak et al. 2007, Lehmann, Solomon et al. 2008, Kleber, Nico et al. 2011, Behrens, Kappler et al. 2012, Solomon, Lehmann et al. 2012, Chen and Sparks 2015), speciation of dissolved carbon in soil pores (Keiluweit, Bougoure et al. 2015), and association of organic matter with clays (Chen, Dynes et al. 2014, Dynes, Regier et al. 2015). NanoSIMS is a relatively new method used to probe molecular speciation in heterogeneous samples such as soils (Behrens, Kappler et al. 2012, Remusat, Hatton et al. 2012, Vogel, Mueller et al. 2014). NanoSIMS collects ion and isotopic composition from sub-micron spots within a sample. Spatially resolved determination of isotopic composition is useful for understanding biogeochemical reaction of 13C, 15N, and 18O (Keiluweit, Bougoure et al. 2012). Other techniques, such as X-ray microtomography (Peth, Chenu et al. 2014) and micro-infrared and Raman spectroscopy (Parikh, Goyne et al. 2014), also show promise for studying chemical speciation in heterogeneous samples such as soils. Use of a combination of techniques allows for better understanding of key soil physical properties, such as bulk density, pore size distribution and root contact; and links soil physical properties and the spatial distribution of biogeochemical processes such as nutrient mineralization and transformation. Enhancing and sustaining Losses of soil C as a result of unsustainable management reduce , proving to be one of the most serious threats to safety of global food supply. A critical area of research need is understanding biogeochemical processes controlling carbon cycling in the soils (Adewopo, VanZomeren et al. 2014, Baveye 2015). There is a need for utilization of integrated and in situ (non-destructive) approaches for studying organo‐ distributions and their , microbial growth and assimilation of C, and coupled mechanisms of aggregate stabilization processes. Coupling of microbiological, high‐resolution spatially resolved synchrotron-based imaging, and ultra-sensitive spectroscopic techniques will enhance our understanding of biogeochemical mechanisms and processes responsible for soil C stability. One of the fundamental contributors to soil C sequestration is when soil C becomes inaccessible to microorganisms, and thus eludes decomposition (Schmidt, Torn et al. 2011, Dungait, Hopkins et al. 2012). Realization of the importance of physical protection emphasizes the significance of nano- and micro-scale C processes, and therefore their importance for uninterrupted global food production. To understand, quantify, and model soil C processes it is crucial to look at it at the scale at which they occur (<1-1000 µm scale) (Young and Crawford 2004, O'Donnell, Young et al. 2007). Advances in analytical and quantitative tools for micro-scale soil research creates tremendous opportunities for advancing our understanding of the processes involved in C sequestration in soil. One such tools is X-ray CT (or μ-CT), which permits acquisition of 3-dimentional images of soil interiors with micron resolutions (Vogel, Weller et al. 2010, Wang, Kravchenko et al. 2012, Peth, Chenu et al. 2014). μ- CT allows for in situ observations and quantifications of plant roots and their growth (e.g., Mooney et al., 2012), as well as in characterization and quantification of decomposition of plant residues and particulate organic matter (Negassa et al., 2015; Kravchenko et al., 2015). Combined with novel staining techniques μ-CT can be directly used to visualize presence of SOM in 3D soil space (Peth et al., 2014), and enables 3D soil mapping at micro-scale resolutions (Hapca, Baveye et al. 2015). Among other novel techniques with great potential in furthering our knowledge of soil C processes are XAFS (e.g., NEXAFS), and synchrotron-based XRF (Schumacher et al., 2005; Wan et al., 2007; Solomon et al., 2009). Particularly promising for deciphering mechanisms of soil C protection is nano-scale

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secondary ion mass spectrometry (NanoSIMS), which enables direct visualization of C isotopes at nano- scale resolutions (Hermann et al., 2007; Vogel et al., 2014). Soil zymography (Spohn, Carminati et al. 2013) permits in situ 2D mapping of enzyme activities, opening new opportunities in understanding interactions between plants, microorganisms, and their contributions to C accrual and protection in soil. Improving agricultural water resources Many traditionally productive agricultural areas are now facing soil degradation and water scarcity. Globally, about 70% of fresh water is currently used for crop irrigation. In many water stressed regions, the use of non-traditional water sources (e.g., reclaimed water and brackish water) for irrigation is increasing. Use of alternative waters may require treatment with cost-effective technologies to meet water quality criteria. Research is needed to evaluate downstream impacts on ecosystem and human health for trace contaminants that are too costly to be removed with current technologies. For instance, pharmaceuticals are not effectively removed because current wastewater treatment plants are not designed to remove these trace contaminants. Veterinary pharmaceuticals in agricultural wastewater are also of great concern as agricultural waste and waters are minimally treated. Nonetheless, biosolids, wastewater effluents, manure, lagoon effluents, or other impaired agricultural waters are often applied to lands for crop production. Therefore, it is critical to track the transport, uptake, and accumulation of emerging contaminants in soil-water-biota continuum using advanced analytical tools. New advancements in analytical techniques including high-resolution mass spectrometry (HRMS) with liquid chromatograph (LC) and LC/MS/MS have been pushing frontiers in determining dissolved trace contaminants and identifying unknown transformation products (Richardson and Ternes 2014). In contrast to dissolved contaminants, colloidal contaminants (including harmful colloids or colloid- associated contaminants) have unique reaction processes that govern their fate, transport, and bioavailability in the environment (Bradford and Torkzaban 2013, Cornelis, Hund-Rinke et al. 2014, Praetorius, Tufenkji et al. 2014). Colloidal contaminants include engineered nanoparticles, pathogenic microorganisms (virus, bacteria, and protozoa), and colloid-associated phosphorus, radionuclides, heavy metals, or organic toxins. In view of the ubiquity of engineered and natural colloids and nanoparticles in the environment, and the challenges of analyzing them, more advanced and accurate analytical tools need to be developed to analyze engineered nanoparticles in environmental samples. This may include single particle inductively coupled plasma – mass spectrometry (SP-ICP-MS) (Mitrano, Barber et al. 2012), hyperspectral spectroscopy, microbial pathogen sensor, and droplet digital PCR (Hindson, Ness et al. 2011). Research in these area will ensure safe food and water and sustainable agriculture in the US. Summary At the core of scientific advancement is basic research that provides both major breakthroughs and smaller incremental discoveries needed to increase efficiency in process or meet an emerging need. The demand for increased food production, water, and securing the health of the environment have created a research challenge for the current and next generation of scientists. To meet these demands requires investment in training agricultural scientists to use advanced instruments to do molecular and microscopic level analysis, and make these tools available for such analysis. Evolution of modern society has been greatly influenced by revolutions, including the industrial revolution, medical revolution, green revolution, space revolution, and information/computing revolution. The next revolution requires producing more food and utilizing energy and water in an eco- sustainable manner. To achieve this requires investment in basic research to understand soil-related processes at the microscopic and molecular level. The NSF should develop programs to meet these challenges.

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NC1187 Committee Chair: Daniel G. Strawn, University of Idaho Vice Chair: Ganga Hettiarachchi, Kansas State University Members: Stephen Anderson Missouri - University of Missouri (MO.) Daniel Gimenez New Jersey - Rutgers University (NJ.) Allen H Goldstein California -Berkeley : University of California, Berkeley (CALB) James Harsh Washington - Washington State University (WN.P) Ganga Hettiarachchi Kansas - Kansas State University (KAN) Robert Hudson Illinois - University of Illinois (ILLU) A.D. Karathanasis Kentucky - University of Kentucky (KY.) Alexandra Kravchenko Michigan - Michigan State University (MICL) Gediminas Mainelis New Jersey - Rutgers University (NJ.) Martin Pentrak Illinois - University of Illinois (ILLU) Auther P Schwab Texas AgriLife Research (TEX) Donald L. Sparks Delaware - University of Delaware (DEL) Daniel G. Strawn Idaho - University of Idaho (IDA) Joseph W. Stucki Illinois - University of Illinois (ILLU) Peter J Tomlinson Kansas - Kansas State university (KAN) Kang Xia Virginia - Virginia Polytechnic Institute and State University (VA Tech) (VA.) Wei Zhang Michigan - Michigan State University (MICL)

Endnotes 2“Science and technology contribute immeasurably to the lives of all Americans. Our high standard of living is largely the product of the technology that surrounds us in the home or factory… And our environment is protected by the use of science and technology. Indeed, our vision of the future is often largely defined by the bounty that we anticipate science and technology will bring.” –President Jimmy Carter, January 16, 1981, The State of the Union Annual Message to Congress. Cited in Augustine et al. 2014.

3“Although basic research does not begin with a particular practical goal, when you look at the results over the years, it ends up being one of the most practical things government does.” – President Ronald Reagan, April 2, 1988, Radio Address to the Nation on the Federal Role in Scientific Research. Cited in Augustine et al. 2014.

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