- Assistant Professor, Environmental Science
I am an ecosystem scientist with A PhD in analytical Chemistry from the Chemistry and Biochemistry departmnet at Florida State University. My overarching research interests revolve around carbon cycling in terrestrial and aquatic ecosystems, the interactions between microbial communities and organic matter, their geochemical environment and the resulting impact on the whole ecosystem. I use a combination of modern analytical molecular techniques (high resolution mass spectrometry, etc.), geochemical (wet chemistry and gas flux) and isotopic techniques (natural abundance, and isotope enrichment) to answer the how, where and how organic matter degradation and formation takes place in different ecosystems. My recent position at PNNL have provided me the opportunity to further advance my research approaches to include a suite of the state-of-the-art and new "omics" approaches to provide unprecedented resolution on microbial community function and organic matter composition. More specifically I am interested in examining the direct relationship between organic matter composition, the activity of the biological community, the geochemical signature of the activity and how that signature may translate between environments thus enhancing our understanding of the current and past processes that drive our planet.
- Ph.D. Analytical Chemistry
- Florida State University, Tallahassee, Florida, United States
- Molecular Characterization of DissolvedOrganic Matter in Northern Peatlands:Identifying the Chemical Signatures ofClimate Change
- B.S. General Chemistry
- Lebanese University, Beirut, Lebanon
- Pacific Northwest National Laboratory (2016 - 2018)
- Pacific Northwest National Laboratory (2014 - 2016)
- Pacific Northwest National Laboratory (2014 - 2016)
- Florida State University, Tallahassee, Florida (2012 - 2014)
- Florida State University, Tallahassee, Florida (2007 - 2011)
Licensure & Certification
- SEDP class of 2018, Pacific Northwest National Laboratory (2018)
Integration of multidisciplinary science to implement field- and laboratory-based investigations to advance understanding of how soil carbon responds to global change and the underlying microbial mechanisms and interactions that determine its response.Expertise: Analytical chemistry, Aquatic and terrestrial organic geochemist, peatland and permafrost biogeochemistry, multi-omics approaches, global change, mass spectrometry, gas fluxes and isotopes, plant-soil-microbiome interactions.
Soil chemistry; Environmental Chemistry; Carbon cycling; Analytical Chemistry; Ecosystem science
Directed ResearchENVS 492 (Fall 2020)
DissertationENVS 920 (Fall 2020)
Microbes BiogeochemistryECOL 410 (Fall 2020)
Microbes BiogeochemistryECOL 510 (Fall 2020)
Microbes BiogeochemistryENVS 410 (Fall 2020)
Microbes BiogeochemistryENVS 510 (Fall 2020)
Microbes BiogeochemistryGEOS 410 (Fall 2020)
Microbes BiogeochemistryGEOS 510 (Fall 2020)
Microbes BiogeochemistryPLS 510 (Fall 2020)
ThesisENVS 910 (Fall 2020)
Directed ResearchENVS 492 (Summer I 2020)
Directed ResearchENVS 492 (Spring 2020)
DissertationENVS 920 (Spring 2020)
DissertationENVS 920 (Fall 2019)
Microbes BiogeochemistryECOL 510 (Fall 2019)
Microbes BiogeochemistryENVS 410 (Fall 2019)
Microbes BiogeochemistryENVS 510 (Fall 2019)
Microbes BiogeochemistryGEOS 410 (Fall 2019)
Microbes BiogeochemistryGEOS 510 (Fall 2019)
Microbes BiogeochemistryPLS 510 (Fall 2019)
DissertationENVS 920 (Spring 2019)
Independent StudyENVS 399 (Spring 2019)
- Tfaily, M., & Wilson, R. (2019). Revisiting the Role of Bio- and Photodegradation on the Global Distribution and Degradation of Dissolved Organic Matter in Watersheds. In Open Watershed Science by Design: Leveraging Distributed Research Networks to Understand Watershed Systems.
- Rue, G. P., Darling, J. P., Graham, E., Tfaily, M., & McKnight, D. M. (2020). Dynamic changes in dissolved organic matter composition in a Mountain Lake under ice cover and relationships to changes in nutrient cycling and phytoplankton community composition. Aquat Sci, 82: 15. doi:https://doi.org/10.1007/s00027-019-0687-3
- Arredondo, M. G., Lawrence, C. R., Schulz, M. S., Tfaily, M. M., Kukkadapu, R., Jones, M. E., Boye, K., & Keiluweit, M. (2019). Root-driven weathering impacts on mineral-organic associations in deep soils over pedogenic time scales. Geochimica et Cosmochimica Acta, 263, 68 - 84.
- Fudyma, J. D., Lyon, J., AminiTabrizi, R., Gieschen, H., Chu, R. K., Hoyt, D. W., Kyle, J. E., Toyoda, J., Tolic, N., Heyman, H. M., Hess, N. J., Metz, T. O., & Tfaily, M. M. (2019). Untargeted metabolomic profiling of Sphagnum fallax reveals novel antimicrobial metabolites. Plant Direct, 3(11), e00179.
- Hopple, A., Pfeifer-Meister, L., Zalmar, C., Keller, J., Tfaily, M., WIilson, R., Chanton, J., & bridgham, S. (2019). Does dissolved organic matter or solid peat fuel anaerobic respiration in peatlands?. Geoderma.
- Kane, E. S., Veverica, T. J., Tfaily, M. M., Lilleskov, E. A., Meingast, K. M., Kolka, R. K., Daniels, A. L., & Chimner, R. A. (2019). Reduction-Oxidation Potential and Dissolved Organic Matter Composition in Northern Peat Soil: Interactive Controls of Water Table Position and Plant Functional Groups. Journal of Geophysical Research: Biogeosciences, 124(11), 3600-3617.
- LaCroix, R. E., Tfaily, M. M., McCreight, M., Jones, M. E., Spokas, L., & Keiluweit, M. (2019). Shifting mineral and redox controls on carbon cycling in seasonally flooded mineral soils. Biogeosciences, 16(13), 2573--2589.
- NuÃ±ez, J. R., Colby, S. M., Thomas, D. G., Tfaily, M. M., Tolic, N., Ulrich, E. M., Sobus, J. R., Metz, T. O., Teeguarden, J. G., & Renslow, R. S. (2019). Evaluation of In Silico Multifeature Libraries for Providing Evidence for the Presence of Small Molecules in Synthetic Blinded Samples. Journal of Chemical Information and Modeling, 59(9), 4052-4060.
- Nuñez, J., Colby, S., thomas, D., Tfaily, M., Tolic, N., Ulrich, E., Sobus, J., Metz, T., Teeguarden, J., & Renslow, R. (2019). Advancing Standards-Free Methods for the Identification of Small Molecules in Complex Samples. Analytical Chemistry.
- Saup, C. M., Bryant, S. R., Nelson, A. R., Harris, K. D., Sawyer, A. H., Christensen, J. N., Tfaily, M. M., Williams, K. H., & Wilkins, M. J. (2019). Hyporheic Zone Microbiome Assembly Is Linked to Dynamic Water Mixing Patterns in Snowmelt-Dominated Headwater Catchments. Journal of Geophysical Research: Biogeosciences, 124(11), 3269-3280.
- Sengupta, A., Indivero, J., Gunn, C., Tfaily, M. M., Chu, R. K., Toyoda, J., Bailey, V. L., Ward, N. D., & Stegen, J. C. (2019). Spatial gradients in the characteristics of soil-carbon fractions are associated with abiotic features but not microbial communities. Biogeosciences, 16(19), 3911--3928.
- Shen, Y., Zhao, R., ToliÄ, N., Tfaily, M. M., Robinson, E. W., Boiteau, R., PaÅ¡a-ToliÄ, L., & Hess, N. J. (2019). Online supercritical fluid extraction mass spectrometry (SFE-LC-FTMS) for sensitive characterization of soil organic matter. Faraday Discuss., 218, 157-171.
- Tfaily, M., Clair, G., Reehl, S., Stratton, K., Monroa, M., Ansong, C., & Kyle, J. (2019). Lipid Mini-On: Mining and ontology tool for enrichment analysis of lipidomic data. Bioinformatics.
- Tfaily, M., Rivas-Ubach, A., Liu, Y., Steiner, A., Sardans, J., Kulkarni, G., Kim, Y., Bourrianne, E., Paša-Tolić, L., Peñuelas, J., & Guenther, A. (2019). Atmo-ecometabolomics: a novel atmospheric particle chemical characterization methodology for ecological research. Environmental Monitoring and Assessment, 191(78). doi:https://doi.org/10.1007/s10661-019-7205-x
- Tfaily, M., Wilson, R., Brewer, H., Chu, R., Heino, H., Hoyt, D., Kyle, J., & Purvine, S. (2019). Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures. J. Vis. Exp, 143, e59035. doi:10.3791/59035
- Zhou, C., Liu, Y., Liu, C., Liu, Y., & Tfaily, M. M. (2019). Compositional changes of dissolved organic carbon during its dynamic desorption from hyporheic zone sediments. Science of The Total Environment, 658, 16 - 23.
- Bhattacharyya, A., Campbell, A. N., Tfaily, M. M., Lin, Y., Kukkadapu, R. K., Silver, W., Nico, P. S., & Pett-Ridge, J. (2018). Redox fluctuations control the coupled cycling of iron and carbon in tropical forest soils. Environmental science & technology.More infoOscillating redox conditions are a common feature of humid tropical forest soils, driven by an ample supply and dynamics of reductants, high moisture, microbial oxygen consumption, and finely textured clays that limit diffusion. However, the net result of variable soil redox regimes on iron (Fe) mineral dynamics and associated carbon (C) forms and fluxes is poorly understood in tropical soils. Using a 44-day redox incubation experiment with humid tropical forest soils from Puerto Rico, we examined patterns in Fe and C transformations under four redox regimes: static anoxic, 'flux 4-day' (4d oxic, 4d anoxic), 'flux 8-day' (8d oxic, 4d anoxic) and static oxic. Prolonged anoxia promoted reductive dissolution of Fe-oxides, and led to an increase in soluble Fe(II) and amorphous Fe oxide pools. Preferential dissolution of the less-crystalline Fe pool was evident immediately following a shift in bulk redox status (oxic to anoxic), and coincided with increased dissolved organic C, presumably due to acidification or direct release of organic matter (OM) from dissolving Fe(III) mineral phases. The average nominal oxidation state of water-soluble C was lowest under persistent anoxic conditions, suggesting that more reduced organic compounds were metabolically unavailable for microbial consumption under reducing conditions. Anoxic soil compounds had high H/C values (and were similar to lignin-like compounds) whereas oxic soil compounds had higher O/C values, akin to tannin- and cellulose-like components. Cumulative respiration derived from native soil organic C was highest in static oxic soils. These results show how Fe minerals and Fe-OM interactions in tropical soils are highly sensitive to variable redox effects. Shifting soil oxygen availability rapidly impacted exchanges between mineral-sorbed and aqueous C pools, increased the dissolved organic C pool under anoxic conditions implying that the periodicity of low-redox events may control the fate of C in wet tropical soils.
- Bottos, E. M., Kennedy, D. W., Romero, E. B., Fansler, S. J., Brown, J. M., Bramer, L. M., Chu, R. K., Tfaily, M. M., Jansson, J. K., & Stegen, J. C. (2018). Dispersal limitation and thermodynamic constraints govern spatial structure of permafrost microbial communities. FEMS microbiology ecology, 94(8).More infoUnderstanding drivers of permafrost microbial community composition is critical for understanding permafrost microbiology and predicting ecosystem responses to thaw. We hypothesize that permafrost communities are shaped by physical constraints imposed by prolonged freezing, and exhibit spatial distributions that reflect dispersal limitation and selective pressures associated with these physical constraints. To test this, we characterized patterns of environmental variation and microbial community composition in permafrost across an Alaskan boreal forest landscape. We used null modeling to estimate the importance of selective and neutral assembly processes on community composition, and identified environmental factors influencing ecological selection through regression and structural equation modeling (SEM). Proportionally, the strongest process influencing community composition was dispersal limitation (0.36), exceeding the influence of homogenous selection (0.21), variable selection (0.16) and homogenizing dispersal (0.05). Fe(II) content was the most important factor explaining variable selection, and was significantly associated with total selection by univariate regression (R2 = 0.14, P = 0.003). SEM supported a model in which Fe(II) content mediated influences of the Gibbs free energy of the organic matter pool and organic acid concentration on total selection. These findings suggest that the dominant processes shaping microbial communities in permafrost result from the stability of the permafrost environment, which imposes dispersal and thermodynamic constraints.
- Boye, K., Herrmann, A., Schaefer, M., Tfaily, M., & Fendorf, S. (2018). Discerning Microbially Mediated Processes During Redox Transitions in Flooded Soils Using Carbon and Energy Balances. Front. Environ. Sci..
- Davis, J., Heckman, K., Fox, P., Nico, P., & Tfaily, M. (2018). Characterization of Natural Organic Matter in Low-Carbon Sediments.. ESS-DIVE, Watershed Function SFA. doi:doi:10.21952/WTR/1470442
- Graham, E. B., Crump, A. R., Kennedy, D. W., Arntzen, E., Fansler, S., Purvine, S. O., Nicora, C. D., Nelson, W., Tfaily, M. M., & Stegen, J. C. (2018). Multi 'omics comparison reveals metabolome biochemistry, not microbiome composition or gene expression, corresponds to elevated biogeochemical function in the hyporheic zone. The Science of the total environment, 642, 742-753.More infoBiogeochemical hotspots are pervasive at terrestrial-aquatic interfaces, particularly within groundwater-surface water mixing zones (hyporheic zones), and they are critical to understanding spatiotemporal variation in biogeochemical cycling. Here, we use multi 'omic comparisons of hotspots to low-activity sediments to gain mechanistic insight into hyporheic zone organic matter processing. We hypothesized that microbiome structure and function, as described by metagenomics and metaproteomics, would distinguish hotspots from low-activity sediments by shifting metabolism towards carbohydrate-utilizing pathways and elucidate discrete mechanisms governing organic matter processing in each location. We also expected these differences to be reflected in the metabolome, whereby hotspot carbon (C) pools and metabolite transformations therein would be enriched in sugar-associated compounds. In contrast to expectations, we found pronounced phenotypic plasticity in the hyporheic zone microbiome that was denoted by similar microbiome structure, functional potential, and expression across sediments with dissimilar metabolic rates. Instead, diverse nitrogenous metabolites and biochemical transformations characterized hotspots. Metabolomes also corresponded more strongly to aerobic metabolism than bulk C or N content only (explaining 67% vs. 42% and 37% of variation respectively), and bulk C and N did not improve statistical models based on metabolome composition alone. These results point to organic nitrogen as a significant regulatory factor influencing hyporheic zone organic matter processing. Based on our findings, we propose incorporating knowledge of metabolic pathways associated with different chemical fractions of C pools into ecosystem models will enhance prediction accuracy.
- Li, L., He, Z. L., Tfaily, M. M., Inglett, P., & Stoffella, P. J. (2018). Spatial-temporal variations of dissolved organic nitrogen molecular composition in agricultural runoff water. Water research, 137, 375-383.More infoLeaching of dissolved organic nitrogen (DON) has been reported as a pathway of N loss from agriculture, but the molecular composition of DON in agricultural water is poorly understood. Runoff water samples were collected from citrus grove furrows (CGF), ditches (CGD) and pasture ditches (PD) in four seasons. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to investigate molecular composition of DON. Chemodiversity index of DON had spatiotemporal variations, while the molecular composition of total DON showed minimal variations, except for PD in November. Lignin derivatives constituted 61% of the total DON compounds. Relative abundance of aliphatic compounds, char and condensed aromatics of unique DON compounds varied spatiotemporally and had a significant correlation with DON concentration. Aromaticity index decreased from CGF to connected CGD, implying that photodegradation is possibly the dominant process that alters molecular composition of aquatic DON during the transport. Significant differences in unique DON composition between CGD and PD indicates that fertilization and land use affect DON composition. The information on molecular characterization of DON should be useful for tracking DON source and developing technologies to remove DON in the agricultural runoff water.
- Orton, D. J., Tfaily, M. M., Moore, R. J., LaMarche, B. L., Zheng, X., Fillmore, T. L., Chu, R. K., Weitz, K. K., Monroe, M. E., Kelly, R. T., Smith, R. D., & Baker, E. S. (2018). A Customizable Flow Injection System for Automated, High Throughput, and Time Sensitive Ion Mobility Spectrometry and Mass Spectrometry Measurements. Analytical chemistry, 90(1), 737-744.More infoTo better understand disease conditions and environmental perturbations, multiomic studies combining proteomic, lipidomic, and metabolomic analyses are vastly increasing in popularity. In a multiomic study, a single sample is typically extracted in multiple ways, and various analyses are performed using different instruments, most often based upon mass spectrometry (MS). Thus, one sample becomes many measurements, making high throughput and reproducible evaluations a necessity. One way to address the numerous samples and varying instrumental conditions is to utilize a flow injection analysis (FIA) system for rapid sample injections. While some FIA systems have been created to address these challenges, many have limitations such as costly consumables, low pressure capabilities, limited pressure monitoring, and fixed flow rates. To address these limitations, we created an automated, customizable FIA system capable of operating at a range of flow rates (∼50 nL/min to 500 μL/min) to accommodate both low- and high-flow MS ionization sources. This system also functions at varying analytical throughputs from 24 to 1200 samples per day to enable different MS analysis approaches. Applications ranging from native protein analyses to molecular library construction were performed using the FIA system, and results showed a highly robust and reproducible platform capable of providing consistent performance over many days without carryover, as long as washing buffers specific to each molecular analysis were utilized.
- Reynolds, L. L., Lajtha, K., Bowden, R. D., Tfaily, M. M., Johnson, B. R., & Bridgham, S. D. (2018). The Path From Litter to Soil: Insights Into Soil C Cycling From Long-Term Input Manipulation and High-Resolution Mass Spectrometry. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 123(5), 1486-1497.
- Stegen, J. C., Johnson, T., Fredrickson, J. K., Wilkins, M. J., Konopka, A. E., Nelson, W. C., Arntzen, E. V., Chrisler, W. B., Chu, R. K., Fansler, S. J., Graham, E. B., Kennedy, D. W., Resch, C. T., Tfaily, M., & Zachara, J. (2018). Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology. Nature communications, 9(1), 585.More infoThe hyporheic corridor (HC) encompasses the river-groundwater continuum, where the mixing of groundwater (GW) with river water (RW) in the HC can stimulate biogeochemical activity. Here we propose a novel thermodynamic mechanism underlying this phenomenon and reveal broader impacts on dissolved organic carbon (DOC) and microbial ecology. We show that thermodynamically favorable DOC accumulates in GW despite lower DOC concentration, and that RW contains thermodynamically less-favorable DOC, but at higher concentrations. This indicates that GW DOC is protected from microbial oxidation by low total energy within the DOC pool, whereas RW DOC is protected by lower thermodynamic favorability of carbon species. We propose that GW-RW mixing overcomes these protections and stimulates respiration. Mixing models coupled with geophysical and molecular analyses further reveal tipping points in spatiotemporal dynamics of DOC and indicate important hydrology-biochemistry-microbial feedbacks. Previously unrecognized thermodynamic mechanisms regulated by GW-RW mixing may therefore strongly influence biogeochemical and microbial dynamics in riverine ecosystems.
- Stegen, J. C., Johnson, T., Fredrickson, J. K., Wilkins, M. J., Konopka, A. E., Nelson, W. C., Arntzen, E. V., Chrisler, W. B., Chu, R. K., Fansler, S. J., Graham, E. B., Kennedy, D. W., Resch, C. T., Tfaily, M., & Zachara, J. (2018). Publisher Correction: Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology. Nature communications, 9(1), 1034.More infoThe original version of this Article contained an error in Fig. 6e, in which the text in the legend was omitted. This has been corrected in both the PDF and HTML versions of the article.
- Tfaily, M. M., Hess, N. J., Koyama, A., & Evans, R. D. (2018). Elevated [CO2] changes soil organic matter composition and substrate diversity in an arid ecosystem. GEODERMA, 330, 1-8.
- Tfaily, M. M., Wilson, R. M., Cooper, W. T., Kostka, J. E., Hanson, P., & Chanton, J. P. (2018). Vertical Stratification of Peat Pore Water Dissolved Organic Matter Composition in a Peat Bog in Northern Minnesota. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 123(2), 479-494.
- Tfaily, M., Stegen, J., Goldman, A., Blackburn, S., Chu, R., Danczak, R., Garayburu-Caruso, V., Graham, E., Grieshauber, C., Lin, X., & Morad, J. (2018). WHONDRS Surface Water Sampling for Metabolite Biogeography. Worldwide Hydrobiogeochemistry Observation Network for Dynamic River Systems (WHONDRS).. ESS-DIVE. doi:doi:10.15485/1484811
- Wilson, R. M., & Tfaily, M. M. (2018). Advanced Molecular Techniques Provide New Rigorous Tools for Characterizing Organic Matter Quality in Complex Systems. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 123(6), 1790-1795.
- Yao, Q., Li, Z., Song, Y., Wright, S. J., Guo, X., Tringe, S. G., Tfaily, M. M., Paša-Tolić, L., Hazen, T. C., Turner, B. L., Mayes, M. A., & Pan, C. (2018). Community proteogenomics reveals the systemic impact of phosphorus availability on microbial functions in tropical soil. Nature ecology & evolution, 2(3), 499-509.More infoPhosphorus is a scarce nutrient in many tropical ecosystems, yet how soil microbial communities cope with growth-limiting phosphorus deficiency at the gene and protein levels remains unknown. Here, we report a metagenomic and metaproteomic comparison of microbial communities in phosphorus-deficient and phosphorus-rich soils in a 17-year fertilization experiment in a tropical forest. The large-scale proteogenomics analyses provided extensive coverage of many microbial functions and taxa in the complex soil communities. A greater than fourfold increase in the gene abundance of 3-phytase was the strongest response of soil communities to phosphorus deficiency. Phytase catalyses the release of phosphate from phytate, the most recalcitrant phosphorus-containing compound in soil organic matter. Genes and proteins for the degradation of phosphorus-containing nucleic acids and phospholipids, as well as the decomposition of labile carbon and nitrogen, were also enhanced in the phosphorus-deficient soils. In contrast, microbial communities in the phosphorus-rich soils showed increased gene abundances for the degradation of recalcitrant aromatic compounds, transformation of nitrogenous compounds and assimilation of sulfur. Overall, these results demonstrate the adaptive allocation of genes and proteins in soil microbial communities in response to shifting nutrient constraints.
- Zalman, C., Keller, J. K., Tfaily, M., Kolton, M., Pfeifer-Meister, L., Wilson, R. M., Lin, X., Chanton, J., Kostka, J. E., Gill, A., Finzi, A. C., Hopple, A. M., Bohannan, B., & Bridgham, S. D. (2018). Small differences in ombrotrophy control regional-scale variation in methane cycling among Sphagnum-dominated peatlands. BIOGEOCHEMISTRY, 139(2), 155-177.
- Bailey, V. L., Smith, A. P., Tfaily, M., Fansler, S. J., & Bond-Lamberty, B. (2017). Differences in soluble organic carbon chemistry in pore waters sampled from different pore size domains. SOIL BIOLOGY & BIOCHEMISTRY, 107, 133-143.
- Boye, K., Noel, V., Tfaily, M. M., Bone, S. E., Williams, K. H., Bargar, J. R., & Fendorf, S. (2017). Thermodynamically controlled preservation of organic carbon in floodplains. NATURE GEOSCIENCE, 10(6), 415-+.
- Dalcin Martins, P., Hoyt, D. W., Bansal, S., Mills, C. T., Tfaily, M., Tangen, B. A., Finocchiaro, R. G., Johnston, M. D., McAdams, B. C., Solensky, M. J., Smith, G. J., Chin, Y. P., & Wilkins, M. J. (2017). Abundant carbon substrates drive extremely high sulfate reduction rates and methane fluxes in Prairie Pothole Wetlands. Global change biology, 23(8), 3107-3120.More infoInland waters are increasingly recognized as critical sites of methane emissions to the atmosphere, but the biogeochemical reactions driving such fluxes are less well understood. The Prairie Pothole Region (PPR) of North America is one of the largest wetland complexes in the world, containing millions of small, shallow wetlands. The sediment pore waters of PPR wetlands contain some of the highest concentrations of dissolved organic carbon (DOC) and sulfur species ever recorded in terrestrial aquatic environments. Using a suite of geochemical and microbiological analyses, we measured the impact of sedimentary carbon and sulfur transformations in these wetlands on methane fluxes to the atmosphere. This research represents the first study of coupled geochemistry and microbiology within the PPR and demonstrates how the conversion of abundant labile DOC pools into methane results in some of the highest fluxes of this greenhouse gas to the atmosphere ever reported. Abundant DOC and sulfate additionally supported some of the highest sulfate reduction rates ever measured in terrestrial aquatic environments, which we infer to account for a large fraction of carbon mineralization in this system. Methane accumulations in zones of active sulfate reduction may be due to either the transport of free methane gas from deeper locations or the co-occurrence of methanogenesis and sulfate reduction. If both respiratory processes are concurrent, any competitive inhibition of methanogenesis by sulfate-reducing bacteria may be lessened by the presence of large labile DOC pools that yield noncompetitive substrates such as methanol. Our results reveal some of the underlying mechanisms that make PPR wetlands biogeochemical hotspots, which ultimately leads to their critical, but poorly recognized role in regional greenhouse gas emissions.
- Graham, E. B., Tfaily, M. M., Crump, A. R., Goldman, A. E., Bramer, L. M., Arntzen, E., Romero, E., Resch, C. T., Kennedy, D. W., & Stegen, J. C. (2017). Carbon Inputs From Riparian Vegetation Limit Oxidation of Physically Bound Organic Carbon Via Biochemical and Thermodynamic Processes. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 122(12), 3188-3205.
- Smith, A. P., Bond-Lamberty, B., Benscoter, B. W., Tfaily, M. M., Hinkle, C. R., Liu, C., & Bailey, V. L. (2017). Shifts in pore connectivity from precipitation versus groundwater rewetting increases soil carbon loss after drought. NATURE COMMUNICATIONS, 8.
- Smith, A. P., Bond-Lamberty, B., Benscoter, B. W., Tfaily, M. M., Hinkle, C. R., Liu, C., & Bailey, V. L. (2017). Shifts in pore connectivity from precipitation versus groundwater rewetting increases soil carbon loss after drought. Nature communications, 8(1), 1335.More infoDroughts and other extreme precipitation events are predicted to increase in intensity, duration, and extent, with uncertain implications for terrestrial carbon (C) sequestration. Soil wetting from above (precipitation) results in a characteristically different pattern of pore-filling than wetting from below (groundwater), with larger, well-connected pores filling before finer pore spaces, unlike groundwater rise in which capillary forces saturate the finest pores first. Here we demonstrate that pore-scale wetting patterns interact with antecedent soil moisture conditions to alter pore-scale, core-scale, and field-scale C dynamics. Drought legacy and wetting direction are perhaps more important determinants of short-term C mineralization than current soil moisture content in these soils. Our results highlight that microbial access to C is not solely limited by physical protection, but also by drought or wetting-induced shifts in hydrologic connectivity. We argue that models should treat soil moisture within a three-dimensional framework emphasizing hydrologic conduits for C and resource diffusion.
- Staley, C., Ferrieri, A. P., Tfaily, M. M., Cui, Y., Chu, R. K., Wang, P., Shaw, J. B., Ansong, C. K., Brewer, H., Norbeck, A. D., Markillie, M., do Amaral, F., Tuleski, T., Pellizzaro, T., Agtuca, B., Ferrieri, R., Tringe, S. G., Paša-Tolić, L., Stacey, G., & Sadowsky, M. J. (2017). Diurnal cycling of rhizosphere bacterial communities is associated with shifts in carbon metabolism. Microbiome, 5(1), 65.More infoThe circadian clock regulates plant metabolic functions and is an important component in plant health and productivity. Rhizosphere bacteria play critical roles in plant growth, health, and development and are shaped primarily by soil communities. Using Illumina next-generation sequencing and high-resolution mass spectrometry, we characterized bacterial communities of wild-type (Col-0) Arabidopsis thaliana and an acyclic line (OX34) ectopically expressing the circadian clock-associated cca1 transcription factor, relative to a soil control, to determine how cycling dynamics affected the microbial community. Microbial communities associated with Brachypodium distachyon (BD21) were also evaluated.
- Tfaily, M. M., Chu, R. K., Toyoda, J., Tolic, N., Robinson, E. W., Pasa-Tolic, L., & Hess, N. J. (2017). Sequential extraction protocol for organic matter from soils and sediments using high resolution mass spectrometry. ANALYTICA CHIMICA ACTA, 972, 54-61.
- Tfaily, M. M., Chu, R. K., Toyoda, J., Tolić, N., Robinson, E. W., Paša-Tolić, L., & Hess, N. J. (2017). Sequential extraction protocol for organic matter from soils and sediments using high resolution mass spectrometry. Analytica chimica acta, 972, 54-61.More infoA vast number of organic compounds are present in soil organic matter (SOM) and play an important role in the terrestrial carbon cycle, facilitate interactions between organisms, and represent a sink for atmospheric CO. The diversity of different SOM compounds and their molecular characteristics is a function of the organic source material and biogeochemical history. By understanding how SOM composition changes with sources and the processes by which it is biogeochemically altered in different terrestrial ecosystems, it may be possible to predict nutrient and carbon cycling, response to system perturbations, and impact of climate change will have on SOM composition. In this study, a sequential chemical extraction procedure was developed to reveal the diversity of organic matter (OM) in different ecosystems and was compared to the previously published protocol using parallel solvent extraction (PSE). We compared six extraction methods using three sample types, peat soil, spruce forest soil and river sediment, so as to select the best method for extracting a representative fraction of organic matter from soils and sediments from a wide range of ecosystems. We estimated the extraction yield of dissolved organic carbon (DOC) by total organic carbon analysis, and measured the composition of extracted OM using high resolution mass spectrometry. This study showed that OM composition depends primarily on soil and sediment characteristics. Two sequential extraction protocols, progressing from polar to non-polar solvents, were found to provide the highest number and diversity of organic compounds extracted from the soil and sediments. Water (HO) is the first solvent used for both protocols followed by either co-extraction with methanol-chloroform (MeOH-CHCl) mixture, or acetonitrile (ACN) and CHCl sequentially. The sequential extraction protocol developed in this study offers improved sensitivity, and requires less sample compared to the PSE workflow where a new sample is used for each solvent type. Furthermore, a comparison of SOM composition from the different sample types revealed that our sequential protocol allows for ecosystem comparisons based on the diversity of compounds present, which in turn could provide new insights about source and processing of organic compounds in different soil and sediment types.
- Tolić, N., Liu, Y., Liyu, A., Shen, Y., Tfaily, M. M., Kujawinski, E. B., Longnecker, K., Kuo, L. J., Robinson, E. W., Paša-Tolić, L., & Hess, N. J. (2017). Formularity: Software for Automated Formula Assignment of Natural and Other Organic Matter from Ultrahigh-Resolution Mass Spectra. Analytical chemistry, 89(23), 12659-12665.More infoUltrahigh resolution mass spectrometry, such as Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS), can resolve thousands of molecular ions in complex organic matrices. A Compound Identification Algorithm (CIA) was previously developed for automated elemental formula assignment for natural organic matter (NOM). In this work, we describe software Formularity with a user-friendly interface for CIA function and newly developed search function Isotopic Pattern Algorithm (IPA). While CIA assigns elemental formulas for compounds containing C, H, O, N, S, and P, IPA is capable of assigning formulas for compounds containing other elements. We used halogenated organic compounds (HOC), a chemical class that is ubiquitous in nature as well as anthropogenic systems, as an example to demonstrate the capability of Formularity with IPA. A HOC standard mix was used to evaluate the identification confidence of IPA. Tap water and HOC spike in Suwannee River NOM were used to assess HOC identification in complex environmental samples. Strategies for reconciliation of CIA and IPA assignments were discussed. Software and sample databases with documentation are freely available.
- Walker, L. R., Tfaily, M. M., Shaw, J. B., Hess, N. J., Paša-Tolić, L., & Koppenaal, D. W. (2017). Unambiguous identification and discovery of bacterial siderophores by direct injection 21 Tesla Fourier transform ion cyclotron resonance mass spectrometry. Metallomics : integrated biometal science, 9(1), 82-92.More infoUnder iron-limiting conditions, bacteria produce low molecular mass Fe(iii) binding molecules known as siderophores to sequester the Fe(iii), along with other elements, increasing their bioavailability. Siderophores are thought to influence iron cycling and biogeochemistry in both marine and terrestrial ecosystems and hence the need for rapid, confident characterization of these compounds has increased. In this study, the type of siderophores produced by two marine bacterial species, Synechococcus sp. PCC 7002 and Vibrio cyclitrophicus 1F53, were characterized by use of a newly developed 21 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR MS) with direct injection electrospray ionization. This technique allowed for the rapid detection of synechobactins from Synechococcus sp. PCC 7002 as well as amphibactins from Vibrio cyclitrophicus 1F53 based on high mass accuracy and resolution allowing for observation of specific Fe isotopes and isotopic fine structure enabling highly confident identification of these siderophores. When combined with molecular network analysis two new amphibactins were discovered and verified by tandem MS. These results show that high-field FTICR MS is a powerful technique that will greatly improve the ability to rapidly identify and discover metal binding species in the environment.
- Hodgkins, S. B., Tfaily, M. M., Podgorski, D. C., McCalley, C. K., Saleska, S. R., Crill, P. M., Rich, V. I., Chanton, J. P., & Cooper, W. T. (2016). Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost thaw chronosequence in a subarctic peatland. GEOCHIMICA ET COSMOCHIMICA ACTA, 187, 123-140.
- Stegen, J. C., Fredrickson, J. K., Wilkins, M. J., Konopka, A. E., Nelson, W. C., Arntzen, E. V., Chrisler, W. B., Chu, R. K., Danczak, R. E., Fansler, S. J., Kennedy, D. W., Resch, C. T., & Tfaily, M. (2016). Groundwater-surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover. NATURE COMMUNICATIONS, 7.
- Stegen, J. C., Fredrickson, J. K., Wilkins, M. J., Konopka, A. E., Nelson, W. C., Arntzen, E. V., Chrisler, W. B., Chu, R. K., Danczak, R. E., Fansler, S. J., Kennedy, D. W., Resch, C. T., & Tfaily, M. (2016). Groundwater-surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover. Nature communications, 7, 11237.More infoEnvironmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater-surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater-surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds.
- Stegen, J. C., Hurlbert, A. H., Bond-Lamberty, B., Chen, X., Anderson, C. G., Chu, R. K., Dini-Andreote, F., Fansler, S. J., Hess, N. J., & Tfaily, M. (2016). Aligning the Measurement of Microbial Diversity with Macroecological Theory. FRONTIERS IN MICROBIOLOGY, 7.
- Stegen, J. C., Hurlbert, A. H., Bond-Lamberty, B., Chen, X., Anderson, C. G., Chu, R. K., Dini-Andreote, F., Fansler, S. J., Hess, N. J., & Tfaily, M. (2016). Aligning the Measurement of Microbial Diversity with Macroecological Theory. Frontiers in microbiology, 7, 1487.More infoThe number of microbial operational taxonomic units (OTUs) within a community is akin to species richness within plant/animal ("macrobial") systems. A large literature documents OTU richness patterns, drawing comparisons to macrobial theory. There is, however, an unrecognized fundamental disconnect between OTU richness and macrobial theory: OTU richness is commonly estimated on a per-individual basis, while macrobial richness is estimated per-area. Furthermore, the range or extent of sampled environmental conditions can strongly influence a study's outcomes and conclusions, but this is not commonly addressed when studying OTU richness. Here we () propose a new sampling approach that estimates OTU richness per-mass of soil, which results in strong support for species energy theory, () use data reduction to show how support for niche conservatism emerges when sampling across a restricted range of environmental conditions, and () show how additional insights into drivers of OTU richness can be generated by combining different sampling methods while simultaneously considering patterns that emerge by restricting the range of environmental conditions. We propose that a more rigorous connection between microbial ecology and macrobial theory can be facilitated by exploring how changes in OTU richness units and environmental extent influence outcomes of data analysis. While fundamental differences between microbial and macrobial systems persist (e.g., species concepts), we suggest that closer attention to units and scale provide tangible and immediate improvements to our understanding of the processes governing OTU richness and how those processes relate to drivers of macrobial species richness.
- Wilson, R. M., Hopple, A. M., Tfaily, M. M., Sebestyen, S. D., Schadt, C. W., Pfeifer-Meister, L., Medvedeff, C., McFarlane, K. J., Kostka, J. E., Kolton, M., Kolka, R. K., Kluber, L. A., Keller, J. K., Guilderson, T. P., Griffiths, N. A., Chanton, J. P., Bridgham, S. D., & Hanson, P. J. (2016). Stability of peatland carbon to rising temperatures. NATURE COMMUNICATIONS, 7.
- Wilson, R. M., Hopple, A. M., Tfaily, M. M., Sebestyen, S. D., Schadt, C. W., Pfeifer-Meister, L., Medvedeff, C., McFarlane, K. J., Kostka, J. E., Kolton, M., Kolka, R. K., Kluber, L. A., Keller, J. K., Guilderson, T. P., Griffiths, N. A., Chanton, J. P., Bridgham, S. D., & Hanson, P. J. (2016). Stability of peatland carbon to rising temperatures. Nature communications, 7, 13723.More infoPeatlands contain one-third of soil carbon (C), mostly buried in deep, saturated anoxic zones (catotelm). The response of catotelm C to climate forcing is uncertain, because prior experiments have focused on surface warming. We show that deep peat heating of a 2 m-thick peat column results in an exponential increase in CH emissions. However, this response is due solely to surface processes and not degradation of catotelm peat. Incubations show that only the top 20-30 cm of peat from experimental plots have higher CH production rates at elevated temperatures. Radiocarbon analyses demonstrate that CH and CO are produced primarily from decomposition of surface-derived modern photosynthate, not catotelm C. There are no differences in microbial abundances, dissolved organic matter concentrations or degradative enzyme activities among treatments. These results suggest that although surface peat will respond to increasing temperature, the large reservoir of catotelm C is stable under current anoxic conditions.
- Corbett, J. E., Tfaily, M. M., Burdige, D. J., Glaser, P. H., & Chanton, J. P. (2015). The relative importance of methanogenesis in the decomposition of organic matter in northern peatlands. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 120(2), 280-293.
- Holmes, M. E., Chanton, J. P., Tfaily, M. M., & Ogram, A. (2015). CO2 and CH4 isotope compositions and production pathways in a tropical peatland. GLOBAL BIOGEOCHEMICAL CYCLES, 29(1), 1-18.
- Tfaily, M. M., Chu, R. K., Tolic, N., Roscioli, K. M., Anderton, C. R., Pasa-Tolic, L., Robinson, E. W., & Hess, N. J. (2015). Advanced Solvent Based Methods for Molecular Characterization of Soil Organic Matter by High-Resolution Mass Spectrometry. ANALYTICAL CHEMISTRY, 87(10), 5206-5215.
- Tfaily, M. M., Chu, R. K., Tolić, N., Roscioli, K. M., Anderton, C. R., Paša-Tolić, L., Robinson, E. W., & Hess, N. J. (2015). Advanced solvent based methods for molecular characterization of soil organic matter by high-resolution mass spectrometry. Analytical chemistry, 87(10), 5206-15.More infoSoil organic matter (SOM), a complex, heterogeneous mixture of above and belowground plant litter and animal and microbial residues at various degrees of decomposition, is a key reservoir for carbon (C) and nutrient biogeochemical cycling in soil based ecosystems. A limited understanding of the molecular composition of SOM limits the ability to routinely decipher chemical processes within soil and accurately predict how terrestrial carbon fluxes will respond to changing climatic conditions and land use. To elucidate the molecular-level structure of SOM, we selectively extracted a broad range of intact SOM compounds by a combination of different organic solvents from soils with a wide range of C content. Our use of electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and a suite of solvents with varying polarity significantly expands the inventory of the types of organic molecules present in soils. Specifically, we found that hexane is selective for lipid-like compounds with very low O/C ratios ( 0.5; methanol (MeOH) has higher selectivity toward compounds characterized with low O/C < 0.5; and hexane, MeOH, ACN, and H2O solvents increase the number and types of organic molecules extracted from soil for a broader range of chemically diverse soil types. Our study of SOM molecules by ESI FTICR MS revealed new insight into the molecular-level complexity of organics contained in soils. We present the first comparative study of the molecular composition of SOM from different ecosystems using ultra high-resolution mass spectrometry.
- Tfaily, M. M., Corbett, J. E., Wilson, R., Chanton, J. P., Glaser, P. H., Cawley, K. M., Jaffe, R., & Cooper, W. T. (2015). Utilization of PARAFAC-Modeled Excitation-Emission Matrix (EEM) Fluorescence Spectroscopy to Identify Biogeochemical Processing of Dissolved Organic Matter in a Northern Peatland. PHOTOCHEMISTRY AND PHOTOBIOLOGY, 91(3), 684-695.
- Tfaily, M. M., Corbett, J. E., Wilson, R., Chanton, J. P., Glaser, P. H., Cawley, K. M., Jaffé, R., & Cooper, W. T. (2015). Utilization of PARAFAC-Modeled Excitation-Emission Matrix (EEM) Fluorescence Spectroscopy to Identify Biogeochemical Processing of Dissolved Organic Matter in a Northern Peatland. Photochemistry and photobiology, 91(3), 684-95.More infoIn this study, we contrast the fluorescent properties of dissolved organic matter (DOM) in fens and bogs in a Northern Minnesota peatland using excitation emission matrix fluorescence spectroscopy with parallel factor analysis (EEM-PARAFAC). EEM-PARAFAC identified four humic-like components and one protein-like component and the dynamics of each were evaluated based on their distribution with depth as well as across sites differing in hydrology and major biological species. The PARAFAC-EEM experiments were supported by dissolved organic carbon measurements (DOC), optical spectroscopy (UV-Vis), and compositional characterization by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectroscopy (FT-ICR MS). The FT-ICR MS data indicate that metabolism in peatlands reduces the molecular weights of individual components of DOM, and oxygen-rich less aromatic molecules are selectively biodegraded. Our data suggest that different hydrologic and biological conditions within the larger peat ecosystem drive molecular changes in DOM, resulting in distinctly different chemical compositions and unique fluorescent fingerprints. PARAFAC modeling of EEM data coupled with ultrahigh resolution FT-ICR MS has the potential to provide significant molecular-based information on DOM composition that will support efforts to better understand the composition, sources, and diagenetic status of DOM from different terrestrial and aquatic systems.
- Hodgkins, S. B., Tfaily, M. M., McCalley, C. K., Logan, T. A., Crill, P. M., Saleska, S. R., Rich, V. I., & Chanton, J. P. (2014). Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 111(16), 5819-5824.
- Lin, X., Tfaily, M. M., Green, S. J., Steinweg, J. M., Chanton, P., Imvittaya, A., Chanton, J. P., Cooper, W., Schadt, C., & Kostka, J. E. (2014). Microbial Metabolic Potential for Carbon Degradation and Nutrient (Nitrogen and Phosphorus) Acquisition in an Ombrotrophic Peatland. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 80(11), 3531-3540.
- Lin, X., Tfaily, M. M., Green, S. J., Steinweg, J. M., Chanton, P., Imvittaya, A., Chanton, J. P., Cooper, W., Schadt, C., & Kostka, J. E. (2014). Microbial metabolic potential for carbon degradation and nutrient (nitrogen and phosphorus) acquisition in an ombrotrophic peatland. Applied and environmental microbiology, 80(11), 3531-40.More infoThis study integrated metagenomic and nuclear magnetic resonance (NMR) spectroscopic approaches to investigate microbial metabolic potential for organic matter decomposition and nitrogen (N) and phosphorus (P) acquisition in soils of an ombrotrophic peatland in the Marcell Experimental Forest (MEF), Minnesota, USA. This analysis revealed vertical stratification in key enzymatic pathways and taxa containing these pathways. Metagenomic analyses revealed that genes encoding laccases and dioxygenases, involved in aromatic compound degradation, declined in relative abundance with depth, while the relative abundance of genes encoding metabolism of amino sugars and all four saccharide groups increased with depth in parallel with a 50% reduction in carbohydrate content. Most Cu-oxidases were closely related to genes from Proteobacteria and Acidobacteria, and type 4 laccase-like Cu-oxidase genes were >8 times more abundant than type 3 genes, suggesting an important and overlooked role for type 4 Cu-oxidase in phenolic compound degradation. Genes associated with sulfate reduction and methanogenesis were the most abundant anaerobic respiration genes in these systems, with low levels of detection observed for genes of denitrification and Fe(III) reduction. Fermentation genes increased in relative abundance with depth and were largely affiliated with Syntrophobacter. Methylocystaceae-like small-subunit (SSU) rRNA genes, pmoA, and mmoX genes were more abundant among methanotrophs. Genes encoding N2 fixation, P uptake, and P regulons were significantly enriched in the surface peat and in comparison to other ecosystems, indicating N and P limitation. Persistence of inorganic orthophosphate throughout the peat profile in this P-limiting environment indicates that P may be bound to recalcitrant organic compounds, thus limiting P bioavailability in the subsurface. Comparative metagenomic analysis revealed a high metabolic potential for P transport and starvation, N2 fixation, and oligosaccharide degradation at MEF relative to other wetland and soil environments, consistent with the nutrient-poor and carbohydrate-rich conditions found in this Sphagnum-dominated boreal peatland.
- Lin, X., Tfaily, M. M., Steinweg, J. M., Chanton, P., Esson, K., Yang, Z. K., Chanton, J. P., Cooper, W., Schadt, C. W., & Kostka, J. E. (2014). Microbial community stratification linked to utilization of carbohydrates and phosphorus limitation in a boreal peatland at Marcell Experimental Forest, Minnesota, USA. Applied and environmental microbiology, 80(11), 3518-30.More infoThis study investigated the abundance, distribution, and composition of microbial communities at the watershed scale in a boreal peatland within the Marcell Experimental Forest (MEF), Minnesota, USA. Through a close coupling of next-generation sequencing, biogeochemistry, and advanced analytical chemistry, a biogeochemical hot spot was revealed in the mesotelm (30- to 50-cm depth) as a pronounced shift in microbial community composition in parallel with elevated peat decomposition. The relative abundance of Acidobacteria and the Syntrophobacteraceae, including known hydrocarbon-utilizing genera, was positively correlated with carbohydrate and organic acid content, showing a maximum in the mesotelm. The abundance of Archaea (primarily crenarchaeal groups 1.1c and 1.3) increased with depth, reaching up to 60% of total small-subunit (SSU) rRNA gene sequences in the deep peat below the 75-cm depth. Stable isotope geochemistry and potential rates of methane production paralleled vertical changes in methanogen community composition to indicate a predominance of acetoclastic methanogenesis mediated by the Methanosarcinales in the mesotelm, while hydrogen-utilizing methanogens predominated in the deeper catotelm. RNA-derived pyrosequence libraries corroborated DNA sequence data to indicate that the above-mentioned microbial groups are metabolically active in the mid-depth zone. Fungi showed a maximum in rRNA gene abundance above the 30-cm depth, which comprised only an average of 0.1% of total bacterial and archaeal rRNA gene abundance, indicating prokaryotic dominance. Ratios of C to P enzyme activities approached 0.5 at the acrotelm and catotelm, indicating phosphorus limitation. In contrast, P limitation pressure appeared to be relieved in the mesotelm, likely due to P solubilization by microbial production of organic acids and C-P lyases. Based on path analysis and the modeling of community spatial turnover, we hypothesize that P limitation outweighs N limitation at MEF, and microbial communities are structured by the dominant shrub, Chamaedaphne calyculata, which may act as a carbon source for major consumers in the peatland.
- Lin, X., Tfaily, M. M., Steinweg, M., Chanton, P., Esson, K., Yang, Z. K., Chanton, J. P., Cooper, W., Schadt, C. W., & Kostka, J. E. (2014). Microbial Community Stratification Linked to Utilization of Carbohydrates and Phosphorus Limitation in a Boreal Peatland at Marcell Experimental Forest, Minnesota, USA. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 80(11), 3518-3530.
- Tfaily, M. M., Cooper, W. T., Kostka, J. E., Chanton, P. R., Schadt, C. W., Hanson, P. J., Iversen, C. M., & Chanton, J. P. (2014). Organic matter transformation in the peat column at Marcell Experimental Forest: Humification and vertical stratification. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 119(4), 661-675.
- Corbett, J. E., Burdige, D. J., Tfaily, M. M., Dial, A. R., Cooper, W. T., Glaser, P. H., & Chanton, J. P. (2013). Surface production fuels deep heterotrophic respiration in northern peatlands. GLOBAL BIOGEOCHEMICAL CYCLES, 27(4), 1163-1174.
- Corbett, J. E., Tfaily, M. M., Burdige, D. J., Cooper, W. T., Glaser, P. H., & Chanton, J. P. (2013). Partitioning pathways of CO2 production in peatlands with stable carbon isotopes. BIOGEOCHEMISTRY, 114(1-3), 327-340.
- Tfaily, M. M., Hamdan, R., Corbett, J. E., Chanton, J. P., Glaser, P. H., & Cooper, W. T. (2013). Investigating dissolved organic matter decomposition in northern peatlands using complimentary analytical techniques. GEOCHIMICA ET COSMOCHIMICA ACTA, 112, 116-129.
- Lin, X., Green, S., Tfaily, M. M., Prakash, O., Konstantinidis, K. T., Corbett, J. E., Chanton, J. P., Cooper, W. T., & Kostka, J. E. (2012). Microbial Community Structure and Activity Linked to Contrasting Biogeochemical Gradients in Bog and Fen Environments of the Glacial Lake Agassiz Peatland. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 78(19), 7023-7031.
- Lin, X., Green, S., Tfaily, M. M., Prakash, O., Konstantinidis, K. T., Corbett, J. E., Chanton, J. P., Cooper, W. T., & Kostka, J. E. (2012). Microbial community structure and activity linked to contrasting biogeochemical gradients in bog and fen environments of the Glacial Lake Agassiz Peatland. Applied and environmental microbiology, 78(19), 7023-31.More infoThe abundances, compositions, and activities of microbial communities were investigated at bog and fen sites in the Glacial Lake Agassiz Peatland of northwestern Minnesota. These sites contrast in the reactivity of dissolved organic matter (DOM) and the presence or absence of groundwater inputs. Microbial community composition was characterized using pyrosequencing and clone library construction of phylogenetic marker genes. Microbial distribution patterns were linked to pH, concentrations of dissolved organic carbon and nitrogen, C/N ratios, optical properties of DOM, and activities of laccase and peroxidase enzymes. Both bacterial and archaeal richness and rRNA gene abundance were >2 times higher on average in the fen than in the bog, in agreement with a higher pH, labile DOM content, and enhanced enzyme activities in the fen. Fungi were equivalent to an average of 1.4% of total prokaryotes in gene abundance assayed by quantitative PCR. Results revealed statistically distinct spatial patterns between bacterial and fungal communities. Fungal distribution did not covary with pH and DOM optical properties and was vertically stratified, with a prevalence of Ascomycota and Basidiomycota near the surface and much higher representation of Zygomycota in the subsurface. In contrast, bacterial community composition largely varied between environments, with the bog dominated by Acidobacteria (61% of total sequences), while the Firmicutes (52%) dominated in the fen. Acetoclastic Methanosarcinales showed a much higher relative abundance in the bog, in contrast to the dominance of diverse hydrogenotrophic methanogens in the fen. This is the first quantitative and compositional analysis of three microbial domains in peatlands and demonstrates that the microbial abundance, diversity, and activity parallel with the pronounced differences in environmental variables between bog and fen sites.
- Tfaily, M. M., Hodgkins, S., Podgorski, D. C., Chanton, J. P., & Cooper, W. T. (2012). Comparison of dialysis and solid-phase extraction for isolation and concentration of dissolved organic matter prior to Fourier transform ion cyclotron resonance mass spectrometry. ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 404(2), 447-457.
- Tfaily, M. M., Podgorski, D. C., Corbett, J. E., Chanton, J. P., & Cooper, W. T. (2011). Influence of acidification on the optical properties and molecular composition of dissolved organic matter. ANALYTICA CHIMICA ACTA, 706(2), 261-267.
- Tfaily, M. (2019, Fall). Microbial controls on biogeochemical cycling of carbon using stable isotope labeling and other novel techniques. HAS. University of Ariozna: HAS department.
- Tfaily, M. (2019, Fall). Quantification of abiotic controls on dissolved organic matter in watersheds. SFA Watershed Community WorkshopPNNL.
- Tfaily, M. (2019, Fall). Quantifying biotic and abiotic controls on dissolved organic matter dynamics in natural systems using complementary analytical techniques. AGU.
- Tfaily, M. (2019, Fall). Towards a Better Understanding of Microbial-Organo-Mineral Interactions Using High Resolution Mass Spectrometry. SSSA.
- Tfaily, M. (2019, January 2019). Molecular-Level Investigation into the Fractionation of Dissolved Organic Carbon during Co-Precipitation with Ferrihydrite. SSSA 2019.
- Tfaily, M. (2019, January 2019). Soil Pore Architecture Drives SOC Transformations with Drought. SSSA 2019.
- Tfaily, M. (2019, January 2019). The Nexus of Water, Physical Structure, and Microbial Communities in Soil: Unpredictable Soil Biogeochemistry in a Changing Earth System. SSSA 2019.
- Tfaily, M. (2019, January 2019). The Persistence of Mineral Associated Organic Matter Among Nutrient Network Grasslands.. SSSA 2019.
- Tfaily, M. (2019, January 2019). Twenty Years of Dirt: Detrital Influences on Soil Carbon Dynamics. SSSA 2019.
- Tfaily, M. (2019, Jnauary 2019). Riparian Carbon Inputs and Sediment Metabolomes, but Not Metagenomes or Metaproteomes, Correspond to Enhanced Water-Soluble C Oxidation and Bound C Protection in the Hyporheic Zone.. SSSA 2019.
- Tfaily, M., & Cardon, Z. (2019, Fall). Beyond the “lollipop” – roots as dynamic participants in root-microbe-mineral interactions. AGU.
- Tfaily, M., & Lybrand, R. (2019, Fall). Soil Geophysical Properties Influence Nest-Site Selection By Ground Nesting Bees in Agricultural Settings. SSSA.
- Tfaily, M., & Lybrand, R. (2019, Fall). dentifying the organic and inorganic products of incipient weathering in natural environments. AGU.
- Tfaily, M., & Lynch, L. (2019, Spring). Moving beyond stoichiometry: Simple substrates do not fully capture complex pathways of root exudate decomposition. Vol. 21, EGU2019-10603, 2019.
- Tfaily, M., & Neurath, R. (2019, Fall). Dynamic carbon association with minerals in the rhizosphere and detritosphere. AGU.
- Tfaily, M., & Sorensen, P. (2019, Fall). Snowmelt mediates microbial metabolic potential and soil metabolite profiles in a high altitude watershed. AGU.
- Tfaily, M., Chanton, J., Tfaily, M., & Pierson1, D. (2019, Fall). Isotopic and high resolution analytical techniques to investigate the stability of peat soils across gradients in latitude and altitude. AGU.
- Tfaily, M. (2018, December 2018). Metabolomic and metagenomic insights into drought- and flood-induced greenhouse gas emissions in soils. AGU 2018.
- Tfaily, M. (2018, December 2018). Subsurface carbon signatures in a coastal watershed experiencing tidal inundation. AGU 2018.
- Tfaily, M. (2018, December 2018). TOWARD THE PREDICTIVE UNDERSTANDING OF GREENHOUSE GAS PRODUCTION IN HIGH LATITUDE. AGU 2018.
- Tfaily, M. (2018, December 2018). Tracking the Fate of new C in Northern Peatlands by a Compound-Specific Stable Isotope-Labeling Approach coupled with multiple analytical techniques and gas fluxes analysis. AGU 2018.
- Tfaily, M., Graham, E., Crump, A., Bramer, L., Fransler, S., Purvine, S., Nicora, C., Artzen, E., Resch, T., Neslon, W., Goldman, A., Kennedy, D., & Stegen, J. (2018, December 2018). Riparian carbon inputs and sediment metabolomes, but not metagenomes or metaproteomes, correspond to enhanced water-soluble C oxidation and bound C protection in the hyporheic zone. AGU 2018.
- Tfaily, M., Stegen, J., & Graham, E. (2018, December 2018). Merging Ecological Theory with Organic Geochemistry and Environmental Metabolomics. AGU 2018.
- Yang, Y., Adhikari, D., Hess, N., Tfaily, M., Kukkadapu, R., Zhao, Q., Chu, R., & Graham, T. (2018, December 2018). Molecular-level investigation into the fractionation of dissolved organic carbon during co-precipitation with ferrihydrite. AGU 2018.
- Meredith, L., & Tfaily, M. (2019, Fall). Soil Genomics into the Study of Biosphere-Atmosphere Trace Gas Fluxes. AGU. SF.
- Tfaily, M. (2019, Fall). Microbial controls on biogeochemical cycling of carbon using stable isotope labeling and other novel techniques. AGU. SF.
- Tfaily, M., & AminiTabrizi, R. (2019, Fall). Controls on organic matter degradation in thawing permafrost peatlands and subsequent greenhouse gas emissions. AGU. SF.
- Tfaily, M., & Anderson, C. (2019, fall). Seasonal flooding impacts on mineral-organic associations regulate carbon export from subalpine floodplains. AGU. SF.
- Tfaily, M., & Chee, T. (2019, Fall). Comparison of Soil Organic Matter (SOM) Composition in the soil column at the Biosphere 2 Tropical Rainforest. AGU. SF.
- Tfaily, M., & Cruz Pérez, R. (2019, Fall). Journey from Roots to Bulk Soil: Organic Matter Characterization in the Biosphere 2 Tropical Rainforest. AGU. SF.
- Tfaily, M., & Dontsova, K. M. (2019, Fall). Spatial differences and temporal change in organic matter composition across artificial hillslope during incipient soil formation. AGU. SF.
- Tfaily, M., & Fudyma, J. (2019, Fall). Untargeted metabolic profiling of Sphagnum fallax from boreal peatlands identifies antimicrobial compounds and novel metabolites. AGU. SF.
- Tfaily, M., & Kelly-Slatten, M. (2019, Fall). Plant Genotype Impacts on Soil Biochemical Profiles and Implications for Soil Carbon Stabilization. AGU. SF.
- Tfaily, M., & Khechfe, A. (2019, Fall). Do payments for ecosystem services promote soil carbon sequestration in the tropics?. AGU. SF.
- Tfaily, M., & Toyoda, J. (2019, Fall). Extraction efficiency and molecular characterization of organic matter from soils and sediments using high resolution mass spectrometry. AGU. SF.
- Tfaily, M., & Wan, J. (2019, Fall). Hydrological controls on subsurface shale bedrock-nitrogen release and export from a mountainous watershed hillslope. AGU.
- Tfaily, M., & Zhao, Q. (2019, Fall). Coupled dynamics of carbon geochemistry and microbial communities in grassland soils. AGU. SF.
- Tfaily, M. (2019. What Does The Future Hold For Our Arid And Semi-Arid Ecosystems?. Science trends. https://sciencetrends.com/?p=50080&preview=1&_ppp=635059e085