Source: UNIVERSITY OF TENNESSEE submitted to
MICROBIAL DECOMPOSITION OF ORGANIC MATTER IN SOILS DURING PULSE EVENTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0233877
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Jan 1, 2013
Project End Date
Dec 31, 2017
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
UNIVERSITY OF TENNESSEE
2621 MORGAN CIR
KNOXVILLE,TN 37996-4540
Performing Department
Biosystems Engineering & Soil Science
Non Technical Summary
Soils are arguably the most biodiverse habitat on earth, home to an astounding abundance and diversity of microbes. Collectively these organisms provide a vast array of ecosystem services that sustain life on Earth. These essential processes include biogeochemical cycling of carbon and nutrients, soil formation and stabilization, production of food and fiber, as well as sequestration and breakdown of contaminants. Of these processes, decomposition of organic matter is one of the most important functions performed by organisms in terrestrial ecosystems, integral to global carbon and nutrient cycling. Soil decomposers are the critical link between above and below ground carbon and nutrient pools, and therefore a key factor governing the creation and stability of soil organic matter. We are beginning to understand the dynamics of microbial carbon and nutrient cycling in soils. These processes are not static, but are heavily influenced by changes in environmental conditions and organic matter inputs. Therefore it is critical that we not just examine these processes under ideal steady state, "background" or "normal" conditions, but also during stressful and pulse events: short moments in time where organic matter influxes are high and microbial dynamics are drastically altered. Climate change models project an increase in extreme events; therefore an understanding of microbial carbon cycling under rapidly changing conditions is essential to accurately modeling global carbon cycling. To this end, our proposed work will seek to clarify dynamics of microbial carbon and nutrient cycling during pulses of inputs, and under environmental stress. While there are many examples of pulse events in nature, our initial focus is on two scenarios, one on moisture pulses in water limited systems (semi-arid and arid soils) and one on nutrient pulses from decomposing carcasses in a high productivity system (temperate forest soil). While they may seem like disparate scenarios, from a microbial perspective they are, in fact, very similar: these are biogeochemical "hot moments", where a rapid pulse of substrate results in increase in microbial activity and rapid cycling of carbon. The responses of microbes are critical to understanding the ultimate fate of carbon in these situations. The overarching goal of our research is to reveal the identity, functional processes, and successional dynamics of soil microbial communities in soils undergoing pulse events and how these interactions ultimately control organic matter stability. We will provide foundational knowledge of soil microbes mediating organic matter recycling in terrestrial ecosystems. We will examine hot spot/hot moment processes, contributing to our understanding of pulse and patch dynamics in a landscape.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020110106050%
1044010107050%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 104 - Protect Soil from Harmful Effects of Natural Elements;

Subject Of Investigation
0110 - Soil; 4010 - Bacteria;

Field Of Science
1060 - Biology (whole systems); 1070 - Ecology;
Goals / Objectives
The overall goal of this project is to reveal the identity, functional processes, and successional dynamics of soil microbial communities in soils undergoing pulse events and how these interactions ultimately control organic matter stability. Specific Objectives: 1. Determine the types of functional shifts in the microbial community in response to pulse events with respect to carbon and nitrogen cycling. 2. Identify the microbial populations that are responding to pulse events (and are therefore responsible for the functional shifts). 3. Determine the long-term consequences of pulse events with respect to 1) identity/diversity of microbial communities 2) ecosystem functions (i.e. bulk microbial processes) and 3) soil chemistry (especially stable SOM). Expected Outputs: 1. An understanding of how pulse or "extreme" events affect microbial carbon cycling and ultimately stability of soil organic carbon 2. Generate process descriptions and data for use in carbon cycling models
Project Methods
General research approach: Two experimental systems which undergo natural pulse events will be targeted: water-limited soils subjected to moisture pulses and high productivity soils subjected to nutrient pulses from decomposing carcasses. We will measure and compare chemical, physical and microbiological changes (community composition, diversity and functional responses) in soils during pulse events. Soil chemical changes will be assessed by a combination of standard chemistry measures and organic matter profiling to track changes in the suite of substrates entering the soil. Microbial community analysis will focus on characterizing abundance (using qPCR), community composition (using rRNA gene sequencing), and functional rates (respiration, biomass production, and extracellular enzyme assays). This project will necessary generate large amounts of data on soil chemistry and microbial community structures. The community structure data will be visualized using multivariate techniques and we will also test hypotheses regarding compositional differences between communities using multivariate ordination (e.g. NMDS) using CANOCO and Primer6 software, as well as the tools in MOTHUR (Schloss et al. 2009). Community diversity and structure data will also be used as linear variables for statistical analyses against the other parameters measured in this study. General linear models will be used to evaluate the relationship between functional processes, physicochemical parameter and diversity/community structure calculations. These statistical approaches will reveal the populations and community structures that are most related to the decomposition processes.

Progress 01/01/13 to 12/31/17

Outputs
Target Audience:Target audiences include: -scientific professionals in microbiology, geology, paleontology; forensic science professionals, reached through conferences, publications and invited talks -graduate and undergraduate students trained by this project in multiple disciplines Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This work has contributed to the training of 1 undergraduate, 2 graduate and 1 postdoctoral scholar over the last year. The multidisciplinary nature of this work has resulted in training across disciplines (soil science, geology, biogeochemistry, ecology, microbiology soil chemistry, forensic anthropology). How have the results been disseminated to communities of interest?Results have been disseminated through publications and conference presentations. Invited talks were given for academic groups at various institutes. DeBruyn has translated this knowledge for the forensic resotration industry and serves as an advisor for the Global BioRisk Advisory Council, which provides advice on mitigation of microbial and biohazardous contamination in indoor environments. Other outreach includes youth eduction via the Forensic Chemistry Camp for middle schoolers. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1 - We characterized biogeochemical shifts in response to nutrient pulses from carrion decomposition. This work was presented at numerous conferences and is now published in Soil Biology and Biochemistry (Keenan et al. 2018) Objective 2 - We conducted lab scale microcosm studies to reveal the role of microbes in the cycling of nitrogen. This work was presented at GSA (Keenan 2018) and a mansucript is being drafted. Objecctive 3 - Long term pulse question was assessed through a continuation of the animal decomposition experiment described in Obj 1 and a study of a 4 year burial event and its impacts on soil biology and chemistry. This work has been presented at ASM (Mason 2018), ISME (Emmons 2018) and a manuscript is in review at PLOS ONE.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Keenan SW, SM Schaeffer, V Jin, JM DeBruyn. 2018. Mortality hotspots: nitrogen cycling in forest soils during vertebrate decomposition. Soil Biology Biochemistry121: 165-176
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Ashworth AJ, FL Allen, PR Owens, JM DeBruyn, CE Sams. 2018. Crop rotations and poultry litter impact long-term soil physicochemical properties and soil biota. Journal of Environmental Quality. DOI: 10.2134/jeq2017.12.0465
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Keenan SW, JM DeBruyn. Spatial and temporal biogeochemical responses to carrion decomposition. Goldschmidt Conference, Boston, MA, Aug 12-17, 2018
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Emmons AE, SW Keenan, AR Mason, K Hoeland, S Campagna, J Davoren, JM DeBruyn, AZ Mundorff. Edaphic and biogenic influences of skeletal DNA degradation in a multi-individual grave. International Society for Microbial Ecology Symposisum, Leipzig, Germany, Aug 12-17, 2018
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Taylor LS, G Phillips, EC Bernard, JM DeBruyn. Depth stratification of nematode communities associated with vertebrate decomposition. Society of Nematologists Annual Meeting, Albuquerque, NM, Jul 22-25, 2018
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Mason AR, SW Keenan, AL Emmons, LS Taylor, G Phillips, AZ Mundorff, EC Bernard, JM DeBruyn. Spatial impact of a multi-individual grave on soil biochemistry and microbial ecology. ASM Microbe, Atlanta, GA, Jun 7-11, 2018
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Keenan SW� and JM DeBruyn. Temperature and microbial effects on nitrogen cycling at simulated mortality decomposition hotspots. Southeastern Region Geological Society of America, Knoxville, TN, Apr 12-13, 2018
  • Type: Conference Papers and Presentations Status: Other Year Published: 2018 Citation: Keenan SW, JM DeBruyn, C Widga. Reconstructing nutrient hotspots in time: insights from the Gray Fossil Site, Tennessee. Southeastern Region Geological Society of America, Knoxville, TN, Apr 12-13, 2018
  • Type: Book Chapters Status: Published Year Published: 2018 Citation: Keenan SW, C Widga, JM DeBruyn, SM Schaeffer. Nutrient hotspots through time: A field guide to modern and fossil taphonomy in east Tennessee. In Engel AS, and RD Hatcher Jr., eds., Geology at Every Scale: Field Excursions for the 2018 GSA Southeastern Section Meeting in Knoxville, Tennessee: Geological Society of America Field Guide 50, p. 114, https://doi.org/10.1130/2018.0050(04)


Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Knowledge was disseminated to the scientific community via invited lectures, conferences and publication of manuscripts. Invited presentations were given for academic groups (several university seminars around the US) and general public (UT Science Forum). International audiences were reached through invited talks at the Chineses Academy of Science - Institute for Applied Ecology, Nankai University and Centro Interna?ional de la Papa, Perus. Chinese researchers were further engaged through a workshop in Shenyang, China (Oct 2016) and the launch of the new US-China Joint Center for Soil Productivity and Environmental Conservation. Graduate students working on this project received training in multiple disciplines (soil science, ecology, microbiology, biogeochemistry, forensic anthropology). Youth educators recieved new educational curricula and training in delivering activities to their students (4-H youth). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This work has contributed to the training of 2 graduate student and 2 undergraduate student over the past year. The multidisciplinary nature of this work has resuted in training in multiple disciplines (soil science, biogeochemistry, ecology, microbiology, soil chemistry, forensic anthropology). How have the results been disseminated to communities of interest?Results have been dissemated through publication in peer review journals and presentation at national and international meetings. Invited talks were given for academic groups (Bowling Green State University Department of Biology, Chinese Academy of Science - Institute of Applied Ecology, Nankai University, Centro Interna?ional de la Papa, Peru). The launch of the new US-China Joint Center for Soil Productivity and Environmental Conservation in Shenyang, China enabled dissemination of results to potential Chineses collaborators. Concepts were also disseminated general public and youth audiences via Bowling Green State University Kids Tech University Program and UT Science Forum. What do you plan to do during the next reporting period to accomplish the goals?Revise and resubmit manuscript for objective 1B. Finalize the data analysis and publication of results under objective 1C, 2 and 3.

Impacts
What was accomplished under these goals? Objective 1. Document shifts in microbial communities during pulse events:1A: An experiment comparing the decomposition dynamics of different mammalian species is finished and manuscript writing is underway. 1B: SWEATER: Severe Weather Events and Terrestrial Ecosystem Response. This project aims to study drought biogeochemistry in West Tennessee REC experimental plots. The effects of severe weather events on microbial soilrespiration (CO2) are thought to be ecosystem specific. In this project, we quantified changes in soil microbial respiration and biomass as a functionof soil moisture content in a Lexington silt loam from West Tennessee. We hypothesized that microbial respiration andbiomass are dependent on the magnitude and duration of changes in moisture content. Under this project we have trained one graduate student and 2 undergraduate students in Earth and Planetary Sciences and presented the reserach at the national meeting of the Geological Society of America. One manuscript was submitted for publication in Applied and Environmental Microbiology, but rejected; this will be revised and resubmitted next year. Two manuscripts on moisture controls on soil microbial activity were published in peer-reviewed journals and results were presented at international meetings in China and Peru, and one workshop presentation in China. Preliminary data used in proposals submitted to USDA-NIFA in 2016 and 2017. 1C. Feedbacks between microbial C utilization, aggregate stability and agricultural management in response to simulated precipitation and drought. The purpose of this project is to collect preliminary data and provide a proof concept that feedbacks between microbial activity and soil moisture can affect the distribution of SOC on the landscape. Namely, we wish to set up experimental manipulations, under different agricultural management conditions, where we can impose dry-wet cycles and observe changes in microbial C-use efficiency, soil aggregation and erodibility. Two graduate student presentations at national meetings in fall 2017, and a webinar was presented to the Intensively Managed Landscapes Critical Zone Observatory (IML-CZO) on wet/dry cycles, C storage and microbial activity. Objective 2. Identify microbial populations responding to pulse events: A field experiment with beaver carcasses was conducted, providing a full complement of nutrient and carbon soil biogeochemistry associated with decomposition. The experiment is complete and data were presented at several conferences. The manuscript describing this experiment has been submitted to Soil Biology Biochemistry. Objective 3. Long term consequences: Our research revealed several observations related to the question of the long term impacts of hot spots on ecosystems: 1) Introduced microbes can have a much longer persistancein soils that we originally thought (published in 2015) 2) Soil biogeochemical signatures are significantly altered a full year after initiation of decomposition (data being analysed) 3) Four years following burial, soil physicochemistry and nematode communities are still significantly impacted in a grave (manuscript in preparation.)

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Ashworth A, JM DeBruyn, FL Allen, M Radosevich, PR Owens. 2017. Microbial community structure is affected by cropping sequences and poultry litter under long-term no-tillage. Soil Biology and Biochemistry 114:210-219
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Wang Z, T Li, X Wen, Y Liu, J Han, Y Liao, JM DeBruyn. 2017. Fungal communities in rhizosphere soil under conservation tillage shift in response to plant growth. Frontiers in Microbiology 8:1301
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: DeBruyn JM, DA Bevard, ME Essington, JY McKnight, SM Schaeffer, HL Baxter, M Mazarei, DGJ Mann, RA Dixon, F Chen, C Zhuo, ZY Wang, CN Stewart. 2017. Field grown transgenic switchgrass (Panicum virgatum L.) with altered lignin does not affect soil chemistry, microbiology and carbon storage potential. Global Change Biology Bioenergy 9:1100-1109.
  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Ashworth AJ, FL Allen, PR Owens, JM DeBruyn CE Sams. Crop rotations and poultry litter impact long-term soil physicochemical properties and soil biota. Submitted to special issue of Journal of Environmental Quality. Dec 1, 2017
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: DeBruyn JM, KL Cobaugh�, M Moats*, JD Stevens�, SW Keenan�. Postmortem Hot Spots: Soil Microbial Community Succession below Decomposing Vertebrate Mortalities. ASA-CSSA-SSSA-Annual Meeting, Phoenix, AZ, Nov. 6-9, 2016
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Keenan SW, SM Schaeffer, VL Jin, JM DeBruyn. Biogeochemistry of vertebrate decomposition in a forest ecosystem. Southeastern Biogeochemistry Symposium. Athens, GA, Mar 31-Apr 2, 2017
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Taylor LS, G Phillips, SW Keenan, EC Bernard, JM DeBruyn. Spatial nematode community distributions associated with human decomposition in a mass grave. Society of Nematologists Annual Meeting, Williamsburg, VA, Aug 13-17, 2017
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Keenan SW, SM Schaeffer, JM DeBruyn. 2017. Stable isotopic composition of vertebrate tissues during decomposition. International Symposium on Environmental Biogeochemistry, Cairns, Australia, Sept 25-29, 2017
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: McKnight, JY, CP Hardin, SM Schaeffer (2017). Soil CO2 flux trends with differences in soil moisture among four types of land use in an Ecuadorian p�ramo landscape. Physical Geography, 38(1):51-61
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: DeBruyn JM, KA Hauther. 2017. Postmortem succession of gut microbial communities in deceased human subjects. PeerJ 5:e3437
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Emmons A, JM DeBruyn, AZ Mundorff, KL Cobaugh, GS Cabana. 2017. The persistence of human DNA in soil following surface decomposition. Science & Justice 57: 341-348
  • Type: Journal Articles Status: Under Review Year Published: 2017 Citation: Keenan SW, SM Schaeffer, V Jin, JM DeBruyn. Mortality hotspots: nitrogen cycling in forest soils during vertebrate decomposition. Submitted to Soil Biology Biochemistry.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Schaeffer, SM, CM Boot, P Homyak, DR Micholett, and JP Schimel (2017). Drought length increases microbial biomass and soluble organic matter in a California annual grassland. Soil Biology and Biochemistry, 115:54-62
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: McKnight, JY, C Hardin, SM Schaeffer (2016). Carbon-cycle effects of differences in soil moisture and soil extracellular enzyme activity at sites representing different land-use histories in high-elevation Ecuadorian p�ramo landscapes. American Geophysical Union Meeting, San Francisco CA
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Pendall, E, LB Flanagan, S Liu, S DelGrosso, B ElMaseri, J Liu, RT Conant, SM Schaeffer (2016). Resilience and Vulnerability of Carbon Cycling in North American Grasslands. American Geophysical Union Meeting, San Francisco CA


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Knowledge was disseminated to the scientific community via invited lectures, conferences and publication of manuscripts. Invited presentations were given for industry professional (restoration industry) and general public. Graduate student received training in multiple disciplines (soil science, ecology, microbiology, biogeochemistry, forensic anthropology). Youth educators recieved new educational curricula and training in delivering activities to their students (4-H youth). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This work has contributed to the training of 1 graduate student over the past year. The multidisciplinary nature of thiswork has resuted in training in multiple disciplines (soil science, ecology, microbiology, soil chemistry, forensic anthropology). How have the results been disseminated to communities of interest?Results have been dissemated through publication in peer review journals and presentation at national and international meetings. Additional invited talks for an industry group (forensic restoration) and general public (via American Society for Microbiology) provided opportunities to convey this research to non-scientific audiences as well. What do you plan to do during the next reporting period to accomplish the goals?Objectives 1 and 2 will be finalized and published. Objective 3 field work will be completed.

Impacts
What was accomplished under these goals? Objective 1. Document shifts in microbial communities during pulse events: 1A: An experiment comparing the decomposition dynamics of different mammalian species is coming to a close. Additional work to characterize the meta-metabolome of the soil microbial communities was done this year, contributing to a chapter of a chemistry PhD student's dissertation. Final data analysis is underway with anticipated submission of manuscripts in 2017. 1B: SWEATER: Severe Weather Events and Terrestrial Ecosystem Response. This project, started in 2014, and completed in 2015, is an active collaboration with faculty in Earth and Planetary Sciences (Terry Hazen) to study drought biogeochemistry in West Tennessee REC experimental plots. The effects of severe weather events on microbial soilrespiration (CO2) are thought to be ecosystem specific. In this project, we quantified changes in soil microbial respiration and biomass as a function of soil moisture content in a Lexington silt loam from West Tennessee. We hypothesized that microbial respiration and biomass are dependent on the magnitude and duration of changes in moisture content. Objective 2. Identify microbial populations responding to pulse events: 2A: Additional analyses were performed on samples collected from previous mammalian decomposition experiments. Metagenomic analyses were used to reveal the compositional shift in microbial communties that involved in carcass decomposition. This work resulted in two conference presentations and two published manuscripts in 2015, with another submission planned for 2017. Objective 3. Long term consequences: Our research revealed that introduced microbes can have a much longer persistance in soils that we originally thought. Data collection for this long term study is still ongoing, however part of it was published in 2015.

Publications

  • Type: Journal Articles Status: Awaiting Publication Year Published: 2016 Citation: 32) Johnson HR, DD Trinidad, S Guzman, Z Khan, JV Parziale, JM DeBruyn, NH Lents. 2016. A machine learning approach for using the postmortem skin microbiome to estimate the postmortem interval. PLoS One In press.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Keenan SW, KA Hauther, JM DeBruyn. Soil responses to a nutrient hotspot: the biogeochemistry of vertebrate decomposition in a forest ecosystem. Midwest Geobiology Conference, Cincinnati, OH Oct 15, 2016
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Keenan SW, AL Emmons, AZ Mundorff, JM Davoren, JM DeBruyn. Bone-associated microbes: Implications for the long-term stability of bone in terrestrial systems. Geological Society of America. Denver, CO Sept 25-28, 2016
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Emmons AL, JM DeBruyn, AZ Mundorff, KL Cobaugh, GS Cabana. Cadaver Decomposition and the Persistence of Human DNA in the Underlying Soil. In, Program of the 85th Annual Meeting of the American Association of Physical Anthropologists, p.21. Poster Presented at the 85th Annual Meeting of AAPA, Atlanta, GA, Apr 13-16, 2016
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Emmons AL, JM DeBruyn, AZ Mundorff, KL Cobaugh, GS Cabana. Examining the Persistence of Human DNA in Soil during Cadaver Decomposition. American Academy of Forensic Sciences. Las Vegas, NV, Feb 22-27, 2016
  • Type: Journal Articles Status: Accepted Year Published: 2016 Citation: McKnight, JY, CP Hardin, SM Schaeffer (2016). Soil CO2 flux trends with differences in soil moisture among four types of land use in an Ecuadorian p�ramo landscape. Physical Geography, Accepted, available online. doi:10.1080/02723646.2016.1256101
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Buckeridge, K, SM Schaeffer, JP Schimel (2016). Vegetation leachate during arctic thaw enhances soil microbial phosphorus. Ecosystems, 19(3):477-489
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: McKnight, JY, C Hardin, SM Schaeffer (2016). Carbon-cycle effects of differences in soil moisture and soil extracellular enzyme activity at sites representing different land-use histories in high-elevation Ecuadorian p�ramo landscapes. American Geophysical Union Meeting, San Francisco CA


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Knowledge was disseminated to the scientific community. Undergraduate student received training in multiple disciplines (soil science, ecology, microbiology, biogeochemistry, forensic anthropology) Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This work has contributed to the training of 1 graduate and 3 undergraduate students. The multidisciplinary nature of this work has resuted in training in multiple disciplines (soil science, ecology, microbiology, soil chemistry, forensic anthropology). In addition 2 students were able to attend national conferences and present their research. How have the results been disseminated to communities of interest?Results have been dissemated through publication in peer review journals and presentation at national and international meetings. What do you plan to do during the next reporting period to accomplish the goals?The work accomplished to date on Objectives 1 and 2 will be finalized and published. In 2016, we will conduct additional decomposition experiments with feral hog carcasses, monitoring for long term changes as described in Objective 3.

Impacts
What was accomplished under these goals? Objective 1. Document shifts in microbial communities during pulse events: 1A: An experiment comparing the decomposition dynamics of different mammalian species is coming to a close. All field work is complete and students are performing the final sample analyses. 1B: SWEATER: Severe Weather Events and Terrestrial Ecosystem Response. This project, started in 2014, and completed in 2015, is an active collaboration with faculty in Earth and Planetary Sciences (Terry Hazen) to study drought biogeochemistry in West Tennessee REC experimental plots. The effects of severe weather events on microbial soil respiration (CO2) are thought to be ecosystem specific. In this project, we quantified changes in soil microbial respiration and biomass as a function of soil moisture content in a Lexington silt loam from West Tennessee. We hypothesized that microbial respiration and biomass are dependent on the magnitude and duration of changes in moisture content. Products to date include: Presentation of research results at the national meeting of the Geological Society of America and preliminary data for a proposal to be submitted to DOE-Terrestrial Ecosystems Study Program in 2016. Objective 2. Identify microbial populations responding to pulse events: 2A: Additional analyses were performed on samples collected from previous mammalian decomposition experiments. Metagenomic analyses were used to reveal the compositional shift in microbial communties that involved in carcass decomposition. This work resulted in two conference presentations and two published manuscripts in 2015. Objective 3. Long term consequences: Our research revealed that introduced microbes can have a much longer persistance in soils that we originally thought. Data collection for this long term study is still ongoing, however part of it was published in 2015.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Hauther KA, KL Cobaugh, L Jantz, T Sparer, JM DeBruyn. 2015. Estimating time since death from post mortem gut microbial communities. Journal of Forensic Sciences 60(5): 1234-1240. DOI: 10.1111/1556-4029.12828
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Cobaugh KL, SM Schaeffer, JM DeBruyn. 2015. Functional and structural succession of soil microbial communities below decomposing human cadavers. PLoS ONE 10(6): e0130201.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Buckeridge, K, SM Schaeffer, JP Schimel (in press). Vegetation leachate during arctic thaw enhances soil microbial phosphorus. Ecosystems, in press
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: An, T, SM Schaeffer, S Li, S Fu, J Pei, H Li, J Zhuang, M Radosevich, and J Wang (2015). Carbon fluxes from plants to soil and dynamics of microbial immobilization under plastic film mulching and fertilizer application using 13C pulse-labeling. Soil Biology and Biochemistry, 80:53-61
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Driver, D, K ODell, C Paradis, N Mahmoudi, J Fortney, SM Schaeffer, T Hazen (2014). Changes in Microbial Respiration in Response to Severe Weather Events. Geological Society of America Meeting, Vancouver BC
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: DeBruyn JM, KL Cobaugh, SM Schaeffer. Succession of soil microbial communities below decomposing human cadavers. ASM General Meeting, New Orleans, LA, May 30-Jun 2, 2015
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2015 Citation: Cobaugh KL�, KA Hauther*, JM DeBruyn. Postmortem succession of human gut microbial communities. American Society for Microbiology General Meeting, New Orleans, LA, May 30-Jun 2, 2015


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Knowledge was disseminated to the scientific community Undergraduate and graduate students received training in multiple disciplines (soil science, ecology, microbiology, biogeochemistry, forensic anthropology) Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has resulted in training of several undergraduate students and a graduate student in multiple disciplines (soil science, ecology, microbiology, soil chemistry, forensic anthropology). How have the results been disseminated to communities of interest? Results have been dissemated through publication in peer review journals and presentation at national and international meetings. What do you plan to do during the next reporting period to accomplish the goals? Objective 1. Document shifts in microbial communities during pulse events: The multispecies decompositon project is on-going and will continue into 2015. We will finish collecting data, analyse and publish. Objective 2. Identify microbial populations responding to pulse events: We will continue documenting the microbial populations involved in pulse events.

Impacts
What was accomplished under these goals? Objective 1. Document shifts in microbial communities during pulse events: 1A: An experiment was initiated comparing the decomposition dynamics of different mammalian species. Students have been responsible for collecting an analysing soil samples, determining how the soil microbes respond to the pulse of decomposition products. Data collection and analysis is currently under way. 1B: Microbial use of carbon during decompositon has been determined in two different systems. The results are published in two manuscripts (Blankenship et al. 2014 and Jagadamma et al. 2014) Objective 2. Identify microbial populations responding to pulse events: 2A: Additional analyses were performed on samples collected from previous mammalian decomposition experiments - metagenomic analyses were used to reveal the compositional shift in microbial communties that involved in carcass decomposition. For one set of samples, a manuscript has been drafted and was accepted for publication (Hauther et al.). For a second data set, data analysis is complete and a manuscript is currently being drafted. Objective 3. Long term consequences: No work has been done on this objective to date.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Jagadamma, S, MA Mayes, JM Steinweg, and SM Schaeffer (2014). Substrate quality alters microbial mineralization of added substrate and soil organic carbon. Biogeosciences Discussions, 11:4451-4482
  • Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Driver, D, K ODell, C Paradis, N Mahmoudi, J Fortney, SM Schaeffer, T Hazen (2014). Changes in Microbial Respiration in Response to Severe Weather Events. Geological Society of America Meeting, Vancouver BC
  • Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Stevens, J, SM Schaeffer, JM DeBruyn. (2014). Effect of the nitrogen extender NBPT on soil nitrogen cycling microbes. Meeting of the Texas Branch of the American Society of Microbiology, New Braunfels TX
  • Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Manzoni, S, JP Schimel, SM Schaeffer, G Katul, T Katterer, G Agren, A Porporato (2014). Modeling physiological responses of soil microbes to drought. Ecological Society of America Meeting, Sacramento CA
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: Hauther KA, KL Cobaugh, L Jantz, T Sparer, JM DeBruyn. Estimating time since death from post mortem gut microbial communities. Journal of Forensic Sciences. In Press.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Blankinship, JC, CA Becerra, SM Schaeffer, and JP Schimel (2014). Separating cellular metabolism from exoenzyme activity in soil organic matter decomposition. Soil Biology and Biochemistry, 71:68-75


Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Forensic and Law Enforcement Officials - through education during a forensic anthropology summer course at University of Tennessee 4-H agents and students - through agent training workshops with newly developed "Backyard STEM" environmental science curriculum K-12 - through various summer camps and training programs Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Results from our work was disseminated to forensic law enforcement officials, who learned about how microbes are involved in human decomposition. We also demonstrated the results of the feral hog composting experiment to land owners and wildlife agents, who will now have greater knowledge of the best approaches for rapid odor-free carcass disposal. What do you plan to do during the next reporting period to accomplish the goals? During the next reporting period, we plan to extend our decomposition experiments to include a comparison of animal species. We will also focus on our second objective, which was to identify microbial populations involved in these processes.

Impacts
What was accomplished under these goals? Issue: Decomposition of organic matter (OM) is one of the most important functions of soil microorganisms. Understanding these processes is critical to determine the fate of soil organic matter (SOM) under a changing climate. Climate change models are dependent on data in order to accurately predict long term responses. Decomposition is also a critical process for disposal of organic wastes, including animal caracasses. Results: We conducted 3 decomposition experiments in the past year. The first revealed the activity and identity of soil microbes responsible for decomposing carcasses, and was a major component of a masters thesis (Cobaugh 2013). The second was conducted in response to a need for disposal of feral hog carcasses, and demonstrated the optimum materials and composting conditions for rapid and scavenger-free meltdown of these carcasses. We are in the process of preparing an extension publication detailing these methods. The third addressed the long term responses of microbes to a pollution event, revealing that even long after pollutants are degraded, the microbes are not the same as those in pristine, undisturbed soil. This suggests that temporary perturbations, like polluntant spills, can still have long term impacts on the environment. Our results are published (Ji et al. 2013). Broader outcomes: Results from our work was disseminated to forensic law enforcement officials, who learned about how microbes are involved in human decomposition. We also demonstrated the results of the feral hog composting experiment to land owners and wildlife agents, who will now have greater knowledge of the best approaches for rapid, clean carcass disposal.

Publications

  • Type: Theses/Dissertations Status: Published Year Published: 2013 Citation: Cobaugh, K. 2013. Soil Microbial Community Succession During Cadaver Decomposition. MS Thesis.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Ji X, SA Ripp, AC Layton, GS Sayler, JM DeBruyn. 2013. Assessing long term effects of bioremediation: Soil bacterial communities 14 years after polycyclic aromatic hydrocarbon contamination and introduction of a genetically engineered microorganism. Journal of Bioremediation & Biodegradation 4(8): 209
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Boot, C. M., S. M. Schaeffer, and J. P. Schimel. 2013. Static osmolyte concentrations in microbial biomass during seasonal drought in a California grassland. Soil Biology and Biochemistry, 57:356-361.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Schadel, C., Y. Luo, R. D. Evans, S. Fei, and S. M. Schaeffer. 2013. Separating soil CO2 efflux into C pool specific decay rates via inverse analysis of soil incubation data. Oecologia, 171:721-732.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Schaeffer, S. M., E. Sharp, J. P. Schimel, and J. M. Welker. 2013. Soil-plant N processes in a High Arctic ecosystem, NW Greenland are altered by long-term experimental warming and higher rainfall. Global Change Biology, 19:3529-3539.