Source: PRINCETON UNIV submitted to NRP
UNDERSTANDING COUPLING BETWEEN BIOGEOCHEMICAL CYCLING AND CLIMATE CHANGE IN NORTHERN ECOSYSTEMS: HISTORICAL ANALYSIS AND FUTURE PROJECTIONS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
0225191
Grant No.
2011-67003-30373
Cumulative Award Amt.
$900,000.00
Proposal No.
2011-00835
Multistate No.
(N/A)
Project Start Date
Jul 1, 2011
Project End Date
Jun 30, 2016
Grant Year
2011
Program Code
[A3151]- Interagency Climate Change
Recipient Organization
PRINCETON UNIV
(N/A)
PRINCETON,NJ 08544
Performing Department
Department of Ecology and Evolutionary Biology
Non Technical Summary
One of the largest sources of uncertainty about the predicted climate changes is the fate of the trillion metric tons of carbon currently locked in soils in the northern extra-tropics. Previous studies have shown that changes in soils in these regions depends critically on local characteristics such as amount of carbon (C), nitrogen (N) and hydrological properties, including patterns of surface water such as the mix of dry and wet conditions. Despite advances in computing, current global Earth System Models (ESMs - models simulating climate, ecosystems, and C and N cycles) typically simulate these processes at the scale of 100-200 km. These models cannot resolve smaller scale, local characteristics of hydrology and are unable to improve climate predictions. The objective of this proposal is (1) to incorporate a model describing within-grid characteristics of soil and hydrology into GFDL ESM and (2) to apply the new ESMs to improve our understanding of how changes in ecosystems will affect future climates. A new model of peatland dynamics will be incorporated into GFDL ESM, capable of simulating emissions of carbon dioxide (CO2) and methane (CH4) and accounting for variations of local dry/wet conditions. The improved ESM will be used to study how emissions of CO2 and CH4 from ecosystems affect climate. ESM simulations will provide allowable greenhouse gas emissions to inform other scientists, policy makers and public and to facilitate climate change policies formulation. All findings and principal data products will be available to the public, scientists, and US agencies.
Animal Health Component
33%
Research Effort Categories
Basic
34%
Applied
33%
Developmental
33%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020199100040%
1320430207030%
1310699107030%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 132 - Weather and Climate; 131 - Alternative Uses of Land;

Subject Of Investigation
0430 - Climate; 0199 - Soil and land, general; 0699 - Trees, forests, and forest products, general;

Field Of Science
2070 - Meteorology and climatology; 1070 - Ecology; 1000 - Biochemistry and biophysics;
Goals / Objectives
Future uptake and release of carbon and other greenhouse gases (e.g. CH4 and N2O) remains one of the greatest uncertainties in our efforts to model the Earth's climate system. Substantial amounts of carbon are stored in extra-tropical ecosystems in the Northern Hemisphere. Both model and observational experiments suggest that nutrient limitation of terrestrial CO2 uptake will become increasingly more prevalent over the next century. Extra-tropical soils store a large amount of organic matter, including peatlands, the decomposition of which can accelerate under warmer and wetter climate, releasing significant amounts of CO2. If peatlands are destabilized and CO2 and/or CH4 are released to the atmosphere, this could have a major impact on climate. Many current Earth System Models (ESMs) account for only a limited number of vegetation and soil C pools (e.g. leaves, roots, stems, etc) and represent only a few mechanisms (e.g. increased respiration or increased photosynthesis) shaping northern biogeochemical cycling. No ESM is currently capable of capturing sub-grid heterogeneity in hydrological features or the subsequent effects on peatlands and biogeochemical cycling. Because policy options and economic costs for stabilizing CO2 are closely tied to whether or not the terrestrial biosphere will continue to serve as a sustained C sink, the resolution of this uncertainty is critical to the national mitigation effort. We bring together a group of experimental, theoretical and modeling scientists to leverage our emerging understanding of vegetation, soils (including peatlands), and their response to climate change under nutrient limitation in northern extra-tropical environments. We will address four pressing challenges in developing and applying the next generation of ESMs: 1. Representation of how nitrogen and other nutrients are coupled to carbon in the terrestrial biosphere. This is particularly important for northern biomes since these regions will likely not benefit from CO2 fertilization and will be nutrient limited, and thus may be highly sensitive to climate change effects. 2. Characterization of peatland biogeochemistry in the ESM framework in a simple yet realistic manner. This will allow us to assess the role of peatlands in the changing climates and implications of these changes for atmospheric CO2 and CH4. 3. Representation of interactions between vegetation dynamics, biogeochemical cycling and soil physical environment (e.g. hydrology and thermodynamics) on a landscape scale. This will allow us to capture the role of sub-grid dynamics within a coarse-grid ESM framework. 4. Improved characterization of hydrological cycle in the high latitudes. The use of the-state-of-the-art National Oceanic Atmospheric Association/Geophysical Fluid Dynamic Laboratory (NOAA/GFDL) atmospheric model AM3 coupled to dynamic land, sea ice and ocean models will allow improved characterization of precipitation regime and possible perturbations to the hydrological cycle due to changes in both atmospheric composition and in the characteristics of land and sea ice.
Project Methods
To explore the role of northern ecosystems in the carbon cycle and methane emissions from preindustrial time and into the future, we will improve biogeochemical cycling and greenhouse gas emissions capabilities of the GFDL ESMs through a new parameterization of peatland dynamics and explicit representation of coupling between ecosystem functioning and sub-grid hydrological heterogeneities. Recently GFDL developed a number of new models, including a new Atmospheric Model AM3 and new Land Model LM3. AM3 is designed to serve as a physical-system component of ESMs and provides new capabilities to improve many features of climate simulations, including northern extra-tropics precipitation. The global land physics and biogeochemistry model LM3 includes dynamic vegetation and a representation of changing land-use practices. LM3 is specifically designed to represent effects of changes in land-use practices, including managed forests and abandonment of agricultural lands. The distribution of croplands and pastures as well as wood harvesting are prescribed from the historical land-use transition dataset and from the future scenarios based on IPCC AR5 RCPs. A new feature of LM3 is a coupled C-N dynamic. We will develop a comprehensive peatland component and integrate it with the capabilities of existing ESMs capabilities for simulation of vegetation and soil C and N. The improved representation of interactions between soil physics and ecosystem functioning will be achieved by using LM3's dynamic tiling infrastructure to allow distinct soil-vegetation regimes to develop along the hydrologicly defined gradients on the basis of model vegetation dynamics, topographic characteristics, and pedalogical and ecological data. We will use the suite of models developed by GFDL, Princeton and UNH scientists in a series of numerical experiments to address specific science questions. Our strategy will be to use a combination of uncoupled and coupled climate-land-C-N-CH4 model simulations to diagnose areas of model error/uncertainty and to isolate the effects of coupling among components. Progress at GFDL in climate physics and dynamics modeling will provide stand-alone land studies with improved estimates of physically consistent, diurnally resolved, climate data. Likewise, ongoing progress in modeling of the terrestrial and marine ecosystems will continue to improve GFDL's ESMs. We will evaluate historic simulations of climate and land dynamics using a comprehensive diagnostic suite developed by the GFDL global atmospheric and land model development teams. Additionally, we will expand our evaluation to include comparisons available through the C-LAMP framework. Specific deliverables and results will include: 1) output data from a set of climate-land-ocean-biogeochemistry models with various interactions on and off; 2) the suite of emissions from the pre-industrial time to present day (including scenarios of land-use) and for the future climate change; and 3) a better understanding of processes in Earth system through scientific publications.

Progress 07/01/11 to 06/30/16

Outputs
Target Audience: During the reporting period results of the research have been presented to a broad group of soil and earth system scientists at the following meetings and workshops: 1. 2nd International Conference on Global Food Security, Ithaca NY, 11-14 October, 2015 2. American Geophysical Union Fall Meeting, San Francisco, 14-18 December, 2015 3. IsoGenie2 "Illuminating the pathways to carbon liberation: a systems and modeling approach to resolving the 'consequential unknowns' of carbon transformation and loss from thawing permafrost peatlands" Tallahassee, FL, Feb 25 - 29, 2016 Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?With support of this project, 2postdoctoral fellows ( Dr. S. Smolander, Dr. X. Zhang) have been trained in developing and application of the NOAA/GFDLEarth System models and its land components. How have the results been disseminated to communities of interest? Results of the research have been published in the peer-reviewed journals and presented by the PIs and postdoctoral scientists at national and international conferences and workshops. The new models have been incorporated into the GFDL ESM global models developed in preparations for the next Coupled Model Comparison Project, phase 6 (CMIP6). The output from the new ESM simulations will be publicly available for the broad scientific community. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We developed novel modelsof coupled nitrogen-carbon cycling and methanein the terrestrial biosphere, which have been integrated into GFDL Earth system models. This models are capable to capture carbon accumulation in frozen soils such as peatlands.These new models captureinteractions between vegetation dynamics, biogeochemical cycling and soil physical environment. The new models include interactions of biogeichemical cycles with sub-grid liquid and frozen heterogeneity, which are critical for simulationsof climate variability and change inhigh latitudes. We explored how changes in both unmanaged and managed ecosystem fucntioning translateinto emisison sof greenhouse gases under different climate change pathways.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Zhang, X., Davidson, E. A., Mauzerall, D. L., Searchinger, T. D., Dumas, P., & Shen, Y. (2015). Managing nitrogen for sustainable development. Nature, 528(7580), 51-59.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: S Smolander, BN Sulman, E Shevliakova, Explicit Microbial Processes to Simulate Methane Production and Oxidation in Wetlands in the GFDL Land Model, AGU Fall Meeting Abstracts, 2015


Progress 07/01/14 to 06/30/15

Outputs
Target Audience: During the reporting period results of the research have been presented to a broad group of soil amd earth system scientists at the following meetings and workshops: Complex Soil Systems Conference September 3-5 2014, David Brower Center, Berkeley, California. AGU Fall meeting, December 15-19, 2014, San Francisco, CA World Concerns Discussion Group, Havenwood/Heritage Heights Senior Center, Concord NH in Nov. 2014. Meeting of the project scientists and collaborators, September 30-October 1, 2014, Princeton, NJ. Annual Meeting 2015 of the EU projects PANDA and MARCOPOLO, 26-29 January 2015, Hamburg, Germany. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? With support of this project, 5 postdoctoral fellows (Dr. Benjamin Sulman, Dr. Zackary Subin, Dr. Chiara Medichi, Dr. S. Smolander, Dr. X. Zhang) have been trained in developing and application of the NOAA/GFDLEarth System models and its land components. UNH PI Frolking's support in this project has contributed to supervision, as research faculty, of a PhD and an MS student at UNH. Ms.Claire Treat was awarded a highly-competitive Dept. of Energy Graduate Fellowship to conduct field and lab research on peat carbon susceptibility to climate change, and Frolking serves on her PhD committee. How have the results been disseminated to communities of interest? Results of the reserach have been published in the peer-reviewed journals and presented at the national and international conferences. The Princeton PI Pacala, co-PI Shevliakova, and the UNH PI Frolking presented invited talks on climate change and terrestrial ecosystem feedbacks such as peatlands potential losses of carbon. What do you plan to do during the next reporting period to accomplish the goals?During the proposed extension period five major tasks are planned: Complete integration of the new soil nitrogen capabilities and evaluation of global model performance, including peatlands, over the control and historical period. Prepare a manuscript documenting the new model. Complete integration and evaluation of the new methane model for pre-industrial and historical period. Prepare a manuscript documenting the new model. Evaluate implications of changes in hydro climate for CO2, CH4 and N2O under future climate (forcing from GFDL CMIP5 simulations) and assess parametric and structural uncertainty in model projections. Document finding of the analysis in a new manuscript.

Impacts
What was accomplished under these goals? During the 2014-2015 period we have continued development of the state-of-the-art soil biogeochemistry and hydrology modules in the terrestrial land model LM3 and its application to advance scientific understanding of soil carbon emissions of greenhouse gasses from soils, including peatlands, under changing climate. There are seven major accomplishments achieved during this year: First, we developed, evaluated, analyzed and documented a new Soil Organic Carbon (SOC) model, LM3-CORPSE. This is the first global terrestrial component of ESMs to include parameterization of microbes and root exudates. We have applied a new model and found in global simulations that microbial priming caused a net loss of SOC in temperate and boreal regions whereas the formation and stabilization of SOC resulted in net gains in the tropics (Sulman et al, 2014). We have integrated LM3-CORPSE into the National Oceanographic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL) Earth System Modeling (ESM) framework, which includes a fully coupled interactive models of atmosphere, ocean, sea and land ice, and land, including fully prognostic global C cycling. Second, we have developed, evaluated and analyzed the first global hill-slope -resolving hydrological model LM3-TiHy (Subin et al, 2014). Earth-System Models (ESMs) generally represent an areal-average soil-moisture state in grid cells at scales of 25 to 200 km and as a result are not able to capture the nonlinear effects of topographically controlled sub-grid heterogeneity in soil moisture, in particular changes in wetland area. The LM3-TiHy model represents hillslope geometries for each gridcell by discretizing them into land model tiles hydrologically coupled along an upland-to-lowland gradient. The new approach allows simulate dynamically past and future changes in the extent of wetlands due to changes in hydroclimate. Third, we have integrated LM3-CORPSE and LM3-TiHy capabilities and simulated implications of sub-grid heterogeneity in hydrological properties for vegetation dynamics and functioning as well as accumulation and losses of carbon and characterize differences in the low-land vs. up-land biogeochemical dynamics. Fourth, we have begun exploring relationship between the peatland net carbon balance and carbon accumulation rates at centennial to millennial time scale in the terrestrial ecosystem model HPM (Frolking et al 2014). Furthermore we have designed and implemented a dynamic peat model in to a coupled LM3-CORPSE-TiHy system. This advance consideration undergoing evaluation, results of which will be presented in a new manuscript. Fifth, we have implemented a new simple denitrification module for both soils and rivers into LM3-TAN and evaluated it performance on decadal timescale for the Chesapeake basin (Lee et al, 2014) and explored effects of interactions between extreme climate and water quality on the regional scale . We have also used the new denitrification capabilities to explore joint implications of changes in land-use management and climate for global emissions of N2O gases. Sixth, we have implemented a global LM3-CORPSE-Nitrogen model, which includes advanced capabilities such as microbial C-N interactions, C&N leaching, denitrification, and vertical heterogeneity in C&N pools. We are currently working on evaluation of this new capability, which will be documented in a new manuscript. Seven, we have designed and are currently implementing a prototype coupled version of LM3-CORPSE-CH4, which includes advanced explicit treatment of acetoclastic and hydrogenotrophic methane production and microbial groups.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Kurnianto, Sofyan, Matthew Warren, Julie Talbot, Boone Kauffman, Daniel Murdiyarso, and Steve Frolking. "Carbon accumulation of tropical peatlands over millennia: a modeling approach." Global change biology 21, no. 1 (2015): 431-444.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2015 Citation: X. Zhang, E.A. Davidson, D.L. Mauzerall, T.D. Searchinger,P. Dumas, Y. Shen. Managing nitrogen for sustainable development. Nature, accepted, doi: 10.1038/nature15743
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Sulman, Benjamin N., Richard P. Phillips, A. Christopher Oishi, Elena Shevliakova, and Stephen W. Pacala. "Microbe-driven turnover offsets mineral-mediated storage of soil carbon under elevated CO2." Nature Climate Change 4, no. 12 (2014): 1099-1102.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Subin, Z. M., P. C. D. Milly, B. N. Sulman, S. Malyshev, and E. Shevliakova. "Resolving terrestrial ecosystem processes along a subgrid topographic gradient for an earth-system model." Hydrology and Earth System Sciences Discussions 11, no. 7 (2014): 8443-8492.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Lee, M., S. Malyshev, E. Shevliakova, and P. R. Jaff�. "Capturing interactions between nitrogen and hydrological cycles under historical climate and land use: Susquehanna watershed analysis with the GFDL Land Model LM3-TAN." Biogeosciences Discussions 11, no. 4 (2014): 5669-5710.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Malyshev, Sergey, Elena Shevliakova, Ronald J. Stouffer, and Stephen W. Pacala. "Contrasting Local vs. Regional Effects of Land-Use-Change Induced Heterogeneity on Historical Climate: Analysis with the GFDL Earth System Model." Journal of Climate 2015 (2015).
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Milly, P. C. D., Sergey L. Malyshev, Elena Shevliakova, Krista A. Dunne, Kirsten L. Findell, Tom Gleeson, Zhi Liang, Peter Phillipps, Ronald J. Stouffer, and Sean Swenson. "An enhanced model of land water and energy for global hydrologic and earth-system studies." Journal of Hydrometeorology 15, no. 5 (2014): 1739-1761.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Frolking S, Talbot J, Subin ZM. 2014. Exploring the relationship between peatland net carbon balance and apparent carbon accumulation rate at century to millennial time scales, The Holocene, 24, 11671173, DOI: 10.1177/0959683614538078.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Quillet A, Garneau M, van Vellen S, Frolking S, Tuittila ES. 2015. Integration of palaeo-hydrological proxies into a peatland model: a new tool for palaeoecological studies, Ecohydrology, 8, 214-229; DOI: 10.1002/eco.1501.


Progress 07/01/13 to 06/30/14

Outputs
Target Audience: During the reporting period results of the research have been presented to a broad group of soil amd earth system scientists at the following meetings and workshops: 1. EaSM PI meeting January 27-29, 2014, Washington, DC 2. AGU Fall meeting, December 9-13, 2013, San Francisco, CA 3.Mer Bleue Workshop, March 3-4, 2014 Montreal, Que., Canada 4.NSF RCN FORECAST workshop “Representing Soil Carbon Dynamics in Global Land Models to Improve Future IPCC Assessments”, June 11-14, 2014 in Breckenridge, CO. 5. 19th Annual CESM Workshop, June 16-19, Breckenridge, CO Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? With support of this project, 3 postdoctoral fellows (Dr. Benjamin Sulman, Dr. Zackary Subin, and Dr. Chiara Medichi) have been trained in developing and application of the NOAA/GFDLEarth System models and its land components. UNH PI Frolking’s support in this project has contributed to supervision, as research faculty, of a PhD and an MS student at UNH. Ms. Claire Treat was awarded a highly-competitive Dept. of Energy Graduate Fellowship to conduct field and lab research on peat carbon susceptibility to climate change, and Frolking serves on her PhD committee. How have the results been disseminated to communities of interest? Results of the reserach have been published in the peer-reviewed journals and presented at the national and international conferences as well as tat he USDA/NSF EasM PI meetings. The Princeton PI Pacala, co-PI Shevliakova, and the UNH PI Frolking presented invited talks on climate change and terrestrial ecosystem feedbacks such as peatlands potential losses of carbon. What do you plan to do during the next reporting period to accomplish the goals? We are planning to conduct a new set of simulations with the newly developed soil carbon and hydrology moels to explore how changes in climate may affect changes in high-latitude wetlands and what implications it will have for the peat carbon. Additionally, we are planning to complete integration of the new soil carbon models with the advances model of nitrogen cycling and the new methane model. We will use the new capability to simulate future emissions of CH4 under the latest scenarios of climate change and variability, including changes in the vegetation distribution in teh Arctic-Boreal zones.

Impacts
What was accomplished under these goals? We developed a first global computer model of soil carbon and its interactions with plant roots and the soil microbial community, and ran the model at global scales to investigate the roles of these processes in the global carbon cycle. Our simulations show that these processes can have dramatic effects on the amount of carbon that is stored in soils: In fact, even as plant growth increases, soil carbon can be lost due to this root-driven increase in microbial activity. The existing computer models used to simulate future climate change generally cannot simulate interactions between plant growth and soil decomposition rates, so this study represents a real advance in our ability to simulate the global carbon cycle. Our model has been integrated into the global land model used for climate simulations by the National Oceanographic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory (GFDL), a major national climate modeling center. This will allow important plant-soil interaction processes to be included in future climate assessments. Earth-system models (ESMs) generally represent an areal- average soil-moisture state in gridcells at scales of 50–200km and as a result are not able to capture the nonlinear effects of topographically-controlled subgrid heterogeneity in soil moisture, in particular where wetlands are present. We addressed this deficiency by building a subgrid representation of hillslope-scale topographic gradients, TiHy (Tiled-hillslope Hydrology), into the Geophysical Fluid Dynamics Laboratory (GFDL) land model (LM3). LM3-TiHy models one or more representativehillslope geometries for each gridcell by discretizing them into land model tiles hydrologically coupled along an upland-to-lowland gradient. With improved parameterization and inclusion of peatland biogeochemical processes, the model could provide a new approach to investigating the vulnerability of Boreal peatland carbon to climate change in ESMs. We explored the relationship betweenpeatland net carbon balance andapparent carbon accumulation rate atcentury to millennial time scalesusing a process-based peatland carbon and water cycle models. We quantifed thetemperature, moisture, and microbial controls on soil organic carbon (SOC) losses following permafros thaw in peat smaples collected in Alaska and then compared their carbon dioxide (CO2) and methane (CH4) emissions. Our analysis suggest that soil organic matter losses depend both on cimatic changes and onorganic matter quality, permafrosthistory, and vegetation dynamics.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: P. C. D. Milly, Sergey L. Malyshev, Elena Shevliakova, Krista A. Dunne, Kirsten L. Findell, Tom Gleeson, Zhi Liang, Peter Phillipps, Ronald J. Stouffer, and Sean Swenson, 2014:An Enhanced Model of Land Water and Energy for Global Hydrologic and Earth-System Studies. J. Hydrometeor, 15, 17391761. doi: http://dx.doi.org/10.1175/JHM-D-13-0162.1
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Lee, M., S. Malyshev, E. Shevliakova, and P. R. Jaff�. "Capturing interactions between nitrogen and hydrological cycles under historical climate and land use: Susquehanna watershed analysis with the GFDL Land Model LM3-TAN." Biogeosciences.
  • Type: Journal Articles Status: Under Review Year Published: 2014 Citation: ubin, Z. M., P. C. D. Milly, B. N. Sulman, S. Malyshev, and E. Shevliakova. "Resolving terrestrial ecosystem processes along a subgrid topographic gradient for an earth-system model." Hydrology and Earth System Sciences Discussions 11, no. 7 (2014): 8443-8492.
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: B. Sulman, R. Phillips , A. Oishi , E. Shevliakova , S. Pacala, 2014:Microbe-driven turnover offsets mineral-mediated storage of soil carbon under elevated CO2, Nature Climate Change
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Frolking S, Talbot J, Subin ZM. 2014. Exploring the relationship between peatland net carbon balance and apparent carbon accumulation rate at century to millennial time scales, The Holocene, 24, 1167-1173.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Treat CC, Wollheim W, Grandy AS, Talbot J, Varner RK, Frolking S. 2014. CO2 and CH4 production is a function of peat type but not permafrost status in Alaskan permafrost peats, Global Change Biology, 20, 26742686, doi: 10.1111/gcb.12572.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Noyce G, Varner RK, Bubier JL, Frolking S. 2014. Effect of Carex rostrata on seasonal and interannual variability in peatland methane emissions, J. Geophys. Res. Biogeosci., 119, doi:10.1002/2013JG002474.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Treat CC, S Frolking. 2013. A permafrost carbon bomb? The fate of permafrost soil carbon following thaw depends on hydrology, Nature Climate Change, 3, 865-867.


Progress 07/01/12 to 06/30/13

Outputs
Target Audience: During this reporting period results of the reserach have been presented to a broad group of scientists at the following meetings and workshops in the US and Europe: EaSM PI meeting July 9-11, 2012, Wahsington, DC. "Methane cycling and climate feedbacks: integrating from genes to ecosystem in a subarctic wetland workshop", March 6-10, 2013 Durham, NH The International Union of Soil Sciences (IUSS) Global Soil Carbon Conference June 3-6, 2013 Madison, WI (http://iuss-c-conference.org) Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Two postdoctoral fellows have been trained in use and application of GFDL modeling tools. In designing the two new modeling framework, they have conducted a literature review of soil hydrology and biogeochemistry, includig synthesis of available observations and modeling approaches. How have the results been disseminated to communities of interest? Postdoctoral fellows and project scientsists have particpitated in a number of workshops and conferences and presented their scientific results, including: EaSM PI meeting July 9-11, 2012, Wahsington, DC. North American Carbon Program (NACP) meeting in Albuquerque, NM in February, 2013 "Methane cycling and climate feedbacks: integrating from genes to ecosystem in a subarctic wetland workshop", March 6-10, 2013 Durham, NH The International Union of Soil Sciences (IUSS) Global Soil Carbon Conference June 3-6, 2013 Madison, WI (http://iuss-c-conference.org) What do you plan to do during the next reporting period to accomplish the goals? During the next reporting period we are planning to finilized and submit manuscripts describing the extensive development and application of the new models. Additionally, We are planning to imrpove soil carbon model and implement methane and denitrifications moduls, which will be documented in the manuscripts and presented at the conferences and workshops. Finally we are planning to perform new numerical experimenst with the improved biogeochemical interactions.

Impacts
What was accomplished under these goals? First, we have developed a framework for a generic, global implementation of a tiled hillslope model for use with terretsrial components of Earth System models (ESMs), such as those developed at NOAA/GFDL. This approach accounts for groundwater transport on a ~1 km scale from hilltop to stream. The template allows for flexible implementation of hillslope geometry, natural disturbance, and land use changes by allowing multiple tiles to exist within the same hillslope “vertical tile cluster” and multiple hillslope units to exist within the same gridcell. We have evaluated this new framework with several alternative hillslope-geometry and stream parameterizations in the 300-yr long numerical experiments. A manuscript describing the new hill-slope framework and its evaluation is in preparation. Second, wedesigned and developed a new vertically-resolved soil carbon model for use with ESMs. The new soil model includes microbial biomass and protected soil carbon pools. We have implemented the model in both a stand-alone version and a version integrated into the NOAA/GFDL LM3 land model, a component of all NOAA/GFDL ESMs. We have evaluated the stand-alone version against measurements from the Duke elevated CO2 experiment, and have submittedd a manuscript describing the model and presenting those results to Global Change Biology. We have also successfully completed preliminary global simulations using the new soil carbon model, and are currently evaluating and analyzing those results. Third, we combined the new hillslope-tiling approach and the new soil model and completed multi-century scale experiments and are currently evaluating effects of hydrological sub-grid heterogeneity on soil carbon pools and fluxes.

Publications

  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Zachary M. Subin, "Representing the Effects of Hillslope-Scale Hydrology on Soil Carbon Distributions within an Earth System Model." AGU Chapman Conference on Soil-mediated Drivers of Coupled Biogeochemical and Hydrological Processes Across Scales, 21 October 2013  24 October 2013, Tucson, AZ, USA
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Shevliakova, Elena, Ronald J. Stouffer, Sergey Malyshev, John P. Krasting, George C. Hurtt, and Stephen W. Pacala. "Historical warming reduced due to enhanced land carbon uptake." Proceedings of the National Academy of Sciences 110, no. 42 (2013): 16730-16735.
  • Type: Journal Articles Status: Under Review Year Published: 2013 Citation: Sulman, Benjamin, A Christopher Oishi, Elena Shevliakova, Stephen Pacala. "Root exudation stimulates decomposition but increases protected carbon formation: Results from a new soil carbon model." Global Change Biology, in review, manuscript ID GCB-13-1275, International Union of Soil Sciences Global Soil C Conference 3-6 June 2013, Madison, WI.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2013 Citation: Sulman, B., E. Shevliakova, S. Malyshev, S. Pacala. "Simulating priming effects, measurable carbon pools, and climate change sensitivity of soil carbon in an earth system model",


Progress 07/01/11 to 06/30/12

Outputs
OUTPUTS: Consistent with the proposal, during Year 1 the majority of effort went into the first goal of the proposal: to incorporate a mechanistic model of sub-grid scale heterogeneity in soil hydrology into a global models of the C and N cycles and vegetation dynamics in the NOAA/GFDL ESMs. We have designed a flexible, dynamic treatment of subgrid heterogeneity, both aboveground and belowground, and begin its implementation in LM3 -land component of the GFDL Earth system model (ESM). We are currently exploring hypothesis that characteristic differences in soil and vegetation biogeochemistry between wetter and drier ecosystems will emerge naturally within this framework, allowing more realistic simulation of peatland dynamics. In the developed design, each gridcell is decomposed into one or several characteristic hillslope types, derived from high-resolution Digital Elevation Model (DEM) data. Each hillslope is itself discretized according to vertical elevation, and spatially heterogeneous land cover change or natural disturbance is represented by splitting hillslope units into unchanged and altered fractions that will then evolve separately over time. In order to simulate peat development and its response to hydrology (a major goal of this project) it will also be necessary to simulate multiple, vertical soil carbon distribution. Current ESMs typically simulate only a single "box" of soil carbon, with no representation of the vertical distribution. We have reviewed the soil carbon literature and identified the most important processes for improving our model of soil carbon decomposition and preservation. We are in the process of refining and implementing a conceptual model that includes microbial communities, physical protection in aggregates, and multiple soil layers. The carbon preservation framework is designed around the conceptual model, which relates microaggregate formation to microbial activity, macroaggregate formation, and macroaggregate lifetime. The preliminary model also includes new functions for the temperature and moisture dependence of soil decomposition. Transfers of carbon between vertical soil layers through leaching and bioturbation are also included. Portions of this model have been implemented in preliminary standalone code to be used for testing of processes. Additionally, with support from other projects, Steve Frolking (the PI on the UNH sub-contract) has worked on peatland/permafrost modeling (Treat et al. in review); on peatland vegetation in the context of ecosystem development and resilience (Tuittila et al. 2012; Turetsky et al. 2012), and on reviews of peatlands and the climate system (Frolking et al. 2011; Previdi et al., in review). PARTICIPANTS: PROJECT PERSONAL: We have conducted a job search and have hired two highly qualified postdoctoral fellows, Dr. Benjamin Sulman (starting June 11, 2012) and Dr. Zackary M. Subin (starting August 1, 2012). Despite the late active project start, we have made substantial progress on the project goals for year 1. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Graduate Student Supervision In addition to providing scientific guidance on this project, PI Pacala has supervised Ms. Caroline Farior and Dr. Ensheng Wang at Princeton University, whose research forms a foundation of a new dynamic vegetation model LM3-Perfect Plasticity Approximation (LM3-PPA). This model explicitly resolves competition among different plant species for light and water, including species in the understory. The new LM3-PPA will be used to introduce bryophyte species to simulate peatland ecosystem dynamics. UNH PI Frolking's support in this project has contributed to supervision, as research faculty, of a PhD and an MS student at UNH. Ms. Claire Treat was awarded a highly-competitive Dept. of Energy Graduate Fellowship to conduct field and lab research on peat carbon susceptibility to climate change, and Frolking serves on her PhD committee. Ms. Kaitlyn Steele completed her MS in Earth Sciences in July 2012, and Frolking served on her MS committee. Her thesis project involved field studies of biogeochemistry (in particular, H2 concentrations and fluxes) at a degrading permafrost peatland site (Stordalen Mire, Sweden) and in a boreal forest organic horizon soil. Service to Research Community and Outreach: Two project scientists (Steve Frolking and Elena Shevliakova) participated in an international Arctic-Boreal Zone Modeling Workshop, held at the NASA Goddard Space Flight Center, 22-24 May 2012. Frolking gave one of two invited plenary talkes, titled "Biogeochemistry in the Arctic-Boreal Climate System"; Frolking also led the Biogeochemistry break-out group at the workshop, and is a contributing author to the workshop report (Piers Sellers, Michele Rienecker, Steve Frolking, David Randall, Earth System Modeling and Field Experiments in the Arctic-Boreal Zone - NASA Workshop Report), which has undergone final revisions and will be submitted to senior NASA personnel this fall. The goal of this workshop (and the subsequent report) is to identify and prioritize gaps in understanding of the arctic-boreal system, particularly those that limit our predictive capabilities as the north is influenced by climate change.

Publications

  • Tuittila E-S, S Juutinen, S Frolking, M Valiranta, AM Laine, A Miettinen, M-L Sevakivi, A Quillet, P Merila. 2012. Wetland chronosequence as a model of peatland development: Vegetation succession, peat and carbon accumulation, Holocene. doi:10.1177/0959683612450197.
  • Turetsky MR, B Bond-Lamberty, E Euskirchen, J Talbot, S Frolking, AD McGuire, E-S Tuittila. 2012. The resilience and functional role of moss in boreal and arctic ecosystems, New Phytologist (Tansley Review), 196, 49-67.
  • Frolking S, Talbot J, Jones M, Treat CC, Kauffman JB, Tuittila ES, Roulet NT. 2011. Peatlands in the Earth's 21st century climate system, Environ. Rev., 19:371-396.
  • Previdi M, BG Liepert, D Peteet, J Hansen, DJ Beerling, AJ Broccoli, S Frolking, JN Galloway, M Heimann, C Le Quere, S Levitus, DM Murphy, V Ramaswamy. 2012-in review. Climate sensitivity in the Anthropocene, Quarterly Journal of the Royal Meteorological Society.
  • Treat CC, D Wisser, S Marchenko, KF Huemmrich, S Frolking. 2012-in review. Relative impacts of climate change and disturbance on permafrost stability in northern organic soils, Mires and Peat.