Jennifer Harden, PhD (Former Employee)
Science and Products
Filter Total Items: 144
Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps
Heterotrophic respiration (HR), the aerobic and anaerobic processes mineralizing organic matter, is a key carbon flux but one impossible to measure at scales significantly larger than small experimental plots. This impedes our ability to understand carbon and nutrient cycles, benchmark models, or reliably upscale point measurements. Given that a new generation of highly mechanistic...
Authors
Ben Bond-Lamberty, Daniel Epron, Jennifer W. Harden, Mark E. Harmon, Forrest Hoffman, Jitendra Kumar, Anthony D. McGuire, Rodrigo Vargas
Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils
Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key to understanding the future response of soil carbon stocks. Permafrost aggradation can control the magnitude of the carbon feedback in peatlands through effects on peat properties. We compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 280 sites) and...
Authors
Claire C. Treat, Miriam C. Jones, P. Camill, A. Gallego-Sala, M. Garneau, Jennifer W. Harden, G. Hugelius, E.S. Klein, Ulla Kokfelt, P. Kuhry, Julie Loisel, J.H. Mathijssen, J.A. O'Donnell, P.O. Oksanen, T.M. Ronkainen, A. B. K. Sannel, J. J. Talbot, C.M. Tarnocal, M. Valiranta
Toward more realistic projections of soil carbon dynamics by Earth system models Toward more realistic projections of soil carbon dynamics by Earth system models
Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other...
Authors
Y. Luo, Anders Ahlstrom, Steven D. Allison, Niels H. Batjes, V. Brovkin, Nuno Carvalhais, Adrian Chappell, Philippe Ciais, Eric A. Davidson, Adien Finzi, Katerina Georgiou, Bertrand Guenet, Oleksandra Hararuk, Jennifer Harden, Yujie He, Francesca Hopkins, L. Jiang, Charles Koven, Robert B. Jackson, Chris D. Jones, M. Lara, J. Liang, A. David McGuire, William Parton, Changhui Peng, J. Randerson, Alejandro Salazar, Carlos A. Sierra, Matthew J. Smith, Hanqin Tian, Katherine E. O Todd-Brown, Margaret S. Torn, Kees Jan van Groenigen, Ying Wang, Tristram O. West, Yaxing Wei, William R. Wieder, Jianyang Xia, Xia Xu, Xiaofeng Xu, T. Zhou
Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost
Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of...
Authors
Eugenie S. Euskirchen, C.W. Edgar, M.R. Turetsky, Mark P. Waldrop, Jennifer W. Harden
A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback
We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate...
Authors
C.D. Koven, E.A.G. Schuur, C. Schädel, T. J. Bohn, E. J. Burke, G. Chen, X. Chen, P. Ciais, G. Grosse, J.W. Harden, D.J. Hayes, G. Hugelius, Elchin E. Jafarov, G. Krinner, P. Kuhry, D.M. Lawrence, A. H. MacDougall, Sergey S. Marchenko, A. David McGuire, Susan M. Natali, D.J. Nicolsky, David Olefeldt, S. Peng, V.E. Romanovsky, Kevin M. Schaefer, J. Strauss, Claire C. Treat, M. Turetsky
Climate change and the permafrost carbon feedback Climate change and the permafrost carbon feedback
Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission...
Authors
E.A.G. Schuur, A. David McGuire, C. Schädel, G. Grosse, J.W. Harden, D.J. Hayes, G. Hugelius, C.D. Koven, P. Kuhry, D.M. Lawrence, Susan M. Natali, David Olefeldt, V.E. Romanovsky, K. Schaefer, M.R. Turetsky, Claire C. Treat, J.E. Vonk
Long-term controls of soil organic carbon with depth and time: a case study from the Cowlitz River Chronosequence, WA USA Long-term controls of soil organic carbon with depth and time: a case study from the Cowlitz River Chronosequence, WA USA
Over timescales of soil development (millennia), the capacity of soils to stabilize soil organic carbon (SOC) is linked to soil development through changes in soil mineralogy and other soil properties. In this study, an extensive dataset of soil profile chemistry and mineralogy is compiled from the Cowlitz River Chronosequence (CRC), WA USA. The CRC soils range in age from 0.25 to 1200...
Authors
Corey R. Lawrence, Jennifer W. Harden, Xiaomei Xu, Marjorie S. Schulz, Susan E. Trumbore
Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice
The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming...
Authors
Stephanie A. Ewing, James B. Paces, J.A. O'Donnell, M.T. Jorgenson, M.Z. Kanevskiy, George R. Aiken, Y. Shur, Jennifer W. Harden, Robert G. Striegl
Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests
Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme...
Authors
Yujie He, Jinyan Yang, Qianlai Zhuang, Jennifer W. Harden, A. David McGuire, Yaling Liu, Gangsheng Wang, Lianhong Gu
Effects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence Effects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence
Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2)...
Authors
Carmel E. Johnston, Stephanie A. Ewing, Jennifer W. Harden, Ruth K. Varner, Kimberly P. Wickland, Joshua C. Koch, Christopher C. Fuller, Kristen L. Manies, M. Torre Jorgenson
The implications of microbial and substrate limitation for the fates of carbon in different organic soil horizon types of boreal forest ecosystems: a mechanistically based model analysis The implications of microbial and substrate limitation for the fates of carbon in different organic soil horizon types of boreal forest ecosystems: a mechanistically based model analysis
The large amount of soil carbon in boreal forest ecosystems has the potential to influence the climate system if released in large quantities in response to warming. Thus, there is a need to better understand and represent the environmental sensitivity of soil carbon decomposition. Most soil carbon decomposition models rely on empirical relationships omitting key biogeochemical...
Authors
Y. He, Q. Zhuang, Jennifer W. Harden, A. David McGuire, Z. Fan, Y. Liu, Kimberly P. Wickland
Modeling the influence of organic acids on soil weathering Modeling the influence of organic acids on soil weathering
Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids...
Authors
Corey R. Lawrence, Jennifer W. Harden, Kate Maher
Science and Products
Filter Total Items: 144
Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps Estimating heterotrophic respiration at large scales: Challenges, approaches, and next steps
Heterotrophic respiration (HR), the aerobic and anaerobic processes mineralizing organic matter, is a key carbon flux but one impossible to measure at scales significantly larger than small experimental plots. This impedes our ability to understand carbon and nutrient cycles, benchmark models, or reliably upscale point measurements. Given that a new generation of highly mechanistic...
Authors
Ben Bond-Lamberty, Daniel Epron, Jennifer W. Harden, Mark E. Harmon, Forrest Hoffman, Jitendra Kumar, Anthony D. McGuire, Rodrigo Vargas
Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils Effects of permafrost aggradation on peat properties as determined from a pan-Arctic synthesis of plant macrofossils
Permafrost dynamics play an important role in high-latitude peatland carbon balance and are key to understanding the future response of soil carbon stocks. Permafrost aggradation can control the magnitude of the carbon feedback in peatlands through effects on peat properties. We compiled peatland plant macrofossil records for the northern permafrost zone (515 cores from 280 sites) and...
Authors
Claire C. Treat, Miriam C. Jones, P. Camill, A. Gallego-Sala, M. Garneau, Jennifer W. Harden, G. Hugelius, E.S. Klein, Ulla Kokfelt, P. Kuhry, Julie Loisel, J.H. Mathijssen, J.A. O'Donnell, P.O. Oksanen, T.M. Ronkainen, A. B. K. Sannel, J. J. Talbot, C.M. Tarnocal, M. Valiranta
Toward more realistic projections of soil carbon dynamics by Earth system models Toward more realistic projections of soil carbon dynamics by Earth system models
Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other...
Authors
Y. Luo, Anders Ahlstrom, Steven D. Allison, Niels H. Batjes, V. Brovkin, Nuno Carvalhais, Adrian Chappell, Philippe Ciais, Eric A. Davidson, Adien Finzi, Katerina Georgiou, Bertrand Guenet, Oleksandra Hararuk, Jennifer Harden, Yujie He, Francesca Hopkins, L. Jiang, Charles Koven, Robert B. Jackson, Chris D. Jones, M. Lara, J. Liang, A. David McGuire, William Parton, Changhui Peng, J. Randerson, Alejandro Salazar, Carlos A. Sierra, Matthew J. Smith, Hanqin Tian, Katherine E. O Todd-Brown, Margaret S. Torn, Kees Jan van Groenigen, Ying Wang, Tristram O. West, Yaxing Wei, William R. Wieder, Jianyang Xia, Xia Xu, Xiaofeng Xu, T. Zhou
Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost
Changes in vegetation and soil properties following permafrost degradation and thermokarst development in peatlands may cause changes in net carbon storage. To better understand these dynamics, we established three sites in Alaska that vary in permafrost regime, including a black spruce peat plateau forest with stable permafrost, an internal collapse scar bog formed as a result of...
Authors
Eugenie S. Euskirchen, C.W. Edgar, M.R. Turetsky, Mark P. Waldrop, Jennifer W. Harden
A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback A simplified, data-constrained approach to estimate the permafrost carbon–climate feedback
We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate...
Authors
C.D. Koven, E.A.G. Schuur, C. Schädel, T. J. Bohn, E. J. Burke, G. Chen, X. Chen, P. Ciais, G. Grosse, J.W. Harden, D.J. Hayes, G. Hugelius, Elchin E. Jafarov, G. Krinner, P. Kuhry, D.M. Lawrence, A. H. MacDougall, Sergey S. Marchenko, A. David McGuire, Susan M. Natali, D.J. Nicolsky, David Olefeldt, S. Peng, V.E. Romanovsky, Kevin M. Schaefer, J. Strauss, Claire C. Treat, M. Turetsky
Climate change and the permafrost carbon feedback Climate change and the permafrost carbon feedback
Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission...
Authors
E.A.G. Schuur, A. David McGuire, C. Schädel, G. Grosse, J.W. Harden, D.J. Hayes, G. Hugelius, C.D. Koven, P. Kuhry, D.M. Lawrence, Susan M. Natali, David Olefeldt, V.E. Romanovsky, K. Schaefer, M.R. Turetsky, Claire C. Treat, J.E. Vonk
Long-term controls of soil organic carbon with depth and time: a case study from the Cowlitz River Chronosequence, WA USA Long-term controls of soil organic carbon with depth and time: a case study from the Cowlitz River Chronosequence, WA USA
Over timescales of soil development (millennia), the capacity of soils to stabilize soil organic carbon (SOC) is linked to soil development through changes in soil mineralogy and other soil properties. In this study, an extensive dataset of soil profile chemistry and mineralogy is compiled from the Cowlitz River Chronosequence (CRC), WA USA. The CRC soils range in age from 0.25 to 1200...
Authors
Corey R. Lawrence, Jennifer W. Harden, Xiaomei Xu, Marjorie S. Schulz, Susan E. Trumbore
Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice
The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming...
Authors
Stephanie A. Ewing, James B. Paces, J.A. O'Donnell, M.T. Jorgenson, M.Z. Kanevskiy, George R. Aiken, Y. Shur, Jennifer W. Harden, Robert G. Striegl
Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests
Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme...
Authors
Yujie He, Jinyan Yang, Qianlai Zhuang, Jennifer W. Harden, A. David McGuire, Yaling Liu, Gangsheng Wang, Lianhong Gu
Effects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence Effects of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence
Permafrost soils store over half of global soil carbon (C), and northern frozen peatlands store about 10% of global permafrost C. With thaw, inundation of high latitude lowland peatlands typically increases the surface-atmosphere flux of methane (CH4), a potent greenhouse gas. To examine the effects of lowland permafrost thaw over millennial timescales, we measured carbon dioxide (CO2)...
Authors
Carmel E. Johnston, Stephanie A. Ewing, Jennifer W. Harden, Ruth K. Varner, Kimberly P. Wickland, Joshua C. Koch, Christopher C. Fuller, Kristen L. Manies, M. Torre Jorgenson
The implications of microbial and substrate limitation for the fates of carbon in different organic soil horizon types of boreal forest ecosystems: a mechanistically based model analysis The implications of microbial and substrate limitation for the fates of carbon in different organic soil horizon types of boreal forest ecosystems: a mechanistically based model analysis
The large amount of soil carbon in boreal forest ecosystems has the potential to influence the climate system if released in large quantities in response to warming. Thus, there is a need to better understand and represent the environmental sensitivity of soil carbon decomposition. Most soil carbon decomposition models rely on empirical relationships omitting key biogeochemical...
Authors
Y. He, Q. Zhuang, Jennifer W. Harden, A. David McGuire, Z. Fan, Y. Liu, Kimberly P. Wickland
Modeling the influence of organic acids on soil weathering Modeling the influence of organic acids on soil weathering
Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids...
Authors
Corey R. Lawrence, Jennifer W. Harden, Kate Maher
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government