Jennifer Harden, PhD (Former Employee)
Science and Products
Filter Total Items: 134
Carbon dynamics within agricultural and native sites in the loess region of Western lowa
In order to quantify the historical changes in carbon storage that result from agricultural conversion, this study compared the carbon dynamics of two sites in the loess region of Iowa: a native prairie and a cropland. Field data were obtained to determine present-day carbon storage and its variability within a landscape (a stable ridgetop vs. eroding upper-midslope vs. depositional lower slope).
Authors
K.L. Manies, J. W. Harden, L. Kramer, W.J. Parton
Mississippi Basin Carbon Project: Upland soil database for sites in Nishnabotna River basin, Iowa
The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton and others, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a re
Authors
J. W. Harden, T. L. Fries, R. Haughy, L. Kramer, Shuhui Zheng
The role of fire in the boreal carbon budget
To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consume
Authors
J. W. Harden, S.E. Trumbore, B.J. Stocks, A. Hirsch, S.T. Gower, K. P. O'Neill, E.S. Kasischke
Parameterizing century to model cultivated and noncultivated sites in the Loess region of western Iowa
One of the main questions remaining for global science involves the cycle of carbon among the atmosphere, oceans, and land. Scientists are trying to better determine the amount of carbon stored in and transferred between these three locations. This task has become more complex because in recent decades the amount of carbon released into the atmosphere has increased due to the burning of fossil fue
Authors
Kristen L. Manies, Jennifer W. Harden, Larry Kramer, William Parton
Mississippi Basin Carbon Project; upland soil database for sites in Yazoo Basin, northern Mississippi
The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton et al, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a result
Authors
J. W. Harden, T. L. Fries, T.G. Huntington
Carbon cycling in boreal wetlands: A comparison of three approaches
Three independent methods were used to measure net ecosystem production (NEP) in four wetlands near Thompson, Manitoba, Canada. The first method calculated NEP by subtracting heterotrophic respiration from net primary productivity, using both measurements and estimates derived from the literature. The second method used radiocarbon data from cores to derive long-term NEP averaged over the past sev
Authors
Susan E. Trumbore, Jill Bubier, Jennifer W. Harden, Patrick M. Crill
Dynamic replacement and loss of soil carbon on eroding cropland
Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site
Authors
J. W. Harden, J. M. Sharpe, W.J. Parton, D.S. Ojima, T. L. Fries, Thomas G. Huntington, S. M. Dabney
Mississippi Basin Carbon Project science plan
Understanding the carbon cycle is one of the most difficult challenges facing scientists who study the global environment. Lack of understanding of global carbon cycling is perhaps best illustrated by our inability to balance the present-day global CO2 budget. The amount of CO2 produced by burning fossil fuels and by deforestation appears to exceed the amount accumulating in the atmosphere and oce
Authors
E.T. Sundquist, R.F. Stallard, N.B. Bliss, H. W. Markewich, J. W. Harden, M.J. Pavich, M.D. Dean
Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi
Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling
Authors
Thomas G. Huntington, J. W. Harden, S. M. Dabney, D. A. Marion, C. Alonso, J. M. Sharpe, T. L. Fries
Sensitivity of boreal forest carbon balance to soil thaw
We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 ?? 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 ?? 0.2 ton C ha-1 year-1 in moss and wood offset by a l
Authors
M. L. Goulden, S.C. Wofsy, J. W. Harden, S.E. Trumbore, P.M. Crill, S.T. Gower, T. Fries, B.C. Daube, S.-M. Fan, D.J. Sutton, A. Bazzaz, J.W. Munger
Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape
Boreal forests and wetlands are thought to be significant carbon sinks, and they could become net C sources as the Earth warms. Most of the C of boreal forest ecosystems is stored in the moss layer and in the soil. The objective of this study was to estimate soil C stocks (including moss layers) and rates of accumulation and loss for a 733 km2 area of the BOReal Ecosystem-Atmosphere Study site in
Authors
G. Rapalee, S.E. Trumbore, E.A. Davidson, Jennifer W. Harden, H. Veldhuis
Implementation of the century ecosystem model for an eroding hillslope in Mississippi
The objective of this study was to parameterize and implement the Century ecosystem model for an eroding, cultivated site near Senatobia, in Panola County, Mississippi, in order to understand the loss and replacement of soil organic carbon on an eroding cropland. The sites chosen for this study are located on highly eroded loess soils where USDA has conducted studies on rates of soil erosion. We u
Authors
Jodie Sharpe, Jennifer W. Harden, Seth M. Dabney, Dennis Ojima, William Parton
Science and Products
Filter Total Items: 134
Carbon dynamics within agricultural and native sites in the loess region of Western lowa
In order to quantify the historical changes in carbon storage that result from agricultural conversion, this study compared the carbon dynamics of two sites in the loess region of Iowa: a native prairie and a cropland. Field data were obtained to determine present-day carbon storage and its variability within a landscape (a stable ridgetop vs. eroding upper-midslope vs. depositional lower slope).
Authors
K.L. Manies, J. W. Harden, L. Kramer, W.J. Parton
Mississippi Basin Carbon Project: Upland soil database for sites in Nishnabotna River basin, Iowa
The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton and others, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a re
Authors
J. W. Harden, T. L. Fries, R. Haughy, L. Kramer, Shuhui Zheng
The role of fire in the boreal carbon budget
To reconcile observations of decomposition rates, carbon inventories, and net primary production (NPP), we estimated long-term averages for C exchange in boreal forests near Thompson, Manitoba. Soil drainage as defined by water table, moss cover, and permafrost dynamics, is the dominant control on direct fire emissions. In upland forests, an average of about 10-30% of annual NPP was likely consume
Authors
J. W. Harden, S.E. Trumbore, B.J. Stocks, A. Hirsch, S.T. Gower, K. P. O'Neill, E.S. Kasischke
Parameterizing century to model cultivated and noncultivated sites in the Loess region of western Iowa
One of the main questions remaining for global science involves the cycle of carbon among the atmosphere, oceans, and land. Scientists are trying to better determine the amount of carbon stored in and transferred between these three locations. This task has become more complex because in recent decades the amount of carbon released into the atmosphere has increased due to the burning of fossil fue
Authors
Kristen L. Manies, Jennifer W. Harden, Larry Kramer, William Parton
Mississippi Basin Carbon Project; upland soil database for sites in Yazoo Basin, northern Mississippi
The conversion of land from its native state to an agricultural use commonly results in a significant loss of soil carbon (Mann, 1985; Davidson and Ackerman, 1993). Globally, this loss is estimated to account for as much as 1/3 of the net CO2 emissions for the period of 1850 to 1980 (Houghton et al, 1983). Roughly 20 to 40 percent of original soil carbon is estimated to be lost as CO2 as a result
Authors
J. W. Harden, T. L. Fries, T.G. Huntington
Carbon cycling in boreal wetlands: A comparison of three approaches
Three independent methods were used to measure net ecosystem production (NEP) in four wetlands near Thompson, Manitoba, Canada. The first method calculated NEP by subtracting heterotrophic respiration from net primary productivity, using both measurements and estimates derived from the literature. The second method used radiocarbon data from cores to derive long-term NEP averaged over the past sev
Authors
Susan E. Trumbore, Jill Bubier, Jennifer W. Harden, Patrick M. Crill
Dynamic replacement and loss of soil carbon on eroding cropland
Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site
Authors
J. W. Harden, J. M. Sharpe, W.J. Parton, D.S. Ojima, T. L. Fries, Thomas G. Huntington, S. M. Dabney
Mississippi Basin Carbon Project science plan
Understanding the carbon cycle is one of the most difficult challenges facing scientists who study the global environment. Lack of understanding of global carbon cycling is perhaps best illustrated by our inability to balance the present-day global CO2 budget. The amount of CO2 produced by burning fossil fuels and by deforestation appears to exceed the amount accumulating in the atmosphere and oce
Authors
E.T. Sundquist, R.F. Stallard, N.B. Bliss, H. W. Markewich, J. W. Harden, M.J. Pavich, M.D. Dean
Soil, environmental, and watershed measurements in support of carbon cycling studies in northwestern Mississippi
Measurements including soil respiration, soil moisture, soil temperature, and carbon export in suspended sediments from small watersheds were recorded at several field sites in northwestern Mississippi in support of hillslope process studies associated with the U.S. Geological Survey's Mississippi Basin Carbon Project (MBCP). These measurements were made to provide information about carbon cycling
Authors
Thomas G. Huntington, J. W. Harden, S. M. Dabney, D. A. Marion, C. Alonso, J. M. Sharpe, T. L. Fries
Sensitivity of boreal forest carbon balance to soil thaw
We used eddy covariance; gas-exchange chambers; radiocarbon analysis; wood, moss, and soil inventories; and laboratory incubations to measure the carbon balance of a 120-year-old black spruce forest in Manitoba, Canada. The site lost 0.3 ?? 0.5 metric ton of carbon per hectare per year (ton C ha-1 year-1) from 1994 to 1997, with a gain of 0.6 ?? 0.2 ton C ha-1 year-1 in moss and wood offset by a l
Authors
M. L. Goulden, S.C. Wofsy, J. W. Harden, S.E. Trumbore, P.M. Crill, S.T. Gower, T. Fries, B.C. Daube, S.-M. Fan, D.J. Sutton, A. Bazzaz, J.W. Munger
Soil carbon stocks and their rates of accumulation and loss in a boreal forest landscape
Boreal forests and wetlands are thought to be significant carbon sinks, and they could become net C sources as the Earth warms. Most of the C of boreal forest ecosystems is stored in the moss layer and in the soil. The objective of this study was to estimate soil C stocks (including moss layers) and rates of accumulation and loss for a 733 km2 area of the BOReal Ecosystem-Atmosphere Study site in
Authors
G. Rapalee, S.E. Trumbore, E.A. Davidson, Jennifer W. Harden, H. Veldhuis
Implementation of the century ecosystem model for an eroding hillslope in Mississippi
The objective of this study was to parameterize and implement the Century ecosystem model for an eroding, cultivated site near Senatobia, in Panola County, Mississippi, in order to understand the loss and replacement of soil organic carbon on an eroding cropland. The sites chosen for this study are located on highly eroded loess soils where USDA has conducted studies on rates of soil erosion. We u
Authors
Jodie Sharpe, Jennifer W. Harden, Seth M. Dabney, Dennis Ojima, William Parton
*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