John Pohlman, PhD
John Pohlman is a Research Chemist with the Woods Hole Coastal and Marine Science Center Gas Hydrates Project.
Science and Products
Filter Total Items: 62
Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment
>In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics – namely production, consumption, and net emissions – is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climate-active trace gases including methane (CH4)...
Authors
S.T. Wilson, A.N. Al-Haj, A. Bourbonnais, C. Frey, R.W. Fulweiler, John D. Kessler, H.K. Marchant, J Milucka, N.E. Ray, P Suntharalingham, B.F. Thornton, R.C. Upstill-Goddard, T.S. Weber, D.L. Arévalo-Martínez, H.W. Bange, H.M. Benway, D. Bianchi, A.V. Borges, B.X. Chang, P.M. Crill, D.A. del Valle, L. Farias, S.B. Joye, A. Kock, J Labidi, C.C. Manning, John Pohlman, G. Rehder, K.J. Sparrow, P.D. Tortell, T. Truede, D.L. Valentine, B.B. Ward, S. Yang, L.N. Yurganov
Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary
Geophysical and geochemical data indicate there is abundant fluid expulsion in the Nootka fault zone (NFZ) between the Juan de Fuca and Explorer plates and the Nootka continental slope. Here we combine observations from > 20 years of investigations to demonstrate the nature of fluid-flow along the NFZ, which is the seismically most active region off Vancouver Island. Seismicity reaching...
Authors
M. Riedel, K .M. M. Rohr, G. D. Spence, D. Kelley, J. Delaney, L. Lapham, John Pohlman, R.D. Hyndman, E.C. Willoughby
Methane oxidation dynamics in a karst subterranean estuary Methane oxidation dynamics in a karst subterranean estuary
Chemical gradients between fresh, brackish and saline waters shape biogeochemical reactions and organic matter transformation within subterranean estuaries. In the Yucatán Peninsula’s karst subterranean estuary (KSE), methane and dissolved organic matter generated during the anaerobic decomposition of tropical forest vegetation are transported into flooded cave networks where microbial...
Authors
David Brankovits, John Pohlman
India National Gas Hydrate Program Expedition 02 Summary of Scientific Results: Gas hydrate systems along the eastern continental margin of India India National Gas Hydrate Program Expedition 02 Summary of Scientific Results: Gas hydrate systems along the eastern continental margin of India
The primary objectives of the India National Gas Hydrate Program Expedition 02 (NGHP-02) were to obtain new data on the occurrence of gas hydrate systems and to advance the understanding of the controls on the formation of gas hydrate accumulations in the offshore of India. In accordance with the ultimate overall goal of the NGHP effort to assess the energy resource potential of marine...
Authors
Timothy S. Collett, Ray Boswell, William F. Waite, Pushpendra Kumar, Sandip Kumar Roy, Krishan Chopra, Sunil Kumar Singh, Yasuhiro Yamada, Norio Tenma, John Pohlman, Margarita Zyrianova
Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment
Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation levels and salinity. This study examined the...
Authors
Faming Wang, Kevin D. Kroeger, Meagan Gonneea Eagle, John W. Pohlman, Jianwu Tang
Hydrologic controls of methane dynamics in karst subterranean estuaries Hydrologic controls of methane dynamics in karst subterranean estuaries
Karst subterranean estuaries (KSEs) extend into carbonate platforms along 12% of all coastlines. A recent study has shown that microbial methane (CH4) consumption is an important component of the carbon cycle and food web dynamics within flooded caves that permeate KSEs. In this study, we obtained high‐resolution (~2.5‐day) temporal records of dissolved methane concentrations and its...
Authors
David Brankovits, John W. Pohlman, Neil K. Ganju, T.M. Iliffe, N. Lowell, E. Roth, S.P. Sylva, J.A. Emmert, L. L. Lapham
An intercomparison of oceanic methane and nitrous oxide measurements An intercomparison of oceanic methane and nitrous oxide measurements
Large-scale climatic forcing is impacting oceanic biogeochemical cycles and is expected to influence the water-column distribution of trace gases, including methane and nitrous oxide. Our ability as a scientific community to evaluate changes in the water-column inventories of methane and nitrous oxide depends largely on our capacity to obtain robust and accurate concentration...
Authors
Samuel Wilson, Hermann Bange, Damian Arevalo-Martinez, Jonathan Barnes, Alberto V. Borges, Ian Brown, John Bullister, Macarena Burgos, David Capelle, Michael Casso, Mercedes de la Paz, Laura Farias, Lindsay Fenwick, Sara Ferron, Gerardo Garcia, MIchael Glockzin, David Karl, Annette Kock, Sarah Laperriere, Cliff S. Law, Cara Manning, Andrew Marriner, Jukka-Pekka Myllykangas, John Pohlman, Andrew Rees, Allison Santoro, Philippe Tortll, Robert C. Upstill-Goddard, David Wisegarver, Gui-Ling Zhang, Gregor Rehder
Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon
Climate-sensitive Arctic lakes have been identified as conduits for ancient permafrost-carbon (C) emissions and as such accelerate warming. However, the environmental factors that control emission pathways and their sources are unclear; this complicates upscaling, forecasting and climate-impact-assessment efforts. Here we show that current whole-lake CH4 and CO2 emissions from widespread...
Authors
Clayton D. Elder, Xiaomei Xu, Jennifer Walker, Jordan L. Schnell, Kenneth M. Hinkel, Amy Townsend-Small, Christopher D. Arp, John W. Pohlman, Benjamin V. Gaglioti, Claudia I. Czimzik
Exudation rates and δ13C signatures of tree root soluble organic carbon in a riparian forest Exudation rates and δ13C signatures of tree root soluble organic carbon in a riparian forest
Tree root exudation (TRE) of water soluble organic carbon (WSOC) is an important but under-assessed component of net primary production, and is thought to strongly influence rhizosphere biogeochemistry. Riparian systems in particular are often viewed as biogeochemical hot spots fueled partially by root exudate WSOC. However, TRE rates have not been previously reported for these systems...
Authors
S. W. Gougherty, J. E. Bauer, J. W. Pohlman
Methane- and dissolved organic carbon-fueled microbial loop supports a tropical subterranean estuary ecosystem Methane- and dissolved organic carbon-fueled microbial loop supports a tropical subterranean estuary ecosystem
Subterranean estuaries extend inland into density-stratified coastal carbonate aquifers containing a surprising diversity of endemic animals (mostly crustaceans) within a highly oligotrophic habitat. How complex ecosystems (termed anchialine) thrive in this globally distributed, cryptic environment is poorly understood. Here, we demonstrate that a microbial loop shuttles methane and...
Authors
D. Brankovits, John W. Pohlman, H. Niemann, M.B. Leigh, M.C. Leewis, K. W. Becker, T.M. Iliffe, Alvarez. F., M.F. Lehmann, B. Phillips
Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane
Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 106 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (
Authors
John W. Pohlman, J. Greinert, Carolyn D. Ruppel, A Silyakova, L Vielstadte, Michael Casso, J Mienert, S Bunz
Methane turnover and environmental change from Holocene biomarker records in a thermokarst lake in Arctic Alaska Methane turnover and environmental change from Holocene biomarker records in a thermokarst lake in Arctic Alaska
Arctic lakes and wetlands contribute a substantial amount of methane to the contemporary atmosphere, yet profound knowledge gaps remain regarding the intensity and climatic control of past methane emissions from this source. In this study, we reconstruct methane turnover and environmental conditions, including estimates of mean annual and summer temperature, from a thermokarst lake (Lake...
Authors
Marcus Elvert, John W. Pohlman, Kevin W. Becker, Benjamin V. Gaglioti, Kai-Uwe Hinrichs, Matthew J. Wooller
Science and Products
Filter Total Items: 62
Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment
>In the current era of rapid climate change, accurate characterization of climate-relevant gas dynamics – namely production, consumption, and net emissions – is required for all biomes, especially those ecosystems most susceptible to the impact of change. Marine environments include regions that act as net sources or sinks for numerous climate-active trace gases including methane (CH4)...
Authors
S.T. Wilson, A.N. Al-Haj, A. Bourbonnais, C. Frey, R.W. Fulweiler, John D. Kessler, H.K. Marchant, J Milucka, N.E. Ray, P Suntharalingham, B.F. Thornton, R.C. Upstill-Goddard, T.S. Weber, D.L. Arévalo-Martínez, H.W. Bange, H.M. Benway, D. Bianchi, A.V. Borges, B.X. Chang, P.M. Crill, D.A. del Valle, L. Farias, S.B. Joye, A. Kock, J Labidi, C.C. Manning, John Pohlman, G. Rehder, K.J. Sparrow, P.D. Tortell, T. Truede, D.L. Valentine, B.B. Ward, S. Yang, L.N. Yurganov
Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary Focused fluid flow along the Nootka Fault Zone and continental slope, Explorer-Juan de Fuca plate boundary
Geophysical and geochemical data indicate there is abundant fluid expulsion in the Nootka fault zone (NFZ) between the Juan de Fuca and Explorer plates and the Nootka continental slope. Here we combine observations from > 20 years of investigations to demonstrate the nature of fluid-flow along the NFZ, which is the seismically most active region off Vancouver Island. Seismicity reaching...
Authors
M. Riedel, K .M. M. Rohr, G. D. Spence, D. Kelley, J. Delaney, L. Lapham, John Pohlman, R.D. Hyndman, E.C. Willoughby
Methane oxidation dynamics in a karst subterranean estuary Methane oxidation dynamics in a karst subterranean estuary
Chemical gradients between fresh, brackish and saline waters shape biogeochemical reactions and organic matter transformation within subterranean estuaries. In the Yucatán Peninsula’s karst subterranean estuary (KSE), methane and dissolved organic matter generated during the anaerobic decomposition of tropical forest vegetation are transported into flooded cave networks where microbial...
Authors
David Brankovits, John Pohlman
India National Gas Hydrate Program Expedition 02 Summary of Scientific Results: Gas hydrate systems along the eastern continental margin of India India National Gas Hydrate Program Expedition 02 Summary of Scientific Results: Gas hydrate systems along the eastern continental margin of India
The primary objectives of the India National Gas Hydrate Program Expedition 02 (NGHP-02) were to obtain new data on the occurrence of gas hydrate systems and to advance the understanding of the controls on the formation of gas hydrate accumulations in the offshore of India. In accordance with the ultimate overall goal of the NGHP effort to assess the energy resource potential of marine...
Authors
Timothy S. Collett, Ray Boswell, William F. Waite, Pushpendra Kumar, Sandip Kumar Roy, Krishan Chopra, Sunil Kumar Singh, Yasuhiro Yamada, Norio Tenma, John Pohlman, Margarita Zyrianova
Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment Water salinity and inundation control soil carbon decomposition during salt marsh restoration: An incubation experiment
Coastal wetlands are a significant carbon (C) sink since they store carbon in anoxic soils. This ecosystem service is impacted by hydrologic alteration and management of these coastal habitats. Efforts to restore tidal flow to former salt marshes have increased in recent decades and are generally associated with alteration of water inundation levels and salinity. This study examined the...
Authors
Faming Wang, Kevin D. Kroeger, Meagan Gonneea Eagle, John W. Pohlman, Jianwu Tang
Hydrologic controls of methane dynamics in karst subterranean estuaries Hydrologic controls of methane dynamics in karst subterranean estuaries
Karst subterranean estuaries (KSEs) extend into carbonate platforms along 12% of all coastlines. A recent study has shown that microbial methane (CH4) consumption is an important component of the carbon cycle and food web dynamics within flooded caves that permeate KSEs. In this study, we obtained high‐resolution (~2.5‐day) temporal records of dissolved methane concentrations and its...
Authors
David Brankovits, John W. Pohlman, Neil K. Ganju, T.M. Iliffe, N. Lowell, E. Roth, S.P. Sylva, J.A. Emmert, L. L. Lapham
An intercomparison of oceanic methane and nitrous oxide measurements An intercomparison of oceanic methane and nitrous oxide measurements
Large-scale climatic forcing is impacting oceanic biogeochemical cycles and is expected to influence the water-column distribution of trace gases, including methane and nitrous oxide. Our ability as a scientific community to evaluate changes in the water-column inventories of methane and nitrous oxide depends largely on our capacity to obtain robust and accurate concentration...
Authors
Samuel Wilson, Hermann Bange, Damian Arevalo-Martinez, Jonathan Barnes, Alberto V. Borges, Ian Brown, John Bullister, Macarena Burgos, David Capelle, Michael Casso, Mercedes de la Paz, Laura Farias, Lindsay Fenwick, Sara Ferron, Gerardo Garcia, MIchael Glockzin, David Karl, Annette Kock, Sarah Laperriere, Cliff S. Law, Cara Manning, Andrew Marriner, Jukka-Pekka Myllykangas, John Pohlman, Andrew Rees, Allison Santoro, Philippe Tortll, Robert C. Upstill-Goddard, David Wisegarver, Gui-Ling Zhang, Gregor Rehder
Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon Greenhouse gas emissions from diverse Arctic Alaskan lakes are dominated by young carbon
Climate-sensitive Arctic lakes have been identified as conduits for ancient permafrost-carbon (C) emissions and as such accelerate warming. However, the environmental factors that control emission pathways and their sources are unclear; this complicates upscaling, forecasting and climate-impact-assessment efforts. Here we show that current whole-lake CH4 and CO2 emissions from widespread...
Authors
Clayton D. Elder, Xiaomei Xu, Jennifer Walker, Jordan L. Schnell, Kenneth M. Hinkel, Amy Townsend-Small, Christopher D. Arp, John W. Pohlman, Benjamin V. Gaglioti, Claudia I. Czimzik
Exudation rates and δ13C signatures of tree root soluble organic carbon in a riparian forest Exudation rates and δ13C signatures of tree root soluble organic carbon in a riparian forest
Tree root exudation (TRE) of water soluble organic carbon (WSOC) is an important but under-assessed component of net primary production, and is thought to strongly influence rhizosphere biogeochemistry. Riparian systems in particular are often viewed as biogeochemical hot spots fueled partially by root exudate WSOC. However, TRE rates have not been previously reported for these systems...
Authors
S. W. Gougherty, J. E. Bauer, J. W. Pohlman
Methane- and dissolved organic carbon-fueled microbial loop supports a tropical subterranean estuary ecosystem Methane- and dissolved organic carbon-fueled microbial loop supports a tropical subterranean estuary ecosystem
Subterranean estuaries extend inland into density-stratified coastal carbonate aquifers containing a surprising diversity of endemic animals (mostly crustaceans) within a highly oligotrophic habitat. How complex ecosystems (termed anchialine) thrive in this globally distributed, cryptic environment is poorly understood. Here, we demonstrate that a microbial loop shuttles methane and...
Authors
D. Brankovits, John W. Pohlman, H. Niemann, M.B. Leigh, M.C. Leewis, K. W. Becker, T.M. Iliffe, Alvarez. F., M.F. Lehmann, B. Phillips
Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane
Continued warming of the Arctic Ocean in coming decades is projected to trigger the release of teragrams (1 Tg = 106 tons) of methane from thawing subsea permafrost on shallow continental shelves and dissociation of methane hydrate on upper continental slopes. On the shallow shelves (
Authors
John W. Pohlman, J. Greinert, Carolyn D. Ruppel, A Silyakova, L Vielstadte, Michael Casso, J Mienert, S Bunz
Methane turnover and environmental change from Holocene biomarker records in a thermokarst lake in Arctic Alaska Methane turnover and environmental change from Holocene biomarker records in a thermokarst lake in Arctic Alaska
Arctic lakes and wetlands contribute a substantial amount of methane to the contemporary atmosphere, yet profound knowledge gaps remain regarding the intensity and climatic control of past methane emissions from this source. In this study, we reconstruct methane turnover and environmental conditions, including estimates of mean annual and summer temperature, from a thermokarst lake (Lake...
Authors
Marcus Elvert, John W. Pohlman, Kevin W. Becker, Benjamin V. Gaglioti, Kai-Uwe Hinrichs, Matthew J. Wooller