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
Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation
As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released...
Authors
Andrew G. Hunt, Laura Stern, John W. Pohlman, Carolyn Ruppel, Richard J. Moscati, Gary P. Landis
Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane
Collectively, marine sediments comprise the largest reservoir of methane on Earth. The flux of methane from the sea bed to the overlying water column is mitigated by the sulphate-dependent anaerobic oxidation of methane by marine microbes within a discrete sedimentary horizon termed the sulphate–methane transition zone. According to conventional isotope systematics, the biological...
Authors
Marcos Y. Yoshinaga, Thomas Holler, Tobias Goldhammer, Gunter Wegener, John W. Pohlman, Benjamin Brunner, Marcel Kuypers, Kai-Uwe Hinrichs, Marcus Elvert
Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments
Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, John Quensen, James M. Tiedje, Mary Beth Leigh
Identification of functionally active aerobic methanotrophs in sediments from an arctic lake using stable isotope probing Identification of functionally active aerobic methanotrophs in sediments from an arctic lake using stable isotope probing
Arctic lakes are a significant source of the greenhouse gas methane (CH4), but the role that methane oxidizing bacteria (methanotrophs) play in limiting the overall CH4 flux is poorly understood. Here, we used stable isotope probing (SIP) techniques to identify the metabolically active aerobic methanotrophs in upper sediments (0–1 cm) from an arctic lake in northern Alaska sampled during...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, Catharine Catranis, John Quensen, James M. Tiedje, Mary Beth Leigh
Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years
Atmospheric contributions of methane from Arctic wetlands during the Holocene are dynamic and linked to climate oscillations. However, long-term records linking climate variability to methane availability in Arctic wetlands are lacking. We present a multi-proxy ~12,000 year paleoecological reconstruction of intermittent methane availability from a radiocarbon-dated sediment core (LQ-West...
Authors
Matthew J. Wooller, John W. Pohlman, Benjamin V. Gaglioti, Peter Langdon, Miriam Jones, Katey M. Walter Anthony, Kevin W. Becker, Kai-Uwe Hinrichs, Marcus Elvert
Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes
Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperatures increase, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is important to predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), and pyrosequencing...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, John Quensen, James M. Tiedje, Mary Beth Leigh
Science and Products
Filter Total Items: 62
Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation Mass fractionation of noble gases in synthetic methane hydrate: Implications for naturally occurring gas hydrate dissociation
As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings may presently be dissociating and releasing methane and other gases to the ocean-atmosphere system. A key challenge in assessing the impact of dissociating gas hydrates on global atmospheric methane is the lack of a technique able to distinguish between methane recently released...
Authors
Andrew G. Hunt, Laura Stern, John W. Pohlman, Carolyn Ruppel, Richard J. Moscati, Gary P. Landis
Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane Carbon isotope equilibration during sulphate-limited anaerobic oxidation of methane
Collectively, marine sediments comprise the largest reservoir of methane on Earth. The flux of methane from the sea bed to the overlying water column is mitigated by the sulphate-dependent anaerobic oxidation of methane by marine microbes within a discrete sedimentary horizon termed the sulphate–methane transition zone. According to conventional isotope systematics, the biological...
Authors
Marcos Y. Yoshinaga, Thomas Holler, Tobias Goldhammer, Gunter Wegener, John W. Pohlman, Benjamin Brunner, Marcel Kuypers, Kai-Uwe Hinrichs, Marcus Elvert
Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments
Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, John Quensen, James M. Tiedje, Mary Beth Leigh
Identification of functionally active aerobic methanotrophs in sediments from an arctic lake using stable isotope probing Identification of functionally active aerobic methanotrophs in sediments from an arctic lake using stable isotope probing
Arctic lakes are a significant source of the greenhouse gas methane (CH4), but the role that methane oxidizing bacteria (methanotrophs) play in limiting the overall CH4 flux is poorly understood. Here, we used stable isotope probing (SIP) techniques to identify the metabolically active aerobic methanotrophs in upper sediments (0–1 cm) from an arctic lake in northern Alaska sampled during...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, Catharine Catranis, John Quensen, James M. Tiedje, Mary Beth Leigh
Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years
Atmospheric contributions of methane from Arctic wetlands during the Holocene are dynamic and linked to climate oscillations. However, long-term records linking climate variability to methane availability in Arctic wetlands are lacking. We present a multi-proxy ~12,000 year paleoecological reconstruction of intermittent methane availability from a radiocarbon-dated sediment core (LQ-West...
Authors
Matthew J. Wooller, John W. Pohlman, Benjamin V. Gaglioti, Peter Langdon, Miriam Jones, Katey M. Walter Anthony, Kevin W. Becker, Kai-Uwe Hinrichs, Marcus Elvert
Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes
Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperatures increase, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is important to predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), and pyrosequencing...
Authors
Ruo He, Matthew J. Wooller, John W. Pohlman, John Quensen, James M. Tiedje, Mary Beth Leigh