Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications
Continuous hourly measurements of gas-phase ammonia (NH3(g)) were taken from 13 July to 7 August 2014 on a research cruise throughout Baffin Bay and the eastern Canadian Arctic Archipelago. Concentrations ranged from 30 to 650 ng m−3 (40–870 pptv) with the highest values recorded in Lancaster Sound...
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00043913 2023-05-15T14:29:02+02:00 Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications Wentworth, Gregory R. Murphy, Jennifer G. Croft, Betty Martin, Randall V. Pierce, Jeffrey R. Côté, Jean-Sébastien Courchesne, Isabelle Tremblay, Jean-Éric Gagnon, Jonathan Thomas, Jennie L. Sharma, Sangeeta Toom-Sauntry, Desiree Chivulescu, Alina Levasseur, Maurice Abbatt, Jonathan P. D. 2016-02 electronic https://doi.org/10.5194/acp-16-1937-2016 https://noa.gwlb.de/receive/cop_mods_00043913 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043533/acp-16-1937-2016.pdf https://acp.copernicus.org/articles/16/1937/2016/acp-16-1937-2016.pdf eng eng Copernicus Publications Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-16-1937-2016 https://noa.gwlb.de/receive/cop_mods_00043913 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043533/acp-16-1937-2016.pdf https://acp.copernicus.org/articles/16/1937/2016/acp-16-1937-2016.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2016 ftnonlinearchiv https://doi.org/10.5194/acp-16-1937-2016 2022-02-08T22:40:19Z Continuous hourly measurements of gas-phase ammonia (NH3(g)) were taken from 13 July to 7 August 2014 on a research cruise throughout Baffin Bay and the eastern Canadian Arctic Archipelago. Concentrations ranged from 30 to 650 ng m−3 (40–870 pptv) with the highest values recorded in Lancaster Sound (74°13′ N, 84°00′ W). Simultaneous measurements of total ammonium ([NHx]), pH and temperature in the ocean and in melt ponds were used to compute the compensation point (χ), which is the ambient NH3(g) concentration at which surface–air fluxes change direction. Ambient NH3(g) was usually several orders of magnitude larger than both χocean and χMP (< 0.4–10 ng m3) indicating these surface pools are net sinks of NH3. Flux calculations estimate average net downward fluxes of 1.4 and 1.1 ng m−2 s−1 for the open ocean and melt ponds, respectively. Sufficient NH3(g) was present to neutralize non-sea-salt sulfate (nss-SO42−) in the boundary layer during most of the study. This finding was corroborated with a historical data set of PM2.5 composition from Alert, Nunavut (82°30′ N, 62°20′ W) wherein the median ratio of NH4+/nss-SO42− equivalents was greater than 0.75 in June, July and August. The GEOS-Chem chemical transport model was employed to examine the impact of NH3(g) emissions from seabird guano on boundary-layer composition and nss-SO42− neutralization. A GEOS-Chem simulation without seabird emissions underestimated boundary layer NH3(g) by several orders of magnitude and yielded highly acidic aerosol. A simulation that included seabird NH3 emissions was in better agreement with observations for both NH3(g) concentrations and nss-SO42− neutralization. This is strong evidence that seabird colonies are significant sources of NH3 in the summertime Arctic, and are ubiquitous enough to impact atmospheric composition across the entire Baffin Bay region. Large wildfires in the Northwest Territories were likely an important source of NH3, but their influence was probably limited to the Central Canadian Arctic. Implications of seabird-derived N-deposition to terrestrial and aquatic ecosystems are also discussed. Article in Journal/Newspaper Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin Canadian Arctic Archipelago Lancaster Sound Northwest Territories Nunavut Niedersächsisches Online-Archiv NOA Arctic Baffin Bay Canadian Arctic Archipelago Guano ENVELOPE(141.604,141.604,-66.775,-66.775) Lancaster Sound ENVELOPE(-83.999,-83.999,74.218,74.218) Northwest Territories Nunavut Atmospheric Chemistry and Physics 16 4 1937 1953 |
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Niedersächsisches Online-Archiv NOA |
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article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Wentworth, Gregory R. Murphy, Jennifer G. Croft, Betty Martin, Randall V. Pierce, Jeffrey R. Côté, Jean-Sébastien Courchesne, Isabelle Tremblay, Jean-Éric Gagnon, Jonathan Thomas, Jennie L. Sharma, Sangeeta Toom-Sauntry, Desiree Chivulescu, Alina Levasseur, Maurice Abbatt, Jonathan P. D. Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
topic_facet |
article Verlagsveröffentlichung |
description |
Continuous hourly measurements of gas-phase ammonia (NH3(g)) were taken from 13 July to 7 August 2014 on a research cruise throughout Baffin Bay and the eastern Canadian Arctic Archipelago. Concentrations ranged from 30 to 650 ng m−3 (40–870 pptv) with the highest values recorded in Lancaster Sound (74°13′ N, 84°00′ W). Simultaneous measurements of total ammonium ([NHx]), pH and temperature in the ocean and in melt ponds were used to compute the compensation point (χ), which is the ambient NH3(g) concentration at which surface–air fluxes change direction. Ambient NH3(g) was usually several orders of magnitude larger than both χocean and χMP (< 0.4–10 ng m3) indicating these surface pools are net sinks of NH3. Flux calculations estimate average net downward fluxes of 1.4 and 1.1 ng m−2 s−1 for the open ocean and melt ponds, respectively. Sufficient NH3(g) was present to neutralize non-sea-salt sulfate (nss-SO42−) in the boundary layer during most of the study. This finding was corroborated with a historical data set of PM2.5 composition from Alert, Nunavut (82°30′ N, 62°20′ W) wherein the median ratio of NH4+/nss-SO42− equivalents was greater than 0.75 in June, July and August. The GEOS-Chem chemical transport model was employed to examine the impact of NH3(g) emissions from seabird guano on boundary-layer composition and nss-SO42− neutralization. A GEOS-Chem simulation without seabird emissions underestimated boundary layer NH3(g) by several orders of magnitude and yielded highly acidic aerosol. A simulation that included seabird NH3 emissions was in better agreement with observations for both NH3(g) concentrations and nss-SO42− neutralization. This is strong evidence that seabird colonies are significant sources of NH3 in the summertime Arctic, and are ubiquitous enough to impact atmospheric composition across the entire Baffin Bay region. Large wildfires in the Northwest Territories were likely an important source of NH3, but their influence was probably limited to the Central Canadian Arctic. Implications of seabird-derived N-deposition to terrestrial and aquatic ecosystems are also discussed. |
format |
Article in Journal/Newspaper |
author |
Wentworth, Gregory R. Murphy, Jennifer G. Croft, Betty Martin, Randall V. Pierce, Jeffrey R. Côté, Jean-Sébastien Courchesne, Isabelle Tremblay, Jean-Éric Gagnon, Jonathan Thomas, Jennie L. Sharma, Sangeeta Toom-Sauntry, Desiree Chivulescu, Alina Levasseur, Maurice Abbatt, Jonathan P. D. |
author_facet |
Wentworth, Gregory R. Murphy, Jennifer G. Croft, Betty Martin, Randall V. Pierce, Jeffrey R. Côté, Jean-Sébastien Courchesne, Isabelle Tremblay, Jean-Éric Gagnon, Jonathan Thomas, Jennie L. Sharma, Sangeeta Toom-Sauntry, Desiree Chivulescu, Alina Levasseur, Maurice Abbatt, Jonathan P. D. |
author_sort |
Wentworth, Gregory R. |
title |
Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
title_short |
Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
title_full |
Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
title_fullStr |
Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
title_full_unstemmed |
Ammonia in the summertime Arctic marine boundary layer: sources, sinks, and implications |
title_sort |
ammonia in the summertime arctic marine boundary layer: sources, sinks, and implications |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/acp-16-1937-2016 https://noa.gwlb.de/receive/cop_mods_00043913 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043533/acp-16-1937-2016.pdf https://acp.copernicus.org/articles/16/1937/2016/acp-16-1937-2016.pdf |
long_lat |
ENVELOPE(141.604,141.604,-66.775,-66.775) ENVELOPE(-83.999,-83.999,74.218,74.218) |
geographic |
Arctic Baffin Bay Canadian Arctic Archipelago Guano Lancaster Sound Northwest Territories Nunavut |
geographic_facet |
Arctic Baffin Bay Canadian Arctic Archipelago Guano Lancaster Sound Northwest Territories Nunavut |
genre |
Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin Canadian Arctic Archipelago Lancaster Sound Northwest Territories Nunavut |
genre_facet |
Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin Canadian Arctic Archipelago Lancaster Sound Northwest Territories Nunavut |
op_relation |
Atmospheric Chemistry and Physics -- http://www.atmos-chem-phys.net/volumes_and_issues.html -- http://www.bibliothek.uni-regensburg.de/ezeit/?2069847 -- 1680-7324 https://doi.org/10.5194/acp-16-1937-2016 https://noa.gwlb.de/receive/cop_mods_00043913 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00043533/acp-16-1937-2016.pdf https://acp.copernicus.org/articles/16/1937/2016/acp-16-1937-2016.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/acp-16-1937-2016 |
container_title |
Atmospheric Chemistry and Physics |
container_volume |
16 |
container_issue |
4 |
container_start_page |
1937 |
op_container_end_page |
1953 |
_version_ |
1766303134549803008 |