Open AccessFirst measurements of nitrous oxide in Arctic sea ice
Author(s) -
Randall Kevin,
Scarratt Michael,
Levasseur Maurice,
Michaud Sonia,
Xie Huixiang,
Gosselin Michel
Publication year - 2012
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jc007340
Subject(s) - sea ice , arctic ice pack , arctic geoengineering , sink (geography) , nitrous oxide , atmospheric sciences , environmental science , arctic , arctic sea ice decline , antarctic sea ice , oceanography , climatology , geology , chemistry , cartography , organic chemistry , geography
Nitrous oxide (N 2 O) contributes ∼6% of the total radiative forcing from long‐lived greenhouse gases. While tropospheric concentrations have increased by 20% since the beginning of the industrial revolution, sources and sinks of N 2 O are still poorly quantified. In the Arctic, N 2 O atmospheric concentrations vary seasonally, due mainly to vertical mixing. The contributions of local natural sources to this cycle are still unknown. Here we report on N 2 O measurements conducted in the bottom 10 cm of the sea ice and in the underlying surface water (USW) from late March to early May 2008 in the southeastern Beaufort Sea and Amundsen Gulf. Bulk N 2 O concentrations in ice were low (∼6 nM) and were consistently undersaturated with respect to the USW (∼40% saturation) and the atmosphere (∼30% saturation). Loss of N 2 O via brine rejection during sea ice formation in fall and winter can explain these low N 2 O ice concentrations. An unknown fraction of this rejected N 2 O is likely ventilated to the atmosphere either directly from the ice or through leads during ice formation, while in spring and early summer, melting of the N 2 O‐depleted sea ice is expected to lower the partial pressure of N 2 O of newly open waters which could act as a sink for atmospheric N 2 O. These first measurements indicate that sea ice formation and melt has the potential to generate sea‐air or air‐sea fluxes of N 2 O, respectively.