EGU21-3651, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-3651
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Climate related variations in atmospheric nitrous oxide concentration during the Mid- to Late Holocene

Syed Azharuddin1, Jinho Ahn1, Yeongjun Ryu2, and Ed Brook3
Syed Azharuddin et al.
  • 1Seoul National University, School of Earth and Environmental Sciences (Bldg #25-1), Laboratory of Ice Core and Paleoclimate (Room #613), Seoul, Korea, Republic of (azhar0606@snu.ac.kr)
  • 2Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
  • 3College of Earth, Ocean & Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331, USA

Nitrous oxide (N2O) is an important greenhouse gas with sources that respond to the biogeochemical processes on land and ocean. The major sources of atmospheric N2O are nitrification and denitrification occurring in terrestrial soils and the ocean. Here we present a new high-resolution atmospheric N2O record obtained from South Pole Ice (SPICE) core site covering the Mid- to Late Holocene (since ~5.5 ka). The N2O analysis was performed in a specialised wet extraction facility installed at Seoul National University that used small ice samples (<20 g) to yield a high precision (average standard deviation of ~1ppb) record. The new N2O data agree well with existing records on the millennial scale and reveal new details on the multi-centennial scale. Our results show a progressive increase in atmospheric N2O during 5.5 to 3.2 ka which correlates well with the increase of marine denitrification around the Arabian Sea (AS) and Peru-Chile Margin (PCM) as well as Indian monsoon precipitation around the same period. A local minimum in N2O is observed around 2.8 ka, possibly related to a sudden decrease in Western Tropical South (WTS) Pacific sea surface temperature and increased La-Nina like conditions which may have supressed denitrification along PCM. These conditions may have further influenced the monsoons and reduced denitrification in land soils. Our record also shows a local N2O maximum around 2.2 ka which may correspond to relaxed La-Nina like conditions around WTS Pacific. Subsequently, the N2O further dropped to attain a pronounced minimum around 1.4 ka. Similar N2O minima are also observed in Styx (Antarctica) and  NEEM (Greenland) ice core records, demonstrating the robustness of the signals.

How to cite: Azharuddin, S., Ahn, J., Ryu, Y., and Brook, E.: Climate related variations in atmospheric nitrous oxide concentration during the Mid- to Late Holocene, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3651, https://doi.org/10.5194/egusphere-egu21-3651, 2021.

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