EGU2020-11874
https://doi.org/10.5194/egusphere-egu2020-11874
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Summer N₂O dynamics in the western Arctic Ocean : Distributions, Processes, and Fluxes

Seong-Su Kim1, Sung-Ho Kang2, Eun Jin Yang3, and Il-Nam Kim4
Seong-Su Kim et al.
  • 1Incheon National University, Marine science, South Korea (seongsukim@inu.ac.kr)
  • 2Korea Polar Research Institute, Incheon, South Korea (shkang@kopri.re.kr)
  • 3Korea Polar Research Institute, Incheon, South Korea (ejyang@kopri.re.kr)
  • 4Department of Marine Science, Incheon National University, Incheon, South Korea (ilnamkim@inu.ac.kr)

We collect seawater samples from 32 stations for N2O analysis between August 6 and August 25, during 2017 ARA08B cruise in western Arctic Ocean (WAO), covering from Southern Chukchi Sea (SC) to Northern Chukchi Sea (NC). At surface depth (~50 m), N2O concentrations were 10.9‒19.4 nmol L-1, and distinct pattern was observed between SC and NC. N2O concentrations were increased from surface to bottom (~50 m) at SC, corresponding to positive relationship of ∆N2O (N2Omeasured - N2Oequilibrium) with DIN (NO- + NO2-) and negative relationship between ∆N2O and N*. It suggests that nitrification and denitrification are the main processes to produce N2O at SC. On the other hand, N2O concentration at NC increased from the south to north, and remained vertically constant. It may be the result of physical processes such as dilution by sea ice melting water, and high solubility that affected by low temperature and low salinity. The highest N2O concentrations were observed at intermediate depth (50‒200 m), ranging 13.4‒21.9 nmol L-1. It would be determined by high solubility and active biogeochemical processes synthetically. Concentrations of N2O were rapidly diminished to 400 m, ranging 10.2‒14.1 nmol L-1, and did not be remarkably altered under 400 m, ranging 11.3‒13.7 nmol L-1. It might be affected by advection of Atlantic Water (AW) and existence of Arctic Bottom Water (ABW), and influence of biogeochemical processes was negligible at deep and bottom depth (below 200 m). N2O flux was calculated to determine that the WAO is sources or sinks region for atmospheric N2O. Positive N2O flux was observed at SC, and it indicate that N2O gas is released to atmosphere at SC. Negative value of N2O flux at NC suggest that atmospheric N2O is absorbed into NC. Furthermore, positive relationship of N2O flux with environmental parameters (temperature, salinity, and ∆N2O) also observed in WAO. These results provide comprehensive information of the spatial N2O distribution and main processes which decide N2O distribution in WAO, and also suggest that air-sea N2O flux could be affected by changing environments of the Arctic Ocean.

How to cite: Kim, S.-S., Kang, S.-H., Yang, E. J., and Kim, I.-N.: Summer N₂O dynamics in the western Arctic Ocean : Distributions, Processes, and Fluxes, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11874, https://doi.org/10.5194/egusphere-egu2020-11874, 2020

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