Distribution and Driving Mechanism of N 2 O in Sea Ice and Its Underlying Seawater during Arctic Melt Season
Nitrous oxide (N 2 O) is the third most important greenhouse gas in the atmosphere, and the ocean is an important source of N 2 O. As the Arctic Ocean is strongly affected by global warming, rapid ice melting can have a significant impact on the N 2 O pattern in the Arctic environment. To better und...
Published in: | Water |
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Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
MDPI AG
2022
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Subjects: | |
Online Access: | https://doi.org/10.3390/w14020145 https://doaj.org/article/429b1a36a3dc4c6aa4d98d0585d78b90 |
Summary: | Nitrous oxide (N 2 O) is the third most important greenhouse gas in the atmosphere, and the ocean is an important source of N 2 O. As the Arctic Ocean is strongly affected by global warming, rapid ice melting can have a significant impact on the N 2 O pattern in the Arctic environment. To better understand this impact, N 2 O concentration in ice core and underlying seawater (USW) was measured during the seventh Chinese National Arctic Research Expedition (CHINARE2016). The results showed that the average N 2 O concentration in first-year ice (FYI) was 4.5 ± 1.0 nmol kg −1 , and that in multi-year ice (MYI) was 4.8 ± 1.9 nmol kg −1 . Under the influence of exchange among atmosphere-sea ice-seawater systems, brine dynamics and possible N 2 O generation processes at the bottom of sea ice, the FYI showed higher N 2 O concentrations at the bottom and surface, while lower N 2 O concentrations were seen inside sea ice. Due to the melting of sea ice and biogeochemical processes, USW presented as the sink of N 2 O, and the saturation varied from 47.2% to 102.2%. However, the observed N 2 O concentrations in USW were higher than that of T-N 2 O USW due to the sea–air exchange, diffusion process, possible N 2 O generation mechanism, and the influence of precipitation, and a more detailed mechanism is needed to understand this process in the Arctic Ocean. |
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