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Stable isotope natural abundance of nitrous oxide emitted from Antarctic tundra soils: effects of sea animal excrement depositions
Author(s) -
Zhu Renbin,
Liu Yashu,
Li Xianglan,
Sun Jianjun,
Xu Hua,
Sun Liguang
Publication year - 2008
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3762
Subject(s) - tundra , soil water , nitrous oxide , stable isotope ratio , chemistry , environmental chemistry , terrestrial ecosystem , δ15n , ecosystem , isotope analysis , isotope , nitrification , abundance (ecology) , isotopes of nitrogen , nitrogen , ecology , environmental science , oceanography , δ13c , geology , soil science , biology , physics , organic chemistry , quantum mechanics
Nitrous oxide (N 2 O), a greenhouse gas, is mainly emitted from soils during the nitrification and denitrification processes. N 2 O stable isotope investigations can help to characterize the N 2 O sources and N 2 O production mechanisms. N 2 O isotope measurements have been conducted for different types of global terrestrial ecosystems. However, no isotopic data of N 2 O emitted from Antarctic tundra ecosystems have been reported although the coastal ice‐free tundra around Antarctic continent is the largest sea animal colony on the global scale. Here, we report for the first time stable isotope composition of N 2 O emitted from Antarctic sea animal colonies (including penguin, seal and skua colonies) and normal tundra soils using in situ field observations and laboratory incubations, and we have analyzed the effects of sea animal excrement depositions on stable isotope natural abundance of N 2 O. For all the field sites, the soil‐emitted N 2 O was 15 N‐ and 18 O‐depleted compared with N 2 O in local ambient air. The mean δ values of the soil‐emitted N 2 O were δ 15 N = −13.5 ± 3.2‰ and δ 18 O = 26.2 ± 1.4‰ for the penguin colony, δ 15 N = −11.5 ± 5.1‰ and δ 18 O = 26.4 ± 3.5‰ for the skua colony and δ 15 N = −18.9 ± 0.7‰ and δ 18 O = 28.8 ± 1.3‰ for the seal colony. In the soil incubations, the isotopic composition of N 2 O was measured under N 2 and under ambient air conditions. The soils incubated under the ambient air emitted very little N 2 O (2.93 µg N 2 ON kg −1 ). Under N 2 conditions, much more N 2 O was formed (9.74 µg N 2 ON kg −1 ), and the mean δ 15 N and δ 18 O values of N 2 O were −19.1 ± 8.0‰ and 21.3 ± 4.3‰, respectively, from penguin colony soils, and −17.0 ± 4.2‰ and 20.6 ± 3.5‰, respectively, from seal colony soils. The data from in situ field observations and laboratory experiments point to denitrification as the predominant N 2 O source from Antarctic sea animal colonies. Copyright © 2008 John Wiley & Sons, Ltd.