南丹麦大学Elizabeth Leon-Palmero团队揭示了阳光驱动淡水和海水中一氧化二氮的非生物形成。相关论文于2025年3月14日发表在《科学》杂志上。
一氧化二氮（N2O）是一种强效温室气体，也是平流层臭氧消耗的主要因素，但其来源尚未得到很好的解决。在这项工作中，研究组实验性地展示了一种以前在温室气体预算中没有考虑过的N2O产生途径，并称之为光化学脱氮。阳光在淡水和海水中的有毒非生物条件下诱导大量和一致的N2O产生。
研究组使用同位素示踪剂测量了光化学N2O的产生率，并确定亚硝酸盐是主要底物，硝酸盐在光还原为亚硝酸盐后也会产生影响。此外，N2O的产生与辐射剂量密切相关。光化学反硝化作用超过了地表水中生物N2O的产生。尽管之前被忽视了，但这一过程可能通过其在淡水和海洋表层水中的出现，对全球N2O排放做出很大贡献。
附：英文原文
Title: Sunlight drives the abiotic formation of nitrous oxide in fresh and marine waters
Author: Elizabeth Leon-Palmero, Rafael Morales-Baquero, Bo Thamdrup, Carolin Lscher, Isabel Reche
Issue&Volume: 2025-03-14
Abstract: Nitrous oxide (N2O) is a potent greenhouse gas and the main stratospheric ozone-depleting agent, yet its sources are not well resolved. In this work, we experimentally show a N2O production pathway not previously considered in greenhouse gas budgets, which we name photochemodenitrification. Sunlight induces substantial and consistent N2O production under oxic abiotic conditions in fresh and marine waters. We measured photochemical N2O production rates using isotope tracers and determined that nitrite is the main substrate and that nitrate can also contribute after being photoreduced to nitrite. Additionally, this N2O production was strongly correlated to the radiation dose. Photochemodenitrification exceeded biological N2O production in surface waters. Although previously overlooked, this process may contribute considerably to global N2O emissions through its occurrence in fresh and marine surface waters.
DOI: adq0302
Source: https://www.science.org/doi/10.1126/science.adq0302