近日，厦门大学教授Kao, Shuh-Ji及其研究团队的最新研究提出了上层氧化亚氮的产生抵消了生物泵的碳封存这一观点。相关论文于2022年12月19日发表于国际顶尖学术期刊《自然—地球科学》杂志上。

研究表明，亚热带海洋上层海域氧化亚氮的产成量随再矿化过程的变化而变化，并对海洋生物泵脱碳的辐射效益产生拮抗作用。碳氮同位素示踪剂孵化实验和氮同位素自然丰度数据表明，生物活性的增强促进了氮的循环，从而通过氧化和还原作用产生大量的氧化亚氮。这些浅水氧化亚氮来源占空气-海洋通量的近一半，抵消了通过生物泵碳输出所实现的温室效应减缓的6-27%(中值为9%)。

据悉，海洋生物泵从大气中过滤二氧化碳的过程是地球气候的一个关键调节器;然而，海洋也是氧化亚氮的一大聚集地，氧化亚氮是一种强有力的温室气体和臭氧消耗物质。虽然生物固碳和一氧化二氮的产生这些主题已在海洋中分别进行了研究，但它们对温室气体净作用力的综合影响仍不确定。

附：英文原文

Title: Epipelagic nitrous oxide production offsets carbon sequestration by the biological pump

Author: Wan, Xianhui S., Sheng, Hua-Xia, Dai, Minhan, Casciotti, Karen L., Church, Matthew J., Zou, Wenbin, Liu, Li, Shen, Hui, Zhou, Kuanbo, Ward, Bess B., Kao, Shuh-Ji

Issue&Volume: 2022-12-19

Abstract: The removal of carbon dioxide from the atmosphere by the marine biological pump is a key regulator of Earth’s climate; however, the ocean also serves as a large source of nitrous oxide, a potent greenhouse gas and ozone-depleting substance. Although biological carbon sequestration and nitrous oxide production have been individually studied in the ocean, their combined impacts on net greenhouse forcing remain uncertain. Here we show that the magnitude of nitrous oxide production in the epipelagic zone of the subtropical ocean covaries with remineralization processes and thus acts antagonistically to weaken the radiative benefit of carbon removal by the marine biological pump. Carbon and nitrogen isotope tracer incubation experiments and nitrogen isotope natural abundance data indicate enhanced biological activity promotes nitrogen recycling, leading to substantial nitrous oxide production via both oxidative and reductive pathways. These shallow-water nitrous oxide sources account for nearly half of the air–sea flux and counteract 6–27% (median 9%) of the greenhouse warming mitigation achieved by carbon export via the biological pump.

DOI: 10.1038/s41561-022-01090-2

Source: https://www.nature.com/articles/s41561-022-01090-2