Loss of fixed nitrogen causes net oxygen gain in a warmer future ocean
Loss of fixed nitrogen causes net oxygen gain in a warmer future ocean
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固定氮的损失导致未来海洋变暖的净氧气增加
DOI：
10.1038/s41467-019-10813-w
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发表时间：
2019
影响因子：
16.6
通讯作者：
P. Kähler
中科院分区：
文献类型：
--
作者：
A. Oschlies;W. Koeve;A. Landolfi;P. Kähler
海洋缺氧事件与地球历史上的温暖气候有关，人们担心当前的海洋缺氧最终可能导致缺氧。在这里，我们展示了一个多千年全球变暖模拟的结果，该结果显示，在短暂的脱氧后，尽管海洋平均变暖3 °C，但海洋氧含量比工业化前高出6%。在以前的研究中没有考虑到的一个走廊海洋氧气来源解释了几千年后达到的氧气过剩的三分之二。这是由于增强的反硝化作用取代了当今海洋在不断扩大的缺氧区域的有氧呼吸作用：由此产生的固定氮的损失相当于海洋氧的增加，并取决于氮固定对反硝化作用的不完全补偿。升高的总氧在一个温暖的海洋与更大的缺氧区域提出了一个新的挑战，解释全球海洋缺氧事件，并要求更好地了解环境控制固氮。海洋缺氧事件威胁着海洋生态系统，预计随着气候变暖，这种事件会增加。Oschlies及其同事利用模型模拟表明，尽管温度升高，但在短暂脱氧后，微生物反硝化可能导致氧气增加超过工业化前的水平。
Oceanic anoxic events have been associated with warm climates in Earth history, and there are concerns that current ocean deoxygenation may eventually lead to anoxia. Here we show results of a multi-millennial global-warming simulation that reveal, after a transitory deoxygenation, a marine oxygen inventory 6% higher than preindustrial despite an average 3 °C ocean warming. An interior-ocean oxygen source unaccounted for in previous studies explains two thirds of the oxygen excess reached after a few thousand years. It results from enhanced denitrification replacing part of today’s ocean’s aerobic respiration in expanding oxygen-deficient regions: The resulting loss of fixed nitrogen is equivalent to an oceanic oxygen gain and depends on an incomplete compensation of denitrification by nitrogen fixation. Elevated total oxygen in a warmer ocean with larger oxygen-deficient regions poses a new challenge for explaining global oceanic anoxic events and calls for an improved understanding of environmental controls on nitrogen fixation. Ocean anoxic events threaten marine ecosystems, and they are predicted to increase as the climate warms. Using model simulations, Oschlies and colleagues show that in spite of rising temperatures, after transitory deoxygenation, microbial denitrification could lead to oxygen increases that exceed preindustrial levels.
影响因子：
18.3
作者：
Ridgwell, Andy;Schmidt, Daniela N.
通讯作者：
Schmidt, Daniela N.
影响因子：
56.9
作者：
Stramma, Lothar;Johnson, Gregory C.;Mohrholz, Volker
通讯作者：
Mohrholz, Volker
影响因子：
64.8
作者：
Schmidtko, Sunke;Stramma, Lothar;Visbeck, Martin
通讯作者：
Visbeck, Martin