Projected Centennial Oxygen Trends and Their Attribution to Distinct Ocean Climate Forcings
Projected Centennial Oxygen Trends and Their Attribution to Distinct Ocean Climate Forcings
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DOI：
10.1029/2018gb005939
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发表时间：
2018-09-01
影响因子：
5.2
通讯作者：
Deutsch, Curtis
中科院分区：
文献类型：
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作者：
Takano, Yohei;Ito, Takamitsu;Deutsch, Curtis
我们使用数值模型探索热带太平洋氧气 (O-2) 的百年变化，以说明百年气候变化下的主导模式和机制。最先进的地球系统模型的未来预测显示出显着的模型间差异，但溶解度降低和通风减弱共同消耗了中高纬度地区的温跃层 O-2。相比之下，热带温跃层 O-2 的变化要小得多，甚至略有增加。使用粗分辨率海洋环流和生物地球化学模型进行的一系列敏感性实验表明，海洋变暖是所有纬度温跃层全球脱氧的主要原因，其次是水文循环变化和风应力调节 O-2 区域变化。热带太平洋温跃层中 O-2 的微小变化反映了由于变暖导致的溶解度下降与表观氧利用率 (AOU) 减少之间的近乎完全补偿。我们进一步量化了由于水团年龄变化和敏感性实验中生物再矿化的影响而导致的 AOU 变化。这两种效应几乎同等地导致热带太平洋温跃层 AOU 的减少（物理循环占 43%，生物循环占 57%）。我们的研究结果表明，更好地了解热带海洋的水团变化是改善预测和减少未来 O-2 变化的不确定性的关键。 通俗易懂的语言总结 未来百年的全球变暖可能会导致海洋中大量氧气流失。这不仅会影响海洋生态系统，还会影响渔业。我们使用模型模拟来研究长期气候变化，例如在人为瞬态作用下海面温度、降水和风的变化，如何影响未来百年的海洋氧气流失。海洋在大部分地区都会失去氧气，但热带海洋实际上可以在局部地区获得氧气。我们调查导致热带太平洋中这些独特的氧气变化的原因。热带太平洋中违反直觉的氧气变化很可能是由于循环变化和生物活动（即通过呼吸消耗氧气）引起的水体供应变化造成的，其影响几乎相同。由于氧气流失对海洋生态系统的影响，热带海洋对氧气流失很敏感。我们的研究可以更好地了解未来海洋中的氧气流失。
We explore centennial changes in tropical Pacific oxygen (O-2) using numerical models to illustrate the dominant patterns and mechanisms under centennial climate change. Future projections from state-of-the-art Earth System Models exhibit significant model to model differences, but decreased solubility and weakened ventilation together deplete thermocline O-2 in middle to high latitudes. In contrast, the tropical thermocline O-2 undergoes much smaller changes or even a slight increase. A suite of sensitivity experiments using a coarse resolution ocean circulation and biogeochemistry model show that ocean warming is the leading cause of global deoxygenation in the thermocline across all latitudes with secondary contributions from changes in hydrological cycles and wind stress modulating regional changes in O-2. The small O-2 changes in the tropical Pacific thermocline reflect near-complete compensation between the solubility decrease due to warming and reduction in apparent oxygen utilization (AOU). We further quantified the changes in AOU due to contributions from changes in water mass age and biological remineralization from the sensitivity experiments. The two effects almost equally contribute to the reduction of AOU in the tropical Pacific thermocline (43% for physical circulations and 57% for biology). Our results suggest that better understanding of water mass changes in the tropical oceans is key to improving projections and reducing the uncertainties of future O-2 changes.Plain Language Summary Global warming in the next hundred years could lead to a large amount of oxygen loss from the ocean. This could impact not only the marine ecosystem but also fisheries. We use model simulations to investigate how long-term climate change, such as changes in sea surface temperature, precipitation, and winds, under the anthropogenic transient could impact oceanic oxygen loss in the next hundred years. The ocean loses oxygen in most of the regions but tropical oceans could actually gain oxygen regionally. We investigate what causes these unique oxygen changes in the tropical Pacific Ocean. The counterintuitive oxygen changes in the tropical Pacific Ocean are likely due to, by an almost equal amount of effects, changes in water mass supply due to changes in circulations and changes in biological activity, that is, consumption of oxygen through respiration. Tropical oceans are sensitive to oxygen loss because of its impact on marine ecosystems. Our study could provide a better understanding of future oxygen loss in the ocean.