Evidences and drivers of ocean deoxygenation off Peru over recent past decades.
Evidences and drivers of ocean deoxygenation off Peru over recent past decades.
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DOI：
10.1038/s41598-021-99876-8
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发表时间：
2021-10-13
影响因子：
4.6
通讯作者：
Colas F
中科院分区：
文献类型：
--
作者：
Espinoza-Morriberón D;Echevin V;Gutiérrez D;Tam J;Graco M;Ledesma J;Colas F
脱氧是对沿海海洋健康的主要威胁，因为它影响海洋生物和关键的生物地球化学循环。了解其驱动因素对于繁荣和高度开发的秘鲁上升流系统至关重要，在该系统中，天然低含氧地下沃茨形成所谓的氧气最小区（OMZ），其上限的轻微垂直移动可能会产生巨大影响。在这里，我们调查的长期脱氧趋势在上部的近岸OMZ关闭秘鲁在1970年至2008年期间。我们使用一套独特的溶解氧原位观测和几个高分辨率的区域动力-地球化学耦合模型模拟。观测和模型都显示，在150 m深度以上的近岸脱氧，最大趋势为-10 µmol kg−1 decade 1，并且氧跃层深度变浅（-6.4 m decade−1）。模式敏感性分析表明，当远程强迫被抑制时，模拟的尖跃层深度呈现出不显著的（+0.9 m decade−1）趋势，而当风变率被抑制时，获得了显著的尖跃层变浅（− 3 m decade−1）。这表明，近岸脱氧可以归因于近赤道向东的电流，输送富含氧气的沃茨向秘鲁海岸的放缓。大的不确定性，在此通气通量的估计和后果，最近和未来的脱氧趋势进行了讨论。
Deoxygenation is a major threat to the coastal ocean health as it impacts marine life and key biogeochemical cycles. Understanding its drivers is crucial in the thriving and highly exploited Peru upwelling system, where naturally low-oxygenated subsurface waters form the so-called oxygen minimum zone (OMZ), and a slight vertical shift in its upper limit may have a huge impact. Here we investigate the long-term deoxygenation trends in the upper part of the nearshore OMZ off Peru over the period 1970–2008. We use a unique set of dissolved oxygen in situ observations and several high-resolution regional dynamical-biogeochemical coupled model simulations. Both observation and model present a nearshore deoxygenation above 150 m depth, with a maximum trend of – 10 µmol kg−1 decade1, and a shoaling of the oxycline depth (− 6.4 m decade−1). Model sensitivity analysis shows that the modeled oxycline depth presents a non-significant (+ 0.9 m decade−1) trend when remote forcing is suppressed, while a significant oxycline shoaling (− 3 m decade−1) is obtained when the wind variability is suppressed. This indicates that the nearshore deoxygenation can be attributed to the slowdown of the near-equatorial eastward currents, which transport oxygen-rich waters towards the Peruvian shores. The large uncertainties in the estimation of this ventilation flux and the consequences for more recent and future deoxygenation trends are discussed.
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