海洋总初级生产力是衡量海洋表层浮游植物光合作用强度及生物碳汇效率的关键指标。然而,生物产氧的光合作用及耗氧的呼吸作用同时进行且难以区分,导致海洋原位总生产力的测量极度困难。溶解氧的三氧同位素异常值(^(17)Δ)不受呼吸作用影...海洋总初级生产力是衡量海洋表层浮游植物光合作用强度及生物碳汇效率的关键指标。然而,生物产氧的光合作用及耗氧的呼吸作用同时进行且难以区分,导致海洋原位总生产力的测量极度困难。溶解氧的三氧同位素异常值(^(17)Δ)不受呼吸作用影响,为评估海洋总生产力提供新指标。自然界中^(17)O的丰度极低且易受到N_(2)的质量干扰,本研究突破三氧同位素(δ^(18)O、^(17)Δ)测量的技术瓶颈,利用气相色谱成功分离了溶解气体中的O_(2)、Ar与N_(2),并确保O_(2)的100%收集。本方法对空气标准^(17)Δ值的长期观测精度达±2.6 per meg,优于国际同类实验室。本研究测定2021年1月南大洋普里兹湾混合层内溶解氧同位素的平均^(17)Δ值为66 per meg,计算得该海域平均总初级生产力(以O_(2)计)为181 mmol/(m^(2)·d),符合夏季高纬度南大洋总初级生产力较低的特征。本研究建立的氧气三氧同位素高精度分析方法在海洋总生产力研究方面具有极大的应用前景,同时也为大气及冰芯包裹气体等地球科学前沿研究提供技术支撑。展开更多
As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based ...As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based on a systematic review of recent studies on OMZ,this paper summarizes the DO thresholds,structural characteristics,distribution patterns,formation and maintenance mechanisms,and driving factors of OMZ in the ocean in the context of global change.The DO thresholds of OMZ typically range from 20 to 100μmol L^(-1).Specifically,the threshold is mostly 20μmol L^(-1) in regions with intense OMZ,such as the Eastern Pacific and Northern Indian Oceans,while it is mostly 100μmol L^(-1) in regions with mild OMZ,including the Western Pacific and Atlantic.In terms of structure,the OMZ is mainly composed of three parts:the upper oxycline,the lower oxycline,and the OMZ core.Significant differences exist in the horizontal and vertical distributions of OMZ across different regions.OMZ is mainly concentrated in tropical and subtropical regions,with the widest distribution in the eastern tropical North Pacific.The upper boundary of OMZ is shallower(50-150 m)in significantly affected regions,whereas it is below 200 m in less affected regions.The formation of OMZ is governed by the continuous consumption of DO in the ocean interior,and the water exchange restriction caused by seawater stratification,whereas the maintenance of the hypoxic state of OMZ relies on two positive feedbacks:increased microbial oxygen consumption due to reduced animal feeding,and increased oxygen consumption by anaerobic metabolic products.In the context of global change,rising temperature is the main driver of OMZ expansion,reducing O_(2) solubility,increasing respiration and decomposition rates,and enhancing seawater stratification.Additionally,the structure and evolution of OMZ is also profoundly affected by ocean circulation such as thermohaline circulation,wind-driven circulation,and upwelling,as well as changes in wind stress,mesoscale eddies and freshwater flux.Future research should focus on establishing OMZ gradient thresholds and classification criteria based on the law of deoxygenation,improving the systematic understanding of the temporal and spatial variations of OMZ,and continuously strengthening studies on OMZ in the Western Pacific.展开更多
文摘海洋总初级生产力是衡量海洋表层浮游植物光合作用强度及生物碳汇效率的关键指标。然而,生物产氧的光合作用及耗氧的呼吸作用同时进行且难以区分,导致海洋原位总生产力的测量极度困难。溶解氧的三氧同位素异常值(^(17)Δ)不受呼吸作用影响,为评估海洋总生产力提供新指标。自然界中^(17)O的丰度极低且易受到N_(2)的质量干扰,本研究突破三氧同位素(δ^(18)O、^(17)Δ)测量的技术瓶颈,利用气相色谱成功分离了溶解气体中的O_(2)、Ar与N_(2),并确保O_(2)的100%收集。本方法对空气标准^(17)Δ值的长期观测精度达±2.6 per meg,优于国际同类实验室。本研究测定2021年1月南大洋普里兹湾混合层内溶解氧同位素的平均^(17)Δ值为66 per meg,计算得该海域平均总初级生产力(以O_(2)计)为181 mmol/(m^(2)·d),符合夏季高纬度南大洋总初级生产力较低的特征。本研究建立的氧气三氧同位素高精度分析方法在海洋总生产力研究方面具有极大的应用前景,同时也为大气及冰芯包裹气体等地球科学前沿研究提供技术支撑。
基金supported by the National Natural Science Foundation of China(Grant Nos.42206135,42476204)the Shandong Provincial Natural Science Foundation(Grant Nos.ZR2025MS664,ZR2025MS611,ZR2022QD019).
文摘As a water layer with significantly reduced dissolved oxygen(DO)in the ocean,the oxygen minimum zone(OMZ)plays a crucial role in regulating marine organism distribution,global material cycles,and climate change.Based on a systematic review of recent studies on OMZ,this paper summarizes the DO thresholds,structural characteristics,distribution patterns,formation and maintenance mechanisms,and driving factors of OMZ in the ocean in the context of global change.The DO thresholds of OMZ typically range from 20 to 100μmol L^(-1).Specifically,the threshold is mostly 20μmol L^(-1) in regions with intense OMZ,such as the Eastern Pacific and Northern Indian Oceans,while it is mostly 100μmol L^(-1) in regions with mild OMZ,including the Western Pacific and Atlantic.In terms of structure,the OMZ is mainly composed of three parts:the upper oxycline,the lower oxycline,and the OMZ core.Significant differences exist in the horizontal and vertical distributions of OMZ across different regions.OMZ is mainly concentrated in tropical and subtropical regions,with the widest distribution in the eastern tropical North Pacific.The upper boundary of OMZ is shallower(50-150 m)in significantly affected regions,whereas it is below 200 m in less affected regions.The formation of OMZ is governed by the continuous consumption of DO in the ocean interior,and the water exchange restriction caused by seawater stratification,whereas the maintenance of the hypoxic state of OMZ relies on two positive feedbacks:increased microbial oxygen consumption due to reduced animal feeding,and increased oxygen consumption by anaerobic metabolic products.In the context of global change,rising temperature is the main driver of OMZ expansion,reducing O_(2) solubility,increasing respiration and decomposition rates,and enhancing seawater stratification.Additionally,the structure and evolution of OMZ is also profoundly affected by ocean circulation such as thermohaline circulation,wind-driven circulation,and upwelling,as well as changes in wind stress,mesoscale eddies and freshwater flux.Future research should focus on establishing OMZ gradient thresholds and classification criteria based on the law of deoxygenation,improving the systematic understanding of the temporal and spatial variations of OMZ,and continuously strengthening studies on OMZ in the Western Pacific.
