Decadal-scale chemical variability in the subtropical North Atlantic deduced from nutrient and oxygen data
Decadal-scale chemical variability in the subtropical North Atlantic deduced from nutrient and oxygen data
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根据营养物和氧气数据推断北大西洋副热带十年尺度的化学变化
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
J. Escánez
中科院分区：
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作者：
H. Garcia;A. Cruzado;L. Gordon;J. Escánez
1992年8月，“赫斯珀里德斯”号考察船重新占据了一个横跨大西洋的断面，该断面名义上是沿沿着24.5度，此前曾在1957年4月和1981年8月取样。据报告，在800米至2 500米深度的海洋层观测到35年来显著变暖（每年0.01摄氏度）。我们研究十年尺度的变化，主要是比较1981年和1992年的部分营养和O2测量。1981年至1992年，流域尺度的水团结构保持相对不变。化学数据的纬向平均差异表明，在1100 m处温度和盐度最大增加的层大致与O2浓度约7 μmol kg−1的明显下降相一致。O2的减少相当于0.6 μmol kg−1 yr−1的平均减少率。垂直整合水柱O2利用率为0.9 mol m2 yr-1。这相当于马尾藻海新产量估计的23-33%。1100 m处的O2减少无法通过使用与营养物再生和O2消耗相关的氧化比率来解释。O2的减少是不是高度相关的纬向平均变化的营养测量。在11年的时间里，营养盐在1100米附近显示出很小或不显著的变化。O2减少的部分原因可能是测量误差（30%）和由于变暖而导致的溶解度变化（20%）。化学变化可能是由进入24.5°N 700-1700 m深度附近的源沃茨的特性变化引起的。
In August 1992 the R/V Hesperides reoccupied a transatlantic section nominally along 24.5°N previously sampled in April 1957 and in August 1981. Observation of significant warming over the 35-year period has already been reported for the ocean layer between 800 and 2500 m depth (∼0.01°C yr−1). We examine decadal-scale variability in the nutrient and O2 measurements primarily comparing the 1981 and 1992 sections. The basin-scale water mass structure remained relatively unchanged from 1981 to 1992. Zonally averaged differences of the chemical data show that the layer of maximum increase in temperature and salinity at 1100 m is roughly coincident with an apparent decrease in O2 concentration of about 7 μmol kg−1. The O2 decrease is equivalent to an average rate of decrease of 0.6 μmol kg−1 yr−1. The vertically integrated water column O2 utilization rate is 0.9 mol m2 yr−1. This is equivalent to 23–33% of the new production rate estimates in the Sargasso Sea. The O2 decrease at 1100 m cannot be explained by using oxidative ratios relating regeneration of nutrients and O2 consumption. The O2 decrease is not highly correlated with zonally averaged changes in the nutrient measurements. The nutrients show small or insignificant changes near 1100 m over the 11-year period. Part of the O2 decrease might be explained by measurement error (30%) and changes in solubility (20%) due to warming. The chemical changes are likely caused by changes in the characteristics of the source waters entering 24.5°N near 700–1700 m depth.