Distribution of hydrogen peroxide in the northwest Pacific Ocean
Distribution of hydrogen peroxide in the northwest Pacific Ocean
复制标题
西北太平洋过氧化氢的分布
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
A. Shiller
中科院分区：
文献类型：
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作者：
Jinchun Yuan;A. Shiller
过氧化氢（H2O2）是一种活性氧中间体，参与金属和溶解有机物的循环。由于其在北太平洋的分布知之甚少，我们确定了H2O2在表面沃茨连续，并获得了从日本到夏威夷巡航期间在9个站的垂直剖面。地表水H2O2的变化范围从小于10到大于250 nmol dm−3。在为期一个月的航行中，仅在一天观察到地表水H2O2（250 nmol dm−3）的昼夜循环。这与基于通常假设光产生作为H2O2的主要输入的预期相反。在巡航期间还进行了实验，以检查光产生和暗衰变。在夏威夷附近的一个观测站，光产生的净速率被确定为8 nmol dm−3 h−1，与大西洋中部和南极洲的速率相似。然而，这个最大的光生估算值也类似于其他机制（生物生产和降雨）输入H2O2的可能速率。暗衰变的伪一级速率常数从0.1到0.2 d−1不等，这是以前报道的H2O2衰变速率的低端，并且观察到与溶解的有机碳浓度成比例地增加。综上所述，这些结果表明，在开放的海洋沃茨中H2O2的光产生可能不如以前认为的那么重要，因此H2O2可能不如预期的那样是表面沃茨光化学反应性的指标。此外，我们观察到，上200米水柱的H2O2库存有一个最大的中纬度地区。我们认为，这是由于在高纬度输入减少，以及在低纬度衰减率增加。
Hydrogen peroxide (H2O2) is a reactive oxygen intermediate involved in the cycling of metals and dissolved organic matter. Because little is known of its distribution in the North Pacific Ocean, we determined H2O2 in surface waters continuously and obtained vertical profiles at nine stations during a cruise from Japan to Hawaii. Surface water H2O2 varied from less than 10 to more than 250 nmol dm−3. A diel cycle in surface water H2O2 (∼25 nmol dm−3) was observed only on one day during the monthlong cruise. This is contrary to expectations based on the usual assumption of photo‐production as the dominant input of H2O2. Experiments were also conducted during the cruise to examine both photo‐production and dark decay. The net rate of photo‐production at a station near Hawaii was determined to be 8 nmol dm−3 h−1, similar to rates reported for the central Atlantic Ocean and Antarctic. However, this maximum estimate of photo‐production is also similar to probable rates of H2O2 input by other mechanisms (biological production and rain). The pseudo‐first‐order rate constant for dark decay varied from 0.1 to 0.2 d−1, which is toward the low end of previous reports of H2O2 decay rates, and was observed to increase proportionately to the dissolved organic carbon concentration. Taken together, these results suggest that photo‐production of H2O2 in open ocean waters may be less important than previously thought and therefore H2O2 is likely less of an indicator of the photo‐chemical reactivity of surface waters than hoped for. Furthermore, we observed that the H2O2 inventory for the upper 200 m of the water column has a maximum at midlatitudes. We suggest that this results from diminished inputs at high latitude as well as increased decay rates at low latitudes.