Measuring pH variability using an experimental sensor on an underwater glider
Measuring pH variability using an experimental sensor on an underwater glider
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使用水下滑翔机上的实验传感器测量 pH 值变化
DOI：
10.5194/os-13-427-2017
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发表时间：
2016
期刊：
影响因子：
3.2
通讯作者：
R. Onken
中科院分区：
文献类型：
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作者：
Michael Hemming;J. Kaiser;K. Heywood;D. Bakker;J. Boutin;K. Shitashima;Gareth A. Lee;Oliver Legge;R. Onken
抽象的。自主水下滑翔机提供了在垂直和水平平面上以高分辨率连续测量海洋参数的能力，时间尺度可以延伸到数月。2014年6月，在地中海西北部的撒丁岛海进行REP14-MED实验期间，一个在总尺度上测量pH值的实验离子敏感场效应晶体管(ISFET)传感器被安装在一架滑翔机上。在部署期间，在深度达1000 m的80 公里横断面上进行了为期12天的PH值采样。从附近的一艘船上采集了水样，分析了溶解的无机碳浓度和总碱度，以得出用于验证ISFET传感器测量的pH值。该pH传感器的垂直分辨率较好(1~2 m)，但稳定性较差，且呈非单调漂移。为了消除传感器漂移，每次潜水都在整个水柱中应用了深度恒定的时变偏移量，将数据的传播减少了大约三分之二。此外，ISFET传感器需要基于温度和压力的校正，这是通过线性回归实现的。对此进行校正后，传感器的表观pH变异性进一步降低了13%至31 %。当地中午时分，阳光导致地表水中传感器的pH值明显下降，降幅高达0.1，这突显了在未来的部署中屏蔽传感器的重要性。来自ISFET传感器的校正后的pH值与滑翔机测量的潜在温度、盐度、潜在密度异常(σθ)和溶解氧浓度(c(O2))一起提供，从而深入了解撒丁岛海的物理和生物地球化学变异性。PH最大值接近夏季叶绿素最大值深度，c(O2)值也较高。深度的纵向pH变化(σθ >； 28. 8 kg m−3)突出了撒丁岛海水团的变异性。盐度为 >； 38. 65的海水pH值较高，盐度在38.3-38.65之间的海水pH值较低。较高的pH值与含盐量较高的黎凡坦中水有关，而较低的pH值可能与有机质的再矿化有关。此外，靠近海岸的浅海等叶珊瑚与低pH和低c(O2)、高盐度、高碱度、高溶解无机碳浓度和叶绿素荧光水域相吻合，可能是上升流的指示。
Abstract. Autonomous underwater gliders offer the capability of measuring oceanic parameters continuously at high resolution in both vertical and horizontal planes, with timescales that can extend to many months. An experimental ion-sensitive field-effect transistor (ISFET) sensor measuring pH on the total scale was attached to a glider during the REP14-MED experiment in June 2014 in the Sardinian Sea in the northwestern Mediterranean. During the deployment, pH was sampled at depths of up to 1000 m along an 80 km transect over a period of 12 days. Water samples were collected from a nearby ship and analysed for dissolved inorganic carbon concentration and total alkalinity to derive the pH for validating the ISFET sensor measurements. The vertical resolution of the pH sensor was good (1 to 2 m), but stability was poor and the sensor drifted in a non-monotonous fashion. In order to remove the sensor drift, a depth-constant time-varying offset was applied throughout the water column for each dive, reducing the spread of the data by approximately two-thirds. Furthermore, the ISFET sensor required temperature- and pressure-based corrections, which were achieved using linear regression. Correcting for this decreased the apparent sensor pH variability by a further 13 to 31 %. Sunlight caused an apparent sensor pH decrease of up to 0.1 in surface waters around local noon, highlighting the importance of shielding the sensor from light in future deployments. The corrected pH from the ISFET sensor is presented along with potential temperature, salinity, potential density anomalies (σθ), and dissolved oxygen concentrations (c(O2)) measured by the glider, providing insights into the physical and biogeochemical variability in the Sardinian Sea. The pH maxima were identified close to the depth of the summer chlorophyll maximum, where high c(O2) values were also found. Longitudinal pH variations at depth (σθ > 28. 8 kg m−3) highlighted the variability of water masses in the Sardinian Sea. Higher pH was observed where salinity was > 38. 65, and lower pH was found where salinity ranged between 38.3 and 38.65. The higher pH was associated with saltier Levantine Intermediate Water, and it is possible that the lower pH was related to the remineralisation of organic matter. Furthermore, shoaling isopycnals closer to shore coinciding with low pH and c(O2), high salinity, alkalinity, dissolved inorganic carbon concentrations, and chlorophyll fluorescence waters may be indicative of upwelling.
滑翔机观测陆架断裂峡谷增强的深水上升流：跨坡碳和养分交换的机制
影响因子：
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作者：
Porter M
通讯作者：
Porter M
氧光极在分析平台上的时间响应及其对流速和温度的依赖性
DOI：
10.4319/lom.2014.12.617
发表时间：
2014
期刊：
Limnology and Oceanography: Methods
影响因子：
--
作者：
Bittig;B. Fiedler;R. Scholz;G. Krahmann;A. Körtzinger
通讯作者：
A. Körtzinger