The Development and Validation of a Profiling Glider Deep ISFET-Based pH Sensor for High Resolution Observations of Coastal and Ocean Acidification
The Development and Validation of a Profiling Glider Deep ISFET-Based pH Sensor for High Resolution Observations of Coastal and Ocean Acidification
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DOI：
10.3389/fmars.2019.00664
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发表时间：
2019-10
影响因子：
3.7
通讯作者：
G. Saba;E. Wright‐Fairbanks;Baoshan Chen;W. Cai;A. Barnard;Clayton Jones;C. Branham;Kui Wang;T. Miles
中科院分区：
文献类型：
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作者：
G. Saba;E. Wright‐Fairbanks;Baoshan Chen;W. Cai;A. Barnard;Clayton Jones;C. Branham;Kui Wang;T. Miles
沿海和海洋酸化可改变海洋生物地球化学，造成生态后果，可能导致经济和文化损失。然而，很少有时间序列和高分辨率的空间和时间测量来跟踪低pH和/或碳酸盐饱和度的水的存在和运动。过去的酸化监测工作要么空间分辨率低(系泊)，要么成本高，时间和空间分辨率低(研究巡航)。我们开发了第一个集成的滑翔机平台和传感器系统，用于对整个沿海海洋的水柱进行pH采样。对基于离子敏感场效应晶体管(ISFET)的深度pH传感器系统进行了改进，并将其集成到Slocum滑翔机中，在天然海水中进行了测试，以确定不同场景下的传感器调节时间，并在美国东北大陆架(NES)部署期间进行了现场验证。用分光光度法从离散海水样品中测得的pH值与滑翔机pH的对比结果表明，该滑翔机pH传感器在近海水柱数周内的准确度为0.011个pH单位或更高，精度为0.005个pH单位或更高。此外，同一滑翔机上多个传感器的同时测量使基于盐度的总碱度(AT)和文石饱和状态(ΩArag)的估计成为可能。在2018年春季中大西洋部署期间，沿跨陆架横断面的滑翔机pH和推导出的AT/ΩArag数据显示，较高的pH和ΩArag与叶绿素和氧气峰值的深度以及更温暖、更咸的水团有关。在经历了一段时间的强降水后，pH和Ω的最低值出现在中陆架和斜坡的底层，以及近岸。在夏季的部署中，生物污垢被发现是该传感器的主要限制，因此pH和AT的偏移量显著增加。防污涂料的进步以及定期清洁和更换传感器的能力可以应对这一挑战。这里提供的数据表明，滑翔机有能力定期提供区域范围内的高分辨率水柱数据，可用于其他沿海地区的酸化监测工作。
Coastal and ocean acidification can alter ocean biogeochemistry, with ecological consequences that may result in economic and cultural losses. Yet few time series and high resolution spatial and temporal measurements exist to track the existence and movement of water low in pH and/or carbonate saturation. Past acidification monitoring efforts have either low spatial resolution (mooring) or high cost and low temporal and spatial resolution (research cruises). We developed the first integrated glider platform and sensor system for sampling pH throughout the water column of the coastal ocean. A deep ISFET (Ion Sensitive Field Effect Transistor)-based pH sensor system was modified and integrated into a Slocum glider, tank tested in natural seawater to determine sensor conditioning time under different scenarios, and validated in situ during deployments in the U.S. Northeast Shelf (NES). Comparative results between glider pH and pH measured spectrophotometrically from discrete seawater samples indicate that the glider pH sensor is capable of accuracy of 0.011 pH units or better for several weeks throughout the water column in the coastal ocean, with a precision of 0.005 pH units or better. Furthermore, simultaneous measurements from multiple sensors on the same glider enabled salinity-based estimates of total alkalinity (AT) and aragonite saturation state (ΩArag). During the Spring 2018 Mid-Atlantic deployment, glider pH and derived AT/ ΩArag data along the cross-shelf transect revealed higher pH and ΩArag associated with the depth of chlorophyll and oxygen maxima and a warmer, saltier water mass. Lowest pH and ΩArag occurred in bottom waters of the middle shelf and slope, and nearshore following a period of heavy precipitation. Biofouling was revealed to be the primary limitation of this sensor during a summer deployment, whereby offsets in pH and AT increased dramatically. Advances in anti-fouling coatings and the ability to routinely clean and swap out sensors can address this challenge. The data presented here demonstrate the ability for gliders to routinely provide high resolution water column data on regional scales that can be applied to acidification monitoring efforts in other coastal regions.