A multi-channel chemical sensor and its application in detecting hydrothermal vents

• Published in: Acta oceanologica Sinica Vol. 38; no. 9; pp. 128 - 134
• Main Authors: Cai, Zhen, Mur Luis, A J, Han, Jiwan, Wang, Kui, Qin, Huawei, Ye, Ying
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Oceanography 01.09.2019; Springer Nature B.V; Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China%Institute of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China; Ocean College, Zhejiang University, Zhoushan 316021, China%Environmental and Rural Sciences, Institute of Biological, Aberystwyth University, Aberystwyth SY233DA, UK%Key Laboratory of Marine Ecosystem and Biogeochemistry, State Oceanic Administration, Hangzhou 310012, China
• Subjects: Anomalies; Change detection; Chemical sensors; Climatology; Deep sea; Deep water; Detection; Earth and Environmental Science; Earth Sciences; Ecology; Electrodes; Engineering Fluid Dynamics; Environmental Chemistry; Hydrogen sulfide; Hydrothermal plumes; Hydrothermal springs; Hydrothermal vents; Marine & Freshwater Sciences; Ocean floor; Oceanographers; Oceanography; Organic chemistry; pH effects; Plumes; Sea trials; Sensors; Turbidity; Underwater exploration; Vents; multi-channel; chemical sensor; hydrothermal vents detection; SWIR; chemical anomalies
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-019-1481-1

There are well-established chemical and turbidity anomalies in the plumes occurring vicinity of hydrothermal vents, which are used to indicate their existence and locations. We here develop a small, accurate multi-channel chemical sensor to detect such anomalies which can be used in deep-sea at depths of more than 4 000 m. The design allowed five all-solid-state electrodes to be mounted on it and each (apart from one reference electrode) could be changed according to chemicals to be measured. Two experiments were conducted using the chemical sensors. The first was a shallow-sea trial which included sample measurements and in situ monitoring. pH, Eh, CO 3 2− and SO 4 2− electrodes were utilized to demonstrate that the chemical sensor was accurate and stable outside the laboratory. In the second experiment, the chemical sensor was integrated with pH, Eh, CO 3 2− and H 2 S electrodes, and was used in 29 scans of the seabed along the Southwest Indian Ridge (SWIR) to detect hydrothermal vents, from which 27 sets of valid data were obtained. Hydrothermal vents were identified by analyzing the chemical anomalies, the primary judging criteria were decreasing voltages of Eh and H 2 S, matched by increasing voltages of pH and CO 3 2− . We proposed that simultaneous detection of changes in these parameters will indicate a hydrothermal vent. Amongst the 27 valid sets of data, five potential hydrothermal vents were targeted using the proposed method. We suggest that our sensors could be widely employed by marine scientists.