Development And Sea Trial Application Of Chemical Sensor For Hydrothermal Detection

In China's "13th Five-Year Plan",the state has paid more and more attention to the exploration,exploitation and utilization of oceanic seabed resources.Hydrothermal detection is an important part of it.In the vicinity of the hydrothermal vents not only accumulated rich in copper,iron,zinc and other metal elements of sulfide resources,but also gave birth to the environment in extreme environments.The detection of hydrothermal vents not only has the strategic significance of reserves of mineral resources,but also can promote the development of geosciences,life sciences,environmental sciences and other fields in the deep-sea extreme environment.Most of the seabed hydrothermal vents are scattered in the vast ocean floor,making it difficult to confirm the specific location of hydrothermal vents.By detecting the hydrothermal plume exiting from the hydrothermal vents,it is the main method to find hydrothermal vents.Compared with the surrounding seawater,the hydrothermal plume generally has the characteristics of high temperature,high turbidity,low Eh,low pH.The hydrothermal plume is also rich in gas components and various metal elements.At present,all countries in the world mainly rely on various sensors to detect hydrothermal plume,however,there is still a lack of a systematic and effective method to determine whether they encounter hydrothermal plume.Foreign countries have been used for hydrothermal detection of sensors,such as the United States Sea Bird's CTD sensor,the United States Pacific Marine Environmental Laboratory's Miniature Autonomous Plume Recorder?MAPR?,the Canada RBR company's hydrothermal detectors.These sensors have been widely used in the detection of hydrothermal plume and related sulfides and other resources.According to the technical results of hydrothermal detection at home and abroad,combined with our sea trial experience,this dissertation presents a set of methods based on chemical anomalies to determine whether or not encountering hydrothermal plume:?1?redox potential Eh and H₂S potential values consistent decline can be used as an important basis for detecting hydrothermal plume.?2?The consistent positive anomalies of pH and CO₃^2-potentials can be used as the auxiliary judgment for detecting hydrothermal plumes.In the abnormal judgments,the introduction of gradient analysis,to avoid the naked eye may lead to wrong judgment.Finally,supplemented by submarine camera,photo confirmation,to ship multi-beam,GPS and other positioning system to confirm the specific location of hydrothermal vents.In response the strategy put forward by the state to speed up the construction of a marine powerful country.We have formed a research group with relevant personnel from Hangzhou Dianzi University and Zhejiang University.Based on the above method for detecting the anomaly of hydrothermal plume,the group developed a chemical sensor for detecting Eh,H₂S,pH and CO₃^2-anomalies in deep seawater.The chemical sensor has been used in many sea tests and worked well.The chemical sensor carried out oceanic science survey with the "XIANGYANGHONG 10" scientific research ship in2017.The sensor in the southwestern Indian Ocean Ridge obtained an effective 27 lines of the 29 test lines and achieved fruitful results.According to the data analysised by the hydrothermal detection method,three hydrothermal anomaly survey lines were found.The results show that this method can discriminate the anomalous area of hydrothermal plume effectively.The chemical sensor is an important tool for ocean hydrothermal detection.