The PIs have developed an in-situ instrument capable of measuring temperature and fluid resistivity as a proxy for chloride concentration. This instrument has been deployed at two RIDGE 2000 Integrated Study Sites for periods of several months. These data indicate unexpected short term changes in chloride concentration. In this proposal the PIs request funds to improve the reliability and durability of these instruments by changing the ceramic insulator in the electrode sensing unit from zirconia to berrylia and to characterize the precision, accuracy and drift characteristics of these new sensors in laboratory experiments under in-situ conditions. The PIs also propose to upgrade the electronics of three existing instruments to provide longer deployments at higher data rates to better characterize the rapid changes in chloride that have been discovered. The concentration of chloride ion is a master variable in controlling the chemical composition of high temperature hydrothermal fluids. Short term and very dramatic temporal changes in the nature and degree of phase separation and the resultant changes in chloride concentration in hydrothermal fluids as a result of magmatic diking and eruptive events have been observed in recent years.
Broader Impacts:
Development of sensors for geo community is one of the highest priorities we have at present. This PI proposes to educate a student in the development and utilization of the sensor as well as to put the sensor out for use by scientists through the UW Tech Transfer program. This proposal is clearly linked to technology development that will be very important for seafloor observatories. It will provide funding for major portion of a graduate student thesis and provide the student with cross-training in oceanography, materials science, and electrical engineering.
