Microelectrodes In The Research Of Ocean Acidificationand Hydrothermal Vents Developments And Applications

Chemical sensors have been well developed in20th century. The sensors have played an important role in fields such as medical treatments, biology and chemistry, and marine research have also been included. In this study, we focused on two kinds of microelectrodes, one is liquid membrane microelectrode and the other is all solid microelectrode. The liquid membrane microelectrode was developed to detect coral micro-environment. The all solid microelectrode was applied in search of hydrothermal vents. This research has great significance on predicting marine calcifiers’response to ocean acidification, corals’ response to multiple factors, coral calcification mechanism. In addition, we tried to find out the distribution patterns of the shallow hydrothermal vents.Preparation procedure was optimized through experiments. The advantages of our current procedure for pH liquid membrane microelectrode, Ca2+liquid membrane microelectrode and CO32-liquid membrane microelectrode comprise of great Nernst response, linear correlation coefficient, wider response range, higher sensitivity and longer lifetime. Therefore, these sensors were capable of observing coral internal chemical micro-environments.Internal pH, Ca2+and CO32-concentration, distribution, transport and calcification mechanisms were studied by the combination of liquid membrane electrodes and micro-manipulator. Complete profiles in coral were first obtained and the calcification layer was observed by the microelectrodes. In general, pH first increased and then decreased along the coral polyp, as well as the CO32-pattern. The pH and CO32-concentration changed periodically when the microelectrode’s position was fixed and the light was controlled. Ca+concentration decreased along the depth. The proton pump hypothesis was confirmed by combining pH data and Ca2+data. Calcification rates, as well as DIC and saturation states in the coral polyp, were calculated for the first time.Two-year multi-factor field experiment was designed. Microelectrodes were used to investigate coral responses to changing pCO2, temperature and nutrients. This experiment could provide insights in to the coral mechanism under ocean acidification, climate change and human activity, and the preservation of coral ecosystem and marine environment.Preparation technology of all-solid dissolved H2S microelectrode was optimized as well. The detect limit was extended from10-4mol/L to10-7mol/L by direct current carrier electroplating system. The optimized dissolved H2S microelectrode was integrated onto multiple sensor system with pH, CO32-and Eh microelectrodes, which was applied in the sea trial of Kuishan Tao on May25th,2011. The sea trial was mainly focused on detecting the hydrothermal vents in Kuishan Tao, northeast of Taiwan. The three dimensional spatial chemical signals were analyzed. Four new hydrothermal vents were found based on the chemical signal.