Formation analysis of maximum value in vertical distribution of dissolved oxygen in the Cold Water Mass of the western Southern Huanghai Sea

Based on the data of dissolved oxygen(DO) collected from Southern Huanghai Sea investigation during July,2006,this paper focused on an analysis of the maximum value phenomenon of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,and the relationship of DO concent ration between the main environmental factors was also studied.The results showed that the maximum value phenomenon was the dominant feature of DO vertical distribution in the Cold Water Mass of the western Southern Huanghai Sea,which was also accom panied with SCM;The depth and value of the DO maximum had obvious regional differences;The temperature and salinity was the main controlling factors of DO in the water volume above DO maximum layer;After the form ation of the therm ocline with a certain streng th,the DO maximum layer appeared in the vicinity of the lower bound of the therm ocline,DO maximun value was contr olled by the thickness of the thermo cline and the biochemical activity,besides,the study also found that the thickness of the therm ocline layer and the DO maximum value were positively correlated;DO concentration was low in bottom water,which was caused by the decomposition of organic matter.Simult aneously,successfully giving the explaination that the location was not match and the value was not related of the DO maximum layer and the subsur face chlor ophyll maximum layer,in addition,a perspective named "DO net cumulative effect" was put forward,not only the formation mechanism of DO maximum value was analyzed from time scale and dynamic angle,but also the constitution of DO value or source in the DO maximum layer was discussed theoretically,and pointing that since the beginning of DO maximum layer to the time of observation,the biochemical activity(or Ch-latotal output) in the water volume under the DO maximum layer and in the euphotic zone was closely related to the DO maximum value.Overall,The water column stratification and biochemistry significantly affected the vertical distribution of DO in the Cold Water Mass of the western Southern Huang hai Sea in summer.