Preliminary research on dissolved oxygen maximum of seawater in low latitude of China

During the multi-disciplinary investigations on the waters of Nansa Islands for three cruises respectively in 1985.1986.1987.it is found that the dissolved oxygen maximum (DO_max) in its vertical distribution usually exists between 20m and 75m deep.The deep position of O₂ maximum is near the thermocline below and above the deep chlorophyll maximum, as well as above the light-beam attenuation coefficient maximum.In the parts of O₂ maximum occurring, the minimum of CO₂ partial pressure and the maximum of pH value are also found at the same depth.It is still difficult to explain the features exactly by using the published research results about the oxygen maximum in its vertical distribution on the waters of middle and high latitude.
In the present paper, the dissolved oxygen maximum in its vertical distribution on the waters of low latitude is described.It is made by an internal wave which holds eddy mixture.The feature appears to arise from the biological photosynthesis with stratification, from the action of the thermocline preventing oxygen from escaping to the atmosphere.when the environment is suitable for organisms to grow.