Estimating the ratios between the nutrients and the apparent oxygen utilization in the South China Sea, China

Nitrogen and phosphorus are the elements which are the basis of phytoplanktons'growth.These elements are removed by the phytoplankton in the upper water.When the phytoplankton and some organic debris subside, these elements are regenerated by biologic oxidation,so the distributed characteristic of the contents is that the contents increase by degrees from upper to bottom in the water column.Of course,the distribution of nutrients is connected with different sea areas. Although the south sea is researched time after time and many data of nutrients are got,the study of the distribution and the regeneration of these parameters are short,so the data got by two cruises in June and November of 1998 are used to study some characteristics of those nutrients.On the basis of analyzing the vertical distribution of the nutrients,the relationship between AOU(apparent oxygen utilization)and those nutrients is got.The result shows that during organic matter regenerating,the mixing water otfers water body whose depth is about 75~1 000 mextra oxygen and the vertical variation of those nutrients in the water column are mostly influenced by regeneration.The efficiency of oxygen's supplement takes place between the depth of 1 000 m and 2 700 m,but the proportion of the regenerated nutrients in water becomes little.