长江口上升流区营养盐的分布及其通量的初步估算

The nutrient distribution and nutrient flux estimation in the upwelling area of the Changjiang estuary

根据2004年5月份长江口调查资料,分析了春季长江口上升流现象及其对营养盐分布的影响;初步估算了春季上升流的营养盐通量。结果表明:在春季,低温、高盐、低溶解氧的上升流稳定存在于122°20′～123°00′E,31°00′～32°00′N海区的10m 层和底层之间,并可以涌升到10m 层以上海区。上升流为上层海区输入了丰富的 PO_4-P 和相对低浓度的 NO_3-N 和 SiO_3-si。对上升流营养盐通量的计算表明,春季上升流中磷酸盐输送通量远高于长江径流输入,可能会成为影响该海区磷酸盐分布以及浮游植物生长的一个值得关注的因素:而氮和硅营养盐则不如长江径流输入量大。

Based on the investigation in May 2004, the influences of spring upwelling in the Changjiang estuary on the nutrient distributions were studied, and then the nutrient fluxes were estimated preliminarily. The results indicate that the upwelling, characterized by low temperature, high salinity, and low dissolved oxygen, existed persistently between the bottom and the layers above 10m in the region of 122°20′- 123°00′E, 31°00＇- 32°00′N in spring. The spring upwelling brought up rich phosphate and relatively poor nitrate and silicate to the upper layers above 10 m. The estimation of nutrient fluxes indicates that the phosphate flux in spring upwelling was two times higher as that of the Changjiang river water, which might be an important factor to influence the phosphate distribution and phytoplankton growth. In contrast, the fluxes of nitrate and silicate were much lower than the inputs from the Changjiang river water.