规模化浅海养殖水域沉积作用的初步研究

Natural sedimentation in large-scale aquaculture areas of Sungo Bay, north China Sea

从2001年9月到2002年7月底分5个阶段,使用沉积物捕获器在桑沟湾养殖海区的扇贝区、牡蛎区和海带区进行自然沉积作用的研究。通过对收集的沉积物进行分析,估算该养殖海区的总氮和总磷由海水到海底的通量。估算结果显示,该海区颗粒物质的年平均沉积速率为278.8g/(m2·d),而每克颗粒物质则携带了190.4μg总氮、472.5μg总磷和0.103g有机物质沉入海底。沉积物的总氮和总磷含量显示了较明显的季节性变化。总氮的峰值出现在5月(春季),最低值出现在12月(冬季)。而总磷含量在12月显著高于5月和7月时段。分析表明,下沉的颗粒物质的氮磷摩尔比为0.67～2,而底泥的氮磷摩尔比为0.025～2。研究结果为桑沟湾沿岸海域氮磷营养盐的通量建模提供了重要参数,并为养殖水域环境容量的研究提供了依据。

Sungo Bay is located to the east of Shandong Peninsula where scallop, oyster and kelp have been cultured in large scale for many years. The experiment was conducted in five periods from September 2001 to July 2002. The scallop, oyster and kelp culture areas were chosen as the experiment spots, and in each spot 3×3 sediment traps were set to collect the falling particulate matter. The concentrations of TN,TP and POM in the particulate matter both from the traps and the sediments of the experimental areas were measured. The results showed that the yearly average sedimentary rate of particulate matter was 278.8 g/(m2.d) in the areas, and 190.4 μg of TN,472.5 μg of TP and 0.103 g of POM in per gram of the particulate sediments were carried down to the bottom. There was an obvious seasonal variation in terms of TN and TP contents in the particles that the peak value of the TN content appeared in May, and the bottom value appeared in December, while the value of TP content was higher in cold season (December) than in warm season (May, July). The N/P ratio of the sinking sediments ranged 0.67-2.0, but that in the sediments was in the range of 0.025-2.0. The purpose of this experiment is to provide a field basis for the studies of the nutrient flux and the carrying capacity of shallow sea aquaculture.