洋山港海域海水压载后理化指标变化规律

Variation of physical and chemical factors in the water after loading from sea to the simulation ballast cabin at Shanghai Yangshan Port

摘要:

通过模拟压载实验，比较分析夏季和冬季洋山港海域海水压载0、1、5、10、15和30 d后水体理化因子的变化，包括光照强度、pH、盐度（Sal）、温度（T）、溶解氧（DO）、浊度、悬浮物（TSS）、亚硝酸盐（NO₂-N）、铵盐（NH₄-N）、硝酸盐（NH₃-N）、磷酸盐（PO₄-P）、总氮（TN）和总磷（TP）。结果显示：压载舱处于黑暗状态，与外界差别巨大；夏季压载第1天温度降低，其后变化不大，冬季温度稳定，后期气温骤降时影响到舱内温度；夏季和冬季压载过程中盐度基本保持稳定；冬季溶解氧保持稳定，夏季压载前期未出现波动，第30天明显下降；夏、冬两季pH均未发生显著变化；自然海水进入压载舱后，浊度以及TSS大幅降低，变化极为显著；冬季总氮含量保持稳定水平，夏季压载后期总氮较原海水显著性上升；夏季总磷含量波动较大，但经过30 d模拟压载后依然高于原海水，冬季总磷在第1天显著降低，此后变化微弱。

Abstract:

In order to understand the variation of physical and chemical factors in ballast water, the simulation ballasting experiment was designed and conducted at land-based test facility. Sample data were collected immediately after pumping finished (0 d) and then on days 1, 5, 10, 15 and 30 respectively. The parameters to be analyzed include water temperature, salinity, pH, DO, turbidity, TSS, NO₂-N, NH₄-N, NH₃-N, PO₄-P, TN and TP. Salinity and temperature fluctuated in a small range, and there was no significant change during holding. Natural light was strong, especially in summer, so that was the main reason why natural sea water temperature has declined after being pumped into the dark environment. It might have a certain impact on the temperature of the ballast tank in case of strong cooling weather in winter. The depletion of oxygen of the plankton in the tank did not show significant changes to the DO. The stability of DO and pH could be maintained throughout the ballasting process. Turbidity and TSS decreased significantly within holding time. There was a large fluctuation of TN, NO₂-N and NH₄-N in summer, and of NH₃-N in winter. The initial concentration of phosphorus in winter was higher than that in summer, but it rapidly decreased. It declined notably in its initial stage during winter time.