辽东湾氮磷营养盐变化特征及潜在性富营养评价

根据2002-06～2002-09之间4个航次的调查资料,阐述了辽东湾海域氮磷营养盐的时空变化特征,并对氨氮NH₄⁺-N、硝酸态氮NO₃^--N和亚硝酸态氮NO₂^--N、磷酸盐PO₄^3--P和pH及盐度进行了相关分析,对海域进行了潜在性富营养化评价.结果表明:该海域氮磷营养盐随月份和空间的不同呈现不同的变化规律,近岸海域受径流影响较大,海区中间则是海洋生物化学过程影响较大.N/P值从6月初的52.5上升到7月初的60.6,在9月初又降到39左右,都远大于Redfield值16.氮磷营养盐和pH及盐度表现出不同的相关关系,如在6月NO₂^--N和pH的相关系数高达0.93.4个航次中辽东湾总氮值为212.0μg/L,磷酸盐值为10.1μg/L,N/P(原子比)为50.77,潜在性富营养化评价结果为:辽东湾在调查期间为磷限制中度营养盐区.

Inorganic Nitrogen and Phosphate and Potential Eutrophication Assessment in Liaodong Bay

On basis of field data measured during 4 cruises from June to September in 2002, variation feature of inorganic nitrogen and phosphate in Liaodong Bay was analyzed. Regression analyses of NH4+(-)N, NO3-(-)N, NO2-(-)N and PO4(3-)-P versus pH as well as inorganic nitrogen and phosphate versus salinity were also conducted. Finally, potential eutrophication of Liaodong Bay was assessed. It is shown that inorganic nitrogen and phosphate in Liaodong Bay vary with different months and different locations. In coast areas inorganic nitrogen and phosphate are mainly affected by rivers, while in central areas of the bay, they are subject to marine biochemical process. Ratio of inorganic nitrogen to phosphate rises to 60.6 from 52.5 in early June, then drops to 39, all far above Redfield value 16. Inorganic nitrogen and phosphate versus pH as well as salinity show different correlation. For example, the correlation coefficient of NO2(-)-N and pH even reaches 0.93. During 4 cruises in Liaodong Bay the total inorganic nitrogen is 212.0 microg/L, phosphate 10.1 microg/L, N/P 50.77. Potential eutrophication assessment indicates that during the survey period Liaodong Bay can be classified as a phosphate-limiting moderate-level nutrient area.