N和P对东海中北部浮游植物的影响研究

调查海域浮游植物种类丰富,海水富营养化趋势明显.采用通径方法分析2001～2003年春夏季数据,在众多环境因子中,N、P含量及其组成与浮游植物关系最为密切,是影响浮游植物的数量和种类组成变化的首要因子.硅藻和甲藻对各种N的利用能力不同,是硅藻在调查海域占据绝对优势的重要原因;在同一季节中,硅藻和甲藻利用不同层次的氮盐,减少了两者间的竞争压力.高NO3-N/TIP对某些种类具有抑制作用,对甲藻而言,这种抑制作用更为明显.NO3-N/TIP在10～20、NH4-N/TIP或NO2-N/TIP小于1时,浮游植物的多样性最为丰富.NO2-N/TIP对硅藻的种类数变化几乎没有影响,而与甲藻的种类数成正相关.

Influence of nitrogen and phosphate on phytoplankton in the middle and northern part of East China Sea

The investigation waters are abundant of phytoplankton in species and quantity,meanwhile the extent of eutrophication in the waters is evident and the tendency is increasing.The datum of the investigations in spring and summer from 2001 to 2003 were analyzed with the path method.According to the results,the concentration and composition of nitrogen and phosphate were closely related with phytoplankton and chief factors among all environmental factors.There is an apparent difference between the using ability of diatom and dinoflagellate to different nitrogen compound,that's why diatom was dominated in the whole investigation area.In the same season,the nitrogen sources used by diatom and dinoflagellate came from the different layers,thus the pressure of competition for same nitrogen compound was decreased.The high ratio of NO_3-N to phosphate confine quantities for several species,and such function was much notable to dinoflagellate.When the ratio of NO_3-N to phosphate from 10 to 20,and the ratio of NH_4-N to phosphate or ratio of NO_2-N to phosphate less than 1,the diversity index of phytoplankton was the highest.There is faint relationship between ratio of NO_2-N to phosphate and species of diatom,but it is obviously related to the species of dinoflagellate.