不同粒径与浓度的清洁疏浚物对新月菱形藻生长的影响

Effects of cleaning dredged materials of different particle size and concentration on the growth of Nitzschia closterium

采用实验生态学方法室内模拟实验研究了不同粒径、不同浓度悬浮清洁疏浚物对新月菱形藻（Nitzschiaclosterium）生长的影响。研究结果表明，在96h的实验周期里，不同粒径清洁疏浚物对新月菱形藻生长的影响非常显著（P〈0．01），在相同浓度清洁疏浚物的情况下，粒径越小，对新月菱形藻生长的影响越大，4种不同粒径清洁疏浚物对新月菱形藻生长的影响由大到小依次是0～16μm〉16～63μm〉63～88μm〉88—125μm。不同浓度清洁疏浚物对新月菱形藻生长的影响同样非常显著（P〈0．01），在相同粒径清洁疏浚物的情况下，浓度越大，对新月菱形藻生长的影响越大，具体影响从9000mg／L浓度到1000mg／L浓度依次递减。悬浮清洁疏浚物对新月菱形藻生长的96h-EC50值，超过以往研究者们对沾污或污染疏浚物中藻类生长的96h-EC50值，清洁疏浚物以消光作用为主的生态效应要远小于沾污或污染疏浚物析出的化学污染对藻类生长的影响，与清洁疏浚物相比，沾污或污染疏浚物对新月菱形藻生长的影响更大，抑制效应更强。清洁疏浚物可能通过遮挡光照减少真光层厚度引起的遮光效应是新月菱形藻生长的主要限制因子。

In this study, the effects of cleaning dredged materials of different particle size and different concentration on the growth of N. closterium was investigated by using the measures of experimental ecology in laboratory. The results were as followed,in the 96 h test of time, different particle size of cleaning dredged materials effects on the N. closterium growth were very significant （P 〈 0.0H ）, in the case of the same concentration of cleaning dredged materials, the smaller of particle size, the greater effects on the growth of N. closterium ,four different particle size cleaning dredged materials effects on the growth of N. closterium in descending order were 0 - 16 μm 〉 16 -63 μm 〉 63 - 88 μm 〉 88 - 125 μm. Different concentrations cleaning dredged materials effects on the N. closterium growth were also very significant （ P 〈 0.01 ） , the specific effects of descending order from 9 000 mg/L to 1 000 mg/L. 96 hours half- inhibition rate （96 h-ECso ） more than previous researchers study value of algae growth in contaminated or polluted dredged materials, cleaning dredged materials role of extinction based ecological effects far less than the contaminated or polluted dredged materials dissolved chemical pollution effects on the growth of algae, contaminated or polluted dredged materials were greater effects on the growth of algae, and inhibit effect stronger. Cleaning dredged materials maybe by blocking light to reduce the thickness of the cuphotic caused shading effect were the main limiting factor of N. closterium growth.