石油烃和营养盐的复合污染对海洋浮游植物的影响Ⅰ. 石油烃对海洋浮游植物吸收营养盐的影响

通过向具有相同营养盐浓度的培养体系中添加不同浓度的石油烃,对中肋骨条藻、赤潮异弯藻、微小亚历山大藻和锥状斯氏藻进行周期性培养,探讨了石油烃对微藻营养盐吸收动力学的影响.结果发现,在开始30min内,微藻对营养盐均有一非耗能的短暂快吸收,随后吸收速率下降并趋于稳定.石油烃对中肋骨条藻和赤潮异弯藻氮、磷的吸收都表现抑制作用,浓度从0.13 mg/L到8.25mg/L的石油烃所呈现的抑制作用基本表现为先减弱后逐渐增强,8.25mg/L浓度的石油烃抑制作用最强.与中肋骨条藻和赤潮异弯藻实验结果不同的是,石油烃对微小亚历山大藻和锥状斯氏藻的氮、磷吸收在低浓度时呈现促进作用,且促进作用的程度随石油烃浓度的增加有先增强后减弱的趋势,在高浓度下促进作用会消失,8.25mg/L的石油烃不表现促进作用.石油烃对微藻营养盐吸收动力学的影响表现出复杂性,这既受石油烃浓度的影响,也与浮游植物的种类有重要关系.

EFFECTS OF PETROLEUM HYDROCARBON ON THE UPTAKE OF NUTRIENTS BY MARINE PHYTOPLANKTON

Petroleum hydrocarbons in different concentrations were added into the cultivation, and four phytoplankton species were cultivated. The effects of petroleum hydrocarbon on the uptake of phosphate and nitrogen by phytoplankton were investigated. In the first 30 minutes, all the four phytoplankton species had a significant uptake of the two nutrients, but after that, the uptake decreased. The uptake of nutrients by Skeletonema costatum and Heterosigma akashiwo decreased when adding petroleum hydrocarbon. The inhibitory effect first weakened then strengthened as the concentration of petroleum hydrocarbon increased. Petroleum hydrocarbon in lower concentration stimulated the uptake of nutrients by Alexandrium minutum and Scrippsiella trochoidea, and as the concentration increased, the positive effect was strengthened until reached its peak, and then was weakened. Petroleum hydrocarbon in concentration of 8.25mg/L did not show stimulant effect. In conclusion, the effects of petroleum hydrocarbon on the uptake of nutrients by marine algae were complex, which related to not only the concentration of petroleum hydrocarbon but also the species of marine phytoplankton.