水动力条件对藻类影响的研究进展

水动力过程是影响水体富营养化状态和水华爆发的重要因素,水动力因素对藻类影响的研究对于富营养化水体藻类控制具有重要意义。归纳分析近年来关于流速、流态对藻类生长和种类变化的研究报道;就水动力条件对藻类的影响及其作用机理等详细地进行了文献综述。水动力条件对藻类生长的影响分为流速和流态两个方面,不论是单一藻种还是混合藻类,低流速、小扰动有利于藻类的生长和聚集,流速增大则导致Chla浓度先递增后递减,不同藻类的临界流速并不相同;藻类生长随着湍流程度的增加而逐渐受到抑制,抑制作用与水流流态（层流、过渡流、湍流）无明显相关关系,水体流态的变化造成水流剪应力的变化,藻类种类的差异导致其对水流剪应力的响应变化。水动力条件变化引起的藻类种群结构变化,主要表现为水体混合加剧导致优势种群的转换。水动力条件对藻类影响的作用原理主要是引起了光强的改变、细胞长度的变化、营养盐运送及捕食行为变化等。综观当前的研究成果,水动力能否真正阻止藻类细胞的生长或聚集,影响藻类生长或种类变化的扰动的最低水平以及水动力对藻类影响的作用机理是这一领域未来研究的重点所在。

Reviews of influences from hydrodynamic conditions on algae

Hydrodynamic conditions are important factors to influence eutrophication and water bloom.It is of significance for the eutrophication control to study effects of hydrodynamic conditions on algal growth and algal species change.This paper reviewed the most recent studies on algal growth influences and species changes due to flow velocity or turbulence status and discussed the effects of hydrodynamic conditions on algae.The influences of hydrodynamic conditions on algal growth include 2 aspects which were flow velocity and flow regime.Small-scale fluid motion or low flow velocity were mostly proved to be good for algal growth and aggre-gation regardless of monoculture or mixed culture.The increases in flow velocity induced initial increases and then subsequent de-creases in the Chla concentration.The critical velocities for various algae were not the same.Algal growth was inhibited when the level of turbulence in the water was increased.The inhibitory effect was not correlated with flow regime（laminar,transitional,or turbulent）.Changes of flow regime led to the changes of shear stress,which caused different responses in various algae.The changes of algal population structure resulted from hydraulic condition changes mostly presented as dominant species shifting caused by in-tensive water mixing.The mechanisms of all these influences were primarily changes in the luminous intensity,cell length,nutrient transport and predatory behavior.Based on the advances in the current research,it is recommended that more studies focused on the actual inhibitory effects from hydrodynamic conditions,the lowest influencing level of turbulence and its mechanisms be conducted.