Response of periphytic algae community structure characteristics to hydrodynamic conditions in an open channel

• DOI: 10.18307/2024.0212
• Publication Date: 2024-05-06T06:17:26Z
• Authors: Duan Shaoyi; ; Yang Mengwei; Guan Guanghua; Zhu Yuxuan; Bi Yonghong
• Keywords: Periphyton

明渠输水系统的着生藻类异常增殖会淤塞拦污栅,降低明渠输水能力,并增加清理工作压力。目前,有关着生藻类对水动力的响应研究多在天然河流、湖泊中开展野外原型观测,针对混凝土衬砌表面着生藻类的水动力研究仍然少见。由于混凝土基质与泥沙基质的显著差异,着生藻类在衬砌明渠和自然水体中对水动力的响应特性不同。为探究水动力对明渠着生藻类生长及群落结构的影响,特开展明渠中着生藻类的培养观测及水动力冲刷实验。通过分析着生藻类叶绿素a含量、群落结构、无灰干重、细胞密度等指标,以探究不同基质粗糙度、不同生长阶段的着生藻类对不同水动力条件的响应。结果表明:着生藻类建群过程具有3个明显阶段,分别为迟滞期、指数生长期、稳定期;随着流速增大,着生藻类生物量先上升后下降,当流速v>0.6 m/s时,着生藻类的生长被显著抑制;冲刷流速增大至v=0.8 m/s的2天后,着生藻类生物量显著减少,群落多样性下降。在着生藻类建群迟滞期(实验中约3周),该阶段提高流速对着生藻类生物量的冲刷剥离效果最明显;基质粗糙度越小,着生藻类建群迟滞期越长,通过水力冲刷的除藻效果越明显。本研究探索了不同水动力条件下明渠着生藻类的响应规律,有助于认识明渠着生藻类的群落特征,可为明渠输水系统内着生藻类水力调控提供重要依据。;Periphytic algae bloom in open channel water delivery system can clog up the sewage barrier, reduce capacity, and increase pressure of clean-up work. At present, most research on response periphytic (PA) to hydrodynamics are carried out natural rivers lakes, studies PA surface concrete lining still rare. Due significant difference between sediment substrate, characteristics lined channels bodies varies. To reveal such different mechanism, cultivation observation hydrodynamic erosion experiment were out. By analyzing chlorophyll-a content, community structure, ash-free dry weight cell density, responses substrate roughness growth stages conditions investigated. Results showed that there three distinct process colony building, which lag period, exponential period stable period. With flow velocity, biomass first increased then decreased. When velocity was above>0.6 m/s, significantly inhibited. After 0.8 m/s for 2 days, decreased significantly, diversity In retardation (about 3 weeks experiment), scour stripping effect increasing obvious. The smaller longer formation, more obvious removal by hydraulic scour. This study explored rules under conditions, is helpful understand living channel, provide an important basis control system.