Changes of Periphyton Abundance and Biomass Driven by Factors Specific to Flooding Inflow in a River Inlet Area in Erhai Lake, China

Wenjing Ren,Xiaolin Zhang,Yu Cao,Zhonghai Zhang,Hao Wang,Te Cao,Leyi Ni,Changbo Yuan,Qing Chuan Chou,Yiqian Yao

doi:10.3389/fenvs.2021.680718

Abstract

Periphyton is an ecological essential in freshwater lakes and rivers. Its abundance and biomass are very dynamic in various habitats and subject to various factors, for example, nutrient and light. Following flooding events, the transitional area adjacent to a river inlet and the shallow lake generates diverse habitats for periphyton with gradients in current velocity, suspended matters, nutrients, and light, which would strongly shape the growth and community of periphyton. In this study, three sampling sites were established around a river inlet in Erhai Lake, China, and a field survey was conducted in the sites from April to August (flooding seasons) in 2019 to investigate the abundance and biomass of periphyton and explore influential factors. The results showed that three study areas have different gradients of current velocity depending on the distance to the river inlet, thereby regulating the concentrations of nutrients and suspended matters, which strongly affected the periphyton community; to be specific, the biomass of periphyton was inhibited by the concentration of suspended matters and high concentrations of silicate mainly reduced the diversity of periphyton. Our results imply that the study on the driving factors of periphyton could help to understand its community assembly mechanism and biomass and species composition of periphyton can provide some reference for trophic state of the lake.

Highlights

Periphyton is a major primary producer and an important component in clearwater and freshwater ecosystems
Field investigations were carried out at the area around the river inlet area in Erhai Lake, China (25°55′N,100°78′E), and the area could be simplified as three types: estuary zone (E zone) in Miju River and Lake Erhai junction, estuary–lake mixing zone (E–L zone), and lake littoral zone (L zone) (Figure 1)
The suspended matter interacts weakly with silicate, explaining the 2.4% periphyton variance (Figure 3B)

Summary

Introduction

Periphyton (attached on the surface of plants) is a major primary producer and an important component in clearwater and freshwater ecosystems. The Effect of Flooding on Periphyton development of periphyton in shallow lakes and rivers has been attributed to the changes of physical, chemical, and biological factors, including light availability (Warren et al, 2017), water velocity (Townsend et al, 2012), nutrient concentrations (Myrstener et al, 2018), grazing by consumers (Jones and Sayer, 2003; Garcia et al, 2015), etc. Benthic fish disturbance will potentially facilitate the release of nutrients from the sediment, thereby promoting periphyton growth (Meerhoff et al, 2007; Jeppesen et al, 2010), while invertebrates can remove periphyton biomass and alter community composition through direct grazing (Garcia et al, 2015; Mormul et al, 2017; Beck et al, 2019; Wolters et al, 2019)

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