Changes of the phytoplankton community as symptoms of deterioration of water quality in a shallow lake

Ewa Anna Dembowska,Paweł Napiórkowski,Tomasz Mieszczankin

doi:10.1007/s10661-018-6465-1

Ewa Anna Dembowska, Paweł Napiórkowski + Show 1 more

Open Access

https://doi.org/10.1007/s10661-018-6465-1

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Abstract

Covering more than 60% of the lake surface, macrophytes determined the taxonomic composition of phytoplankton. We have found numerous indications of ecological deterioration and an increased trophic level year to year: an increased total number of taxa; a significantly increased number of species of Chlorophyta, Bacillariophyceae and Cyanoprokaryota; a decreased number of Chrysophyceae; increased Nygaard index, and high diversity and variability of phytoplankton functional groups. Within 2 years (2002 and 2003) algal biomass doubled: from 3.616 to 7.968 mg l−1. An increased contribution of Chlorococcales and Cyanoprokaryota indicates progressive eutrophication of the lake. The average size of planktonic algae increased, particularly Cyanoprokaryota, where small-celled decreased dramatically and were replaced by large colonies. Cyanoprokaryota remained the dominant group of phytoplankton after 10 years, and the ecosystem of the lake remained in the turbid state. This group of algae had the average biomass 9.734 mg l−1, which constituted almost 92% of the total biomass.

Highlights

Phytoplankton serves as an indicator of trophic state and ecological condition of lakes and rivers (Padisák et al 2006; Szilágyi et al 2008; Pasztaleniec and Poniewozik 2010; Phillips et al 2014; Dembowska and Józefowicz 2015; Dembowska et al 2015)
A clear-water state is typical of lakes with low concentration of suspended particulate matter (SPM) and low phytoplankton abundance where the bottom is covered with submerged macrophytes
A turbid state is typical of lakes with high concentration of SPM, responsible for low water transparency

Summary

Introduction

Phytoplankton serves as an indicator of trophic state and ecological condition of lakes and rivers (Padisák et al 2006; Szilágyi et al 2008; Pasztaleniec and Poniewozik 2010; Phillips et al 2014; Dembowska and Józefowicz 2015; Dembowska et al 2015). The trophic state (connected with a nutrient level) cannot be considered the only factor determining algal growth. A clear-water state is typical of lakes with low concentration of suspended particulate matter (SPM) and low phytoplankton abundance where the bottom is covered with submerged macrophytes. A turbid state is typical of lakes with high concentration of SPM, responsible for low water transparency. Li (1998) distinguished several intermediate stages between the clear-water and turbid states, the stability of which is determined by many factors including nutrient loading and concentration, and the relationships between macrophytes and phytoplankton A turbid state is typical of lakes with high concentration of SPM, responsible for low water transparency. Li (1998) distinguished several intermediate stages between the clear-water and turbid states, the stability of which is determined by many factors including nutrient loading and concentration, and the relationships between macrophytes and phytoplankton

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