Zooplankton as Indicator of the Ecological State of Protected Aquatic Ecosystems (Lake Borovoe, Burabay National Nature Park, Northern Kazakhstan)

Elena Krupa,Sophia Romanova,Galym Berkinbaev,Natalya Yakovleva,Erlan Sadvakasov

doi:10.3390/w12092580

Abstract

The enrichment of the protected Borovoe Lake with nutrients has taken place within the last 100 years, from the moment the first resort was formed on its shores. The purpose of this study was to assess the current ecological state of Borovoe based on the structure of zooplankton. According to the chemical data, in the summer of 2019, the content of nutrients in the water was, relatively, not high; the content of heavy metals was very low. Twenty-seven species were found in zooplankton. The average abundance of zooplankton was 988.8 thousand ind./m3 with a biomass of 1.52 g/m3. Rotifera dominated. Cladocera sub-dominated. The Shannon index values were 2.31 bit/ind. and 2.57 bit/mg; the values of Clarke’s W-statistics and Δ-Shannon were negative. The abundance of zooplankton increased more than nine times, but the average individual mass of an organism decreased from 0.0112 to 0.0016 mg over the past decade. Despite the relatively low content of nutrients, the structure of zooplankton demonstrated that the nutritional load on Lake Borovoe is currently close to critical. Statistical mapping of the data and redundancy analysis (RDA) showed that the primary source of lake pollution is the village of Borovoe and sanatoriums located on the southeast and northwest coasts.

Highlights

Water bodies of protected areas are remote from industrial enterprises; the content of toxic substances in them is usually low [1,2]
The toxins released by some Cyanobacteria species during blooms pose a severe threat to human health when using the water of a blooming water body [5,6]
The chemical analysis of water takes into account only some part of the total amounts of components contained in a water body

Summary

Introduction

Water bodies of protected areas are remote from industrial enterprises; the content of toxic substances in them is usually low [1,2]. The accumulation of nutrients in water bodies leads to the mass reproduction of blue-green algae [3], an increase in primary productivity, a decrease in transparency, and a deterioration in water quality [4]. Water quality assessment of water bodies can be performed based on chemical or biological methods; both of them have certain limitations. Organic substances and nutrients entering water bodies are used by primary producers [7], or accumulate in bottom sediments [8]. The chemical analysis of water takes into account only some part of the total amounts of components contained in a water body. Bioindication provides an integrated assessment of the quality of the water bodies [9,10].

Objectives

Methods

Results

Discussion

Conclusion