Acclimation of phytoplankton to diverse environmental variables at the initial operation stage of a free water surface constructed wetland

Abstract

Phytoplankton played vital roles in aquatic biodiversity and monitoring environmental variations due to the rapid succession of their communities. Weekly studies on phytoplankton species composition and abundance were conducted at a newly established free water surface constructed wetland (FwsCW) from July to October in 2019. Consequences of diversity investigation exhibited there were 124 species of phytoplankton collected, including 57 species or taxa of Bacillariophyta, with the average relative abundance of 44.33 %, 34 species or taxa of Cyanophyta (28.25 %), 17 species or taxa of Chlorophyta (22.62 %), and some of the less collected freshwater community representatives (i.e., Euglenophyta (2.2 %), Pyrrophyta (1.68 %), and Cryptophyta (0.92 %)). The survey credibly revealed the effect of environmental variables on phytoplankton community structure was obvious, especially in the first month (July) and the fourth month (October), and the coexisting species or taxa in each adjacent month were greatly different. Since they entered the FwsCW, existing communities had transited to more diverse ones. The results of principal component analysis (PCA) showed that overall communities’ acclimation process was controlled by hydrochemical and hydrological indices. The most direct factors affecting the growth and reproduction of phytoplankton were the availability of nutrients and the water temperature. The investigation was devoted to the study of some environmental variables which affect the structure of the phytoplankton community, and revealed the importance of integrated management of artificial aquatic ecosystem. The findings also proposed that the long-term operation effects of FwsCW could be pre-evaluated via the structural variation of phytoplankton communities.