Benefits of Morphology-Based Functional Group Classification to Study Dynamic Changes in Phytoplankton in Saline-Alkali Wetlands, Taking Typical Saline-Alkali Wetlands in Northeast China as an Example

Abstract

Phytoplankton are sensitive to the change in hydrological environment and can effectively reflect the health status of water, so they are often used for water quality assessment. To understand the recovery process of phytoplankton community structure characteristics and water quality conditions, two methods of phytoplankton classification functional group (FG) and morphology-based functional group (MBFG) were compared based on morphological differences and applicability. In this study, we investigated the changes in the aquatic environmental conditions and phytoplankton functional groups in the saline wetland of Dagangzipao during the restoration process of the Songnen Plain. The functional group division method suitable for saline-alkali wetlands was also determined. The results showed that there were 86 species belonging to 47 genera and seven phyla. The average phytoplankton biomass range in 2020 is 0.37 mg/L–3.59 mg/L, and the average phytoplankton biomass range in 2021 is 0.01 mg/L–1.44 mg/L. The Q-index showed that the water quality was in a good state. The redundancy analysis showed that the characteristics of phytoplankton functional groups showed a good indication of the habitat characteristics of saline-alkali wetlands, and the environmental interpretation of the MBFG was higher than that of the FG. The results provide a reference for the sustainable development of saline wetland water environment protection and ecological restoration.