Composition of the aquatic photosynthetic organism community and its effect on trace elements in karst areas

Abstract

Objective Trace elements are an important factor affecting the water quality of karst surface waters. Aquatic photosynthetic organisms can absorb and remove harmful elements in the process of photosynthetic metabolism. However, little research has been conducted on the absorption effect and removal potential of trace elements by different aquatic photosynthetic organism community structures. Methods This study was conducted at the Puding Karst Ecosystem National Observation and Research Station, which constructed a vegetation-soil-groundwater-surface water simulation ecosystem consisting of five types of land use: bare rock land, bare land, cultivated land, grassland and shrub land. Among them, the surface aquatic ecosystem was taken as the research object to carry out research on the removal potential and control mechanism of trace elements by the composition of aquatic photosynthetic organism community structure. Results Results showed that (1) The surface water chemistry parameters and aquatic photosynthetic biomass were significantly affected by seasonal changes and land use types; (2) The concentrations of Cr, Mn, Co, Ni, Fe and Zn varies significantly in different aquatic photosynthetic ecosystems, and the absorption and removal of Mn, Co, Ni, Fe, and Zn by the planktonic-submerged coexistence system were better than those of a single planktonic system; (3) The formation of a highly dissolved inorganic carbon (DIC) environment in surface water bodies was promoted by the restoration of natural vegetation (shrublands and grasslands) in karst areas, which was conducive to the growth of submerged plants, simultaneously increasing the impact on Mn, Co, Ni, Fe and Zn removal potential in surface water bodies. Conclusion This understanding will contribute to research on the regulatory mechanism of trace elements in surface water by the structure of aquatic photosynthetic organisms in karst areas.

Keywords

• trace element
• land use
• aquatic photosynthetic organism
• response mechanism
• karst area