Hydrochemistry Characteristics in front of the Wulixia Reservoir Dam Associated with Feedback from Aerobic Anoxygenic Phototrophic Bacteria

Abstract

Micro-organisms are the main drivers of the water biogeochemical cycle and the major player in energy metabolism, which are pivotal processes for maintaining diversity and stability in ecological water systems. Aerobic anoxygenic phototrophic bacteria (AAPB), the important functional groups widespread in the water, can acquire energy from light and further affect the hydrochemical composition. The importance of AAPB is well recognized and has been studied extensively. In order to study the relationship between the hydrochemical characteristics and the AAPB feedback effect in front of the Wulixia Reservoir dam, water samples from different layers were collected. Based on the stable carbon isotope of dissolved organic carbon and particulate organic carbon isotope composition, the distribution pattern of AAPB was measured by real-time PCR technology. Results show that the hydrochemical type in the front of the reservoir dam water system was HCO3--Ca2+-Mg2+ type and had a poor-moderate eutrophication state during the sampling period. The results of dissolved oxygen, stable carbon isotope and the C/N showed that the main source of organic carbon was produced by micro-organisms. The ratio of AAPB to total planktonic bacteria in the Wulixia Reservoir water was 1.33%-1.60%, and the variation degree of AAPB abundance was greater than that of the total planktonic bacteria abundance, which means that the AAPB feedback is more sensitive to the hydrochemical characteristics compared with that of total planktonic bacteria. The canonical correspondence analysis reveals the relationship between hydrochemical composition and AAPB. Canonical correspondence analysis (CCA) results show that AAPB and total planktonic bacteria are strongly influenced by turbidity, which makes it possible to apply marine microbiological pump theory in karst reservoirs. Hydrochemical characteristic feedback on AAPB will improve understanding of the metabolic system of CO2-H2O-carbonate and micro-organisms.

Keywords

• aerobic anoxygenic phototrophic bacteria
• real-time pcr
• karst hydrochemistry characteristics
• wulixia reservoir
• infertile reservoir