ABSTRACT
From November 2021 to September 2022, we conducted four field surveys on macroinvertebrates and water environmental factors in Xinyang section of the Huaihe River main stream. We analyzed the structure and spatiotemporal distribution characteristics of the functional feeding groups of macroinvertebrates, and evaluated river water quality. A total of 73 macroinvertebrate species were collected in the basin, belonging to 42 families, 7 classes, and 3 phyla. The dominant species of macroinvertebrates changed significantly in different months, with Exopalaemon modestus being the absolute advantage species in the basin in July and September 2022. In different sampling months, the functional feeding group of macroinvertebrates was mainly dominated by shredders, accounting for 35.9%. The results of redundancy analysis showed that the main environmental factors affecting the distribution of functional feeding groups of macroinvertebrates varied across different months, with conductivity in February, temperature in July, and oxidation-reduction potential in September and November. The evaluation based on the biolo-gical index and Shannon index of macroinvertebrates indicated that water quality in the investigated section was at a light pollution level.
Subject(s)
Invertebrates , Water Quality , Humans , Animals , Ecosystem , Rivers/chemistry , Environmental Monitoring/methodsABSTRACT
The allelopathic influence of Myriophyllum spicatum on chlorophyll content and chlorophyll fluorescence parameters of Microcystis aeruginosa was studied in coexistence condition. Chlorophyll fluorescence parameters included q(N) (non-photochemical quenching), Y II (effective quantum yield), F(v)/F(m) (maximum quantum yield), F'(v)/F'(m) (effective quantum yield of photosystem II photochemistry) and ETR (electron transport rate). During the three days under coexistence condition, chlorophyll content and chlorophyll fluorescence parameters of M. aeruginosa were affected by M. spicatum and presented different sensitivities. Chlorophyll content of M. aeruginosa was significantly inhibited by 20.80% on the second day at 10.0 g/L of M. spicatum (P < 0.05). However, chlorophyll fluorescence parameters of M. aeruginosa decreased earlier and rapider than chlorophyll content. On the first day, q(N) and Y II of M. aeruginosa were significantly inhibited by 15.59% and 13.00% at 5.0 g/L of M. spicatum (P < 0.05), and F(v)/F(m) and F'(v) /F'(m) were declined by 15.87% and 12.07% at 10.0 g/L (P < 0.05), respectively. On the third day, ETR and three parameters based on ETR were affected at all levels of M. spicatum (P < 0.05). The inhibition effects on the photosynthetic activity of M. aeruginosa might be considered as one of the target sites of M. spicatum and chlorophyll fluorescence parameters were more sensitive parameters than chlorophyll content, especially q(n).
