Effect of Rust on Litter Decomposition and Nutrient Release in the Water-Level Fluctuation Zone of Danjiangkou Reservoir un-der the Influence of Nano-ZnO
Effect of Rust on Litter Decomposition and Nutrient Release in the Water-Level Fluctuation Zone of Danjiangkou Reservoir un-der the Influence of Nano-ZnO
The decomposition of plant litter in the water-level fluctuation zone of large reservoirs often occurs in the water,being an important process in the nutrient cycle and energy flow between water and land.To ex-plore the effects of plant disease and water environment pollution on the litter decomposition process,micro-cosmic experiments were carried out to simulate different degrees of nano-ZnO pollution.The decomposing rate,enzyme activities,and nutrient release of reed(Phragmites australis)litter with different grades of rust in the Danjiangkou Reservoir were determined.The effects of rust and nano-ZnO on litter decomposition and water quality were studied.The results showed that severely rusted litter decomposed faster,while nano-ZnO generally inhibited the decomposition process,with the strongest inhibitory effect at a high concentration(200 mg • L-1).The medium and low concentrations(100 mg • L-1 and 20 mg • L-1)of nano-ZnO only in-hibited the normal leaves with low rust grades.The activities of extracellular enzymes involved in decomposi-tion in the water were significantly affected by the interactive effects of nano-ZnO concentration,rust and de-composition time.Nano-ZnO pollution and rust reduced the water pH value during the decomposition process,and increased the content of dissolved organic carbon and total nitrogen in the water.The results pro-vide a basis for revealing the effects of plant rust and nano-ZnO on the biogeochemical cycling of water and assessing water ecological security in the water-level fluctuation zone.
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