New insights into odor release from sediments in Lake Chaohu and the potential role of sediment microbial communities

Abstract

Odor events often occur along with algal blooms, posing potential threats to water quality and human health. However, studies on the role of sediments and microbial communities in the production and release of odor compounds remain limited. Seasonal monitoring of Lake Chaohu revealed that pore-terpenoids significantly contributed to terpenoid concentrations in water, explaining 37.1% of their variability. Environmental factors like temperature primarily influenced terpenoid concentrations by regulating the diffusion of pore-terpenoids. Conversely, pore-nor-carotenoids explained only 11.2% of nor-carotenoid variability, with phytoplankton communities explaining 59.4%. Abiotic factors like nutrients influenced nor-carotenoid levels by impacting phytoplankton growth. Microbial communities with a greater proportion of cyanobacteria exhibited more fragile microbial networks, increased competition, and enhanced metabolic activity. We hypothesized that microbial community composition may influence odor production. Laboratory experiments further supported this: sediments with added cyanobacteria showed a 48.1% reduction in 2-methylisoborneol contents after 30-day incubation, whereas the control group exhibited a 66.38% increase. Conversely, the experimental group showed significant increases in β-cyclocitral (99.19%) and β-ionone (48.55%), while the control group experienced reductions of 54.01% and 43.53%, respectively. These findings underscore the importance of considering microbial interactions and sediment dynamics in future odor research, offering insights for water quality management in eutrophic lakes.