The volatilome reveals microcystin concentration, microbial composition, and oxidative stress in a critical Oregon freshwater lake

Abstract

Toxins commonly produced by cyanobacterial blooms in freshwater lakes are a serious public health problem. The conditions leading to toxin production are currently unpredictable, thereby requiring expensive sampling and monitoring programs globally. We explored the potential of volatile organic compounds (VOCs) to indicate microcystin presence and concentration, and microbial community composition in Upper Klamath Lake, OR. Elastic net regularization regression selected 29 of 229 detected m/z+1 values (corresponding to unique VOCs) in models predicting microcystin toxicity that outperformed or significantly improved upon regression models based on environmental parameters, including chlorophyll, pH, and temperature. Several m/z+1 values selected by elastic net were putatively identified as saturated fatty aldehydes (SFAs), which are important in defending cyanobacteria against oxidative stress. Unique sets of m/z+1 values were also identified by elastic net regression that predicted the relative abundance of the most dominant bacterial phyla, classes, and cyanobacterial genera. These results show that VOCs may be a key component of lake monitoring strategies.