Abstract
The main objective of this study was to explore the composition and distribution of volatile organic compounds (VOCs) and the factors that affect their distribution in the salt lake sediments. Thirteen sediment samples were collected from a depth profile in the East Taijinar Lake, China. VOCs of different samples were extracted by headspace solid phase microextraction. Gas chromatography-ion mobility spectrometry, gas chromatography-mass spectrometry, and X-ray diffraction were used to analyze the VOCs, n-alkanes, and minerals present in samples. Thirty-four VOCs were identified and classified into seven types, including terpenes, furans, esters, aldehydes, ketones, alcohols, and acids, apart from six contaminants. It was found that 24 of the most prevalent compounds in clay were on average 101.45% higher than those in sandstone and halite because of the sedimentary environment, while the remaining ten (2-acetylfuran, 2-pinene D, etc.) were on average 13.27% higher in sandstone and halite sediments than in clay. This can be attributed to their different biological sources, porosity, and higher salinity. Based on the Q-cluster analysis, the 13 sediment samples were split into two groups, including the group according to composition and the group based on distribution of VOCs. In this study, it was found that the VOCs correlate positively with detrital minerals, with Group I exhibiting a high content of detrital minerals (>25%), while Group II showed the opposite characteristics. The consumption of organic matter (OM) by microorganisms leads to the formation of VOCs in sediment. The values of carbon preference index and n-alkane further demonstrate that the organic matter of the two groups came from different sources, exogenous and endogenous. Pr/Ph ratios, Pr/C17, and Pr/C18 also suggest that the OM in all sediments was strongly affected by microorganisms in an anoxic environment. Together, these results demonstrate that the OM from different biological sources and microbial activities played a critical role in deciding the composition and distribution of VOCs in the sediment. This study also shows that the proportion of VOCs in halite was discernably higher than that in clay and sandstone and that the content of VOCs should be considered when studying OM in salt lake sediments.
Highlights
IntroductionVolatile organic compounds (VOCs) are ubiquitous in the environment and can be of biological origin, including plants (Dudareva et al, 2013), bacteria (Mohnke and Buijten, 1993; Korpi et al, 2009; Insam and Seewald, 2010; Zhang et al, 2017), algae, and marine organisms (Whelan, 1984; Kidanu et al, 2017); or anthropogenic origin (Kuránand Soják, 1996; Sattler et al, 2013)
The Volatile organic compounds (VOCs) values ranged from 0.01 to 0.06%; and the VOC content of clay ranged from 0.01 to 0.06%, while that of sandstone and halite ranged from 0.01 to 0.02%. This observation is quite different from the findings of Bianchi et al (1991), who reported that the values of VOCs identified by GC-MS in Southampton’s estuarine sediments ranged from
The VOC concentration was significantly different in clay, sandstone, and halite sediments
Summary
Volatile organic compounds (VOCs) are ubiquitous in the environment and can be of biological origin, including plants (Dudareva et al, 2013), bacteria (Mohnke and Buijten, 1993; Korpi et al, 2009; Insam and Seewald, 2010; Zhang et al, 2017), algae, and marine organisms (Whelan, 1984; Kidanu et al, 2017); or anthropogenic origin (Kuránand Soják, 1996; Sattler et al, 2013). VOCs supply nutrients for microbial cells and mediate intercellular interactions, and they play a critical role in regulating the diversity, compositions, and network structures of prokaryotic communities in saline sediments (Ding et al, 2020). They serve important roles by acting as both a source and sink of organic compounds (Bravo-Linares and Mudge, 2007). It is crucial to measure VOCs in salt lake sediments. The type of marine sediment influences the type of VOCs produced. More reduced species such as dimethyl sulfide and methyl mercaptan are produced in anoxic and muddy sediments (Kiene and Taylor, 1988)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
