Abstract
Sediment nitrogen and sulfur cycles are essential biogeochemical processes that regulate the microbial communities of environmental ecosystems, which have closely linked to environment ecological health. However, their functional couplings in anthropogenic aquaculture sedimentary ecosystems remain poorly understood. Here, we explored the sediment functional genes in shrimp culture pond ecosystems (SCPEs) at different culture stages using the GeoChip gene array approach with 16S amplicon sequencing. Dissimilarity analysis showed that the compositions of both functional genes and bacterial communities differed at different phases of shrimp culture with the appearance of temporal distance decay (p < 0.05). During shrimp culture, the abundances of nitrite and sulfite reduction functional genes decreased (p < 0.05), while those of nitrate and sulfate reduction genes were enriched (p < 0.05) in sediments, implying the enrichment of nitrites and sulfites from microbial metabolism. Meanwhile, nitrogen and sulfur reduction genes were found to be linked with carbon degradation and phosphorous metabolism (p < 0.05). The influence pathways of nutrients were demonstrated by structural equation modeling through environmental factors and the bacterial community on the nitrogen and sulfur reduction functions, indicating that the bacterial community response to environmental factors was facilitated by nutrients, and led to the shifts of functional genes (p < 0.05). These results indicate that sediment nitrogen and sulfur reduction functions in SCPEs were coupled, which are interconnected with the SCPEs bacterial community. Our findings will be helpful for understanding biogeochemical cycles in anthropogenic aquaculture ecosystems and promoting sustainable management of sediment environments through the framework of an ecological perspective.
Highlights
Biogeochemical cycles play irreplaceable roles in global ecosystem sustainability
We examined the relationships among sediment physicochemical properties, the bacterial community, and nitrogen and sulfur reduction functions using a structural equation modeling (SEM) framework
This study found that sediment nitrogen and sulfur reduction functional genes; sediment functional genes were coupled, which were highly correlated with the microbial community
Summary
Biogeochemical cycles play irreplaceable roles in global ecosystem sustainability. The cycles are strongly linked to environmental pollution (Nriagu and Coker, 1983; Kondratyev et al, 2004; Kuypers et al, 2018). Nitrogen and sulfur cycles are important biogeochemical processes in global ecosystems (Canfield and Farquhar, 2012; Kuypers et al, 2018). Nitrite can be generated by the metabolism of amino acids from microbes (Neis et al, 2015), and sulfite is generated by the metabolism of methionine and cysteine, and from sulfates in response to bacterial lipopolysaccharides (Kabil et al, 2014). Both sediment nitrogen and sulfur compounds can be the causes of acidification of the aquatic and soil environments (Nriagu and Coker, 1983; Doney et al, 2007; Kissel et al, 2020). Those processes are generally coupled with microbial metabolism such as degradation processes of organic matter by microbes (Kleindienst et al, 2014), while the relationships between nitrite and sulfite generation and the environmental microbial community need further investigation
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