Response of freshwater sediment archaeal community to metal spill

Archaea play an important role in the biogeochemical cycling of elements in the environment. Heavy metals are ubiquitous pollutants in the environment. Previous studies have revealed a considerable influence of metal pollution on the archaeal community, but the short-term response of the archaeal community to metal pollution remains unclear. Hence, the present study investigated the short versus long-term responses of overall archaeal communities in freshwater sediments after exposure to accidental metal pollution caused by the discharge of heavy metal-containing wastewater from an indium-producing factory. Quantitative PCR was used to determine the archaeal abundance, while Illumina MiSeq sequencing was applied to characterize the diversity and structure of the archaeal community. The abundance (2.47 × 10⁵-1.55 × 10⁸ archaeal 16S rRNA gene copies per gram dry sediment), diversity (Shannon diversity index = 2.49-4.45) and structure of overall archaeal community illustrated a drastic temporal change. The archaeal communities mainly comprised the phyla Euryarchaeota, Thaumarchaeota and Bathyarchaeota. The exposure to metal pollution induced an increase in the proportion of Euryarchaeota but lowered the proportion of Thaumarchaeota. The accidental metal pollution exerted a profound impact on the archaeal community in freshwater sediment. This study could contribute our understanding of the short versus long-term response of archaeal communities to metal pollution.