Tritium and Carbon-14 Contamination Reshaping the Microbial Community Structure, Metabolic Network, and Element Cycle in the Seawater Environment

The
potential ecological risks caused by entering radioactive
wastewater
containing tritium and carbon-14 into the sea require careful evaluation.
This study simulated seawater’s tritium and carbon-14 pollution
and analyzed the effects on the seawater and sediment microenvironments.
Tritium and carbon-14 pollution primarily altered nitrogen and phosphorus
metabolism in the seawater environment. Analysis by 16S rRNA sequencing
showed changes in the relative abundance of microorganisms involved
in carbon, nitrogen, and phosphorus metabolism and organic matter
degradation in response to tritium and carbon-14 exposure. Metabonomics
and metagenomic analysis showed that tritium and carbon-14 exposure
interfered with gene expression involving nucleotide and amino acid
metabolites, in agreement with the results seen for microbial community
structure. Tritium and carbon-14 exposure also modulated the abundance
of functional genes involved in carbohydrate, phosphorus, sulfur,
and nitrogen metabolic pathways in sediments. Tritium and carbon-14
pollution in seawater adversely affected microbial diversity, metabolic
processes, and the abundance of nutrient-cycling genes. These results
provide valuable information for further evaluating the risks of tritium
and carbon-14 in marine environments.

含有氚（tritium）与碳-14（carbon-14）的放射性废水排入海洋所引发的潜在生态风险，需开展审慎评估。本研究模拟了海水受氚与碳-14污染的场景，并分析其对海水及沉积物微环境的影响。氚与碳-14污染主要改变了海水环境中的氮、磷代谢过程。通过16S rRNA测序（16S rRNA sequencing）分析发现，在氚与碳-14暴露条件下，参与碳、氮、磷代谢及有机质降解的微生物相对丰度发生显著变化。代谢组学（metabonomics）与宏基因组分析（metagenomic analysis）结果显示，氚与碳-14暴露会干扰涉及核苷酸与氨基酸代谢物的基因表达，这与微生物群落结构的分析结果一致。氚与碳-14暴露还会调控沉积物中参与碳水化合物、磷、硫及氮代谢通路的功能基因（functional genes）丰度。海水中的氚与碳-14污染会对微生物多样性、代谢过程以及养分循环基因丰度产生不利影响。本研究结果可为进一步评估氚与碳-14在海洋环境中的生态风险提供重要参考依据。