Thaumarchaeota are abundant and active in marine waters, where they contribute to aerobic ammonia oxidation and light-independent carbon fixation. The ecological function of thaumarchaeota in marine sediments, however, has rarely been investigated, even though marine sediments constitute the majority of the Earth's surface. Thaumarchaeota in the upper layer of sediments may contribute significantly to the reservoir of nitrogen oxides in ocean waters and thus to productivity, including the assimilation of carbon. We tested this hypothesis in the northern South China Sea (nSCS), a section of a large oligotrophic marginal sea with limited influx of nutrients, including nitrogen, by investigating the diversity, abundance, community structure, and spatial distribution of thaumarchaeotal signatures in surface sediments. Quantitative real-time PCR using primers designed to detect 16S rRNA and amoA genes in sediment community DNA revealed a significantly higher abundance of pertinent thaumarchaeotal than betaproteobacterial genes. This finding correlates with high levels of hcd genes, a signature of thaumarchaeotal autotrophic carbon fixation. Thaumarchaeol, a signature lipid biomarker for thaumarchaeota, constituted the majority of archaeal lipids in marine sediments. Sediment temperature and organic P and silt contents were identified as key environmental factors shaping the community structure and distribution of the monitored thaumarchaeotal amoA genes. When the pore water PO4(3-) concentration was controlled for via partial-correlation analysis, thaumarchaeotal amoA gene abundance significantly correlated with the sediment pore water NO2(-) concentration, suggesting that the amoA-bearing thaumarchaeota contribute to nitrite production. Statistical analyses also suggest that thaumarchaeotal metabolism could serve as a pivotal intersection of the carbon, nitrogen, and phosphorus cycles in marine sediments.

中文翻译：

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南海北部沉积物中奇古菌特征基因分布：海洋碳、氮、磷循环代谢交叉的指标？

Thaumarchaeota 在海水中丰富且活跃，它们有助于有氧氨氧化和不依赖光的碳固定。然而，尽管海洋沉积物构成了地球表面的大部分，但很少研究海洋沉积物中奇古菌的生态功能。沉积物上层中的奇异古菌可能对海水中氮氧化物的储存做出重大贡献，从而提高生产力，包括碳的同化。我们在南海北部 (nSCS) 测试了这一假设，这是一片大型贫营养边缘海，营养物质（包括氮）流入有限，通过调查表层沉积物中奇生物特征的多样性、丰度、群落结构和空间分布. 使用设计用于检测沉积物群落 DNA 中的 16S rRNA 和 amoA 基因的引物进行的定量实时 PCR 显示，相关 thaumarchaeotal 的丰度显着高于 betaproteobacterial 基因。这一发现与高水平的 hcd 基因相关，这是 thaumarchaeotal 自养碳固定的特征。Thaumarchaeol 是 thaumarchaeota 的标志性脂质生物标志物，构成了海洋沉积物中古菌脂质的大部分。沉积物温度和有机磷和淤泥含量被确定为影响监测的 thaumarchaeotal amoA 基因群落结构和分布的关键环境因素。当通过偏相关分析控制孔隙水PO4(3-)浓度时，thaumarchaeotal amoA基因丰度与沉积物孔隙水NO2(-)浓度显着相关，表明含有 amoA 的 thaumarchaeota 有助于亚硝酸盐的产生。统计分析还表明，thaumarchaeotal 代谢可以作为海洋沉积物中碳、氮和磷循环的关键交叉点。