Department of Environmental Science and Ecological Engineering, Korea University, Seoul 136-713, Republic of Korea.
J Microbiol Biotechnol. 2013 Sep 28;23(9):1187-96. doi: 10.4014/jmb.1305.05017.
Global warming will have far-reaching effects on our ecosystem. However, its effects on Antarctic soils have been poorly explored. To assess the effects of warming on microbial abundance and community composition, we sampled Antarctic soils from the King George Island in the Antarctic Peninsula and incubated these soils at elevated temperatures of 5°C and 8°C for 14 days. The reduction in total organic carbon and increase in soil respiration were attributed to the increased proliferation of Bacteria, Fungi, and Archaea. Interestingly, bacterial ammonia monooxygenase (amoA) genes were predominant over archaeal amoA, unlike in many other environments reported previously. Phylogenetic analyses of bacterial and archaeal amoA communities via clone libraries revealed that the diversity of amoA genes in Antarctic ammonia-oxidizing prokaryotic communities were temperature-insensitive. Interestingly, our data also showed that the amoA of Antarctic ammonia-oxidizing bacteria (AOB) communities differed from previously described amoA sequences of cultured isolates and clone library sequences, suggesting the presence of novel Antarctic-specific AOB communities. Denitrification-related genes were significantly reduced under warming conditions, whereas the abundance of amoA and nifH increased. Barcoded pyrosequencing of the bacterial 16S rRNA gene revealed that Proteobacteria, Acidobacteria, and Actinobacteria were the major phyla in Antarctic soils and the effect of short-term warming on the bacterial community was not apparent.
全球变暖将对我们的生态系统产生深远的影响。然而,其对南极土壤的影响尚未得到充分探索。为了评估变暖对微生物丰度和群落组成的影响,我们从南极半岛的乔治王岛采集了南极土壤,并将这些土壤在升高的温度(5°C 和 8°C)下孵育 14 天。总有机碳的减少和土壤呼吸的增加归因于细菌、真菌和古菌的大量繁殖。有趣的是,与之前报道的许多其他环境不同,细菌氨单加氧酶(amoA)基因比古菌 amoA 更占优势。通过克隆文库对细菌和古菌 amoA 群落进行系统发育分析表明,南极氨氧化原核生物群落中 amoA 基因的多样性对温度不敏感。有趣的是,我们的数据还表明,南极氨氧化细菌(AOB)群落的 amoA 与先前描述的培养分离株和克隆文库序列的 amoA 序列不同,表明存在新型的南极特异性 AOB 群落。在升温条件下,与脱氮相关的基因显著减少,而 amoA 和 nifH 的丰度增加。细菌 16S rRNA 基因的条形码焦磷酸测序显示,变形菌门、酸杆菌门和放线菌门是南极土壤中的主要门,短期升温对细菌群落的影响并不明显。