Shotgun metagenomes of wet tundra soils across the Arctic Coastal Plain, Alaska April 2018

This dataset includes 64 shotgun metagenomes (Illumina PE150) generated from three depths (5-10 centimeters (cm), 10-25 cm, and 30-35cm, when available) of three replicate soil cores from eight locations in the Arctic Coastal Plain, ranging from coastal sites near Utqiagvik to inland sites at Ivotuk and Toolik Lake Field Station. These sequences support a study of biological chlorine cycling in the Arctic and its influence on greenhouse gas production. Microbes that can decompose chlorinated organic compounds were once considered relevant only in areas contaminated with pesticides and organic solvents. However, biological chlorine cycling is proving to be widespread in natural environments. Previous studies of biological chlorine cycling were mostly limited to forested ecosystems. This project was the first to demonstrate the importance of the production and degradation of chlorinated organic compounds in Arctic soils. Furthermore, there was little information about the linkages between chlorine cycling and other important ecosystem processes, such as production of carbon dioxide and methane from soils. Species in the genus Dehalococcoides are highly specialized, using hydrogen, acetate, vitamin B12-like compounds, and organic chlorine produced by the surrounding community. We studied which neighbors might produce these essential resources for Dehalococcoides species. We found that Dehalococcoides species are ubiquitous across the Arctic Coastal Plain and are closely associated with a network of microbes that produce or consume hydrogen or acetate, including the most abundant anaerobic bacteria and methanogenic archaea. We also found organic chlorine and microbes that can produce these compounds throughout the study area. Therefore, Dehalococcoides could control the balance between carbon dioxide and methane (a more potent greenhouse gas) when suitable organic chlorine compounds are available to drive hydrogen and acetate uptake, making them unavailable for methane production.本数据集包含64份霰弹枪宏基因组（shotgun metagenome）样本，采用Illumina PE150双端测序技术生成，样本取自北极海岸平原8个采样点位的3根重复土壤岩心，采样深度涵盖5–10厘米（cm）、10–25厘米及30–35厘米（视采样可行性而定）；采样区域覆盖从乌特恰维克附近沿海站点至伊沃图克与图勒湖野外站的内陆站点。该测序数据支撑了一项针对北极生物氯循环及其对温室气体产生影响的研究。 能够降解氯化有机化合物的微生物，曾被认为仅与农药和有机溶剂污染的区域相关。然而现有研究证实，生物氯循环在自然环境中广泛分布。此前针对生物氯循环的研究大多局限于森林生态系统。本研究首次揭示了北极土壤中氯化有机化合物的产生与降解的重要性。此外，此前几乎没有关于氯循环与其他重要生态系统过程（如土壤产生二氧化碳与甲烷）之间关联的研究资料。 脱卤球菌属（Dehalococcoides）的物种具有高度特化的代谢特性，可利用周围微生物群落产生的氢气、乙酸盐、类维生素B12化合物及有机氯。本研究探究了可为脱卤球菌属物种提供此类必需营养物质的伴生微生物类群。研究发现，脱卤球菌属物种广泛分布于北极海岸平原，且与参与氢气或乙酸盐合成与消耗的微生物网络紧密关联，其中包括丰度最高的厌氧细菌与产甲烷古菌（methanogenic archaea）。本研究还在整个研究区域内检测到有机氯以及可合成此类物质的微生物。因此，当存在适宜的有机氯化合物以驱动氢气与乙酸盐的摄取时，脱卤球菌属物种可调控二氧化碳与甲烷（一种强效温室气体）之间的平衡，从而使这些底物无法用于甲烷生成。