Soil chemical and physical data, Arctic Coastal Plain of northern Alaska, April 2018

This data set contains chemical and physical data for soil cores collected from eight sites across the Arctic Coastal Plain of northern Alaska in April 2018. Three replicate soils cores were collected at each site and cores were divided into 5 centimeter (cm) horizons. These data 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2018年4月从阿拉斯加北部北极海岸平原（Arctic Coastal Plain）8个采样点采集的土壤芯的化学与物理数据。每个采样点采集3个重复土壤芯，并将其划分为5厘米（cm）厚的土层。这些数据为北极地区生物氯循环（biological chlorine cycling）及其对温室气体产生的影响研究提供支持。能够分解含氯有机化合物的微生物曾被认为仅存在于受农药和有机溶剂污染的区域。然而，生物氯循环已被证实广泛存在于自然环境中。以往关于生物氯循环的研究多局限于森林生态系统。本项目首次证实了北极土壤中含氯有机化合物的产生与降解的重要性。此外，关于氯循环与其他重要生态系统过程（如土壤中二氧化碳和甲烷的产生）之间的关联信息十分匮乏。Dehalococcoides属物种具有高度专一性，利用周围群落产生的氢、乙酸盐、类维生素B12化合物及有机氯。我们研究了哪些邻近微生物可能为Dehalococcoides属物种提供这些必需资源。我们发现Dehalococcoides属物种在北极海岸平原广泛存在，且与产氢或耗氢、产乙酸或耗乙酸的微生物网络密切相关，其中包括最丰富的厌氧细菌和产甲烷古菌。我们还在整个研究区域发现了有机氯以及能够产生这些化合物的微生物。因此，当存在合适的有机氯化合物以驱动氢和乙酸盐的吸收（使其无法用于甲烷产生）时，Dehalococcoides属物种可调控二氧化碳与甲烷（一种更强效的温室气体）之间的平衡。