Total chlorine and bromine in soils of Arctic Coastal Plain, northern Alaska 2018 - 2021

• Main Author: David Lipson
• Format: Dataset
• Language: unknown
• Published: Arctic Data Center 2021
• Subjects: tundra; halogens; X-ray fluorescence; Arctic; Tundra; Alaska
• Online Access: https://doi.org/10.18739/A2H70819B

These data were generated using X-ray fluorescence to determine total chlorine and bromine concentrations in soils collected from various locations along the Arctic Coastal Plain. This study used soils collected in 2017-2018 specifically for this purpose, as well as archived soils from previous studies in the region, collected from 2008-2011. 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.