A new nitrogen-fixing Clostridium species from a high Arctic ecosystem.

A hitherto undescribed species of yellow-pigmented, Gram-negative Clostridium sp., possessing nitrogenase activity, has been isolated from a number of sampling sites on the Truelove Lowland of Devon Island in the Canadian high Arctic. This bacterium, tentatively designated Clostridium arcticum sp. nov., accounted for 19% of all isolates recovered which were capable of anaerobic nitrogen fixation.