RT Journal Article
SR Electronic
T1 Non-cyanobacterial diazotrophs dominate dinitrogen fixation in biological soil crusts during early crust formation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 013813
DO 10.1101/013813
A1 Charles Pepe-Ranney
A1 Chantal Koechli
A1 Ruth Potrafka
A1 Cheryl Andam
A1 Erin Eggleston
A1 Ferran Garcia-Pichel
A1 Daniel H Buckley
YR 2015
UL http://biorxiv.org/content/early/2015/01/15/013813.abstract
AB Biological soil crusts (BSC) are key components of ecosystem productivity in arid lands and they cover a substantial fraction of the terrestrial surface. In particular, BSC N2-fixation contributes significantly to the nitrogen (N) budget of arid land ecosystems. In mature crusts, N2-fixation is largely attributed to heterocystous cyanobacteria, however, early successional crusts also fix N2 but possess few N2-fixing cyanobacteria and this suggests that microorganisms other than cyanobacteria mediate N2-fixation during the critical early stages of BSC development. DNA stable isotope probing (DNA-SIP) with 15N2 revealed that Clostridiaceae and Proteobacteria are the most common microorganisms that assimilate 15N in early succes-sional crusts. The low abundance of these groups in BSC may explain why these heterotrophic diazotrophs have not previously been characterized. Diazotrophs play a critical role in BSC formation and characterization of these organisms represents a crucial step towards understand-ing how anthropogenic change will affect the formation and ecological function of BSC in arid ecosystems.