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Carbon and nitrogen fixation differ between successional stages of biological soil crusts in the Colorado Plateau and Chihuahuan Desert

Journal of Arid Environments

By:
, , ,
DOI: 10.1016/j.jaridenv.2005.11.014

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Abstract

Biological soil crusts (cyanobacteria, mosses and lichens collectively) perform essential ecosystem services, including carbon (C) and nitrogen (N) fixation. Climate and land-use change are converting later successional soil crusts to early successional soil crusts with lower C and N fixation rates. To quantify the effect of such conversions on C and N dynamics in desert ecosystems we seasonally measured diurnal fixation rates in different biological soil crusts. We classified plots on the Colorado Plateau (Canyonlands) and Chihuahuan Desert (Jornada) as early (Microcoleus) or later successional (Nostoc/Scytonema or Placidium/Collema) and measured photosynthesis (Pn), nitrogenase activity (NA), and chlorophyll fluorescence (Fv/Fm) on metabolically active (moist) soil crusts. Later successional crusts typically had greater Pn, averaging 1.2-1.3-fold higher daily C fixation in Canyonlands and 2.4-2.8-fold higher in the Jornada. Later successional crusts also had greater NA, averaging 1.3-7.5-fold higher daily N fixation in Canyonlands and 1.3-25.0-fold higher in the Jornada. Mean daily Fv/Fm was also greater in later successional Canyonlands crusts during winter, and Jornada crusts during all seasons except summer. Together these findings indicate conversion of soil crusts back to early successional stages results in large reductions of C and N inputs into these ecosystems.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Carbon and nitrogen fixation differ between successional stages of biological soil crusts in the Colorado Plateau and Chihuahuan Desert
Series title:
Journal of Arid Environments
DOI:
10.1016/j.jaridenv.2005.11.014
Volume
66
Issue:
4
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Arid Environments
First page:
620
Last page:
634
Number of Pages:
15