TY - JOUR
T1 - Bacterial diversity, pigments and nitrogen fixation of biological desert crusts from the Sultanate of Oman
AU - Abed, Raeid M.M.
AU - Al Kharusi, Samiha
AU - Schramm, Angela
AU - Robinson, Michael D.
PY - 2010/6
Y1 - 2010/6
N2 - Biological desert crusts are relatively common in the arid deserts of the Sultanate of Oman; however, little is known about their microbial community composition and role in soil fertilization. We compared three crusts from geographically different locations for their soil texture, bacterial community structure, pigment composition and nitrogenase activity. The crusts were growing on alkaline (pH 7.6-8.7) loamy sand and silty loam soils. Microscopically, Microcoleus vaginatus was the most abundant cyanobacterium, but Nostoc and Scytonema types dominated in cultures. The 16S rRNA gene sequences showed close similarities in the crusts' bacterial composition, with 77-81% of the total clones belonging to cyanobacteria and the rest distributed among Alpha- and Deltaproteobacteria, Bacteriodetes, Gemmatimonas and Planctomycetes. Thirty-seven percent of the cyanobacterial clones were affiliated with heterocystous types such as Nostoc, Scytonema, Brasilonema and Petalonema. Chlorophyll a concentrations suggest a similar abundance of phototrophs in all crusts. High levels of the UVA sunscreen scytonemin were detected in the exposed crusts. The three crusts exhibited comparable acetylene reduction rates in the light and in the dark, with a maximum rate of 58.5±2.6 μmol C 2H2 reduced m-2 h-1. We conclude that the crusts, regardless of their geographical location, were rich in heterocystous cyanobacteria that can fix nitrogen and could possibly improve soil stability and productivity.
AB - Biological desert crusts are relatively common in the arid deserts of the Sultanate of Oman; however, little is known about their microbial community composition and role in soil fertilization. We compared three crusts from geographically different locations for their soil texture, bacterial community structure, pigment composition and nitrogenase activity. The crusts were growing on alkaline (pH 7.6-8.7) loamy sand and silty loam soils. Microscopically, Microcoleus vaginatus was the most abundant cyanobacterium, but Nostoc and Scytonema types dominated in cultures. The 16S rRNA gene sequences showed close similarities in the crusts' bacterial composition, with 77-81% of the total clones belonging to cyanobacteria and the rest distributed among Alpha- and Deltaproteobacteria, Bacteriodetes, Gemmatimonas and Planctomycetes. Thirty-seven percent of the cyanobacterial clones were affiliated with heterocystous types such as Nostoc, Scytonema, Brasilonema and Petalonema. Chlorophyll a concentrations suggest a similar abundance of phototrophs in all crusts. High levels of the UVA sunscreen scytonemin were detected in the exposed crusts. The three crusts exhibited comparable acetylene reduction rates in the light and in the dark, with a maximum rate of 58.5±2.6 μmol C 2H2 reduced m-2 h-1. We conclude that the crusts, regardless of their geographical location, were rich in heterocystous cyanobacteria that can fix nitrogen and could possibly improve soil stability and productivity.
KW - Acetylene reduction rate
KW - Biological desert crusts
KW - Clone libraries
KW - Cyanobacteria
KW - Nitrogen fixation
KW - Pigments
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U2 - 10.1111/j.1574-6941.2010.00854.x
DO - 10.1111/j.1574-6941.2010.00854.x
M3 - Article
C2 - 20298501
AN - SCOPUS:77951948934
SN - 0168-6496
VL - 72
SP - 418
EP - 428
JO - FEMS Microbiology Ecology
JF - FEMS Microbiology Ecology
IS - 3
ER -