Alga‐ and Lichen‐stabilized Surface Crusts as Soil Nitrogen Sources

Shields, Lora Mangum; Mitchell, Charles E.; Drouet, Francis

doi:10.1002/j.1537-2197.1957.tb10568.x

Cited by 50 publications

(16 citation statements)

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“…Inasmuch as the al-gal associate of the lichen Co/lema tenax, the commonest component of the cryptophyte cover, is a blue-green alga, it seems likely that the cryptophytic components of the community may make some positive contribution to the nitrogen economy of the community also. Shields (1957) and Shields, Mitchell, and Drouet (1957) consider the role of algae and lichens in surface soil stabilization and nutrient cycling. Cryptogams are instrumental in the buildup of organic matter and soil nutrients.…”

Section: Discussionmentioning

confidence: 99%

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Kleiner

Harper

1972

Ecology

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Sixty uniformly distributed stands in adjacent areas, 40 in Virginia Park (virgin) and 20 in Chesler Park (grazed), were analyzed. Cryptogamic and vascular species were recorded; cover was analyzed by the point sampling method, and frequency by means of 25 quadrats (each 0.125 m2) per stand. The prevalent species (26 in Virginia, 23 in Chesler) were selected on the basis of a constancy—times—frequency index. Interspecific association patterns were determined by means of simple procedures based on quadrat frequency values for each species in the individual stands. Major environmental variables were recorded at each stand, and soil samples from four depths were collected at each site. Soil samples were analyzed for texture, bulk density, pH organic matter, total nitrogen, and available K+, PO4°, and Ca++. Although the parks are similar in gross environment and vascular plant cover, cryptogamic vegetation and community structure differ markedly between the areas. Many vascular species occur in greater abundance in one park than the other. Floristically, Virginia was much richer than Chesler Park. Cryptogamic cover was about seven times greater in the ungrazed park. The lichen and moss ground cover is apparently important in stabilization of the highly erodable, sandy soils against wind and water erosion. Cryptogams also have a important influence on chemical characteristics of the surface 5 cm of soil, and the difference in surface soils between the parks may be related to the presence of these species. Community pattern in the virgin park is more definite than in the adjacent, grazed park, a condition which is contrary to the concept that minimum association between species (pattern) is to be expected in stable as opposed to successional vegetations.

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Section: Discussionmentioning

confidence: 99%

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Kleiner

Harper

1972

Ecology

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“…;Shields et al 1957). Other common species include M. paludosus, Nostoc commune, Oscillatoria sp., Phormidium sp., Plectonema nostocorum, Schizothrix californica Dr., S. lamyi Gom., and Scytonema hofmannii.…”

Section: Chihuahuanmentioning

confidence: 99%

Biological Soil Crusts of North America

Rosentreter¹,

Belnap²

2001

Ecological Studies

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“…In addition to the availability of water, nitrogen (N) controls the primary production and most other biological activities in desert ecosystems 1, 2. The biological fixation of atmospheric nitrogen by cyanobacteria in biological soil crusts and lichens is considered—besides that of free‐living N 2 ‐fixing bacteria in C‐rich macrophytic patches—to be a main N input pathway into dryland ecosystems 3–11. Soil crusts have been found in locations such as arid and semi‐arid areas all over the world 3–5, 7, 10, 12–14.…”

mentioning

confidence: 99%

“…Refs. 3–9), but the determination of the N fixation under field conditions has many methodological problems 5, 7, 11. Most of the information about the contribution to the N input in different dry ecosystems only originates from lab investigations or simple estimates based on crust development and total N content.…”

mentioning

confidence: 99%

A natural ¹⁵N approach to determine the biological fixation of atmospheric nitrogen by biological soil crusts of the Negev Desert

Russow

Veste

Böhme

2005

Rapid Comm Mass Spectrometry

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Biological soil crusts are important cryptogamic communities covering the sand dunes of the north-western Negev. The biological crusts contain cyanobacteria and other free-living N(2)-fixing bacteria and are hence able to fix atmospheric nitrogen (N). This is why they are considered to be one of the main N input pathways into the desert ecosystem. However, up to now, in situ determinations of the N(2) fixation in the field are not known to have been carried out. We examined the natural (15)N method to determine the biological N(2) fixation by these soil crusts under field conditions. This novel natural (15)N method uses the lichen Squamarina with symbiotic green algae--which are unable to fix N(2)--as a reference in order to determine N(2) fixation. Depending on the sampling location and year, the relative biological fixation of atmospheric nitrogen was estimated at 84-91% of the total N content of the biological soil crust. The cyanobacteria-containing soil lichen Collema had a fixation rate of about 88%. These fixation rates were used to derive an absolute atmospheric N input of 10-41 kg N ha(-1) year(-1). These values are reasonable results for the fixation of atmospheric N(2) by the biological crusts and cyanolichens and are in agreement with other comparable lab investigations. As far as we are aware, the results presented are the first to have been obtained from in situ field measurements, albeit only one location of the Negev with a small number of samples was investigated.

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Alga‐ and Lichen‐stabilized Surface Crusts as Soil Nitrogen Sources

Cited by 50 publications

References 11 publications

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Biological Soil Crusts of North America

A natural ¹⁵N approach to determine the biological fixation of atmospheric nitrogen by biological soil crusts of the Negev Desert

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Alga‐ and Lichen‐stabilized Surface Crusts as Soil Nitrogen Sources

Cited by 50 publications

References 11 publications

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Environment and Communiy Organization in Grasslands of Canyonlands National Park

Biological Soil Crusts of North America

A natural 15N approach to determine the biological fixation of atmospheric nitrogen by biological soil crusts of the Negev Desert

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Product

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A natural ¹⁵N approach to determine the biological fixation of atmospheric nitrogen by biological soil crusts of the Negev Desert