Man-made desert algal crusts as affected by environmental factors in Inner Mongolia, China

Macromolecular and chemical features of the excreted extracellular polysaccharides in induced biological soil crusts of different ages

“…It is known that EPSs, which are secreted by cyanobacteria and other organisms such as fungi and green algae, besides playing a structural role in stabilizing crust structure, are also decomposed by the crust biota and utilized as carbon and energy source (Mager and Thomas, 2011). It was previously reported that secreted EPSs have different characteristics owing to a number of biotic and abiotic factors, including N levels, water availability (Chen et al, 2006;Mager and Thomas, 2011), salinity, pH and growth stage of the microbial community (Staats et al, 2000, Smith andUnderwood, 2000). On these basis, monosaccharidic composition should not be considered specific for different crustal cyanobacteria but controlled by environmental factors (Nicolaus et al, 1999;Pereira et al, 2009).…”

“…and Scytonema javanicum Born et Flah, were mass cultivated in raceway ponds located in a greenhouse and then mixed (M. vaginatus: S. javanicum ¼ 10:1 w/w ratio) and inoculated onto the sandy soil in three different sites of the investigation area. The inoculation procedure used has been described in details by Chen et al (2006) and Wang et al (2009). Briefly, cultures were harvested by filtration through silk and inoculated directly onto unconsolidated sand with a sprayer, as homogenously as possible.…”

“…Samples of IBSCs were manually ground to pieces of roughly 1 cm 3 , air-dried and treated with 95% ethanol in the dark at 4 C for 24 h. Samples were then centrifuged at 6000 Â g for 10 min and the supernatants were spectrophotometrically quantified according to Chen et al (2006).…”

“…dehydrogenase and sucrase activities) in induced biological soil crusts (IBSCs) displayed within an investigation area in Hobq Desert (Dalatequi County, Inner Mongolia, China). At the time of this study (2011), IBSCs of different ages were available due to previous massive inoculations of sandy dunes carried out in different years (2003, 2005 and 2007) with ex-situ cultivated cyanobacteria (Chen et al, 2006).…”

Ethanol outperforms multiple solvents in the extraction of chlorophyll-a from biological soil crusts

“…Wright et al, 1997;Hawkes, 2001;Bowker et al, 2002;Liu et al, 2008). However, it is difficult to compare such Chl-a data between different studies, because ethanol (Chen et al, 2006;Xie et al, 2007), acetone (Tsujimura et al, 2000), DMF (Wang et al, 2007) and DMSO (Büdel et al, 2009;Langhans et al, 2009) have all been used as Chla solvents in such studies. The extraction efficiencies of different solvents have been confirmed to be different in aquatic ecosystems (including the pure algae cultures; Shoaf, 1976;Schumann et al, 2005;Li et al, 2006;Yang et al, 2007), but have not been adequately examined in BSCs or soils.…”