Distribution of Terrestrial Algae within the Nevada Test Site

Shields, Lora Mangum; Drouet, Francis

doi:10.2307/2439709

Cited by 31 publications

(13 citation statements)

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“…Thus, at the north-facing midslope, patches devoid of crusts are scattered among low-chlorophyll cyanobacterial crusts and adjacent high-chlorophyll moss-dominated crusts, all of which have similar parent material. The data do not support Shields and Drouet (1962), Danin (1978) and Danin et al (1989) assumptions suggesting an increase in crust biomass as a function of higher silt and clay amounts. Rather, the findings may indicate an increase in the efficiency of highbiomass crusts to trap dust.…”

Section: Discussioncontrasting

confidence: 78%

Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev Desert

Kidron

Vonshak

Abeliovich

2009

Earth Surf Processes Landf

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Microbiotic crusts play an important role in arid and semi-arid regions. Yet, very little information exists regarding the factors that impact their development. In an attempt to assess the main factors that may determine their growth, measurements of the amount of fines (silt and clay), rain, moisture content, wetness duration and wind erosion and deposition were carried out along a 12 station transect within a partially crusted dune field in the western Negev Desert and compared to the crust cover and chlorophyll content. Surface stability was the only variable that exhibited significant relationship with crust cover while daylight wetness duration exhibited strong positive relationship (r 2 = 0·92-0·99) with the crust's chlorophyll content. The data point out that microbiotic crusts may serve as a useful biomarker for surface stability. While wetness duration and wind will control crust cover and the crust chlorophyll content in semi-stable habitats (with absolute annual change in sand level of 2-3 mm), stable habitats (absolute change <1 mm) will be controlled primarily by moisture, while habitats with low surface stability (absolute change of tens and hundreds of millimeters) will be primarily controlled by wind. Furthermore, owing to the strong positive relationship between daylight wetness duration and the crust's chlorophyll content, the crust may serve as a useful biomarker for the quantification of surface wetness duration. (100 to 200 m) interdunes. The dunes are characterized by relatively long north-facing slopes and by relatively short south-facing slopes. Most of the dunes have a mobile crest Figure 4. General layout of the transect (a), and average annual crust cover (b), chlorophyll a content (c), crust thickness (d) and wetness duration (e). Bars represent one standard deviation.Figure 5. The relationship between crust thickness and the crust chlorophyll content.Figure 11. (a) Suggested relationships between chlorophyll, wetness duration and surface stability, (b) and surface stability as a function of wetness duration and chlorophyll content.

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Section: Discussioncontrasting

confidence: 78%

Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev Desert

Kidron

Vonshak

Abeliovich

2009

Earth Surf Processes Landf

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“…Desert biological soil crusts are typically dominated by cyanobacteria, but may also contain bryophytes, lichens, fungi and can even be dominated by free‐living unicellular green algae in moister, colder environments (Cameron 1960; Shields & Drouet 1962; Cameron 1964; Friedmann & Ocampo‐Paus 1967; Belnap, Budel & Lange 2001). During periods of desiccation, many crust organisms lie dormant.…”

Section: Introductionmentioning

confidence: 99%

Photosynthetic recovery following desiccation of desert green algae (Chlorophyta) and their aquatic relatives

Gray

Lewis

Cardon

2007

Plant Cell & Environment

127

132

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Recent molecular data suggest that desert green algae have evolved from freshwater ancestors at least 14 times in three major classes (Chlorophyceae, Trebouxiophyceae and Charophyceae), offering a unique opportunity to study the adaptation of photosynthetic organisms to life on land in a comparative phylogenetic framework. We examined the photorecovery of phylogenetically matched desert and aquatic algae after desiccation in darkness and under illumination. Desert algae survived desiccation for at least 4 weeks when dried in darkness, and recovered high levels of photosynthetic quantum yield within 1 h of rehydration in darkness. However, when 4 weeks of desiccation was accompanied by illumination, three of six desert taxa lost their ability to recover quantum yield during rehydration in the dark. Aquatic algae, in contrast, recovered very little during dark rehydration following even just 24 h of desiccation. Re-illuminating rehydrated algae produced a nearly complete recovery of quantum yield in all desert and two of five aquatic taxa. These contrasts provide physiological evidence that desert green algae possess mechanisms for photosynthetic recovery after desiccation distinct from those in aquatic relatives, corroborating molecular evidence that they are not happenstance, short-term visitors from aquatic environments. Photosensitivity during desiccation among desert algae further suggests that they may reside in protected microsites within crusts, and species specificity of photosensitivity suggests that disturbances physically disrupting crusts could lead to shifts or losses of taxonomic diversity within these habitats.

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“…These microbial crusts are assemblages of non‐vascular photosynthetic organisms, fungi, and bacteria, which form intimate associations with surface soils (Eldridge and Greene ) and alter the physiochemical attributes of the soil. They affect soil stability (Danin ), soil development (Shields and Drouet ), fertility (Zobeck and Fryrear ) and the water regime (Verrecchia et al. ).…”

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confidence: 99%

Biodiversity of soil cyanobacteria in the hyper‐arid Atacama Desert, Chile

Patzelt

Hodač

Friedl

et al. 2014

Journal of Phycology

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The cyanobacterial diversity of soils of the Atacama Desert (Chile) was investigated using 16S rRNA gene cloning/sequencing directly from soil samples and 16S rRNA gene sequencing from unialgal cultures. Within the hyper-arid Atacama Desert, one of the driest parts of the world, 10 sites with differing altitude and distance to the shore were sampled along a total air-line distance (from south to north) of ~1,100 km. Filamentous cyanobacteria belonging to Nostocophycideae and Synechococcophycideae were present. Oscillatoriophycideae exhibited the highest species richness among the subclasses of cyanobacteria, and included mostly filamentous species along with some coccoids (e.g., Chroococcidiopsis). Thirty species-level phylotypes could be recognized using a cut-off of 99% 16S rRNA sequence similarity within the 22 genera defined at 97% 16S rRNA sequence similarity. Eight of the 30 taxa could be detected by both clonal and culture sequences. Five taxa were observed only in cultures, whereas the cloning approach revealed 17 additional taxa, which might be in the collection but unsequenced, hard-to-cultivate, or entirely unculturable species using standard cultivation media. The Atacama Desert soils have a high diversity of phylotypes, among which are likely both new genera and new species awaiting characterization and description.

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Distribution of Terrestrial Algae within the Nevada Test Site

Cited by 31 publications

References 0 publications

Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev Desert

Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev Desert

Photosynthetic recovery following desiccation of desert green algae (Chlorophyta) and their aquatic relatives

Biodiversity of soil cyanobacteria in the hyper‐arid Atacama Desert, Chile

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