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Biological soil crusts (BSCs) are an integration of external photoautotrophs and internal heterotrophic communities. Sand burial is a ubiquitous disturbance that affects the biodiversity and ecological function of BSCs, but little is known about the influence of sand burial on microbial communities in arid sandy deserts. Here, based on a long-term field experiment and utilizing high-throughput sequencing, we assessed the influence of sand burial on bacterial and fungal communities inhabiting two typical successional stages of BSCs (cyanobacterial crusts for early successional stage and mixed crusts for late successional stage) at the three-sand buried depth (0, 0.5, and 10 mm) in the Tengger Desert, Northern China. We found that the diversity, abundance, and composition of the bacterial and fungal communities were all altered by the sand burial treatment. Different indicator taxa were identified in unburied and buried (shallow and deep) BSCs. Changes in soil properties caused by sand burial have been suggested as a possible cause of changes in the bacterial and fungal community composition in BSCs. [ABSTRACT FROM AUTHOR]

Bacterial, archaeal, and eukaryota diversity in mountainous areas varies along elevational gradients, but details remain unclear. Here, we use a next-generation sequencing method based on 16S/18S rRNA to reveal the soil microbial diversity and community compositions of alpine meadow ecosystems along an elevation span of nearly 2,000 m (1,936–3,896 m) in China's Qilian Mountains. Both bacterial and eukaryota diversity increased linearly with increasing elevation, whereas archaeal diversity increased, but not significantly. The diversity patterns of several phyla in the bacterial, archaeal, and eukaryota communities were consistent with the overall elevational trend, but some phyla did not follow this pattern. The soil microbial community compositions were shaped by the coupled effects of regional climate and local soil properties. Intradomain links were more important than interdomain links in the microbial network of the alpine meadows, and these links were mostly positive. The bacteria formed more connections than either archaea or eukaryota, but archaea may be more important than bacteria in building the soil microbial co-occurrence network in this region. Our results provide new visions on the formation and maintenance of soil microbial diversity along an elevational gradient and have implications for microbial responses to climate change in alpine ecosystems. [ABSTRACT FROM AUTHOR]

Tiantishan Grottoes, a famous site well known for its historical status in the spread of Buddhism art in ancient China, were selected for a comparison and analysis of microbial taxonomic characteristics on the wall paintings under different preservation conditions: in situ and ex situ conservation. A total of 12 samples were collected from three different cave wall paintings preserved in situ or ex situ . The 16/18S rRNA gene-based sequences revealed a high bacterial diversity and a relative low fungal abundance, including bacterial groups Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, Acidobacteria, Deinococcus-Thermus and Fusobacteria; and fungal groups Ascomycota and Basidiomycota. Among them, two bacterial genera of the Promicromonospora and Planomicrobium and fungal order of the Sordariales and the family of Trichocomaceae were dominant in the samples preserved ex situ . Some of them have been reported at other cultural heritage sites and associated with the biodeterioration of cultural relics. The over-growth of these microbes led to the abundant filaments formed visible on the surface of the ex situ wall paintings, which preserved under museum conditions. Application of preservation materials including animal glue and wet gypsum to take them off from grottoes and strengthen, and subsequent long-term preservation under poor conditions in museums were mainly responsible for the microbial outbreaks. To avoid similar problems in the future, reasonable intervention measures and strict micro-environmental control must be implemented to the ex situ preservation of wall paintings. Our results have profound significance for clarify the occurrence of microbial invasions and mechanisms on the wall paintings; it is helpful to development a reasonable artificial intervention measures for conservation work of the wall paintings in the future. [ABSTRACT FROM AUTHOR]

In this study, a culture-independent Illumina MiSeq sequencing strategy was applied to investigate the microbial communities colonizing the ancient painted sculptures of the Maijishan Grottoes, a famous World Cultural Heritage site listed by UNESCO in China. Four mixed samples were collected from Cave 4–4 of the Maijishan Grottoes, the so-called Upper Seven Buddha Pavilion, which was built during the Northern Zhou Dynasty (557-581AD). The 16/18S rRNA gene-based sequences revealed a rich bacterial diversity and a relatively low fungal abundance, including the bacterial groups Actinobacteria, Acidobacteria, Bacteroidetes, Cyanobacteria, Chloroflexi, Firmicutes, Proteobacteria and Verrucomicrobia and the fungal groups Ascomycota, Basidiomycota and Chytridiomycota. Among them, the bacteria genera of Pseudonocardia and Rubrobacter and unclassified fungi in the order of Capnodiales were dominant. The relative abundance of Pseudonocardia in the painted layer samples was higher than that in the dust sample, while Cyanobacteria dominated in the dust sample. Many of them have been discovered at other cultural heritage sites and associated with the biodeterioration of cultural relics. The presence and activity of these pioneering microorganisms may lead to an unexpected deterioration of the painted sculptures that are preserved in this heritage site. Thus, proper management strategies and potential risk monitoring should be used in the Maijishan Grottoes to improve the conservation of these precious painted sculptures. [ABSTRACT FROM AUTHOR]

The Beishiku (North Grottoes) Temple is suffering from serious weathering erosion as well as biological attacks. In this study, the total genomic DNA of 72 samples was extracted to elucidate the communities and distribution of both bacteria and archaea in biodeteriorated and weathered sandstone materials using a high-throughput sequencing analysis. As a result, the predominant bacterial communities belonged to the genera Deinococcus , Thermus , Pseudomonas , Rubrobacter , and Chroococcidiopsis. Interestingly, archaea (particularly the Candidatus Nitrocosmicus genus) with a putative ammonia-oxidizing function were dominant in the biodeteriorated samples where halophilic archaeal groups (particularly Halalkalicoccus and Halococcus genera) were also enriched. Moreover, the CCA showed that the distribution of microbial communities was mainly driven by the sunlight intensity, moisture, soluble salts and pH. In addition, a co-occurrence network analysis indicated that a more complex and stable community structure existed in the outside surface samples. The ecological functions of these community members were mainly predicted to be associated with chemoheterotrophy, phototrophy and aerobic ammonia oxidation, which maintained the common survival of biodeteriogens on stone heritage. Our findings unveil the distribution patterns of bacteria and archaea on sandstone sculptures in the subhumid climate, highlight the key factors affecting these patterns, and thus provide a reference basis for mitigation management and policies to prevent biodeterioration and protect such cultural heritages. • The distribution of bacterial and archaeal communities was mainly driven by the sunlight intensity, moisture, salinity, and pH. • Co-occurrence network analysis indicated that a more stable and complex community structure existed in the outside samples. • Ecological functions of chemoheterotrophy, phototrophy and aerobic ammonia oxidation, maintained the survival of biodeteriogens on stone heritage. [ABSTRACT FROM AUTHOR]