scholarly journals Bacterial and archaeal spatial distribution and its environmental drivers in an extremely haloalkaline soil at the landscape scale

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6127 ◽  
Author(s):  
Martha Adriana Martínez-Olivas ◽  
Norma G. Jiménez-Bueno ◽  
Juan Alfredo Hernández-García ◽  
Carmine Fusaro ◽  
Marco Luna-Guido ◽  
...  

Background A great number of studies have shown that the distribution of microorganisms in the soil is not random, but that their abundance changes along environmental gradients (spatial patterns). The present study examined the spatial variability of the physicochemical characteristics of an extreme alkaline saline soil and how they controlled the archaeal and bacterial communities so as to determine the main spatial community drivers. Methods The archaeal and bacterial community structure, and soil characteristics were determined at 13 points along a 211 m transect in the former lake Texcoco. Geostatistical techniques were used to describe spatial patterns of the microbial community and soil characteristics and determine soil properties that defined the prokaryotic community structure. Results A high variability in electrolytic conductivity (EC) and water content (WC) was found. Euryarchaeota dominated Archaea, except when the EC was low. Proteobacteria, Bacteroidetes and Actinobacteria were the dominant bacterial phyla independent of large variations in certain soil characteristics. Multivariate analysis showed that soil WC affected the archaeal community structure and a geostatistical analysis found that variation in the relative abundance of Euryarchaeota was controlled by EC. The bacterial alpha diversity was less controlled by soil characteristics at the scale of this study than the archaeal alpha diversity. Discussion Results indicated that WC and EC played a major role in driving the microbial communities distribution and scale and sampling strategies were important to define spatial patterns.

Parasitology ◽  
2005 ◽  
Vol 131 (5) ◽  
pp. 713-722 ◽  
Author(s):  
C. P. GOATER ◽  
R. E. BALDWIN ◽  
G. J. SCRIMGEOUR

Populations of hosts vary extensively in the types and numbers of parasites that the average individual contains. Understanding the factors that lead to this variation is an important goal for parasite ecologists. We characterized patterns of helminth component community structure in whitefish collected from a cluster of 7 lakes located on an isolated plateau in northern Alberta, Canada. Component communities were species rich (5–6 species per lake), high in mean helminth intensity (approximately 80–500 individuals/host), and high in between-lake similarity (50–100%), a pattern consistent with results from studies on whitefish sampled from other localities in Northern Canada and Europe. Multivariate analyses indicated that the structure of the component communities was associated with 2 opposing environmental gradients. One was defined primarily by water colour, the second by phosphorous concentration. Thus, 4 lakes were characterized by a combination of high colour, low productivity, low parasite intensities, and the absence of larval acanthocephalans. Habitat/species associations were less clear as intensities increased, but the 3 remaining lakes tended to have the opposite characteristics. These results provide evidence that variation in helminth component community structure in fish is associated with variation in physicochemical characteristics that are linked to aquatic productivity.


2021 ◽  
Author(s):  
Fletcher W. Halliday ◽  
Mikko Jalo ◽  
Anna-Liisa Laine

AbstractPredicting disease risk in an era of unprecedented biodiversity and climate change is more challenging than ever, largely because when and where hosts are at greatest risk of becoming infected depends on complex relationships between hosts, parasites, and the environment. Theory predicts that host species characterized by fast-paced life-history strategies are more susceptible to infection and contribute more to transmission than their slow-paced counterparts. Hence, disease risk should increase as host community structure becomes increasingly dominated by fast-paced hosts. Theory also suggests that environmental gradients can alter disease risk, both directly, due to abiotic constraints on parasite replication and growth, and indirectly, by changing host community structure. What is more poorly understood, however, is whether environmental gradients can also alter the effect of host community structure on disease risk. We addressed these questions using a detailed survey of host communities and infection severity along a 1100m elevational gradient in southeastern Switzerland. Consistent with prior studies, increasing elevation directly reduced infection severity, which we attribute to abiotic constraints, and indirectly reduced infection severity via changes in host richness, which we attribute to encounter reduction. Communities dominated by fast pace-of-life hosts also experienced more disease. Finally, although elevation did not directly influence host community pace-of-life, the relationship between pace-of-life and disease was sensitive to elevation: increasing elevation weakened the relationship between host community pace-of-life and infection severity. This result provides the first field evidence, to our knowledge, that an environmental gradient can alter the effect of host community structure on infection severity.


2021 ◽  
pp. 1-11
Author(s):  
Limin Wang ◽  
Dongfeng Huang

Microbes play vital roles in soil quality; however, their response to N (nitrogen) and P (phosphorus) fertilization in acidic paddy soils of subtropical China remains poorly understood. Here, a 10-year field experiment was conducted to evaluate the effects of different fertilization treatments on microbial communities by Illumina MiSeq sequencing. The results showed that different fertilization treatments did not exert a significant effect on microbial alpha diversity, but altered soil properties, and thus affected microbial community composition. The microbial communities in the T1 (optimized N and P fertilizer) and T2 (excessive N fertilizer) treated soils differed from those in the T0 (no N and P fertilizer) and T3 (excessive P fertilizer) treated soils. In addition, the bacterial phyla Proteobacteria, Chloroflexi, and Acidobacteria, and the fungal phyla Ascomycota and Basidiomycota dominated all the fertilized treatments. Soil total potassium (TK) concentration was the most important factor driving the variation in bacterial community structure under different fertilization regimes, while the major factors shaping fungal community structure were soil TN and NO3–-N (nitrate N). These findings indicate that optimization of N and P application rates might result in variations in soil properties, which changed the microbial community structure in the present study.


2011 ◽  
Vol 19 (3) ◽  
pp. 369-376
Author(s):  
Gu Yunfu ◽  
Zhang Xiaoping ◽  
Tu Shihua ◽  
Lindström Kristina

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1938
Author(s):  
Han Aricha ◽  
Huasai Simujide ◽  
Chunjie Wang ◽  
Jian Zhang ◽  
Wenting Lv ◽  
...  

Mongolian cattle from China have strong adaptability and disease resistance. We aimed to compare the gut microbiota community structure and diversity in grazing Mongolian cattle from different regions in Inner Mongolia and to elucidate the influence of geographical factors on the intestinal microbial community structure. We used high throughput 16S rRNA sequencing to analyze the fecal microbial community and diversity in samples from 60 grazing Mongolian cattle from Hulunbuir Grassland, Xilingol Grassland, and Alxa Desert. A total of 2,720,545 high-quality reads and sequences that were 1,117,505,301 bp long were obtained. Alpha diversity among the three groups showed that the gut microbial diversity in Mongolian cattle in the grasslands was significantly higher than that in the desert. The dominant phyla were Firmicutes and Bacteroidetes, whereas Verrucomicrobia presented the highest abundance in the gut of cattle in the Alxa Desert. The gut bacterial communities in cattle from the grasslands versus the Alxa Desert were distinctive, and those from the grasslands were closely clustered. Community composition analysis revealed significant differences in species diversity and richness. Overall, the composition of the gut microbiota in Mongolian cattle is affected by geographical factors. Gut microbiota may play important roles in the geographical adaptations of Mongolian cattle.


Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2139
Author(s):  
Feilong Deng ◽  
Yushan Li ◽  
Yunjuan Peng ◽  
Xiaoyuan Wei ◽  
Xiaofan Wang ◽  
...  

Archaea are an essential class of gut microorganisms in humans and animals. Despite the substantial progress in gut microbiome research in the last decade, most studies have focused on bacteria, and little is known about archaea in mammals. In this study, we investigated the composition, diversity, and functional potential of gut archaeal communities in pigs by re-analyzing a published metagenomic dataset including a total of 276 fecal samples from three countries: China (n = 76), Denmark (n = 100), and France (n = 100). For alpha diversity (Shannon Index) of the archaeal communities, Chinese pigs were less diverse than Danish and French pigs (p < 0.001). Consistently, Chinese pigs also possessed different archaeal community structures from the other two groups based on the Bray–Curtis distance matrix. Methanobrevibacter was the most dominant archaeal genus in Chinese pigs (44.94%) and French pigs (15.41%), while Candidatus methanomethylophilus was the most predominant in Danish pigs (15.71%). At the species level, the relative abundance of Candidatus methanomethylophilus alvus, Natrialbaceae archaeon XQ INN 246, and Methanobrevibacter gottschalkii were greatest in Danish, French, and Chinese pigs with a relative abundance of 14.32, 11.67, and 16.28%, respectively. In terms of metabolic potential, the top three pathways in the archaeal communities included the MetaCyc pathway related to the biosynthesis of L-valine, L-isoleucine, and isobutanol. Interestingly, the pathway related to hydrogen consumption (METHANOGENESIS-PWY) was only observed in archaeal reads, while the pathways participating in hydrogen production (FERMENTATION-PWY and PWY4LZ-257) were only detected in bacterial reads. Archaeal communities also possessed CAZyme gene families, with the top five being AA3, GH43, GT2, AA6, and CE9. In terms of antibiotic resistance genes (ARGs), the class of multidrug resistance was the most abundant ARG, accounting for 87.41% of archaeal ARG hits. Our study reveals the diverse composition and metabolic functions of archaea in pigs, suggesting that archaea might play important roles in swine nutrition and metabolism.


2016 ◽  
Vol 62 (6) ◽  
pp. 485-491 ◽  
Author(s):  
Samiran Banerjee ◽  
Nabla Kennedy ◽  
Alan E. Richardson ◽  
Keith N. Egger ◽  
Steven D. Siciliano

Archaea are ubiquitous and highly abundant in Arctic soils. Because of their oligotrophic nature, archaea play an important role in biogeochemical processes in nutrient-limited Arctic soils. With the existing knowledge of high archaeal abundance and functional potential in Arctic soils, this study employed terminal restriction fragment length polymorphism (t-RFLP) profiling and geostatistical analysis to explore spatial dependency and edaphic determinants of the overall archaeal (ARC) and ammonia-oxidizing archaeal (AOA) communities in a high Arctic polar oasis soil. ARC communities were spatially dependent at the 2–5 m scale (P < 0.05), whereas AOA communities were dependent at the ∼1 m scale (P < 0.0001). Soil moisture, pH, and total carbon content were key edaphic factors driving both the ARC and AOA community structure. However, AOA evenness had simultaneous correlations with dissolved organic nitrogen and mineral nitrogen, indicating a possible niche differentiation for AOA in which dry mineral and wet organic soil microsites support different AOA genotypes. Richness, evenness, and diversity indices of both ARC and AOA communities showed high spatial dependency along the landscape and resembled scaling of edaphic factors. The spatial link between archaeal community structure and soil resources found in this study has implications for predictive understanding of archaea-driven processes in polar oases.


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