Spatial heterogeneity of physicochemical properties explains differences in microbial composition in arid soils from Cuatro Cienegas, Mexico

Abstract

Arid ecosystems are characterized by high spatial heterogeneity, and the variation among vegetation patches is a clear example. Soil biotic and abiotic factors associated with these patches have also been well documented as highly heterogeneous in space. Given the low vegetation cover and little precipitation in arid ecosystems, soil microorganisms are the main drivers of nutrient cycling. Nonetheless, little is known about the spatial distribution of microorganisms and the relationship that their diversity holds with nutrients and other physicochemical gradients in arid soils. In this study, we evaluated the spatial variability of soil microbial diversity and chemical parameters (nutrients and ion content) at local scale (meters) occurring in a gypsum-based desert soil, to gain knowledge on what soil abiotic factors control the distribution of microbes in arid ecosystems. We analyzed 32 soil samples within a 64 m2 plot and: (a) characterized microbial diversity using T-RFLPs of the bacterial 16S rRNA gene, (b) determined soil chemical parameters, and (c) identified relationships between microbial diversity and chemical properties. Overall, we found a strong correlation between microbial composition heterogeneity and spatial variation of cations (Ca2, K+) and anions (HCO, Cl−, SO) content in this small plot. Our results could be attributable to spatial differences of soil saline content, favoring the patchy emergence of salt and soil microbial communities.

Bacterial Diversity and Interaction Networks of Agave lechuguilla Rhizosphere Differ Significantly From Bulk Soil in the Oligotrophic Basin of Cuatro Cienegas

“…Coupled with this, the low nutrient availability to soil microbes and vegetation, observed in the low C/N ratio, suggests deficiency of soil organic C that can limit the N cycle. Despite the great heterogeneity of this arid environment, the oligotrophic conditions seem to be a general characteristic of the soils in all the Basin (Loṕez-Lozano et al, 2012;Tapia-Torres et al, 2015;Pajares et al, 2016). The bacterial composition found in our samples clearly reflect their origin, since many of the identified taxa have been reported in arid zones (Walker and Pace, 2007;Bachar et al, 2010;Saul-Tcherkas and Steinberger, 2011;Andrew et al, 2012;Loṕez-Lozano et al, 2012;Marasco et al, 2012;Torres-Corteś et al, 2012;An et al, 2013;Kavamura et al, 2013;Desgarennes et al, 2014;Coleman-Derr et al, 2016;Postma et al, 2016).…”

Understanding the Mechanisms Behind the Response to Environmental Perturbation in Microbial Mats: A Metagenomic-Network Based Approach

“…Although the three sites are very close in space, the fact that they have different dynamics and diversity along the time-series indicates site specific community dynamics. This is not surprising given the large microbial beta-diversity observed in CCB in general ( Bonilla-Rosso et al, 2012 ; Espinosa-Asuar et al, 2015 ; Pajares et al, 2016 ) and in the studied Lagunita pond in particular ( Lee et al, 2017 ). We believe that such community differentiation in the space could be due to historical factors –such as early colonizers establishing the ground rules of interactions-, but also by stochastic events such as virus predation of the dominant taxa following a “king of the hill” model ( Taboada et al, 2018 ).…”

Environmental Controls on Soil Microbial Communities in a Seasonally Dry Tropical Forest

“…KEYWORDS soil bacterial community structure, functional N genes, tropical dry forest, rainfall seasonality, soil heterogeneity, N deposition, nitrogen deposition S oil microorganisms constitute the largest proportion of the world's biodiversity, play key roles in biogeochemical cycles, and are a fundamental driver of soil fertility and primary productivity (1,2). Environmental factors (e.g., rainfall seasonality, temperature, and vegetation type) and soil properties (e.g., pH, texture, organic matter, and nutrient contents) tend to drive seasonal and spatial changes in soil microbial abundance and composition (3)(4)(5), and these changes can influence ecosystem processes (6). Thus, understanding the factors that drive changes in the diversity of soil microbial communities is important for the prediction of ecosystem responses to a changing environment (7).…”