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Malik, A. A.

Publications and source records attributed to Malik, A. A..

2 recordsLinked to original sources

Defining trait-based microbial strategies with consequences for soil carbon cycling under climate change

Microorganisms are critical in terrestrial carbon cycling because their growth, activity and interactions with the environment largely control the fate of recent plant carbon inputs, as well as the stability of assimilated carbon (Gleixner, 2013; Schimel and Schaeffer, 2012). Soil carbon stocks reflect a balance between microbial decomposition and stabilization of organic carbon. The balance can shift under altered environmental conditions (Davidson and Janssens, 2006), and new research suggests that knowledge of microbial physiology may be critical for projecting changes in soil carbon and improving the prognosis of climate change feedbacks (Allison et al., 2010; Bradford et al., 2016; Liang et al., 2017; Wieder et al., 2015). Still, predicting the ecosystem implications of microbial processes remains a challenge. Here we argue that this challenge can be m ...

ecology

Bacterial physiological adaptations to contrasting edaphic conditions identified using landscape scale metagenomics

Environmental factors relating to soil pH are widely known to be important in structuring soil bacterial communities, yet the relationship between taxonomic community composition and functional diversity remains to be determined. Here, we analyze geographically distributed soils spanning a wide pH gradient and assess the functional gene capacity within those communities using whole genome metagenomics. Low pH soils consistently had fewer taxa (lower alpha and gamma diversity), but only marginal reductions in functional alpha diversity and equivalent functional gamma diversity. However, coherent changes in the relative abundances of annotated genes between pH classes were identified; with functional profiles clustering according to pH independent of geography. Differences in gene abundances were found to reflect survival and nutrient acquisition strategies, with organic-rich acidic soils harboring a greater abundance of cation efflux pumps, C and N direct fixation systems and fermentation pathways indicative of anaerobiosis. Conversely, high pH soils possessed more direct transporter-mediated mechanisms for organic C and N substrate acquisition. These findings show that bacterial functional versatility may not be constrained by taxonomy, and we further identify the range of physiological adaptations required to exist in soils of varying nutrient availability and edaphic conditions.

microbiology