Onshore soil microbes and endophytes respond differently to geochemical and mineralogical changes in the Aral Sea

Function-Based Rhizosphere Assembly along a Gradient of Desiccation in the Former Aral Sea

“…Different sampling sites represent a gradient of salinity (high, medium, and low) and natural revegetation events in the Aral Sea basin where bulk soil and rhizosphere samples were collected (A). Geochemistry, mineralogy, and the number of visible plants species were previously described ( 3 ). Bacterial and archaeal 16S rRNA gene copy numbers were calculated by using qPCR (B, C, and D).…”

“…The natural lab constituted by the dried-out Aral Sea basin allowed us to study rhizosphere assembly of the indigenous pioneer plant Suaeda acuminata across a time-dependent gradient of desiccation, which is characterized by decreased salinity and higher vegetation density ( 3 ). Here, we showed that microbiome structure and functioning also followed that gradient.…”

“…The desertification of the Aral Sea basin in Uzbekistan and Kazakhstan represents one of the most serious anthropogenic environmental disasters of the last century ( 1 ). Since the 1960s, the world’s fourth-largest inland body of water has been, due to unsustainable expansion of intense, irrigated plant production, especially cotton, under arid conditions, continuously shrinking, which has resulted in an extreme increase of salinity up to 100 g L −1 ( 1 – 3 ). In parallel, many hazardous and carcinogenic substances, as well as heavy metals, i.e., Pb, Ni, Cu, and Cd, mainly originating from agricultural effluents and pesticide residues, were deposited in the Aral Sea basin ( 4 – 6 ).…”

“…The salt- and toxin-enriched dried-out Aral Sea basin provides a natural laboratory for studying microbial community structures and their ecological roles. First insights into the microbial composition revealed the presence of diverse halophilic and novel prokaryotic taxa ( 32 ), and their main drivers, i.e., desiccation, salinity, and local plant species ( 3 ), but information on microbiome function is missing. Therefore, we investigated structural and functional characteristics of plant-associated prokaryotic communities in the Aral Sea basin.…”

Diversity and Biocontrol Potential of Cultivable Endophytic Bacteria Associated with Halophytes from the West Aral Sea Basin

“…According to the follow-up survey records of the Institute of Natural Sciences, Academy of Karakalpakstan, from the 1970s to 2018, owing to the shrinking water area, the western Aral Sea has formed a huge exposed zone, which extended to about 1500 m from the shoreline to the far shore [ 23 ]. We defined the original exposed zone as E1970S, followed by E1980S, E1990S, E2000S, and E2009S, which indicated that these soil bands were exposed in about the 1970s, 1980s, 1990s, 2000s, and 2009 respectively.…”