AME - Vol. 76 No. 3 - Feature article

Microbial community assemblages and cell densities are determined by organic contamination rather than mineral properties. Image: Christian Griebler & Clemens Karwautz

Grösbacher M, Spicher C, Bayer A, Obst M, Karwautz C, Pilloni G, Wachsmann M, Scherb H, Griebler C

 

Organic contamination versus mineral properties: competing selective forces shaping bacterial community assembly in aquifer sediments

 

Elementary composition, sorption characteristics, and surface roughness of minerals in sediments are known factors involved in shaping sessile microbial communities in terms of density, diversity, and composition. Our field investigation in a contaminated aquifer shows that petroleum hydrocarbons at high concentrations outcompete sediment and mineral characteristics as selective forces. No difference in community composition, diversity and abundance of attached bacterial communities was found on translucent quartz particles [SiO2] in comparison to mica [K(Mg,Fe)3AlSi3O10(OH)2] in the zone of high organic contamination. In zones outside the main contamination, mineral composition, sediment surface and sorption characteristics exhibited influence on microbial community assemblage, revealing most pronounced differences in bacterial diversity, community composition and total bacterial cell counts for the different minerals analyzed.

 

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