Soil bacterial and archaeal community composition reflects high spatial heterogeneity of pH, bioavailable Zn, and Cu in a metalliferous peat soil

Because Zn, Cd, and Cu are chalcophilic (sulfur-loving) heavy-metals, understanding the spatial variability in soil chemical variables and relationships with soil microbial community composition will lead to a better understanding of their cycling and availability. In this study, we evaluate field-scale spatial variability in soil chemical parameters and relationships with the soil microbial community composition in the Elba muck soils of Western NY which are drained annually. In May, 2005, soil samples were collected along a series of transects in order to capture spatial heterogeneity across the site (approximate field dimensions: 36 × 90 m). Soils were collected at two depths, 0–15 and 15–30 cm, and analyzed for % H20, pH, total, as well as 0.01 M CaCl2-extractable S, Zn, Cd, and Cu. Soil Bacteria and Archaea community composition were characterized by terminal restriction fragment length polymorphism (T-RFLP) analysis. Field hedgerow willow (Salix purpurea L.) tissues were also analyzed for total S, Zn, Cd, and Cu. Spatial variability across the field was vast within all measured parameters. Soil pH, total soil S, extractable soil Cu and Zn exerted the greatest influence on the composition of the soil microbial communities, and willow tissue concentrations reflected bioavailable fractions of soil heavy metals. Our results demonstrate the intricate link between soil chemistry and soil microbial community composition over a field scale in organic soils with high soil S and heavy metals content.