Assessing Biomineral Formation by Iron‐oxidizing Bacteria in a Circumneutral Creek

Abstract

AbstractIron oxidizing bacteria and environmental conditions influence the formation of iron biominerals in aquatic environments. This 10‐week Research Experience for Undergraduates (REU) study focused on elucidating how water chemistry and iron oxidizing bacteria affect the formation of iron oxides in creeks with circumneutral pH. Two locations, each with multiple microenvironments containing abundant iron oxide deposits, were studied. Water chemistry was assessed via both in situ and laboratory analysis over a 5‐week period, revealing correlations between aqueous components that indicate differing groundwater sources may feed nearby discharge points. Microscopy of iron oxide deposits reveals morphologies consistent with the presence of iron oxidizing bacteria. Although efforts to isolate iron oxidizing bacteria did not produce pure cultures, 16S ribosomal DNA analysis also suggests the presence of iron oxidizing bacteria in these sites. Taken together, these results show the diversity of iron oxide forming microenvironments in spatially collocated sites, which may result in unique formations of iron oxide structures, microbial communities, and aqueous chemical cycling.