Iron oxide/oxyhydroxide formation in hydrothermal vent area microbial mat nano-scale electron microscopy analysis

Abstract

Hydrothermal vent systems consisting of hydrothermal vent, hydrothermal sediment and microbial mat are widely spread around the ocean, particularly spreading axis, continental margin and back-arc basin. Scientists have perceived that thehydrothermal systems, which reflect the primeval earth environment, are one of the best places to reveal the origin of life and extensive biogeochemical process of microbe-mineral interaction. Microbial mat sample around the hydrothermal vent area, recovered by Canadian scientific submersible ROPOS on South Pacific North Fiji basin KIOST hydrothermal vent expedition 1602. Various morphologies of minerals in the microbial mat observed by scanning electron microscopy (SEM) showed sheath shaped, resembled with Leptothrix microbial structure, stalks shaped, similar with Mariprofundus microbial structure. Biological association with iron oxide and iron oxyhydroxide formation revealed the variation in crystallinity, iron oxidation states of goethite & iron oxyhydroxide and carbon C-K edge ELNES structure utilizing focused ion beam (FIB) technique, transmission electron microscopy (TEM), scanning transmission electron microscopy-spectrum image (STEM-SI). In this study presents iron oxide & iron oxyhydroxide formation and transformation schematic mechanism with biological effect in natural environment.