2015/05/28 by Marco Blöthe, Anna V. Wegorzewski, F. Max Müller +3 · 2 citations
Earth and Planetary Sciences · Chemistry · #Geochemistry and Elemental Analysis #Paleontology and Stratigraphy of Fossils #Radioactive element chemistry and processing
paper · doi:10.1021/es504930v
openalex publication_date 2015/05/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
Polymetallic nodules (manganese nodules) have been formed on deep sea sediments over millions of years and are currently explored for their economic potential, particularly for cobalt, nickel, copper, and manganese. Here we explored microbial communities inside nodules from the northeastern equatorial Pacific. The nodules have a large connected pore space with a huge inner surface of 120 m(2)/g as analyzed by computer tomography and BET measurements. X-ray photoelectron spectroscopy (XPS) and electron microprobe analysis revealed a complex chemical fine structure. This consisted of layers with highly variable Mn/Fe ratios (<1 to >500) and mainly of turbostratic phyllomanganates such as 7 and 10 Å vernadites alternating with layers of Fe-bearing vernadite (δ-MnO2) epitaxially intergrown with amorphous feroxyhyte (δ-FeOOH). Using molecular 16S rRNA gene techniques (clone libraries, pyrosequencing, and real-time PCR), we show that polymetallic nodules provide a suitable habitat for prokaryotes with an abundant and diverse prokaryotic community dominated by nodule-specific Mn(IV)-reducing and Mn(II)-oxidizing bacteria. These bacteria were not detected in the nodule-surrounding sediment. The high abundance and dominance of Mn-cycling bacteria in the manganese nodules argue for a biologically driven closed manganese cycle inside the nodules relevant for their formation and potential degradation.