Bacterial diversity in the sediment from polymetallic nodule fields of the Clarion-Clipperton Fracture Zone

Abstract

The Clarion-Clipperton Fracture Zone (CCFZ) is located in the northeastern equatorial Pacific and contains abundant polymetallic nodules. To investigate its bacterial diversity, four libraries of 16S rRNA genes were constructed from sediments of four stations in different areas of the CCFZ. In total, 313 clones sequenced from the 4 libraries were assigned into 14 phylogenetic groups and 1 group of 28 unclassified bacteria. High bacterial diversity was predicted by the rarefaction analysis. The most dominant group overall was Proteobacteria, but there was variation in each library: Gammaproteobacteria was the most dominant group in two libraries, E2005-01 and ES0502, while Alphaproteobacteria and Deltaproteobacteria were the most dominant groups in libraries EP2005-03 and WS0505, respectively. Seven groups, including Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Betaproteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes, were common to all four libraries. The remaining minor groups were distributed in libraries with different patterns. Most clones sequenced in this study were clustered with uncultured bacteria obtained from the environment, such as the ocean crust and marine sediment, but only distantly related to isolates. Bacteria involved in the cycling of metals, sulfur and nitrogen were detected, and their relationship with their habitat was discussed. This study sheds light on the bacterial communities associated with polymetallic nodules in the CCFZ and provides primary data on the bacterial diversity of this area.

The Benthic Megafaunal Assemblages of the CCZ (Eastern Pacific) and an Approach to their Management in the Face of Threatened Anthropogenic Impacts

“…The data revealed a relatively high taxonomic diversity within all faunal categories, with many species new to science. These findings have been confirmed in the more recent literature (Peterson et al, 1998;Glover et al, 2002;Wang et al, 2010;Janssen et al, 2015;Paterson et al, 2015). Key faunal groups within the CCZ are the cnidarians, echinoderms and sponges among the megafauna, and polychaete worms, nematode worms and protozoan foraminifera among the macrofauna and meiofauna; these taxa represent >50% of faunal abundance and species richness in abyssal sediments and display a broad range of ecological and life history types.…”

Microbial diversity in deep-sea sediment from the cobalt-rich crust deposit region in the Pacific Ocean

“…Sequence analyses of this library indicated that Gammaproteobacteria and Alphaproteobacteria are most abundant in 11 phylotypes. The most recent investigation of microbial diversity in polymetallic nodule fields of the Clarion‐Clipperton Fracture Zone in the Pacific recovered three dominant groups ( Alpha‐ , Gamma‐ and Deltaproteobacteria ) and 14 other groups (Wang et al ., ). We compared these studies and concluded that many bacterial phylotypes are common among these metal‐rich environments, suggesting similar biological processes in these ecosystems.…”

The detection of magnetotactic bacteria in deep sea sediments from the east Pacific Manganese Nodule Province

“…The bacterial diversity in sediments from the Clarion‐Clipperton Fracture Zone has been reported to be related to metal (e.g. Mn and Fe) cycling, because of its importance in the formation and growth of polymetallic nodules; this diversity included clones associated with Magnetovibrio blakemorei strain MV‐1 (Wang et al ., ). Previous research has also shown that heavy metals accumulate in the cells of uncultured MTB, especially in phosphorus‐rich granules (Keim et al ., ).…”

“…Various morphological forms of MTB (cocci, rods, spirilla and vibrio‐shaped) have been observed in sediments at water depths ranging from approximately 600 to 3000 m (Stolz et al ., ; Vali et al ., ; Petermann and Bleil, ). Metagenomic and Restriction Fragment Length Polymorphism (RFLP) approaches applied to deep sea (> 5000 m) sediments from the Polymetallic Nodule Province in the east and northeast equatorial Pacific Ocean have also identified 16S rDNA gene sequences closely related to Magnetospirillum species and Magnetovibrio blakemorei strain MV‐1 respectively (Xu et al ., ; Wang et al ., ). Magnetosomes can be preserved as magnetofossils in sediments following the death of MTB bacteria.…”

“…Microorganisms involved in the precipitation of these metals are believed to drive the formation and maintenance of the nodules. Hence, the bacterial communities associated with nodules and surrounding deep sea sediments have been investigated using clone libraries, metagenomic libraries and pyrosequencing approaches (Xu et al ., 2005; 2007; Wang et al ., ; Tully and Heidelberg, ; Wu et al ., ; Zhang et al ., ; Blöthe et al ., ). It has also been shown that heavy metals (Zn, Mn, Sr, Cd, Al, Cr and Pb) can accumulate in the cells of uncultured MTB collected using magnetic concentration (Keim et al ., ), and studies have indicated that large quantities of Mn and Co can be incorporated into magnetosomes formed by uncultured and cultured MTB respectively (Staniland et al ., ; Keim et al ., ).…”