Microbial community composition and diversity in the Indian Ocean deep sea REY-rich muds.

Shuyan Wang,Jiaqiang Wei,Mu Huang,Hao Chen,Xuefa Shi,Miao Yu,Tzen-Yuh Chiang

doi:10.1371/journal.pone.0208230

Abstract

Studies about the composition and diversity of microbial community in the Rare Earth Elements-rich muds are limited. In this research, we conducted a characterization for the composition and diversity of bacterial and archaeal communities from rare earth elements-rich gravity core sediment at approximately 4800 meters deep in the Indian Ocean by Illumina high-throughput sequencing targeting 16S rRNA genes. The results showed that the most abundant bacteria were Proteobacteria, followed by Firmicutes and Actinobacteria. Amongst Proteobacteria, Gammaproteobacteria are present in all sections of this sediment core accounted for a particularly large proportion of bacterial sequences. Candidatus Nitrosopumilus, with a higher relative abundance in our samples, belongs to Thaumarchaeota. This is the first report on the composition and diversity of rare earth elements-rich muds microbial communities in the Indian Ocean deep sea.

Highlights

Rare earth elements (REY) are comprised of the lanthanides, scandium and yttrium in the periodic table
For sediment nutrients contents profile of this sampling site, along with increasing depths, the content of total nitrogen (TN) has declined in fluctuation, and the content of total carbon (TC) and moisture content (MC) showed a downward trend on the whole but they could be roughly divided into two sections with 140 or 100 cm below seafloor as the boundary respectively: the percentages of content in the upper layer was higher and the magnitude of volatility in the lower layer was smaller
We employed Illumina high-throughput sequencing of the 16S rRNA gene to survey the composition and diversity of REY-rich muds bacterial and archaeal communities in the central Indian Ocean basin and we suggest that various microorganisms may participate in the deep-sea REY mineralization

Summary

Introduction

Rare earth elements (REY) are comprised of the lanthanides (atomic numbers 57–71), scandium (atomic number 21) and yttrium (atomic number 39) in the periodic table. Due to its special atomic structure and active chemical properties, REY, by combining other elements, can produce various advanced materials and widely applied to agricultural activities [1] and global usage of technological devices such as superconductors, magnets, rechargeable batteries, cell phones, fluorescent monitors and so on [2]. Rare earths had remained undisturbed in the deep-sea environment from an earlier, yet it was not until 2011 that Yasuhiro Kato reported deep-sea mud contains high concentrations of these elements in the eastern South and central North Pacific [3]. Given the limited research on the rare earth minerals distributed in seafloor, the formation mechanism of these deposits in deep-water is still an unknown scientific issue up to now.

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