Fe-Mn nodule morphotypes from the NE Clarion-Clipperton Fracture Zone, Pacific Ocean: Comparison of mineralogy, geochemistry and genesis

Reykhard, L. E.; Shulga, N. A.

doi:10.1016/j.oregeorev.2019.102933

Cited by 24 publications

(14 citation statements)

References 55 publications

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“…These microfossils were identified in the interior of the Fe-rich and Mn-rich nodules. The same structures were previously observed in Fe–Mn nodules of the Pacific and Indian Ocean 11 , 20 , 45 – 47 . Well-crystallized Fe- and Mn-oxides around the microfossils indicate a post-accretional diagenetic process within the nodules.…”

Section: Discussionsupporting

confidence: 86%

Fast-growing Arctic Fe–Mn deposits from the Kara Sea as the refuges for cosmopolitan marine microorganisms

Shulga

Abramov

Klyukina

et al. 2022

Sci Rep

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The impact of biomineralization and redox processes on the formation and growth of ferromanganese deposits in the World Ocean remains understudied. This problem is particularly relevant for the Arctic marine environment where sharp seasonal variations of temperature, redox conditions, and organic matter inflow significantly impact the biogenic and abiotic pathways of ferromanganese deposits formation. The microbial communities of the fast-growing Arctic Fe–Mn deposits have not been reported so far. Here, we describe the microbial diversity, structure and chemical composition of nodules, crust and their underlying sediments collected from three different sites of the Kara Sea. Scanning electron microscopy revealed a high abundance of microfossils and biofilm-like structures within the nodules. Phylogenetic profiling together with redundancy and correlation analyses revealed a positive selection for putative metal-reducers (Thermodesulfobacteriota), iron oxidizers (Hyphomicrobiaceae and Scalinduaceae), and Fe-scavenging Nitrosopumilaceae or Magnetospiraceae in the microenvironments of the Fe–Mn deposits from their surrounding benthic microbial populations. We hypothesize that in the Kara Sea, the nodules provide unique redox-stable microniches for cosmopolitan benthic marine metal-cycling microorganisms in an unsteady environment, thus focusing the overall geochemical activity of nodule-associated microbial communities and accelerating processes of ferromanganese deposits formation to uniquely high rates.

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Section: Discussionsupporting

confidence: 86%

Fast-growing Arctic Fe–Mn deposits from the Kara Sea as the refuges for cosmopolitan marine microorganisms

Shulga

Abramov

Klyukina

et al. 2022

Sci Rep

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“…The main factor determining the geochemical characteristics of Arctic sediments seems to be the composition and textural features of minerals [22]. A slight dependence on the pelite proportion was observed only for Mn and Cu (Table S3), which was due to their predominant fine-grained carriers (oxyhydroxides, organic matter) [44]. On the contrary, the predominance of the coarser silt-sandy material in four samples (Sts.…”

Section: Controlling Factors Of Elements Distributionmentioning

confidence: 96%

The Features of Distribution of Chemical Elements, including Heavy Metals and Cs-137, in Surface Sediments of the Barents, Kara, Laptev and East Siberian Seas

et al. 2022

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Over the recent few decades, due to climate warming and the continuing exploration of Arctic seas’ mineral resources, the scientific interest in contamination problems has deepened significantly. In this study, for the first time, we characterize the distribution features of 47 elements (major and trace elements, including heavy metals, metalloid As, and Cs-137 technogenic radionuclide) in surface bottom sediments from some areas of the Barents, Kara, Laptev, and East-Siberian Seas. The lithogenic material was the main factor that controlled variability in many elements (Be, Al, Ti, Cr, Ga, Rb, Sr, Y, Zr, Nb, Ba, REE, Pb, Th, U, W, and Cs). Among the hydrogenic processes, the formation of Fe and Mn oxyhydroxides has the greatest impact on the Mn, Fe, Co, Ni, Cu, Ge, and Mo, and insignificantly V and Sb, variability in sediments. These, along with minor to moderate values of enrichment factor (EF) for most elements, allowed us to conclude that the observed element distribution is related to predominantly natural processes of thermal abrasion, river-run, and atmospheric input. The exception is As, which exhibited the elevated EF (up to 20) in the western and central Kara Sea, as well as in the Vilkitsky Strait. Since no significant relationship between As and Fe andMn oxyhydroxides distribution was found, we may assume primarily an anthropogenic source of As, related to the peat and/or coal combustion. According to the criteria of Ecological Risks assessment, all the examined areas have a low degree of risk. Data on the specific activity of Cs-137 correspond to the background average values characteristic for these regions. The highest levels of Cs-137 concentration (Bq/kg) were detected in the sediments of the Ob and Yenisei Rivers’ estuaries.

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“…Surface sediments in the KODOS area where the nodule samples were collected are dominated by quartz, feldspar, illite, smectite, and biogenic silica [26]. Sediments within the nodules may have somewhat different mineralogical composition, but a study from the UK license area in the CCZ have shown that quartz, feldspar, phillipsite, and various clay minerals make up a sizable portion in the bulk mineralogy of nodules [25]. The concentration of such minerals can explain the enrichment of Al and K in the nodule fines.…”

Section: Causes Of Compositional Variationmentioning

confidence: 99%

“…Most previous studies focused only on the size reduction of nodule fragments and paid little attention to their chemistry or mineralogy. Considering that polymetallic nodules are both physically and chemically heterogeneous with numerous microlayers, inclusions, and impurities [24,25], the composition of the nodule fines produced can be largely different from that of the bulk nodules.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Fines Produced by Degradation of Polymetallic Nodules from the Clarion–Clipperton Zone

et al. 2021

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The discharge of fluid–particle mixture tailings can cause serious disturbance to the marine environment in deep-sea mining of polymetallic nodules. Unrecovered nodule fines are one of the key components of the tailings, but little information has been gained on their properties. Here, we report major, trace, and rare earth element compositions of <63 μm particles produced by the experimental degradation of two types of polymetallic nodules from the Clarion–Clipperton Zone. Compared to the bulk nodules, the fines produced are enriched in Al, K, and Fe and depleted in Mn, Co, Ni, As, Mo, and Cd. The deviation from the bulk composition of original nodules is particularly pronounced in the finer fraction of particles. With X-ray diffraction patterns showing a general increase in silicate and aluminosilicates in the fines, the observed trends indicate a significant contribution of sediment particles released from the pores and cracks of nodules. Not only the amount but also the composition of nodule fines is expected to significantly differ depending on the minimum recovery size of particles at the mining vessel.

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Fe-Mn nodule morphotypes from the NE Clarion-Clipperton Fracture Zone, Pacific Ocean: Comparison of mineralogy, geochemistry and genesis

Cited by 24 publications

References 55 publications

Fast-growing Arctic Fe–Mn deposits from the Kara Sea as the refuges for cosmopolitan marine microorganisms

Fast-growing Arctic Fe–Mn deposits from the Kara Sea as the refuges for cosmopolitan marine microorganisms

The Features of Distribution of Chemical Elements, including Heavy Metals and Cs-137, in Surface Sediments of the Barents, Kara, Laptev and East Siberian Seas

Characterization of Fines Produced by Degradation of Polymetallic Nodules from the Clarion–Clipperton Zone

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