• Journal of the Korean Geophysical Society
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• v.9 no.4
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• pp.427-441
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• 2006

Sub-bottom profiler and deep tow imaging system were performed in the KODOS (Korea Deep Ocean Study) area in order to find out controlling factor in nodule formation from the relationship between distribution of Mn nodules and micro-scale topographic change. Although abundance of r- and t- types nodules increase on the seafloor of thin upper transparent layer, no significant correlation was found between the thickness of upper transparent layer and total nodule abundance in the study area. Our results show that distribution pattern of nodule, including abundance, continuity, and facies, can vary with small scale in similar abyssal plain.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.355-359
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• 1987

Texture and mineralogy of different microlayers of deep-sea manganese nodules are investigted to reveal the environmental changes of nodules during a nodule formation. Basically a nodule can have three types (A, B and C) of microlayer. Some nodules show only one or two types of microlayer. The classification is based primarily on the texture. The surface torture of type A is coarsely porous globular microstructure whereas type B and C are intermediate to finely porous textures. The type A is characterized by its highest Mn content $(30.6\%)$ and relatively well-crystallized todorokite as veil as the rapid growth rate. Smectite and biogenic silica (radiolaria) are also easily observed in the type A layer. It appears that the hydrothermal activity is one of the favorable mechanism of formation for the type A layer. The hydrothermal solution is possibly supplied from nearby fracture zone and spreading center.

• 한국해양학회지
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• v.27 no.3
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• pp.210-227
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• 1992

KODOS-89 area, the northwestern part of Clarion-Clarion-Clipperton fracture zones in the Northeast Pacific, was surveyed in order to study the occurrence and distribution of manganese nodules. Variations in the nodule characteristics are related mainly to seafloor topography. Nodules from abyssal plain have high Mn/Fe ratio and high Mn, Cu, Ni and Zn concentrations, whereas those from seamount are characterized by low Mn/Fe ratio and high Fe and Co concentrations. These compositional characteristics are attributed to toxic diagnosis and hydrogenesis, respectively. Nodules of the early diegenetic origin tend to accurate crystalline Mn-oxides uniformly within the topmost sediment layers and maintain a regular spheroidal, ellipsoidal to discoidal shape with rough surface textures. On the other hand, those of hydrogenetic origin are characterized by polynucleation, irregualr shape, and smooth surface textures. Nodule abundance is high (avg. 13.4 kg/m$^2$) in seamount area, resulting from ample supply of nucleating materials by auto-fragmentation of older nodules. Nodule abundance in abyssal plain is relatively low (avg. 3.9 kg/m$^2$) and tends to increase southward. This phenomenon results from facilitation of taking seed materials from adjacent seamount and enhancement of the early diagenesis by sufficient supply of organic materials. Nodule abundance is considered to be controlled primarily by seeding effects and secondly by supplies of organic materials.

• Journal of Applied Biological Chemistry
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• v.42 no.1
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• pp.12-18
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• 1999

Sucrose synthase (EC 2.4.1.13) has been purified from the plant cytosolic fraction of chickpea (Cicer arietinum L. cv. Amethyst) nodules. The native enzyme had a molecular mass of $356{\pm}15kD$. The subunit molecular mass was $87{\pm}2kD$, and a tetrameric structure is proposed for sucrose synthase of chickpea nodule. Optimum activities in the sucrose cleavage and synthesis directions were at pH 6.5 and 9.0, respectively. The purified enzyme displayed typical hyperbolic kinetics with substrates in cleavage and synthesis reactions. Chickpea nodules sucrose synthase had a high affinity for UDP ($K_m$, $8.0{\mu}M$) and relatively low affinities for ADP ($K_m$, 0.23 mM), CDP ($K_m$, 0.87 mM), and GDP ($K_m$, 1.51 mM). The $K_m$ for sucrose was 29.4 mM. In the synthesis reaction, UDP-glucose ($K_m$, $24.1{\mu}M$) was a more effective glucosyl donor than ADP-glucose ($K_m$, 2.7 mM), and the $K_m$ for fructose was 5.4 mM. Divalent cations, such as $Ca^{2+}$, $Mg^{2+}$, and $Mn^{2+}$, stimulated the enzyme activity in both the cleavage and synthesis directions, and the enzyme was very sensitive to inhibition by $HgCl_2$ and $CuSO_4$.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.547-556
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• 2000

A study have been conducted for the adsorption and desorption characteristics of Cu ion using manganese nodule as adsorbent. For 100 ppm Cu ion solution, the adsorbed amount of Cu ion was more than 90 % at equilibrium state. Adsorption was equilibrated in 42 hours the adsorption reaction was shown to be first order reaction. For the desorption reaction of Cu ion in the region of solution pH 3.5~9.5, the desorption was completed in the acidic region, but it has been decreased as the pH was raised. Also, the desorption rate was higher in the acidic region compared with alkaline region. The desorbed amount was decreased as the reaction temperature increased, therefore, the desorption reaction was thought to be exothermic. Also, several thermodynamic properties were calculated based on experimental results and compared with theoretically driven values. To see the effect of complexing agent on the desorption of Cu ion, EDTA was introduced and the des orbed amount increased in the presence of EDTA.

• Journal of Periodontal and Implant Science
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• v.34 no.4
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• pp.771-780
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• 2004

Chronic exposure to high levels of manganese (Mn) leads a pronounced and debilitating disorder known as manganism. Research on the toxic manifestation of manganese have focused primarily on its neurological effects because exposure to high levels of the metal produces a distinct and irreversible extrapyramidal dysfunction resembling the dystonic movements associated with Parkinson's physiological and biochemical systems in the body. The purpose of this study is to determine the effects of Mn on mineralization in primary rat calvarial cells. The experimental groups were in concentration of 0, 10, 30 and 60 ${\mu}M$. The results were as follows: 1. ALP activity was decreased in concentration of 30 and 60 ${\mu}M$ (p<0.01). 2. Bone nodule formation was depressed in concentration of 30 and 60 ${\mu}M$ at day 14 and 21 (p<0.01). 3. RT-PCR results showed an altered expression of bone matrix proteins. These result suggested that manganese might decrease or alter the expression of the osteoblast phenotype.

• 한국해양학회지
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• v.23 no.3
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• pp.110-122
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• 1988

Between the Clarion and Clipperton fracture zones of the Northeastern Pacific, nodules and crusts were collected from abyssal plain and hills by the Korea Ocean Research and Development Institute in December, 1983 aboard the R/V KANA KEOKI of the Hawaii Institute of Geophysics. Mineralogical and geochemical data of bulk nodules are obtained and compared with analyses of other studies. Mechanisms of nodule formation are discussed based on these data. Generally, the nodules of the KONOD-1 site are composed of todorokite and ${\delta}-MnO_2$. The contents of Mn, Fe, Ni, and Cu of the bulk nodules are variable and the average contents of metals are slightly lower (Mn, 21.40%; Ni, 0.9%; Cu, 0.8%) than those of nodules from other abyssal plains between the Clarion and Clipperton fracture zones. High Mn/Fe (average 3.9; maximum 5.9) and Cu/Ni (average 0.8; maximum 1.0) ratios are similar to the nodules that were formed diagenetically in the northeast Pacific. The chemical characteristics of the KONOD-1 nodules reflect their sedimentary environments; nodules with higher diagenetic signatures occur in areas of thin Quaternary siliceous ooze, and nodules of lower diagenetic influence occur in topographically irregular abyssal hill areas.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.3
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• pp.193-200
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• 2004

This pot experiment was conducted to investigate the effects of systematic variation application of Fe, Mn, Cu, and Zn on forage performance of orchardgrass and white clover. The treatments of systematic variation were 0/100, 25/75, 50/50, 75/25, and $100/0\%$ in the Fe/Cu(trial-1), Mn/Zn(trial-2), and Fe+Cu/Mn+Zn(trial-3), respectively. The treatments of Fe/Mn/Cu/Zn(trial-4) were composed of $70\%$ in main element and $10\%$ in other 3 elements, respectively. 1. By the systematic variations of Fe, Mn, Cu, and Zn, the yields were more significantly influenced in white clover than in orchardgrass. In addition, the yields of white clover were closely correlated to the trends of root/nodule growth and flowering. In the Fe/Cu trial, the relatively high yields were obtained at the $100/0\%$ in orchardgrass and at the $75/25\%$ in white clover. The yields of white clover were more negatively influenced by the 100/0(Cu control) than by the 0/100(Fe control). The yields of orchardgrass, however, tended to be opposite to the above trends. 2. In the Mn/Zn trial, both forages showed generally high yields at the high ratios of Mn/Zn. Compared with orchardgrass, the yields of white clover were greatly decreased by the Mn-deficiency(low ratio of Mn/Zn). The effects of Zn on forage yields, however, were not recognized. 3. In the Fe+Cu/Mn+Zn trial, the yields of orchardgrass tended to be slightly different among the treatments. The yields of white clover, however, were relatively' high at the 75/25, and showed a severe decrease at the 100/0 in the 2nd half cuts. In the Fe/Mn/Cu/Zn trial, the yields of white clover tended to be relatively high at the Cu and Zn treatments. It was likely to be caused by the balanced Fe/Mn ratio.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.303-312
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• 2023

The determination of the oxidation states of metal elements in manganese nodules sheds light on the understanding of the formation mechanism of nodules, providing insights into the paleo-environmental conditions such as the redox potential of the aqueous system. This study aims to reveal the oxidation states and chemical bonding of manganese in the natural polymetallic nodules, utilizing conventional X-ray photoelectron spectroscopy (XPS). Specifically, shallow manganese nodules from the Siberian Arctic Sea, effectively recording mineralogical variations, were used in this study. Detailed analysis of XPS Mn 2p spectra showed changes in the manganese oxidation state from the center to the outer parts of the nodules. The central part of the nodules showed a higher Mn⁴⁺ content, approximately 67.9%, while the outermost part showed about 63% of Mn⁴⁺ due to an increase in the Mn³⁺+Mn²⁺. The decrease in the Mn oxidation state with the growth is consistent with the previously reported mineralogical variations from todorokite to birnessite with growth. Additionally, the O 1s spectra presented a predominance of Mn-O-H bonds in the outer layers compared to the center, suggesting hydration by water in the layered manganates of outer layers. The results of this study demonstrate that XPS can be directly applied to understand changes in paleo-environmental conditions such as the redox states during the growth of manganese nodules. Finally, future studies using high-resolution synchrotron-based XPS experiments could achieve details in oxidation states of manganese and trace metal elements.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.427-437
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• 2020

Manganese nodules, which are evaluated as potential metal resources, have been found in the Arctic Ocean as well as in the abyssal plains of the Pacific and Indian Oceans. Manganese nodules exhibit strong variations in the morphology, internal texture, chemical composition and mineralogy as they grow. The relationship between the texture and chemical elemental composition during the growth process is well documented, but the mineral composition variation during the growth process is not. Because the manganese oxide minerals in nodules are fine-grained and poorly crystalline, quantitative analysis for the mineral composition is challenging for the bulk nodule sample. This study investigated the internal texture and Mn-oxide mineral composition of manganese nodules obtained from the East Siberian Sea. Semi-quantitative analysis was attempted for three main Mn-oxide minerals constituting the manganese nodules (i.e., todorokite, buserite and birnessite) using the peak area ratio of X-ray diffraction analysis graphs. In the East Siberian Sea manganese nodules, birnessite is more abundant than buserite or todorokite, and no correlation is found between the mineral composition and the internal texture. Instead a correlation is found between the relative content of todorokite and the lamellae depth. The todorokite content tends to increase from the surface to the core of the nodules, which can be attributed to a recrystallization process or difference in the growth rate within the nodule. This study shows that semi-quantitative analysis of manganese oxide minerals using the peak area ratio is useful in the mineralogical study of manganese nodules.