• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.20 no.4
• /
• pp.159-168
• /
• 2015

Forty-four surface sediments from Doam Bay were analyzed for total organic carbon (TOC), total nitrogen (TN), total metal (Al, Fe, Mn, Cr, Cu, Ni, Pb, Zn) and further chemical partitioning of metals were carried out in some samples. The TOC (0.32~3.10%) and TN (0.03~0.26%) values of the samples were similar to those of other coastal area. The C/N ratios ranged from 7.9 to 11.9 with an average 9.3 which revealed that contribution of terrestrial organic matters was relatively rare. Contents of analysed metals showed a level lower than threshold effects level (TEL) in sediment quality guidelines. Based on the chemical speciation of metals, the lattice fractions were found in the order Cr > Cu > Ni > Zn > Pb > Mn, while Mn and Pb are the ratio of the non-lattice fractions accounted for more than 50%. The average baseline values were obtained relative cumulative frequency curves and linear regression analysis. The respective baseline concentrations for Cu, Ni, Pb, Zn, Cr and Mn were 11.8, 23.1, 26.8, 76.6, 56.7, 585 mg/kg, respectively. Based on geoaccumulation index ($I_{geo}$) with a baseline values of Mn showed that face the contamination phase from estuarine stations. However, in case of Zn and Pb, although there is no sign of contamination, it could be release from sediment when there is a change in the environment, which is caused from the high ratio of non-lattice fractions.

• The Korean Journal of Zoology
• /
• v.31 no.1
• /
• pp.11-20
• /
• 1988

A comparison between two species of Hyla japonica and H. suweonesis in Korea was carried out to clarify their morphological, genetic and ecological differences, to estimate presumed divergent time between them, and to elucidate their probable process and mechanism of speciation. The results are as follows; 1.The breeding season of H. japonica was earlier than that of H. suweonensis about one and half months. 2.H.japonica was distributed all over the country, while H. suweonensis was restricted in Kyonggi plains. 3.On the extemal morphometric characters, differences were hardiy seen between two species. But on the discriminant function analysis, there was apparent differences between them. 4.Genic variation based on 24 loci showed that H. japonica populations were about two fold more variable than that of H. suweonensis populations. 5.Genetic relatedness between two species was rather remote (S =0.520, D=0.634) 6.Their presumed divergent time was estimated to be about three and a quarter mfllon years. It is presumed that H. suweonensis was originated from H. japonica during the period of late pleocene and early pleistocene. 7.Premating isolating mechanisrns (breeding season, mating call, and microhabitat segregation) may be operating to prevent gene ifow between them.

• Korean Journal of Plant Taxonomy
• /
• v.34 no.4
• /
• pp.335-358
• /
• 2004

To investigate molecular phylogenetic relationships and to test hypothesis of hybrid origin of Ranunculus cantoniensis (Ranunculaceae), the sequences of nrDNA and chloroplast DNA were analyzed for 8 taxa and 25 accessions including 5 accessions of outgroup. In the phylogenetic trees by analyses of maximum parsimony and maximum likelihood for ITS nrDNA sequences and combined data of psbA-trnH, rps16 and trnL sequences of cpDNA, R. cantoniensis was most closely related to R. chinensis, and then to R. taciroi and R. silerifolius. The molecular phylogenetic relationships were not congruent with the previous report that R. cantoniensis was most closely related to R. silerifolius. In the sequence analysis of ITS and psbA-trnH, rps16, trnL for R. cantoniensis and the related taxa, R. cantoniensis showed polymorphism. It supported that the polymorphism also was reported in chromosome number and karyotype of R. cantoniensis. Ranunculus cantoniensis shared the marker gene of R. chinensis and R. silerifolius in ITS, and one of R. silerifolius in cpDNA. These results supported the hypothesis that R. cantoniensis was caused by hybridization between R. chinensis and R. silerifolius based on chromosome number and karyotype, and also estimated that R. silerifolius might be of maternal origin and R. chinensis be paternal.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.6
• /
• pp.937-944
• /
• 2010

Cu and Zn can be accumulated in plastic film house soils by long-term application of livestock manure or compost. The mobility and bioavailability of Cu and Zn accumulated in soils are strongly influenced by their chemical or geochemical species in soils. In order to assess the accumulation, mobility, and bioavailability of Cu and Zn in plastic film house soils, we determined their geochemical species using a sequential extraction, grouped into three pods: the total pool, the potentially mobil pool, and the mobil pool. Total contents of Cu and Zn, ranged from 14.9 to 53.1 mg $kg^{-1}$ for Cu and from 55.4 to 169 mg $kg^{-1}$ for Zn, lied by far below the soil contamination standards, but exhibited little accumulation compared with their geogenic concentrations. Mobile contents of Cu and Zn and their percentage of total contents were strongly affected by soil pH in addition to total contents and soil organic matter. Mobile contents of Cu, ranged from <0.01 to 1.71 mg $kg^{-1}$, showed their minimum between pH 5.0 and 6.0 and increased above pH 6.0 to 8.0. In contrast, mobile contents of Zn, varied from <0.01 to 12.4 mg $kg^{-1}$, showed their minimum above pH 7.0 and increased strongly with decreasing pH below 5.5~6.0. Potentially mobile and total contents of Cu and Zn rose with ascending soil organic matter. To assess ecological and toxic effects of Cu and Zn in soils, mobile and potentially mobile contents, as bioavailable and potentially bioavailable pools, should be considered more important than total contents.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.4 no.1
• /
• pp.25-32
• /
• 1999

In order to examine the degree of heavy metal pollutions around Samcheonpo and Youngkwang power plants, marine sediment samples were analyzed to determine heavy metal contents. Some of these sediment samples were also analyzed by using of a sequential extraction technique to know geochemical forms of the metals. The results showed that the spatial distribution of heavy metals coincided very well with those of mean grain size, carbonates and organic matters. The chemical speciation data using sequential extraction analysis also showed that a considerable amount of heavy metals except for Mn were bounded in the residual fraction, which mode of occurrence of heavy metals was generally interpreted as being the result of the lithogenic origin.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.11
• /
• pp.3362-3366
• /
• 2013

A simple and quick separation technique for selenite in natural water was developed using $TiO_2$@$SiO_2/Fe_3O_4$ nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the $TiO_2$ shell. The synthesized nanoparticles were used to separate selenite ($Se^{4+}$) in the presence of $Se^{6+}$ or selenium anions for the photocatalytic reduction to $Se^0$ atom on the $TiO_2$ shell, followed by magnetic separation using $Fe_3O_4$ nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.8
• /
• pp.1156-1160
• /
• 2004

The technique of an on-line preconcentration by the direct sulfide precipitation has been developed. Sn was homogeneously precipitated by sulfide, which was generated in situ from the hydrolysis of thioaceteamide. Precipitate was collected on a filter in the line and dissolved out instantaneously by KOH to be sent to an ICP. The enrichment factor was 4 with the sampling speed of 15/hr for 1.0 mL of sample. It was increased to more than 40 times when the sampling volume was increased to 10 mL with the sampling speed of 5/hr. $Sn^{2+}/Sn^{4+}$ could be separately determined with the on-line precipitation technique. The method was applied to the analysis of NIST SRM 1566 Oyster sample and yielded good agreement with the certified value.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.6
• /
• pp.726-732
• /
• 1993

A comparative study on cadmium(II) complexation with three well characterized humic acids (SHA: soil humic acid from the Okchun Metamorphic Belt; AqHA: aquatic humic acid from Gorleben underground aquifer, Germany; CoHA: commercially available humic acid from the Aldrich Co.) was carried out in 0.1 M $NaClO_4$ at different solution pH(5.0, 5.5, and 6.0) using the ultrafiltration technique. The maximum binding ability (MBA) of the humic acids for cadmium(II) was observed to vary with their origins and solution pH. The results suggest that 1 : 1 complex predominates within the experimental range, and the conditional stability constants were calculated based on the assumption of cooperative binding, yielding log K values that were quite similar (CoHA: 4.17${\pm}$0.08; AqHA: 4.14${\pm}$0.07; SHA: $4.06{\pm} 0.12\;l\;mol^{-1}$ at pH 6.0) irrespective of humic acid origins or pH. By contrast a nonlinear Schatchard plot was obtained, using the cadmium(II) ion selective electrode speciation analysis method, which indicated that humic acid may have two or more classes of binding sites, with $log\;K_1\;and\;log\;K_2$ of 4.73${\pm}$ 0.08 and $3.31{\pm}0.14\;l\;mol^{-1}$ respectively.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.5
• /
• pp.574-578
• /
• 1993

Laser-induced photoacoustic spectroscopy (LIPAS), which utilizes the photothermal effect that results from nonradiative relaxation of excited state molecules, was used in the speciation analysis of the complexes of neodymium(III) and water soluble synthetic polyelectrolyte, poly methacrylic acid (PMAA), in 0.1 M $NaClO_4$ at pH of 6.0. The minimum detection limit of Nd(III) by LIPAS was $5.O{\times}10^{-6}$ M. Experiment was carried out at low concentration ratio of Nd(III) to PMAA to assure that 1 : 1 complexes predominate. The bound and free Nd(III) species were characterized by measuring nonradiative relaxation energy of the excited states $(^2GM{7/2}\;and\;^4G_{5/2})$ to the metastable state $(^4G_{3/2})$. Two species were quantified by deconvolution of the mixed spectrum using their respective reference spectra. The conditional stability constant measured by LIPAS was 5.52 L$mol^{-1}$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.4
• /
• pp.489-497
• /
• 2021

Climate change is affecting the evolutionary trajectories of individual species and ecological communities, partly through the creation of new species groups. As population shift geographically and temporally as a result of climate change, reproductive interactions between previously isolated species are inevitable and it could potentially lead to invasion, speciation, or even extinction. Four species of abalone, genus Haliotis are present along the Korean coastline and these species are important for commercial and fisheries resources management. In this study, genetic markers for fisheries resources management were discovered based on genomic information, as part of the management of endemic species in response to climate change. Two thousand one hundred and sixty one single nucleotide polymorphisms (SNPs) were discovered using genotyping-by-sequencing (GBS) method. Forty-one SNPs were selected based on their features for species classification. Machine learning analysis using these SNPs makes it possible to differentiate four Haliotis species and hybrids. In conclusion, the proposed machine learning method has potentials for species classification of the genus Haliotis. Our results will provide valuable data for biodiversity conservation and management of abalone population in Korea.