Southern Coast Of South Korea Research Articles

Analysis of Tsunami Characteristics of Korea Southern Coast Using a Hypothetical Scenario

Large-scale earthquakes are occurring globally, especially in the South Asian crust, which is experiencing a state of tension in the aftermath of the 2011 East Japan Earthquake. Uncertainty and fear regarding the possibility of further seismic activity in the near future have been on the rise in the region. The National Disaster Management Research Institute has previously studied and analyzed the overflow characteristics of a tsunami and the rate of flood forecasting through tsunami numerical simulations of the East Sea of South Korea. However, there is currently a significant lack of research on the Southern Coast tsunamis compared to the East Coast. On the Southern Coast, the tidal difference is between 1~4 m, and the impact of the tides is hard to ignore. Therefore, it is necessary to analyze the impact of the tide propagation characteristics on the tsunami. Occurrence regions that may cradle tsunamis that affect the southern coast region are the Ryukyu Island and Nankai Trough, which are active seafloor fault zones. The Southern Coast has not experienced direct damage from tsunamis before, but since the possibility is always present, further research is required to prepare precautionary measures in the face of a potential event. Therefore, this study numerically simulated a hypothetical tsunami scenario that could impact the southern coast of South Korea. In addition, the tidal wave propagation characteristics that emerge at the shore due to tide and tsunami interactions will be analyzed. This study will be used to prepare for tsunamis that might occur on the southern coast through tsunami hazard and risk analysis.

A new species of Agauopsis (Acari, Halacaridae) from South Korea belonging to A. brevipalpus group

A new marine halacarid mite of the genus Agauopsis Viets, 1927 is recorded from mussels in the intertidal bedrock of the southern coast of South Korea. Agauopsis bisetosa n. sp. belonging to the A. brevipalpus group, is characterized by an ‘H’-shaped areola on the anterior dorsal plate, two pairs of costae on the posterior dorsal plate, a tectum with a truncate anterior margin, posterior epimeral plate with two ventral setae, telofemur I with one ventral and two ventromedial dentate spines, and tibia II with one ventral and one ventromedial dentate spines. Notably, the presence of two ventral setae on the posterior epimeral plate is a unique characteristic of the new species. This study deals with a description of A. bisetosa n. sp., accompanied by detailed illustrations drawn under a differential interference contrast microscope and scanning electron microscope photomicrographs. Additionally, it includes a character comparison table of the A. brevipalpus group and a key for known Agauopsis species in the northwest Pacific, both including the new species.

On the Species Identification of Korean Geoduck Clam (Panopea sp. 1) Based on the Morphological and Molecular Evidence

The geoduck clam is a high-value species in South Korea. However, the molecular and morphological characteristics of geoduck clams from the southern coast of South Korea remain unexamined. The accurate identification of native geoduck clams is crucial for their conservation and management. Therefore, this study used a combination of molecular and morphological analyses to characterize native geoduck clams from the southern coast of South Korea. Based on complete mitochondrial genome and morphological analyses, the native species of geoduck clam from this study area was identified as Panopea sp. 1. The complete mitochondrial genome sequencing of Panopea sp. 1 revealed a total of 16,225 bp in length with 37 genes (13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes). It was also shown that Panopea sp. 1 belongs to the family Hiatellidae based on a phylogenetic analysis tree with 11 bivalve species. In particular, Panopea sp. 1 is closely related to three other Panopea species (Panopea sp., Panopea abrupta, and Panopea japonica). The phylogenetic analysis correlated with the morphological analysis. Overall, this is the first reliable record of Panopea sp. 1 in South Korea. These findings provide a basis for accurate species identification based on morphological characteristics and complete mitochondrial genome sequencing.

Jeju Island- A “Visa-Free” South Korean Destination, Not Free to All: A Legal Remedy

Jeju Island, a picturesque island off the southern coast of South Korea, is a popular destination known for its stunning natural landscapes and unique culture. Unlike South Korea’s general visa policy, which requires visas for many nationalities, Jeju Island offers a more lenient visa-free policy, allowing most travelers to stay for up to 30 days without a visa, providing they satisfy the requirement of arriving via direct flight outside mainland South Korea. However, the island's visa policy is only partially inclusive, as it excludes nationals from 23 countries designated by the South Korean Ministry of Justice.
 While allowing visa-free travel for tourists is a concept explored previously, South Korea's restriction on certain nationalities undercuts its goal of promoting tourism and economic development on Jeju Island. Interestingly, other countries that have visa-free island policies do not impose such restrictions, including Vietnam’s Phú Quốc Island, Iran’s Kish and Qeshm Islands, and Norway’s Svalbard.
 This article delves into Jeju Island’s visa policy, the list of excluded countries, and the policies of other countries with visa-free islands. It proposes a straightforward legal remedy that could promote more inclusive tourism by allowing all nationalities to visit Jeju Island without visa restrictions. Such a move would enhance the island’s reputation as a welcoming and inclusive tourist destination and foster greater international cooperation.

Spatiotemporal distribution characteristics of yessotoxins and pectenotoxins in phytoplankton and shellfish collected from the southern coast of South Korea

The distribution characteristics of lipophilic marine biotoxins (LMTs), such as yessotoxins (YTXs) and pectenotoxins (PTXs) in phytoplankton, mussels, and commercial seafood were determined for the southern coast of South Korea. Gonyaulax spinifera and Dinophysis acuminata, which are the causative microalgae of YTXs and PTXs, were recorded during summer. Homo-YTX and PTX-2 were predominantly detected in phytoplankton (max: 5.7 μg g−1 ww), whereas only YTXs were detected in mussels (max: 1.1 μg g−1 ww). LMT concentrations in mussels were positively correlated with those in phytoplankton. However, there was a 1-month time gap in maximum LMT concentrations between mussels and phytoplankton. Homo-YTX was detected in commercial seafood, including red scallop and comb pen shell. However, homo-YTX concentrations in shellfish were below the recommended value of the European Food Safety Authority (3.75 mg YTX equivalents kg−1); thus, the consumption of this seafood was not considered to be a significant risk for human health.

Comparison of live shrimp bait catch efficiency in single line fishery

On the southern coast of South Korea, dark-banded rockfish, sea bass, and red seabream are caught by single-line fishing. In particular, red seabream and sea bass are caught in the Jeollanam-do region using gear with attached fishing hooks, such as long-line and single-line gear, with live shrimp as bait. The objective of this study was to compare the catch efficiency of two types of live shrimp (naturally grown Shiba shrimp [Metapenaeus joyneri] and cultured whiteleg shrimp [Litopenaeus vannamei]) used as bait. The investigation included interviews, on-board surveys, and water tank experiments. Interviews were conducted with relevant parties to determine the preference for live shrimp as bait, and the results showed a greater preference for cultured whiteleg shrimp. Further, an on-board survey was conducted to compare catch efficiency between these two types of live shrimp bait for single-line fishing. The on-board investigations were conducted once or twice a month between June and October. In total, the amounts of fish caught using naturally grown Shiba shrimp and cultured whiteleg shrimp were 56 and 52, respectively. Of these, the numbers of sea bass, the primary target fish species, caught using naturally grown Shiba shrimp and cultured whiteleg shrimp were 43 and 40, respectively. Thus, the results showed that there was almost no difference in the number of fish caught based on the bait used. However, according to a water tank experiment, cultured whiteleg shrimp survived longer than naturally grown Shiba shrimp.

Phosphorus Dynamics Associated With Organic Carbon Mineralization by Reduction of Sulfate and Iron in Sediment Exposed to Fish Farming

The expansion of the aquaculture industry has resulted in accumulation of phosphorus (P)-rich organic matter via uneaten fish feed. To elucidate the impact of fish farming on P dynamics, P speciation, and benthic P release along with partitioning of organic carbon (Corg) mineralization coupled to sulfate reduction (SR) and iron reduction (FeR) were investigated in the sediments from Jinju Bay, off the southern coast of South Korea, in July 2013. SR in the farm sediment was 6.9-fold higher than the control sediment, and depth-integrated (0–10 cm) concentrations of NH4+, PO43–, and H2S in pore water of the farm sediment were 2.2-, 3.3-, and 7.4-fold higher than that in control sediment, respectively. High biogenic-P that comprised 28% of total P directly reflected the impact of P-rich fish feed, which ultimately enhanced the bioavailability (58% of total P) of P in the surface sediment of the farm site. In the farm sediment where SR dominated Corg mineralization, H2S oxidation coupled to the reduction of FeOOH stimulated release of P bound to iron oxide, which resulted in high regeneration efficiency (85%) of P in farm sediments. Enhanced P desorption from FeOOH was responsible for the increase in authigenic-P and benthic P flux. Authigenic-P comprised 33% of total P, and benthic P flux to the overlying water column accounted for approximately 800% of the P required for primary production. Consequently, excessive benthic P release resulting directly from oversupply of P-rich fish feed was a significant internal source of P for the water column, and may induce undesirable eutrophication and harmful algal blooms in shallow coastal ecosystems.

Characteristics of Energy Dissipation Rate Observed from the High-Frequency Sonic Anemometer at Boseong, South Korea

The characteristics of low-level turbulence at Boseong, located on the southern coast of South Korea, were investigated in terms of eddy dissipation rate (EDR) using 1-year (2018) of wind data obtained from the Boseong Meteorological Observatory (BMO), a World Meteorological Organization testbed. At BMO, a 307 m tall tower is installed on which four high-frequency (20 Hz) sonic anemometers are mounted at 60, 140, and 300 m above ground level (AGL). In addition, a sonic anemometer at 2.5 m AGL is located to the south of the tower. EDRs are estimated from the wind measurements based on three different EDR estimation methods. The first two methods use the inertial dissipation method derived from Kolmogorov turbulence theory, and the third uses a maximum likelihood estimation assuming a von Kármán spectral model. Reasonable agreement was obtained between the three methods with various fluctuations, including diurnal variations for all seasons, while the EDR calculated from the third method displayed slightly higher EDR values than the other two methods. The result of the analysis showed that the mean (standard deviations) of logarithms of EDR had larger values as height decreased (increased), and the means were higher in the unstable planetary boundary layer (PBL) than in the stable PBL for this heterogeneous location adjacent to the coastlines. The probability density functions (PDFs) of the EDRs showed that the distribution was well-represented by a lognormal distribution in both the stable and unstable PBL, although the PDFs at the lowest level (2.5 m) deviated from those at other levels due to surface effects. Seasonal variations in the PDFs showed that there was less difference in the shape of the PDFs depending on atmospheric stability in the wintertime. Finally, we calculate the 1-yr statistics of the observed EDR, which will be used for future LLT forecast systems in Korea.

16235 An investigation of prevalence, risk factors, and health services utilization for onychomycosis in South Korea fishing villages

There have been many studies about onychomycosis (OM) with various populations. However, no study was conducted on people living in fishing villages who seem to be susceptible to OM. The aim of this study was to investigate the prevalence, risk factor of OM in population in fishing villages in South Korea. Subjects who lived in three different fishing village in Geoje island located off the southern coast of South Korea were included in this study. Inspection was performed and mycologic examination was done for those with clinically diagnosed OM. Questionnaires regarding type of occlusive wear, hygiene habits, treatment history were surveyed. Among 94 subjects enrolled, 64 (68.1%) were diagnosed as OM with inspection and causative organisms were identified in 47. Among clinically diagnosed OM, DLSO was the most common clinical type (70.3%), followed by TDO (25%). The first finger and toenail were the most common, and more than 5 nails were involved more than half of them. Trichophyton rubrum was identified the most commonly. Wearing rubber boots was significantly related to OM (P = .019). Among patients who experienced OM treatment, most of them answered ineffectiveness and indifference. Many of them had tried to cure only with conventional topical agents. The prevalence and severity of onychomycosis in fishing villages were high. Wearing occlusive footwear may be one of the risk factors. Insufficient way of treatment and unawareness hindered them to be cured. Therefore, proper education and medical service for onychomycosis should be provided in association with specific occupational background.

Multi-proxy records of Holocene hydroclimatic and environmental changes on the southern coast of South Korea

A well-dated sediment core from the Goheung area of the southern coast of the Korean Peninsula was used to reconstruct the history of environmental and vegetation changes in response to variability in the East Asian summer monsoon (EASM) and the sea-level change during the Holocene. A multi-proxy analysis (palynomorphs, mean grain size, TOC, TS, C/N ratio, and δ13CTOC data) indicated that the study area underwent a change in environment from a fluvio-coastal (a fluvial to intertidal zone) to a subtidal zone due to a sea-level rise at ca. 7500 cal yr BP. Since ca. 6000 cal yr BP, it has gradually returned to a brackish-dominant environment (intertidal zone) due to coastal regression, with a decrease in relative sea-level. Palynological data show that the climate of the southern coast of the Korean Peninsula underwent a gradual cooling trend after ca. 5900 cal yr BP, due to weakening EASM intensity in response to decreasing insolation in the Northern Hemisphere. Therefore, the long-term vegetation dynamics in this study area were controlled primarily by solar insolation–driven temperature changes during the Holocene. They were also associated with sea surface temperature (SST) changes in the western tropical Pacific (WTP). The vegetation dynamics (sharp reduction of broad-leaved trees and freshwater discharge indicators) in our study area indicate cold and dry climatic conditions since ca. 4500 cal BP, which may have been caused by the decreasing SST in the WTP. In addition, the strong link between the Holocene vegetation dynamics in the East Asian coastal area (especially, Quercus-Lepidobalanus and Pinus-Diploxylon) and SST variation in the WTP may suggest that the centennial-timescale recurring variations in EASM activity have been controlled by low-latitude ocean forcing induced by El Niño Southern Oscillation activity.

Spatio‐temporal drought patterns of multiple drought indices based on precipitation and soil moisture: A case study in South Korea

This study aims to explore the spatio‐temporal characteristics of meteorological and agricultural droughts using the standardized precipitation index (SPI) and standardized soil moisture index (SSI), respectively, as well as their relationships over the past three decades (1986–2016) in South Korea. The SSI shows less frequent droughts and longer drought duration compared to the SPI, due to the gradual decrease in the autocorrelation functions of the SSI. The strongest cross‐correlations are observed at a 1‐month lag between the SPI and SSI for most stations. Thus, the SPI could be more appropriate for defining the onset of a drought, whereas the SSI appears to be more effective for describing drought persistence. Moreover, the transition from meteorological to agricultural droughts is significantly dependent on the season, indicating that the transition between them is highly correlated with antecedent moisture conditions. The copula‐based multivariate standardized drought index (MSDI) is introduced to explicitly postulate interdependence between the SPI and SSI in the context of a multivariate probability distribution. We employ a hierarchical agglomerative clustering approach along with a quantile regression model to better understand the spatio‐temporal pattern of the MSDI. More drought episodes under moderate to severe drought conditions are observed along the southern coast of South Korea. Additionally, persistent droughts with higher severity are observed in the northern part of South Korea, which may be attributed to a significant decreasing trend (or increasing drought risk).

High genetic diversity of Vibrio parahaemolyticus isolated from tidal water and mud of southern coast of South Korea.

A horizontal, fluorophore-enhanced, repetitive extragenic palindromic-polymerase chain reaction (rep-PCR) DNA fingerprinting technique was adapted to examine the genotypic richness and source differentiation of Vibrio parahaemolyticus (n = 1749) isolated from tidal water and mud of southern coast of South Korea. The number of unique genotypes observed from June (163, 51.9%), September (307, 63.9%), December (205, 73.8%) and February (136, 74.7%), indicating a high degree of genetic diversity. Contrary, lower genetic diversity was detected in April (99, 46.8%), including predominant genotypes comprised >30 V. parahaemolyticus isolates. Jackknife analysis indicated that 65.1% tidal water isolates and 87.1% mud isolates were correctly assigned to their source groups. Sixty-nine isolates of pathogenic V. parahaemolyticus were clustered into two groups, separated by sampling month, source of isolation and serogroups. Serotypes O1, O4, O5, O10/O12 and O11 were the dominant serovariants, while serotypes O3/O13 were highly detected in April where there were no pathogenic V. parahaemolyticus isolates. Most of the V. parahaemolyticus isolates were resistant to ampicillin, ceftazidime and sulfamethoxazole. Interestingly, four V. parahaemolyticus isolates resistant to carbepenem did not contain the known carbapenemase-encoding gene, but possess an extended-spectrum β-lactamase blaTEM.

COUPLED HYDRODYNAMIC-HYDROLOGICAL MODELING FOR STORM SURGE INUNDATION IN THE COASTAL AREA

Tropical cyclone easily causes inundation damage to low-lying coastal area and the damage may be amplified due to tide motion, sea-level rise, riverine discharges. Specifically, typhoons are accompanied by intensive rainfall, which will of course raise the river water level and thus enhance the flooding damages. If the tidal cycle coincides the high water, flooding will be even aggravated. In the present study, we simulated storm surge motions at the coastal area considering combined effects of tidal and river discharge with aim to improve the accuracy of flooding prediction. The quasi 3-dimension ocean circulation model, Delf3D was used which solves the unsteady shallow water equation in the 2D and 3D. Since Delft3D is much applicable to accommodate the indirect flooding factors such as riverine discharge and short waves, outer-coupled modeling system was established to account for combined tide-surge-riverine discharge effects. In such integrated system, 11 tidal constituents were input as open boundary condition using TPXO 7.2 model, while the water level per unit time was preliminary calculated by HEC-HMS model and input as the upstream boundary conditions for river inside the domain. Typhoon MAEMI which attacked Masan city located at southern coast of South Korea and caused severe inundation damages in 2003 was selected for the study event. Basic information for typhoon such as path, wind speed, atmospheric pressure every 3 hours was provided by the Korea Meteorological Agency and was adopted. The simulation was implemented with tide and storm surge boundary conditions focusing on the target area, Masan, while the additional consideration on the discharge of the river inside the domain was also made. Simulated water level at the fixed location was compared to the observation for its verification and the extent of inundation areas of Masan were compared between observed and calculated. The marginal contribution of riverine discharge on the flooding area(or depth) was assessed by comparing tide-surge with tide-surge-riverine discharge simulations. Finally, the importance of the specific consideration on the riverine discharge during storm surge modeling can be addressed.

PBDEs and their structural analogues in marine environments: Fate and expected formation mechanisms compared with diverse environments

The concentrations and relative distributions of 27 polybrominated diphenyl ethers (PBDEs) and 17 methoxylated (MeO-) and 8 hydroxylated (OH-) BDEs were determined in marine environments including sediments, bivalves, and seawater along the southern coast of South Korea to understand their fates and possible formation mechanisms. The relative and substituent distributions of the PBDEs and their structural analogues varied according to the characteristics of the media. PBDEs were dominant in marine sediments and seawater, whereas MeO-BDEs made the highest contributions in bivalves. Similar patterns were previously identified in inland environments in Korea, except in river water where OH-BDEs were dominant. The natural formation of structural analogues might be the main mechanism in marine, as ortho-substituted naturally occurring MeO- and OH-BDEs were dominant in all media and seemed to be more produced than in inland environments. In addition, the higher concentrations of meta-substituted MeO-BDEs nearshore than offshore was observed. This is the first study comparing marine (near- and offshore) and inland to understand the differences in their fate and possible formation mechanisms in each environmental conditions.

Season-Specific Occurrence of Potentially Pathogenic Vibrio spp. on the Southern Coast of South Korea.

The presence of enteropathogenic Vibrio species (Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus), which cause acute diarrheal infection, septicemia, and wound infections upon ingestion through food and water, is usually associated with temperature. The World Health Organization (WHO) has estimated that there are 1.4 to 4.3 million cases and 28,000 to 142,000 deaths per year worldwide caused by cholera disease. In South Korea alone, consumption is as much as 52.4 kg of fish and shellfish per year per capita. Our findings suggested that seasonally specific acceleration of these possible pathogenic Vibrio spp. may threaten seafood safety and increase the risk of illness in South Korea, where local people consume raw fish during warmer months.

Development and experimental testing of an autonomous jellyfish detection and removal robot system

The development of an autonomous jellyfish removal robot system, named JEROS, and related experimental results are presented in this paper. The number of jellyfish has drastically increased due to changes to the marine environment. Large jellyfish swarms are threatening marine ecosystems and inducing enormous damage globally to marine-related industries. JEROS has been designed based on a twin hull-type surface vehicle equipped with a device for shredding jellyfish. Additionally, an electrical control system, a guidance, navigation, and control (GNC) system, and a vision-based jellyfish detection system are embedded to remove jellyfish autonomously. The jellyfish removal mission starts when the location of jellyfish is detected, followed by planning a path for jellyfish removal, tracking the path using an autonomous navigation system, and shredding jellyfish while tracking. The performance of the vision-based jellyfish detection, navigation, and jellyfish removal was demonstrated through experiments in a pond and field tests in Masan Bay located on the southern coast of South Korea.

Morphological and molecular affinities of two East Asian species of Stenhelia (Crustacea, Copepoda, Harpacticoida).

Definition of monophyletic supraspecific units in the harpacticoid subfamily Stenheliinae Brady, 1880 has been considered problematic and hindered by the lack of molecular or morphology based phylogenies, as well as by incomplete original descriptions of many species. Presence of a modified seta on the fifth leg endopod has been suggested recently as a synapomorphy of eight species comprising the redefined genus Stenhelia Boeck, 1865, although its presence was not known in S. pubescens Chislenko, 1978. We redescribe this species in detail here, based on our freshly collected topotypes from the Russian Far East. The other species redescribed in this paper was collected from the southern coast of South Korea and identified as the Chinese S. taiae Mu & Huys, 2002, which represents its second record ever and the first one in Korea. A fragment of the mtCOI gene was successfully PCR-amplified from two specimens of each species, which represents the first molecular data for this genus, and from additional 19 specimens belonging to six different species of other stenheliins from Korea and Russia. Reconstructed phylogenies confirm previously postulated monophyly of Stenhelia and polyphyly of the closely related genus Delavalia Brady, 1869. Average pairwise maximum likelihood distances between S. pubescens and S. taiae are only slightly above 10%, suggesting a very close relationship despite numerous newly discovered micro-morphological differences and despite macro-morphological similarities being probable plesiomorphies.

Nonlabens arenilitoris sp. nov., a member of the family Flavobacteriaceae isolated from seashore sand

A Gram-staining-negative, non-spore-forming, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated M-M3(T), was isolated from marine sand on the southern coast of South Korea and subjected to a polyphasic study. Strain M-M3(T) was observed to grow optimally at 25-30 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain M-M3(T) fell within the clade comprising Nonlabens species, joining the type strain of Nonlabens ulvanivorans, with which it exhibited the highest 16S rRNA gene sequence similarity value of 99.4 %. Sequence similarity to the type strains of the other Nonlabens species was 93.0-95.2 % and <92.2 % to those of other species used in the phylogenetic analysis. Strain M-M3(T) was found to contain MK-6 as the predominant menaquinone and iso-C15:0 and iso-C17:0 3-OH as the major fatty acids. The major polar lipids were determined to be phosphatidylethanolamine, five unidentified lipids and one unidentified aminolipid. The DNA G+C content of strain M-M3(T) was determined to be 38.2 mol% and its DNA-DNA relatedness values with N. ulvanivorans DSM 22727(T) was 42 ± 6.2 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain M-M3(T) is separate from other Nonlabens species. On the basis of the data presented, strain M-M3(T) is considered to represent a novel species of the genus Nonlabens, for which the name Nonlabens arenilitoris sp. nov. is proposed. The type strain is M-M3(T) (=KCTC 32109(T) = CCUG 62919(T)).

Biosorption of heavy metal ions by brown seaweeds from southern coast of Korea

Heavy metal ions (Pb2+, Cd2+, Mn2+, Cu2+, and Cr2O72−) were biosorbed by brown seaweeds (Hizikia fusiformis, Laminaria japonica, and Undaria pinnatifida) collected from the southern coast of South Korea. The biosorption of heavy metal ions was pH-dependent showing a minimum absorption at pH 2 and a maximum biosorption at pH 4 (Pb2+, Cd2+, Mn2+, and Cr2O72−) or pH 6 (Cu2+). Biosorption increased most noticeably for pH changes from 2 to 3. In the latter pH range, biosorption increased, because a higher pH decreased the electrostatic repulsion between metal ions and functional groups on the seaweed. In the pH range of 2 ∼ 4, biosorption of negatively-charged chromium species (Cr2O7−2) followed the pattern of positively-charged metal ions (Pb2+, Cd2+, Mn2+, and Cu2+). This suggests that the most prevalent chromium species were positively-charged Cr3+, reduced from Cr6+ in Cr2O7−2. Whereas positively-charged heavy metal ions (Pb2+, Cd2+, Mn2+, and Cu2+) reached a plateau after the maximum level, biosorption of chromium ions decreased noticeably between pH 5 and 8. Kinetic data showed that biosorption by brown seaweed occurred rapidly during the first 10 min, and most of the heavy metals were bound to the seaweed within 30 min. Equilibrium adsorption data for a lead ion could fit well in the Langmuir and Freundlich isotherm models with regression coefficients (R2) between 0.93 and 0.98.

Roseovarius litoreus sp. nov., isolated from seawater of southern coast of Korean peninsula

A gram-negative, non-flagellated and ovoid- to rod-shaped bacterial strain, designated GSW-M15(T), was isolated from seawater on the southern coast of South Korea. Strain GSW-M15(T) grew optimally at 30°C, at pH 7.0-7.5 and in the presence of 2 % (w/v) NaCl. The phylogenetic trees based on 16S rRNA gene sequences revealed that strain GSW-M15(T) belonged to the genus Roseovarius. Strain GSW-M15(T) exhibited highest 16S rRNA gene sequence similarity values (98.3 and 97.5 %) to Roseovarius halotolerans HJ50(T) and Roseovarius pacificus 81-2(T) and 92.8-96.2 % sequence similarity values to the type strains of the other Roseovarius species. Strain GSW-M15(T) contained Q-10 as the predominant ubiquinone and C(18:1) ω7c and 11-methyl-C(18:1) ω7c as the major fatty acids. The major polar lipids detected in strain GSW-M15(T) were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The DNA G+C content of strain GSW-M15(T) was 62.9mol% and its mean DNA-DNA relatedness values with R. halotolerans KCTC 22224(T) and R. pacificus LMG 24575(T) were 33 and 18 %, respectively. Differential phenotypic properties of strain GSW-M15(T), together with the phylogenetic and genetic distinctiveness, demonstrated that this strain is distinguishable from other Roseovarius species. On the basis of the data presented here, strain GSW-M15(T) (=KCTC 23897(T)=CCUG 62218(T)) represents a novel species of the genus Roseovarius, for which the name Roseovarius litoreus sp. nov. is proposed.