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Characteristics of Meiofaunal Communities in the Infralittoral-Circalittoral Transition Zone Compared to the Infralittoral Zone Around Dokdo, Korea
No full textDokdo is a volcanic island with an island mass effect in the East Sea, which is called a “Miniature Ocean.” In this study, we identified the community structures and distribution patterns of meiofaunal communities inhabiting the depth range within the Infralittoral-Circalittoral Transition zone (ICTz) around Dokdo by comparing them with meiofaunal communities in the Infralittoral zone (Iz). Five stations in the Iz within a depth of 30 m were surveyed in 2015, 2017, 2019, and 2020, and five other stations in the ICTz between a depth range of 50 m and 100 m were surveyed once or twice a year from 2021 to 2023. The results revealed that meiofauna density ranged from 94 to 1,068 individuals per 10 cm2 (inds./10cm2) and contained 24 taxa. Cluster analysis revealed clear differences in the community structure between the Iz and the ICTz. Harpacticoid copepods and nematodes, respectively, dominated the Iz and the ICTz. The mean meiofaunal density was higher in the Iz (520 inds./10 cm2) than in the ICTz (304 inds./10 cm2). In contrast, the mean Shannon and Weaver’s diversity index (H′) calculated at the major group level was higher in the ICTz (1.67) than in the Iz (1.21), indicating a clear difference between the two depth zones. These differences showed significant correlations with the depth. In addition, the community composition of meiofauna in the ICTz was most strongly influenced by bottom salinity and mean grain size among environmental variables.11Nsciescopuskc
Tracing the contrasting fates of terrestrial and marine organic matter in coastal waters using stable carbon isotopes
No full textWe measured the concentrations of dissolved oxygen, nutrients, particulate (POC) and dissolved organic carbon (DOC), and their δ13C values in Lake Sihwa, Korea, during spring (May 2024) and summer (August 2023) to determine the fates of terrestrial and marine POC and DOC. NO3− mainly originated from freshwater, whereas NH4+ and PO43− were additionally supplied from bottom sediments in the innermost bay. Although POC and DOC originated primarily from biological production and freshwater, respectively, their δ13C values provided further insights into their sources and transformation processes, which could not be inferred from bulk concentrations alone. Based on a two end-member mixing model using δ13C, the spatiotemporal behaviors of terrestrial and marine POC and DOC were identified. Marine POC increased in spring due to enhanced biological production, but decreased markedly in the subsurface layer during summer due to active microbial degradation, contributing to oxygen consumption and the regeneration of nutrients, such as NH4+ and PO43−. In contrast, terrestrial POC remained in the subsurface layer during summer due to sediment resuspension. Marine DOC was influenced by both biological production and microbial transformation of POC, whereas terrestrial DOC remained largely unaltered, potentially being exported to the open ocean. Thus, our results suggest that in-situ produced marine organic matter (OM) and its subsequent degradation contribute more substantially to the regulation of water quality than the direct input of refractory terrestrial OM, while terrestrial OM is more important for the transport to the open ocean.11Nsciescopu
Novel scFv detection system targeting the glycoprotein of harbor porpoise rhabdovirus (HPRV) through computational and experimental validation
No full textHarbour porpoise rhabdovirus (HPRV), with its distinct bullet-shaped nucleocapsid and negative-sense RNA genome, has become a subject of concern owing to its cytotoxic effects on marine mammals and the potential risks associated with zoonotic transmission of a recently discovered rhabdovirus affecting Harbor porpoises. Existing diagnostic techniques for marine viruses are limited, especially for cetaceans. single-chain variable fragment (scFv) technology offers a potential alternative because of its compact size, specificity, and efficient production capability in the E. coli system. This study focused on the characterization and development of a prospective diagnostic system using scFv antibodies to identify HPRV. Through the bio-panning selection process, high affinity scFv candidates were discovered and subsequently subjected to expression optimization, purification, molecular docking and molecular dynamics simulation were conducted to evaluate their binding affinities against HPRV glycoproteins. Thus, ELISA binding ability and specificity tests validated G2 as the best candidate with significant specificity and sensitivity for HPRV antigen detection without cross-reactivity with host proteins. We demonstrated that the scFv double domain is preferable to the single domain following antigen interaction, based on our computational evaluation. This study offers essential insights into an scFv-based diagnostic tool, enhancing the detection capabilities of marine rhabdoviruses in cetaceans and facilitating potential applications in zoonotic virus control.11Ysciescopu
Projecting the Shift of Chub Mackerel (Scomber japonicus) Spawning Grounds Driven by Climate Change in the Western North Pacific Ocean
No full textSpawning grounds may shift due to climate change and subsequent variations in the marine environment, but few studies have aimed to project shifts in the spawning grounds of chub mackerel driven by climate change. We projected the effects of climate change on the spawning grounds of chub mackerel (Scomber japonicus) by developing and applying a suitable spawning ground index based on a regional ocean circulation model for the western North Pacific. Our model indicated that the potential spawning grounds of chub mackerel extended from southern waters of the East China Sea to the Korea Strait, Yellow Sea, and Japan/East Sea. Despite some uncertainty, our model based on climate change scenarios projected that, by the 2050s, spawning grounds will shift northward due to warming of the ocean surface, resulting in a subsequent westward shift of nursery grounds from the Japan/East Sea to the Korea Strait and Yellow Sea. Our projections will contribute to clarifying the impacts of climate change on the distribution of exploitable chub mackerel, the adaptation of fisheries to climate change, and the reliability of stock assessments used for fisheries management in the region.11Ysciescopu
Comparative Analysis of GloSea6 Hindcasts for Two Extreme El Niño Events and Their Impact on Indo-Western North Pacific Climate
No full textIn this study, GloSea6 hindcast (HCST) from the UK Met Office is used to investigate the model prediction skill for the impacts on the East Asian summer associated with two extreme El Niño cases (1997/1998 and 2015/2016). For the 1998 case, we found that GloSea6 model is able to predict the ocean–atmosphere circulations one to two seasons ahead, including the anomalously positive sea surface temperature (SST) in the Tropical Indian Ocean (TIO) and the anomalous anticyclone (AAC) in the Western North Pacific during the spring and summer seasons. However, for the 2016 case it fails to capture the observed fast cooling of the spring TIO SST and the rapid decaying of the summer AAC, due to an overestimated linkage between the summer TIO and the precedent winter El Niño. Physically, the exaggerated model SST warming over both the eastern and western Indian Ocean suppresses the development of the surface westerly wind that enhances the summer monsoon flow in the TIO and cools the warmed SST as in the real world. According to further analysis, the sensitivity of the TIO is linked to the formation of the spring AAC, which is influenced by the longitudinal position of warm Pacific SST, causing the HCST to display a more idealized El Niño-TIO-AAC teleconnection than the observations. Thus, simulating the decaying El Niño and its teleconnection to the TIO is crucial for reliable seasonal forecasts of East Asian climate during post-El Niño summers.11Nsciescopuskc
Effect of Light Regime on Candidatus Puniceispirillum marinum IMCC1322 in Nutrient-Replete Conditions
No full textPrevious studies showed no improvement in bacterial biomass for Candidatus Puniceispirillum marinum IMCC1322 under light regimes. Nevertheless, in nutrient-replete cultures with higher inoculating cell densities, strain IMCC1322 exhibited proteorhodopsin photoheterotrophy. Increasing both inoculum size and the amino acid pool can eliminate quorum sensing and starvation responses in strain IMCC1322. Light regimes affected IMCC1322 cultures in stationary/death phases, where cellular ATP levels ranged from 0.0331 to 1.74 mM, with ATP/cell ranging from 13.9 to 367 zeptomoles. In nutrient-depleted conditions, strain IMCC1322 may suffer from excessive protons generated by proteorhodopsin under light conditions. IMCC1322 may tolerate excessive periplasmic protons through ATP-dependent proton pumping and protonation of augmented amino acids. Meanwhile, acid stress could also be mitigated by refining membrane permeability through unsaturation and cyclopropanation of phospholipids. Oceanic bacteria such as IMCC1322 and SAR11 preferred anaplerotic TCA cycles over glycolysis and rely on the Entner-Doudoroff (ED) pathway for growth. Although ATP generation is less efficient in the ED pathway, it offers advantages during rapid growth owing to its strong thermodynamic driving force. The metabolism of IMCC1322 favors gluconeogenesis over glycolysis, aligning with the metabolism of SAR11 reported in previous studies. However, the additional light-driven, PR-dependent ATP synthesis in IMCC1322 is expected to be insufficient to support protein turnover after the log phase, as well as in nutrient-limited conditions. Stable isotope measurements showed no significant differences in the inorganic carbon assimilation between constant light and constant dark cultures in late log phase.11Nsciescopuskc
Characterization and quantification of iron species in the banded iron formations (BIFs) in China Craton to explore the potential for H2 production using XRD and Mössbauer spectroscopy
No full textBanded iron formations (BIFs), significant iron ore deposits formed approximately 2.3 billion years ago under low-oxygen conditions, have recently gained attention as potential geological sources for evaluating hydrogen (H₂) production. BIFs are characterized by high concentrations of iron oxide (20 to 40 wt.%) and low Fe3⁺/Fetot ratios, representing a major source of ferrous iron on Earth. This study investigates the mineralogical and geochemical characteristics of iron ore samples from the Wugang and Hengyang BIFs in China using X-ray diffraction (XRD) and Mössbauer spectroscopy to examine H2 generation potential. XRD analysis and microscopic observations showed that the magnetite and hematite are the primary ore minerals in BIFs in China Craton. Mössbauer spectroscopic results provided the quantified information on the fractions of each iron species in varying minerals. Particularly, the Fe3+ tetrahedral sites and octahedral sites occupied by both Fe2+ and Fe3+ in magnetite and Fe3+ octahedral sites in hematite were determined. We estimated H₂ production potential by calculating the relative fraction of Fe2+ in magnetite relative to total number of iron atoms in the bulk samples from the Mössbauer results. The pyroxene-bearing BIF in Wugang (P-BIF) contains magnetite predominantly (~30.4 wt%), and the fraction of Fe2+ in magnetite is ~26%. Based on the quantified values, the maximum potential for H2 generation from P-BIF in Wugang could be ~630 mmol H₂/kg rock. Due to the variation of mineralogical composition depending on the types and locations of occurrence of BIF, the H2 generation potential also varies. For example, contrast to P-BIF in Wugang, the hematite-rich BIF from Hengyang, containing ~6.0 wt% of magnetite, showed significantly lower Fe2+ fraction in magnetite (~5%), resulting in low H2 potential (~120 mmol H₂/kg rock). This study presents that a prevalence of magnetite in BIFs has considerable potential for H₂ production due to low Fe3+/Fetot, suggesting that the magnetite-rich iron ore can be effectively utilized as the source of stimulated hydrogen production. The current results also highlight that the Mössbauer spectroscopy is essential to provide the database of relative fractions for each iron species in BIFs, which allows us to estimate the quantity of H2 released from BIFs.11Ysciescopu
Bivalves as a Mercury Bioindicator: A National Isotopic Survey along the Coast of South Korea
No full textMercury (Hg) is a contaminant that poses health risks for human populations relying on seafood consumption. To mitigate its impact, identifying and monitoring Hg sources have become priorities, notably under the Minamata Convention. Bivalves are commonly used as sentinels in contaminant biomonitoring but can accumulate Hg from diverse environmental media. To investigate their Hg sources, bivalves (blue mussel, Mytilus edulis, and Pacific oyster, Crassostrea gigas) and their associated sediment were sampled along the coast of South Korea and analyzed for Hg concentration and isotopic values. Oysters displayed low Δ199Hg (0.19 ± 0.19‰) and δ202Hg (−0.35 ± 0.55‰), highlighting a sedimentary source, whereas mussels exhibited higher values (0.72 ± 0.87 and 0.09 ± 0.72‰, respectively) indicating bioaccumulation from the water column. Sulfur, carbon, and nitrogen stable isotopes suggested that such a difference was not due to feeding niches. However, Hg isotopic trajectory analysis showed that environmental conditions controlling the desorption and remobilization of sediment Hg, notably via tidal flows, were likely to drive the observed source(s). While sediment Hg is not systematically reflected in biota, bivalves, which typically display Hg pools accumulated by benthic or pelagic food webs, appear valuable for Minamata Convention biomonitoring, though their fluctuating Hg sources require careful interpretation.11Nsciescopu
Questionnaire improvements in second-generation, multilingual decision support tools for invasion risk screening of non-native taxa
No full textAs a result of the increasing threats posed by non-native species invasions, there has been a rise in the demand for decision support tools that can more efficiently identify those non-native species likely to become invasive. As part of the risk screening (first) step in the environmental risk analysis process, three multilingual decision support tools are currently available for the screening of aquatic and terrestrial organisms: the Aquatic Species Invasiveness Screening Kit (AS-ISK), the Terrestrial Animal Species Invasiveness Screening Kit (TAS-ISK) and the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). Here, we describe the recent improvements to the questionnaire that forms the base of these second- generation Weed Risk Assessment-type tools. We subjected the AS-ISK and TASISK questionnaires to a thorough revision and extended these improvements for the development of the TPS-ISK. Overall, this involved an improvement of the AS-ISK and TAS-ISK questionnaires, an alignment of the questionnaires across the three toolkits, and the translation of the three resulting questionnaires in all 30 nonEnglish languages supported by the toolkits. Given the most extensive usage of the AS-ISK and, in perspective, of the recently released TAS-ISK and TPS-ISK, it is timely to provide researchers and decision-makers in the field of invasion biology with a suite of updated toolkits designed to streamline and improve the risk screening process. These enhancements will be crucial for the delivery of reports to stakeholders and decision-makers also in the languages supported by the toolkits as applicable, and in line with the ecology-of-language paradigm at the base of the toolkits' multilingual interface development.11Ysciescopu
TRIANGULAR ARTIFICIAL REEF THAT PROMOTES GROWTH OF SEAWEED
No full text- 본 발명은 2개의 정삼각형과 세 개의 이등변 삼각형이 결합 된 삼각뿔 형태의 골조와 삼각뿔을 이루는
세 개의 기둥(골조)에 해조류의 착생과 성장이 유리한 구조물(원형, 구형, 사각형 등의 구조물을 베란다형
으로 배체)이 구비되며, 삼각뿔의 세 개의 기둥 하부에는 황동구리 성물을 결착하는 것으로 구성되어 있음
- 몸체부를 이루는 슈퍼콘크리트 블록에는 성게류의 기피물질 또는 해조류 착생 촉진제가 혼합될 수 있
고, 삼각뿔을 이루는 세 개의 기둥 하부에는 성게류의 기피물질 코팅층 또는 황동구리 성물을 결착할 수
있으며, 윙(베란다 형)을 이루는 자연석 성물은 해조류 착생 촉진제와 성게류 기피제를 포함하는 코팅층
을 포함할 수 있음
- 재질 : 슈퍼콘크리트/자연석(돌)/황동구리
- 본 기술은 슈퍼콘크리트 블록과 자연석(돌) 그리고 성게류의 기피물질이 이루는 새로운 성물을 이용한
구조물이 수중에 설치되어 어류, 부착성저서동물 및 패류의 서식처로 이용되며, 구조물의 표면에 각종 해
조류가 착생하여 조식동물(예, 성게류) 섭식압에 대해 안정적으로 성장하게 되는 인공어초에 대한 것임
- 형태적 특성(밑면이 정삼각형인 삼각산형 구조)에 기인하여 수중에 설치 시 물리적 안정성이 우수하고,
재질의 특성(슈퍼콘크리트, 자연석, 황동구리)에 기인하여 내염성과 구조적 안정성이 우수한 친환경 인공
어초