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Effect of diet changes in benthic ecosystems owing to climate change on the physiological responses of Turbo sazae in waters around Jeju Island, Korea
No full textThe benthic ecosystem in temperate regions is becoming barren owing to the replacement of macroalgae by calcareous algae as a result of climate change-induced increases in water temperature. The aim of this study was to observe how the top shell, Turbo sazae, an invertebrate that feeds on macroalgae, adapts to a benthic environment with a reduced macroalgae population owing to replacement by calcareous algae. Using tank experiments, the top shells were cultured for 18 weeks. Within this period, they were fed a diet comprising either Eclonia cava or Corallina officinalis. Thereafter, hemocyte response, reproductive development, and the levels of biochemical compounds in the individuals under investigation were analyzed. The results obtained showed no significant differences in immunological responses, gonad development, and general body weight between the two feeding groups. However, amino acid profiling showed a decreasing trend in amino acid contents in both feeding groups, but no significant differences were observed with respect to overall protein content. These findings indirectly suggested that even in a macroalgae-depleted environment, the top shells can survive by consuming crustose calcareous algae, but with the change in diet affecting the levels of some amino acids in their bodies. Therefore, this study provides valuable insights into the adaptability of the top shells inhabiting the waters around Jeju Island to changes in their feeding environment and may also serve as basis for enhancing resource management strategies in response to climate change-induced changes in the benthic ecosystem.11Nsciescopu
Community-based fishing ground artificial reef block
No full text- 마을어장의 해조류를 안정적으로 증식시키고자 콘크리트어초를 주로사용 하는데 효과가 없는 이유는, 콘
크리트구조물내의 시멘트 성분이 Ph12의 강한 알카리 성분으로 인하여 해조류의 포자가 안정적으로 착생하
지 못하므로 실패의 원인으로 지목 된다, 이를 해결하고자 상부에 자연석 잔자갈 또는 대리석을 배치함으
로서 문제점을 해결하는 것이 핵심기술임,
-또한 증식어초블럭의 빈 공간 및 홈통을 최대한 많이 배치하므로서 저서생물의 산란장, 은신처, 어류자치
어의 보육 및 성육장으로 기능을 부여하는 기술이 특허 및 디자인기술에 해당하며 무게의 경량화와 경제성
을 확보하는데 특징이 있다.
- 증식어초 블록은 취급의 용이성 및 안정성 배치기술의 경제성 확보를 위하여 개별 또는 연결 모듈식 조
립으로 공간이용에 대한 효과를 최대한 확보하였
Multi-sequential order transgressive cycles from the last interglacial to the Holocene revealed by deep-core sediment facies analysis in the Baeksu tidal deposits, south-west coast of Korea
No full textHigh-resolution sequence analysis of three drill-cores with well-constrained optically simulated luminescence ages reveals a stratigraphic evolution of the Baeksu tidal flat (south-west coast of Korea) that documents the development of tide-dominated estuary infill interacting with minimal fluvial processes since marine isotope stage 6. The stratigraphic architecture and its correlation along an upper mudflat-to-subtidal transect showcase two different hierarchies of sequences and small-scale (fifth-order) subsequences that are nested within larger-scale (fourth-order) sequences. Two fourth-order sequences with a frequency of 100 kyr consist of lower fluvial deposits and overlying tidal deposits, respectively, reflecting a twofold regressive–transgressive sedimentary sequence related to glacial–interglacial cycles. The sequence boundary is marked by an abrupt facies change from oxidised spit gravels (marine isotope stage 3) to tidal muds (marine isotope stage 1). An interesting feature is the presence of two packages of retrograding spit/tidal deposits corresponding to marine isotope stage 5a/b and marine isotope stage 3 interstadials deposited during short-lived sea-level rise, in spite of the long-term phase of glacial sea-level fall spanning from marine isotope stage 5d to marine isotope stage 2. Identification of deeply oxidised tidal deposits dated to marine isotope stage 5a/b confirms that two short-term fluctuations in sea level occurred during the long-lived glacial period. Such nested successions are assigned as fifth-order subsequences with 40 kyr time intervals. The late Quaternary Baeksu tidal flat succession was thus mainly controlled by two different frequencies and magnitudes of sea-level changes, associated with major interglacials (marine isotope stage 5e and 1) and minor interstadials (marine isotope stage 5a and 3). More importantly, transgressive episodes are significantly better preserved than regressive phases. This study provides a good example of how multi-order, multiple transgressive deposition may be preserved in a tide-dominated estuarine setting, particularly where river inputs are negligible.11Ysciescopu
Algorithm for Shoreline Position Determination in a Dynamic Coastal Environment Using Images Obtained from a Video Monitoring System
No full textVideo systems are extensively utilized globally in coastal monitoring strategies, facilitating high temporal and spatial sampling frequencies with reduced logistical efforts. This paper presents a novel and simple tool for processing coastal images, designed for automatic shoreline detection and data analysis using MATLAB. The algorithm is based on applying the region-grow function to pre-selected points and extracting the border between these points which corresponds to the sea/land boundary from averaged images produced from a Video Monitoring System. The study was conducted at Hellshire Bay Beach on the southern coast of Jamaica. The variance/error of the shoreline position produced by the algorithm when compared to a manually delineated shoreline is on average -1.09 and +1.11 pixels, which is comparable to other studies. The data from a single day within the period between September, 2022 and February, 2023 illustrate that the Hellshire beach is highly dynamic, with both erosion and accretion occurring in distinct sections of the beach, corroborating findings from other studies in the area. This further validates the accuracy of both the images generated by the video monitoring system and the algorithm developed to delineate shoreline positions from these images.11Nsci
Study on the Wake Characterization of a Horizontal-Axis Tidal Stream Turbine Utilizing a PIV System in a Large Circulating Water Tunnel
No full textIn this study, a particle image velocimetry (PIV) system was used in a large circulating water tank to investigate the wake of a horizontal-axis tidal turbine model, focusing on minor blockage effects and scale influence. A wake map of the turbine was constructed based on PIV measurements, using velocity deficit, turbulence intensity (TI), and turbulence kinetic energy (TKE) as key indicators. The results showed that TKE developed later than TI, forming a plateau-like shape. This plateau was considered the decay region, with the transition and far-wake regions located before and after it, respectively. Additionally, the power law exponent of TI decreased from −0.731 in the decay region to −0.765 in the far wake, indicating a steeper decay further downstream. Overall, the wake map of the tidal stream turbine model exhibited similarities to that of a previously reported wind turbine model.11Nsciescopu
Insights into the Genetic Connectivity and Climate-Driven Northward Range Expansion of Turbo sazae (Gastropoda: Turbinidae) Along the Eastern Coast of Korea
No full textTurbo sazae, a commercially and ecologically significant marine gastropod traditionally found in Jeju Island and the southern coast of Korea, is experiencing a reported northward expansion into the East Sea, likely influenced by rising seawater temperatures. This study provides preliminary genetic insights into the genetic structure and connectivity of T. sazae populations between Jeju and the East Sea using mitochondrial COI sequences. Samples from 6 geographically distinct locations were analyzed, with three cloned replicates generated to enhance sequence reliability. Genetic diversity, haplotype distribution, and population differentiation were then assessed. Our analysis reveals potential genetic connectivity between Jeju and East Sea populations, possibly driven by larval dispersal via the Kuroshio and Tsushima Currents, highlighted by the predominance of shared haplotype EJ1 (60.0% in Jeju, 50.0% in East Sea). Bayesian phylogenetic analysis estimated the time to the most recent common ancestor (MRCA) between Jeju and East Sea populations at approximately 9.7 to 23.3 million years ago, indicating ancient divergence rather than very recent separation. Pairwise FST values and AMOVA results showed generally low levels of genetic differentiation. Given the small sample sizes and use of a single mitochondrial marker, these findings should be interpreted cautiously as preliminary evidence. Nevertheless, this study highlights the need for continued genetic monitoring of T. sazae populations under climate-driven range shifts and provides a foundation for future research incorporating broader genomic approaches.11Nsciescopu
Organotropism of metals and Znsingle bondCu isotope ratios in hydrothermal vent mussels (Bathymodiolus) and sea snails (Ifremeria and Alviniconcha): Implications for bioaccumulation mechanisms
No full textThis study investigated metal organotropism and Znsingle bondCu isotopic compositions in hydrothermal vent mussels (Bathymodiolus sp.) and sea snails (Ifremeria sp. and Alviniconcha sp.). In mussels, bioaccumulation of Al, V, Cr, Mn, Fe, Co, Ni and Zn occurred mainly in the byssus and digestive gland, whereas Cu, As, Ag, Cd, and Pb were found in the gills, suggesting that bioaccumulation of these metals occurs via the respiratory system. In sea snails, the digestive glands tended to have higher metal concentrations than other organs. Zn showed higher intratissue isotope variability than Cu. For Cu isotopes, the digestive glands of vent mollusks had the highest δ65Cu values. However, while Zn concentrations were consistently elevated in the digestive glands, δ66Zn values did not exhibit a corresponding trend. In vent mussels, during sequenced transport or metal partitioning processes after accumulation via the gills and digestive glands, Zn and Cu concentrations decreased with isotopic fractionation, indicating that lighter isotopes are preferentially used. Both sea snail species differed from mussels in that they preferentially accumulated lighter Zn isotopes in the digestive glands with higher Zn content. The metal and isotopic signatures accumulated in the internal organs of hydrothermal vent mollusks suggest species-dependent dietary strategies and mechanisms of uptake, accumulation, and detoxification. Our findings related to the organotropism of Zn and Cu isotopes offer new insights into the bioavailability and bioaccumulation processes of hydrothermal vent mollusks.33Nscopu
Long-Term Observations from Ieodo Ocean Research Station (I-ORS) for Monitoring Climate Change in the East China Sea
No full textThe East China Sea is a climate-sensitive hotspot where rapid changes in oceanic and ecological conditions have been observed in recent years. Long-term and systematic observational data are essential for accurately assessing these changes. The Ieodo Ocean Research Station (I-ORS), established in June 2003, has been monitoring various oceanic and atmospheric variables in real time. As the first OceanSITES-registered continental shelf observation platform, I-ORS has accumulated valuable data over the past two decades. This long-term dataset is critical for understanding the impacts of large-scale climate change on coastal and shelf regions, revealing significant signals of climate variability in the East China Sea. Notably, I-ORS observations show a significant rise in sea surface temperature, increasing by 0.6°C per decade since 2004—approximately two times faster than the global average rate of 0.3°C. This rapid warming trend underscores the East China Sea's increased vulnerability to climate change, with I-ORS data providing key insights for predicting future changes and mitigating marine disasters.1
산내 Ni-Cu 황화물 광상의 황화광물 분화 과정 연구
No full text전라북도 남원시 산내면에 위치한 산내 Ni-Cu 황화물 광상은 영남육괴의 선캠브리아기 화강암질 편마암을 관입한 휘록암 내에 발달한다. 휘록암은 북서-남동 방향의 계곡을 따라 기울어진 T자 모양으로 대략 300 m 연장과 20―30 m 폭으로 노출된다. 휘록암과 화강암질 편마암의 동측 접촉부는 주로 수직 경계를 보이며, 두 암석의 접촉부를 따라 휘록암 내로 폭 2 m 이하의 세립질 냉각연변이 발달하고 화강암질 편마암 내로 수 cm 규모의 반응연이 발달한다. 화강암질 편마암은 주로 석영, 장석, 운모로 구성되고 10 cm 내외의 장석 반상조직이 관찰되고 휘록암과의 접촉부에서 소량의 자류철석과 황동석이 산점상으로 산출된다. 휘록암의 최외곽부에 발달한 냉각연변은 상대적으로 세립의 투휘석, 각섬석, 금운모가 발달한다. 반면, 휘록암의 중심부는 조립·등립의 투휘석과 감람석이 우세하게 산출되며, 일부 각섬석 및 금운모는 사문석 및 녹니석으로 각각 교대되었고 감람석의 사문석화 작용은 세립의 자철석을 발달시켰다. 연구지역의 Ni-Cu 황화물 광체는 주로 화강암질 편마암과 접촉한 휘록암 내에 발달하며, 북측에서 약 100 m 그리고 남측에서 수 m의 연장된 노두가 확인된다. Ni-Cu 황화광물은 최외곽부 냉각연변에서 세립으로 산점상 또는 망상으로 발달하고 중심부는 주로 산점상으로 발달하며, 중심부로 갈수록 Ni-Cu 황화광물의 산출은 감소한다. 휘록암의 휘석과 감람석을 교대한 각섬석, 휘석, 금운모, 방해석은 주로 불혼화 황화광물 블렙(bleb) 주변에 산출된다. 황화광물 블렙은 수 mm에서 수 cm 크기로 다양하게 발달하며, 자류철석, 황동석, 펜틀란다이트로 구성된다. 펜틀란다이트와 황동석은 주로 자류철석 결정 연변부에 산출하며, 일부 자류철석에서 펜틀란다이트가 불꽃 형태(flame)의 용리 조직이 관찰된다. 황화광물 블렙은 자류철석-펜틀란다이트-황동석, 자류철석-황동석, 자류철석-펜틀란다이트의 조합을 보인다. 바이올라라이트(violalite)는 일부 펜틀란다이트 결정의 연변부에서 교대하여 발달한다. 황화광물 블렙의 백금족 원소 분석결과, 루테늄(Ru), 로듐(Rh), 오스뮴(Os), 이리듐(Ir), 백금(Pt)은 펜틀란다이트, 황동석, 자류철석 모두 검출 한계 이하로 확인된다. 팔라듐(Pd)은 자류철석에서 검출한계 이하로 확인되며, 황동석은 대부분 3 ppm 이하의 함량을 보이고 최대 9 ppm 까지 분석되었다. 펜틀란다이트의 팔라듐은 대부분 0~10 ppm 범위이며, 최대 34 ppm 까지 확인된다. 산내 Ni-Cu 황화물 광상은 마그마의 결정화 및 분화과정에서 농집된 황화물 용융체가 Ni-Cu 광체를 형성하였으며, 백금족 원소들은 황화물 용융체의 결정화 과정에서 일부 펜틀란다이트 내에 함유되었지만, 대부분 외부로 유출된 것으로 판단된다.2
안정동위원소 비 기반 황해와 동해 주요 자치어의 에너지원 및 영양단계 평가
No full text어류의 초기 생활사에 해당하는 자치어 시기는 사망률이 높은 것으로 알려져 있어 이들의 생존 및 성장에 영향을 미치는 요인들에 대한 관심도가 매우 높다. 특히 외부 섭식이 제대로 이루어지지 않게 되면 성어로 가입되는 양에 직접적으로 영향을 미치기 때문에 자치어 시기에 어떠한 먹이로부터 에너지를 공급받고 있는지 이해하는 것은 매우 중요하다. 그러나 현장 채집과 종 동정 등의 어려움으로 이들의 먹이원에 대한 충분한 이해는 부족한 실정이다. 본 연구는 안정동위원소를 활용하여 황해와 동해에 서식하는 주요 자치어의 에너지원 및 먹이망 내 영양단계를 파악하고자 하였으며, 이를 위해 2021년 10월(황해), 2023년 10월(황해, 동해), 2024년 3월(동해)에서 자치어 및 동물플랑크톤, 크기를 구분한 입자유기물, 퇴적물 시료를 채집하여 이들의 탄소 및 질소 안정동위원소 비를 분석하였다. 그 결과, 두 해역에 서식하는 주요 자치어의 경우 전반적으로 Calanus sinicus를 포함한 동물플랑크톤 성체의 탄소 및 질소 안정동위원소 비와 가까운 값을 나타내었으며 이는 이들의 먹이원 및 영양단계가 비교적 유사함을 의미한다. 또한 일부 계절에 크기를 구분한 입자유기물의 질소 안정동위원소 비가 가벼운 값을 보였는데, 동일 시기에 채집된 동물플랑크톤과 자치어의 질소 안정동위원소 비 역시 가벼워지는 경향을 보였다. 이러한 결과는 황해와 동해에 서식하는 자치어가 동물플랑크톤의 성체와 유사한 먹이원을 이용하며 이들의 영양단계도 큰 차이가 없음을 시사한다.2