Characterization of Frequency and Aggregation of the Antarctic Krill (<Emphasis Type="Italic">Euphausia superba</Emphasis>) Using Acoustics     

Seok-Gwan?Choi  Eun-A?Yoon  Doo-Hae?An  Sangdeuk?Chung  Jaebong?Lee  Kyounghoon?LeeEmail author 《Ocean Science Journal》2018,53(4):667-677

In this study, the dB difference and characteristics of krill swarms inhabiting Subarea 48.1, which includes the west and south of the South Shetland Island and the Elephant Island peripheries, were estimated to distinguish Antarctic krill, using acoustics. From April 13 to 24, 2016, acoustic data were collected along 24 survey lines using the frequencies 38 and 120 kHz, and middle trawling was performed at 7 stations. Using the difference between the dB values of two volume backscattering strength (Sv) frequencies (38 and 120 kHz), a clear acoustic distinction could be made between Antarctic krill (4.9 to 12.0 dB) and fish (?4.0 to ?0.2 dB). The distributions and mean Sv of krill swarms in the Elephant Island peripheries and south of South Shetland Island were higher than those in the west of South Shetland Island. The mean length/ height ratio of krill swarms in the west of the South Shetland Island (64.5) was higher than that in the south (35.9) and the Elephant Island peripheries (33.8), with the length of the aggregations exceeding their height. Most krill swarms were distributed between the surface layer (less than 10 m below sea level) and within 200 m of water depth. These results are expected to serve as baseline data for evaluating krill density and biomass by distinguishing them from fish, using acoustics.  相似文献   

Submarine groundwater discharge revealed by aerial thermal infrared imagery: a case study on Jeju Island,Korea          下载免费PDF全文

Eunhee Lee  Ki‐mook Kang  Sung Pil Hyun  Kil‐Yong Lee  Heesung Yoon  Seung Hee Kim  Yongcheol Kim  Zhen Xu  Duk‐jin Kim  Dong‐Chan Koh  Kyoochul Ha 《水文研究》2016,30(19):3494-3506

Submarine groundwater discharge (SGD) is a global phenomenon that carries large volumes of groundwater and dissolved chemical species such as nutrient, metals, and organic compounds to coastal zones. We report the influence of SGD on the coastal waters of Jeju Island, Korea, using high‐resolution aerial thermal infrared (TIR) mapping techniques and field investigations. An aircraft‐based system was implemented using a cost‐effective TIR camera for aerial TIR mapping. Ground‐based calibrations and system integration with GPS/IMU (global positioning system/inertial measurement unit) were performed for the aerial systems. The aerial surveys showed distinct low‐temperature signatures of SGD along the coasts of Jeju Island, revealing large groundwater inputs from the coastal aquifers to the ocean. Multiple aerial surveys over a range of seasons and tidal stages revealed that SGD rates dynamically affect the sea surface temperature (SST) of the coastal zone. The in‐situ measurements supported that SGD has a substantial influence on the coastal water chemistry as well as SST. Our observations highlight the extent to which aerial‐based TIR mapping can serve as a powerful tool for studying SGD and other coastal processes. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Factors controlling typhoons and storm rain on the Korean Peninsula during the Little Ice Age   总被引：1，自引：0，他引：1  

Kota Katsuki  Dong-Yoon Yang  Koji Seto  Moriaki Yasuhara  Hiroyuki Takata  Masashi Otsuka  Toshimichi Nakanishi  Yoonyeol Yoon  In-Kwon Um  Richard C. W. Cheung  Boo-Keun Khim  Kaoru Kashima 《Journal of Paleolimnology》2016,55(1):35-48

  相似文献   

Performance of activated carbon-impregnated cellulose filters for indoor VOCs and dust control     

S. Y. Kim  Y. H. Yoon  K. S. Kim 《International Journal of Environmental Science and Technology》2016,13(9):2189-2198

An activated carbon-impregnated cellulose filter was fabricated, and the capacity to remove dust and volatile organic compounds was evaluated in a laboratory. The adsorption capacities for benzene, toluene, ethyl benzene and m-xylene gases were compared by an adsorption isotherm test conducted as a preliminary test, showing that m-xylene and benzene were the most and least favorable for adsorption onto activated carbon, respectively. Cellulose filters were made with four levels of activated carbon contents, and dust removal was performed with all of the filters showing 99 % and higher efficiencies stable with a small variation during the experiment. Activated carbon content of 5 g in the unit filter area (125 g/m²) was found optimum for benzene, toluene, ethylbenzene and m-xylene removal, as it appeared that higher than 5 g activated carbon content was unnecessary for the improvement of its capacity. With increasing benzene, toluene, ethylbenzene and m-xylene loading, the highest removal rates were determined as 0.33–0.37 mg/cm² s for as short as 0.0046 s of air filter residence time. The rapid removal was possible because of the high surface area of the activated carbon-impregnated cellulose filter provided by powdered activated carbon, which is distinguished from the granular form in conventional activated carbon towers. As fixed within a cellulose scaffolding structure, the powdered activated carbon performed excellent benzene, toluene, ethylbenzene, and m-xylene adsorption (98.9–100 %), and at the same time, particular matters were removed in average 99.7 % efficiency after being filtered through the cellulose filter sheet.  相似文献   

Carbon and nitrogen dynamics of the intertidal seagrass, <Emphasis Type="Italic">Zostera japonica</Emphasis>, on the southern coast of the Korean peninsula     

Jong-Hyeob Kim  Seung Hyeon Kim  Young Kyun Kim  Kun-Seop Lee 《Ocean Science Journal》2016,51(4):635-645

Seagrasses require a large amount of nutrient assimilation to support high levels of production, and thus nutrient limitation for growth often occurs in seagrass habitats. Seagrasses can take up nutrients from both the water column and sediments. However, since seagrasses inhabiting in the intertidal zones are exposed to the air during low tide, the intertidal species may exhibit significantly different carbon (C) and nitrogen (N) dynamics compared to the subtidal species. To examine C and N dynamics of the intertidal seagrass, Zostera japonica, C and N content and stable isotope ratios of above- and below-ground tissues were measured monthly at the three intertidal zones in Koje Bay on the southern coast of Korea. The C and N content and stable isotope (δ¹³C and δ¹⁵N) ratios of seagrass tissues exhibited significant seasonal variations. Both leaf and rhizome C content were not significantly correlated with productivity. Leaf δ¹³C values usually exhibited negative correlations with leaf productivity. These results of tissue C content and δ¹³C values suggest that photosynthesis of Z. japonica in the study site was not limited by inorganic C supply, and sufficient inorganic C was provided from the atmosphere. The tissue N content usually exhibited negative correlations with leaf productivity except at the upper intertidal zone, suggesting that Z. japonica growth was probably limited by N availability during high growing season. In the upper intertidal zone, no correlations between leaf productivity and tissue elemental content and stable isotope ratios were observed due to the severely suppressed growth caused by strong desiccation stress.  相似文献   

Vertical distribution of giant jellyfish, <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> using acoustics and optics     

Seonghun Kim  Kyounghoon Lee  Won Duk Yoon  Hyungbeen Lee  Kangseok Hwang 《Ocean Science Journal》2016,51(1):59-65

Nemopilema nomurai jellyfish, which are believed to complete their development in the East China Sea, have started migrating into the Yellow Sea in recent years. We obtained biomass estimates of this species in the Yellow Sea using bottom trawl fishing gear and sighting surveys over a 5-year period. These methods are effective for obtaining N. nomurai jellyfish density estimates and information about the community distribution near the bottom or surface of the sea. To verify the vertical distributions of giant jellyfish between, we used hydroacoustic equipment, including an optical stereo camera system attached to a towed sledge and an echo counting method with scientific echosounder system. Acoustic and optical data were collected while the vessel moved at 3 knots, from which the distribution and density of N. nomurai jellyfish were analyzed. Subsequently, the camera system was towed from a 7 m mean depth to sea level, with the detection range of the acoustic system extending from an 8 m depth to the bottom surface. The optical and acoustic methods indicated the presence of vertical distribution of 0.11³ (inds/m³) and 0.064 (inds/m3), respectively. However, the vertical distribution indicated that around 93% of individuals occurred at a depth range of 10–40 m; thus, a 2.4-fold greater density was estimated by acoustic echo counting compared to the optical method.  相似文献   

Morphology and phylogeny of <Emphasis Type="Italic">Triadinium polyedricum</Emphasis> (Pouchet) Dodge (Dinophyceae) from Korean coastal waters     

Hyeon Ho Shin  Zhun Li  Eun Song Kim  Joo Yeon Youn  Seul Gi Jeon  Seok Jin Oh  Weol-Ae Lim 《Ocean Science Journal》2016,51(4):647-654

  相似文献   

Geotechnical design parameter evaluation using the alluvial plain characteristics in southeastern Iraq     

Jinung Do  Ong Heo  Yeo-Won Yoon  Ilhan Chang 《Arabian Journal of Geosciences》2018,11(20):647

Geotechnical construction is responsible for the overall stability of superstructures, and if there are design errors, the structure will be exposed to potential problems. Geotechnical design starts with the correct interpretation of the target ground. Southeastern Iraq is mainly comprised of an alluvial plain with diverse geological features, and, therefore, geotechnical design requires a detailed interpretation and understanding of the area. This paper reports on laboratory and field tests and in-depth analyses conducted on these alluvial plains. The results reveal that the upper layer of this area is highly over-consolidated. This may have been caused by the removal of overburden pressure as a result of glaciation and desiccation. The highly over-consolidated soils caused considerable sample disturbance by swelling the bored sample; this provided less reliable results. However, the cone penetration test was regarded as the most appropriate field assessment method for deriving sensible geotechnical design parameters. Despite its limitations in clayey soils, the standard penetration test provided results that matched well with previous observations due to the high penetration resistance of the highly over-consolidated ground. Down-hole tests and plate load tests were considered less reliable methods due to their limited applicability in this area. This study considers geographical features, laboratory methods, and empirical correlations from in situ tests, and, therefore, provides a well-summarized guideline to evaluate special geotechnical characteristics of the alluvial plain in southeastern Iraq.  相似文献   

Holocene and Eemian climatic optima in the Korean Peninsula based on textural and carbon isotopic records from the stalagmite of the Daeya Cave,South Korea     

Kyoung-nam Jo  Kyung Sik Woo  Hyoun Soo Lim  Hai Cheng  R. Lawrence Edwards  Yongjin Wang  Xiuyang Jiang  Ryeon Kim  Jae Il Lee  Ho Il Yoon  Kyu-Cheul Yoo 《Quaternary Science Reviews》2011,30(9-10):1218-1231

Textural and stable isotopic records from the absolute-dated stalagmite of the Daeya Cave (DY-1) provide new insights into the climatic evolution of the Korean Peninsula during the Holocene and Eemian climatic optima. The stalagmite yielded ages of 8572 ± 227 to 5907 ± 158 and 1,23,456 ± 535 to 1,19,837 ± 1089 years, which coincide with the Holocene and Eemian climatic optima, respectively. The stalagmite’s δ¹³C record closely resembles previously reported Chinese speleothem δ¹⁸O data. Thus it can be suggested that textural and geochemical results of the DY-1 reflect East Asian monsoon intensity, which is forced by summer insolation patterns in the northern hemisphere. Lighter carbon isotopic compositions, well-developed fibrous calcite crystals, and their relatively faster growth rate in the stalagmite sample are interpreted to reflect the warmest and wettest climate conditions of the Holocene and Eemian interglacials. Both climatic optima took place when insolation was decreasing from its maximum level, temperature in Greenland was highest, and sea level approached its maximum level. These climatic optima also coincide with decreasing Antarctic temperatures. Compared the DY-1 data to other proxies, it is suggested that the Holocene and Eemian climatic optima developed through a balance among boreal insolation, monsoon intensity, and sea level (also continental ice volume), which are the main climatic forcing factors in the northern hemisphere. These trends also follow the bi-polar seesaw mechanism as previously described.  相似文献   

Plutonic inclusions and olivines in high-K volcanics from Ulreung island,Korea     

Yoon Kyu Kim  Hirokazu Fujimaki 《Mineralogy and Petrology》1987,37(2):117-136

Summary Major and trace element data are presented for four alkali gabbroic inclusions, two monzonitic inclusions, and nine syenitic inclusions from Ulreung island, Korea. Analytical results are also given for the mineral constituents. Although the major element chemistry suggests that the plutonic inclusions are comagmatic with the associated volcanic rocks, the trace element data demonstrate that they do not represent a simple liquid line of descent. In addition, the mineralogical data indicate that they are not likely to represent cumulates on the floor of the magma chamber from which the observed volcanic rocks have been derived. Titanbiotite crystallization preceded kaersutite crystallization in the plutonic rocks but that order was inverse in the volcanic rocks. The trachytic-phonolitic rocks contain Fe-rich olivine phenocrysts, whereas the plutonic inclusions do not. These discrepancies can be accounted for by the assumption that the investigated plutonic rocks represent some cumulus parts of intrusive bodies solidified at shallower depth than the magma reservoir beneath the island. Petrographic features of the gabbroic inclusions are suggestive that olivine was probably in a reaction relationship with liquid to form titanbiotite. Comparison with petrological data of the volcanic rocks also implies that olivine was in a reaction relationship with an intermediate alkalic magma in both the intruded magmas at shallow depth and in the magma chamber at great depth. This is the cause of the olivine compositional gap in the high-K volcanic suite. Titanbiotite is a major reaction product.

---

Plutonische Einschlüsse und Olivine in Kalium-reichen Vulkaniten von Ulreung Island, Korea

Zusammenfassung Haupt- und Spurenelementdaten von vier alkalischen gabbroiden, zwei monzonitische Haupt- und Spurenelementdaten von vier alkalischen gabbroiden, zwei monzonitische und neun syenitischen Einschlüssen von Ulreung Island, Korea, sowie analytische Daten der Mineralkomponenten werden vorgelegt. Obwohl der Hauptelementchemismus andeutet, daß die plutonischen Intrusionen und die vergesellschafteten vulkanischen Gesteine comagmatisch sind, zeigen die Spurenelementdaten, daß diese nicht eine einfache Magmenlinie darstellen. Außerdem zeigen die mineralogischen Daten an, daß die Gesteine wahrscheinlich keine Kumulate vom Boden der Magmenkammer sind, von welcher die beobachteten vulkanischen Gesteine herstammen. In den plutonischen Gesteinen kristallisierte Titan-Biotit früher als der Kaersutit. In den vulkanischen Gesteinen ist diese Reihenfolge jedoch umgekehrt. Die trachitischen/phonolitischen Gesteine enthalten im Gegensatz zu den plutonischen Einschlüssen Fe-reiche Olivin-Phenokrysten. Diese Unterschiede können durch die Annahme erklärt werden, daß die untersuchten plutonischen Gesteine bestimmte Kumulate eines intrusiven Körpers sind, der in geringerer Tiefe als das Magmenreservoir unterhalb der Inseln erstarrte. Petrographische Kennzeichen von gabbroischen Einschlüssen deuten darauf hin, daß der Olivin wahrscheinlich mit der Schmelze reagiert hat und Titan-Biotit bildete. Ein Vergleich der petrographischen Daten der vulkanischen Gesteine Vergleich der petrographischen Daten der vulkanischen Gesteine läßt ebenfalls den Schluß zu, daß Olivin mit einem intermediären alkalischen Magma in beiden, dem intrudierten Magma in geringer Tiefe und der Magmakammer in großer Tiefe, reagierte. Dies ist der Grund für die Lücke in der Olivinzusammensetzung in der Kalium-reichen vulkanischen Suite. Titan-Biotit ist ein Hauptreaktionsprodukt.

---

---

With 9 Figures  相似文献