Marine Benthic Algal Community at Dadohaehaesang National Park, South-west Coast of Korea

This paper investigates the response characteristics of a stow net under wave and current excitations, as well as the feasibility of its monitoring system to check net functionality and prevent loss of fishing gears. The stow-net model is based on one of existing types used in southwest coast of South Korea. The measured wave and current data there are acquired and inputted as environmental loads for numerical simulations. The Morison equation for a moving object with equivalent net model is utilized as the external-force estimator, which has been validated by many researchers regarding fish-cage studies. Since the modelling of all the net elements is inefficient in terms of computational time in time-domain simulations, cruder equivalent-drag net elements are devised with equivalent wet mass, projected area, and axial stiffness. The performance of stow net is highly influenced by current velocity. Stow nets submerge more in stronger currents, which results in less wave forces. The proposed monitoring system can provide useful information, such as net functionality and loss of stow net, using the minimum number of monitoring sensors.

Dynamic-analysis results of a 300-m-long bottom-set gillnet are presented under wave excitations and current. A bottom-set-gillnet design is based on one of existing types utilized in South Korea. Environmental conditions are chosen based on measured wave and current data obtained from the southwest coast of South Korea. The cruder equivalent net model is designed by matching projected drag area and wet weight to save computational time in time-domain simulations. The Morison-force model is utilized to calculate hydrodynamic forces acting on the entire gillnet. Stretching performance of the modelled gillnet is good even at low current velocity. Motions induced by wave excitations are small in operational conditions at given submergence depth, whereas significant variations occur for the fishery-prohibition condition.

We obtained a 15 m drill core from Deukryang Bay on the southwest coast of Korea, which is now an area of reclaimed land used for agriculture. We investigated changes in the depositional environment and hydrological climate responses to sea level changes using sedimentary facies, radiocarbon ages, grain-size analysis, total organic carbon (TOC), total sulfur (TS), and stable carbon isotopes (δ13C). Sediment deposition began at 12,000 cal yr BP and was divided into four stages based on changes from fluvial to intertidal environments related to Holocene marine transgression events. Stage 1 (>10,000 cal yr BP) is represented by fluvial sediments; Stage 2 (10,000–7080 cal yr BP) is represented by the deposition of mud facies in an intertidal zone in response to sea level rise; Stage 3 (7080–3300 cal yr BP) was a period of gradually descending sea level following the Holocene maximum sea level and is characterized by gradual changes in TOC, TS, and C/S ratios compared with the mud facies of Stage 2. Stage 4 (3300 to present) was deposited in a supratidal zone and contains low TS and an abundance of TOC. Based on our TS and C/S ratio results, the south coast of Korea was mainly affected by sea level rise between 7000 and 3000 cal yr BP, during the middle Holocene. At 3000 cal yr BP, sea level began to stabilize or gradually decrease. In addition, changes in δ13C values are clearly observed since ca. 5000 cal yr BP, in particular, large hydrological changes via freshwater input are confirmed in 4000–3000 cal yr BP. We consider these shifts in freshwater input indicators of an increased influence of El Niño and La Niña conditions, related to the weakening of the East Asian Summer Monsoon (EASM) and changes in sea surface temperature (SST) of the Western Pacific Ocean during the middle Holocene climatic optimum (between 7800 and 5000 cal yr BP). The cooling periods of SST in East Asia between 8400 and 6600 cal yr BP reported from the west coast of Korea are related closely to changes in vegetation (as evidenced by δ13C) from 7700 cal yrs BP to the present in the southwest coast of Korea. We interpret the freshwater input events at 4000–3000 cal yr BP to be related to changes in SST in response to the weakening of the EASM on the southwest coast of Korea. However, additional research is needed to study the southward migration effect of the westerly jet related to SST and atmospheric circulation controlling terrestrial climate in the middle Holocene.

Generated power by 5 MW wind turbine was predicted by using measured wind data at weather station called Herald of Meteorological and Oceanographic Special Unit-1 (HeMOSU-1) which is installed at south west coast of Korea. Transient time history of turbulent wind was generated from 10-min mean wind speed stored at HeMOSU-1 and then it was used in estimation of electric power by Bladed. Those estimated powers were used in both polynomial regression and neural network based power estimation. They were compared with each other for daily power and yearly power. Effect of mean wind speed and turbulence intensity was quantitatively analyzed and discussed. This technique further can be used to assess lifetime power of wind turbine.

Discovery of Eemian marine deposits along the Baeksu tidal shore, southwest coast of Korea

Offshore wind power plants are under construction worldwide, and concerns about the adverse effects of underwater noise generated during their construction on the marine environment are increasing. As part of an environmental impact assessment, underwater noise generated by impact pile driving was measured during the construction of an offshore wind farm off the southwest coast of Korea. The sound exposure levels of impact pile driving noise were estimated as a function of distance and compared with those predicted by a damped cylindrical spreading model and broadband parabolic equation simulation. Source level at 1 m was estimated to be in a range of 183–184 dB re 1μPa2s in the sound exposure level based on the model predictions and it tended to decrease by 21log⁡r as the distance increased. Finally, the spatial distribution of impact pile driving noise was predicted. This result, if combined with noise-induced damage thresholds for marine life, may be used to assess the effects of wind farm construction on marine ecosystems.

As interest in the development of renewable energy increases, a large number of offshore wind farms are being built worldwide. Accordingly, the potential impacts of underwater operational noise on marine ecosystems have become an issue, and thus it is necessary to understand the mechanisms and acoustic characteristics of underwater operational noise for the environmental impact assessment. For this paper, underwater noise was measured for about 10 days near a 3-MW wind turbine off the southwest coast of Korea, and the acoustic characteristics of the operational noise and its relationship with rotor speed were investigated. The tonal frequencies of the underwater operational noise varied with rotor speed, and particularly the peak level at a frequency of ~198 Hz increased by ~20 dB or more at the rated rotor speed. Additional experiments were conducted to determine the relationship between underwater noise and wind turbine tower vibration, and finally, the underwater noise correlated highly with the tower vibration acceleration signal, wind speed, and rotor speed, with correlation coefficients of 0.95 or higher.

La estructura de la comunidad de macroinvertebrados bentonicos esta directamente relacionada con factores ambientales tales como las caracteristicas del agua, la disponibilidad de habitats y la diversidad de sustratos. El objetivo de este estudio fue caracterizar la comunidad de macroinvertebrados bentonicos y comparar los atributos de esta comunidad en los arroyos internos (zona preservada) y externos (zona alterada) del Parque Nacional Iguazu, al oeste de Parana, Brasil, en dos periodos estacionales (seco y humedo). Se tomaron tres repeticiones por sitio, con colector Surber, en cuatro microhabitats (hojas en remanso, hojas en la corriente, sedimentos en remanso y sedimentos en la corriente). Se encontro una discriminacion significativa en la composicion de la fauna bentonica entre las areas de estudio (Wilks=0.091; F272,746=2.249, P<0.0001). Las taxa Corbiculidae, Hyalellidae y Trichodactylidae caracterizaron al arroyo Macuco; Talitridae, Libellulidae y Naucoridae caracterizaron a los arroyos Poco Preto y Dourado; Oligoneuridae, Leptoceridae y Hydropsychidae caracterizaron al arroyo Apepu, y Tubificidae, Corduliidae y Elmidae caracterizaron al arroyo Tamandua. Se observaron diferencias significativas (P<0.05) en la densidad media y la riqueza, y entre los arroyos de las dos regiones (externas e internas). La mayor riqueza se registro en la zona preservada y en microhabitats de hojas en remanso. El analisis RDA separo los arroyos preservados e impactados y los organismos, de acuerdo con las variables ambientales. Las diferencias estuvieron relacionadas con las condiciones de conservacion del bosque ripario, cuya presencia en los arroyos conservados proporciono una mayor diversidad de habitats; esto contribuyo al patron de distribucion de los organismos sobre el sustrato. Por otro lado, se puede citar una cantidad de impactos atribuidos a los contaminantes agroquimicos, al suelo alterado y a la degradacion de la vegetacion riberena como factores que contribuyeron a las diferencias entre los arroyos analizados.

In recent years, extensive populations of burrowing mud shrimp have suddenly invaded the tidal flats in South Korea where clams, Ruditapes philippinarum, are harvested. These shrimp pose a serious threat to the clam industry along the west coast of South Korea. While conducting a mud shrimp monitoring program, we collected six female/male pairs of a pseudionine bopyrid isopod, Orthione griffenisMarkham, 2004, which in North America has been considered an introduced species from Asia that threatens northeastern Pacific estuarine ecosystems. We report the occurrence of this isopod as an inhabitant of the branchial chambers of the host shrimp, Upogebia major(de Haan, 1841), a very common species along the South Korean west coast, along with a morphological description and phylogenetic analysis based on COI barcodes. DNA analysis supported strongly that South Korean Orthioneis the same species of western Pacific (USA), O. griffenis. Two regionally disjunct isopods showed very low (0.8%) genetic variation in the mitochondrial COI (cytochrome oxidase subunit I) sequences. The implications of the occurrence of this species with respect to marine bioinvasion are also discussed.

The role of nitrogen in mediating algal-microbial interactions in a rocky intertidal ecosystem

Coral reef mesopredator trophodynamics in response to reef condition

Wind power generation of 5 MW wind turbine was predicted by using wind measurement data from HeMOSU-1 which is at south west coast of Korea. Time histories of turbulent wind was generated from 10-min mean wind speed and then they were used as input to Bladed to estimated electric power. Those estimated powers are used in both polynominal regression and neural network training. They were compared with each other for daily production and yearly production. Effect of mean wind speed and turbulence intensity were quantitatively analyzed and discussed. This technique further can be used to assess lifetime power of wind turbine.

Principal Component Analysis on eight community metrics of benthic macroinvertebrate data collected from 47 sites in the Tongariro National Park, New Zealand, Feb-April 2007

Se analizó la comunidad bentónica asociada a TIJOlassia testudinum y su relación con algunos parámetros bióticos y abióticos, en tres localidades del Parque Nacional MOlTocoy, Falcón-Venezuela; éstas fueron seleccionadas de acuerdo al grado de exposición al mar abierto: A(protegída), B (intermedia) y C (expuesta). En cada localidad se demarcó un área de 20 x 20m, se muestrearon aleatoriamente 10cuadrantesfmes, (130 cuadrantesflocalidad). Se efectuaron registros de oxígeno disuelto, salinidad, temperatura, porcentajes de materia orgánica, carbono y nitrógeno, textura del sedimento, biomasa foJiar y de rizoma de T. testudinum. Todos los parámetros analizados presentaron un gradiente escalonado. Materia Orgánica, Carbono y Nitrógeno, Oxígeno disuelto, Salinidad y Temperatura presentaron el gradiente: A&gt;B&gt;C, Los porcentages de Arena, Limo y Arcilla presentaron un gradiente inverso. El patrón en la Diversidad, Equidad y Dominancia fue: B&gt;C&gt;A. La fauna colectada estuvo compuesta por los grupos: Coelenterata (Anthozoa), Polichaeta, Sipuncula, Mnlusca, Crustacea y Echinodermata. Se identificaron 15 especies de moluscos (gastrópodos y bivalvos), (3 % de los invertebrados colectados).

Tourism industry has widened its scope from traditional tourism to a more sustainable one in the recent decades. Sustainable tourism, ecotourism or green tourism has been the latest jargon used by the industry to attract tourists to be more sustainable and enjoy their holiday in nature. If sustainable development refers to meeting the needs of the present without compromising the ability of future generations to meet their own needs, sustainable tourism would denote tourism which respect and conserve as well as not to harm biodiversity and socio-cultural balance. The greatest task to conserve the remaining biodiversity however may come down to some developing countries. They are now confronted with the real challenges to create sustainable community while coping with their rapid economic growth. Malaysia for instance has gazetted several national parks but those areas are exposed to illegal loggings and deforestation which will have great impact on its biodiversity. The remaining forests in Malaysia should be considered as a protected area as it plays a vital role in achieving specific conservation objectives. They are the sources of water supply, forest produce for human and animals as well as for recreational purposes and sustainable tourism activities. For that matter, under the National Physical Plan (NPP) of 2006, the protected areas shall include all gazetted national and state parks, wildlife reserve or sanctuaries, marine parks, protected forests and other areas designated for statutory protection. It is the intention of this paper to highlight the legislations designed for conservation, management and planning of Taman Negara, the premier national park of Malaysia. The study concludes that the management and planning activities in the national park must be integrated through effective legal framework in order to ensure a proper and systematic usage of the biodiversity and for more successful sustainable tourism activities.