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Gijang gun, South Korea

Kim K.-S.,Pukyong National University | Shim J.H.,Marine Environment Research Division | Kim S.,Pukyong National University
Ocean Science Journal | Year: 2015

It widely thought that ocean acidification processes that caused by atmospheric CO2 increase and accordingly lower seawater pH conditions might cause serious harm to marine food webs in certain ecosystems in the near future. Little is known about how marine fishes respond to reduced pH conditions. We investigated the effects of CO2 conditions on the growth of olive flounder (Paralichthys olivaceus) larvae. Newly hatched larvae were reared at three different levels of pCO2 (574, 988 and 1297 µatm) in temperature-controlled (21 ± 0.5°C) water tanks for four weeks until metamorphosis. The experiment was repeated three times in May, June, and July 2011, and body lengths and weights were measured at the completion of each experiment. The results indicated that the body length and weight of flounder larvae significantly increased with increasing CO2 concentrations (P < 0.05). A higher daily growth rate during the early larval stage (hatching to 14 days) was found among the larvae reared in low pCO2 conditions, while a significantly lower growth rate was found among larvae in higher pCO2 water conditions. On the other hand, in the late larval stage (18 days after hatching to metamorphosis), the daily growth rate of larvae was much higher in high CO2 water. Bone density of larvae, however, decreased with increasing CO2 concentration in the water © 2015, Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source


Park J.-I.,Marine Eco Technology Institute | Son M.H.,Marine Eco Technology Institute | Kim J.B.,Marine Environment Research Division | Lee K.-S.,Pusan National University
Ocean Science Journal | Year: 2014

Phyllospadix japonicus is an abundant surfgrass that thrives mainly along the exposed rocky shores of Northeastern Asia. On the eastern coast of Korea, surfgrass populations have been adversely affected by increasing human pressures. We developed a seeding method using an artificial reef for the restoration of P. japonicus. In January 2005, we planted P. japonicus seeds on the lower part of coarse hemp-plant brush that was embedded densely on the concave surface on the top of artificial reefs. The reefs were then installed on an exposed rocky shore. To evaluate the feasibility of this seed-based surfgrass restoration technique, we monitored the seedling/shoot density and morphological characteristics of the shoots over a 2-year period. Seedlings began to emerge within the first month after seeding, reaching densities of up to 275.0 shoots m-2 by April 2005. After an initial decline, shoot density increased through the production of lateral shoots, and densities of up to 997.1 shoots m-2 were observed by the end of the experiment. Shoot height, the number of leaves, and leaf width rapidly increased during the first year after seeding, whereas the number of rhizome internodes and rhizome length rapidly increased during the second year. The P. japonicus shoots exhibited approximately 63.4 mm of rhizome elongation during the study period. Because seeded P. japonicus on the artificial reefs were successfully established at the study site, this seeding method using an artificial reef may offer an effective approach to restoring surfgrass habitat. © 2014, Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source


Lee S.H.,Pusan National University | Joo H.T.,Pusan National University | Lee J.H.,Pusan National University | Kang J.J.,Pusan National University | And 3 more authors.
Ocean Science Journal | Year: 2015

A short (4–5 hour) incubation method for a 13C-15N dual isotope tracer technique has been widely applied for the measurements of daily primary and new productions of phytoplankton. However, there has been no research conducted to determine if there are any differences in the estimated daily productions between short incubation periods and 24 hour incubations. Based on hourly uptake rates estimated from a 4 hour incubation at a coastal site in the East/Japan Sea, the daily carbon and nitrogen uptake rates of total phytoplankton were approximately 60% overestimated compared to those derived from a 24 hour incubation. Especially for large phytoplankton, the daily carbon uptake rates based on the 4 hour incubation were greatly overestimated (> 200%). In contrast, the daily rates of small phytoplankton were not significantly different between the two different incubations. This is mainly because the daily carbon and nitrogen uptake rates of large phytoplankton were significantly correlated with light intensity. Consequently, the contributions of small phytoplankton were underestimated whereas large phytoplankton contributions were overestimated in daily carbon and nitrogen uptake rates based on a 4 hour incubation. Further investigations into these potential overestimations in daily carbon and nitrogen uptake rates of phytoplankton, especially for large size cells, will be needed to be carried out in order to obtain better estimations of annual primary and new productions. © 2015, Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source


Park J.-I.,Marine Eco Technology Institute | Kim J.B.,Marine Environment Research Division | Lee K.-S.,Pusan National University | Son M.H.,Marine Eco Technology Institute
Ocean Science Journal | Year: 2013

To select the optimal site for the restoration of seagrass habitats in the Taehwa River estuary, we transplanted the eelgrass Zostera marina to three potential candidate sites in March 2007 and monitored the transplanted seagrass and associated environmental factors for six months. In all three sites, the transplanted seagrasses exhibited no initial morphological loss due to transplanting stress. The transplanted seagrass communities at sites 2 and 3 showed more than a 180% increase in density over the entire survey period. In contrast, despite a density increase in the first month after transplantation, most of the transplanted seagrasses at site 1 died. This may be due to the large decrease in underwater irradiance reaching the seagrass leaves at site 1 for two months during June and July, which fell below the level of compensation irradiance. The growth rate and size of the seagrass shoots were also larger at sites 2 and 3 compared with site 1. This is probably due to higher nutrient concentrations in the sediment pore water at sites 2 and 3 compared with site 1, although water depth, salinity, and the nutrient concentrations in the water columns from the three sites were similar. Therefore, for the restoration of seagrass habitats in the Taehwa River estuary, sites 2 and 3 were preferable to site 1 as transplantation sites. © 2013 Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source


Lee J.S.,Oceanographic Measurement and Instrument Calibration Service Center | Kim E.-S.,Oceanographic Measurement and Instrument Calibration Service Center | Kahng S.-H.,Oceanographic Measurement and Instrument Calibration Service Center | Yoon S.-H.,Marine Environment Research Division | And 3 more authors.
Ocean Science Journal | Year: 2012

We have developed a novel miniature in situ microprofiler (NAFRI BelpI) for coastal and deep-sea studies. The BelpI can carry up to three oxygen microsensors, and it allows for simultaneous replicate measurements in a relatively small area. All functions can be controlled and programmed via a small magnetic bar and three reed switches; this feature facilitates the initial setup both onboard and underwater. The large LCD window shows basic information such as the movement intervals of the linear stage, number of replicate measurements, waiting time between measurements, and the pA from the microsensors. From high-resolution vertical profiles of oxygen in coastal sediment measured using the microsensors, the diffusivity boundary layer thicknesses was determined to be in the range 0. 30-0. 35 mm. In addition, the time-series measurement of oxygen profiles in permeable sandy sediment showed advective transport of oxygen into pore water by tidal agitation. Two examples of in situ measurement using a BelpI suggest that it can be widely applied to the study of the sediment-water interface. © 2012 Korea Ocean Research & Development Institute (KORDI) and the Korean Society of Oceanography (KSO) and Springer Science+Business Media Dordrecht. Source

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