• Ocean and Polar Research
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• 제37권1호
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• pp.37-47
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• 2015

The effects of low salinity (fertilization success and larval survival) on the limpet Cellana grata were studied at early stages of development using the marine bioassay technique. It was shown that, under normal conditions for development from fertilization to the post veliger stage, the salinity must be not less than 20.0~35.0 psu. However, the fertilization rate and larval survival of C. grata was obviously reduced at 5.0 psu and 10.0 psu, respectively. Mass mortality was estimated to occur at <20.0 psu (48-h $EC_{50}=19.54psu$) and the survival rate of normal veliger larvae decreased with experimental time during exposure. No observed effective concentration (NOEC) and lowest observed effect concentration (LOEC) of post veliger were estimated at 30.0 psu and 25.0 psu, respectively, during 48-h exposure. The tolerance limits of the test species to salinity revealed various concentration ranges of salinity, which may reflect the physiology and ecology of the initial development stages of C. grata. These results demonstrate that reduced salinity is detrimental to the reproductive success and larval survival of C. grata, and if salinity is lowered by natural or anthropogenic sources during spawning, this would lead to decreased reproductive success and larval settlement.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.54-62
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• 2018

Objective: Due to the threat of global warming, the livestock industry is increasingly interested in exploring how feed additives may reduce anthropogenic greenhouse gas emissions, especially from ruminants. This study investigated the effect of Rhodophyta supplemented bovine diets on in vitro rumen fermentation and rumen microbial diversity. Methods: Cannulated Holstein cows were used as rumen fluid donors. Rumen fluid:buffer (1:2; 15 mL) solution was incubated for up to 72 h in six treatments: a control (timothy hay only), along with substrates containing 5% extracts from five Rhodophyta species (Grateloupia lanceolata [Okamura] Kawaguchi, Hypnea japonica Tanaka, Pterocladia capillacea [Gmelin] Bornet, Chondria crassicaulis Harvey, or Gelidium amansii [Lam.] Lamouroux). Results: Compared with control, Rhodophyta extracts increased cumulative gas production after 24 and 72 h (p = 0.0297 and p = 0.0047). The extracts reduced methane emission at 12 and 24 h (p<0.05). In particular, real-time polymerase chain reaction analysis indicated that at 24 h, ciliate-associated methanogens, Ruminococcus albus and Ruminococcus flavefaciens decreased at 24 h (p = 0.0002, p<0.0001, and p<0.0001), while Fibrobacter succinogenes (F. succinogenes) increased (p = 0.0004). Additionally, Rhodophyta extracts improved acetate concentration at 12 and 24 h (p = 0.0766 and p = 0.0132), as well as acetate/propionate (A/P) ratio at 6 and 12 h (p = 0.0106 and p = 0.0278). Conclusion: Rhodophyta extracts are a viable additive that can improve ruminant growth performance (higher total gas production, lower A/P ratio) and methane abatement (less ciliateassociated methanogens, Ruminococcus albus and Ruminococcus flavefaciens and more F. succinogenes.

• 한국광물학회지
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• 제23권2호
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• pp.99-106
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• 2010

금번 연구에서는 2009년 1월 1일부터 12월 31일 사이에 대전광역시 유성구 지역에서 확보한 강수 시료를 대상으로 강수에 의한 오염 희석 규명을 시도하였다. 강수여과물에 대해 등온잔류자화(Isothermal remanent magnetization) 측정과 현미경 분석 및 정성적인 화학 성분 분석을 실시하였다. 비강수일에 포집한 먼지 시료와 황사발생일에 채취한 먼지 시료도 비교를 위해 실험에 사용하였다. 자화특성 실험과 현미경 관찰 결과를 바탕으로 판단하면, 강수에서 여과된 고체 시료에 존재하는 자성 물질은 자철석이다. 관찰된 자성 물질의 특이한 형태(구형/타원체형)와 탄소 함유를 고려하면, 인위적인 연소에 의해 형성된 자철석이라 해석된다. 강수에서 여과된 고체 시료의 등온잔류자화는 일반 먼지보다도 낮고 황사에 비해서는 현저히 낮은데, 이는 강수에 의해 발생하는 상당한 양의 자성물질 희석 효과라 판단된다.

• ALGAE
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• 제34권2호
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• pp.153-162
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• 2019

Anthropogenic disturbances, including coastal habitat modification and climate change are threatening the stability of kelp beds, one of the most diverse and productive marine ecosystems. To test the effect of temperature and irradiance on the microscopic gametophyte and juvenile sporophyte stages of the rare kelp, Saccharina angustissima, from Casco Bay, Maine, USA, we carried out two sets of experiments using a temperature gradient table. The first set of experiments combined temperatures between $7-18^{\circ}C$ with irradiance at 20, 40, and $80{\mu}mol\;photons\;m^{-2}\;s^{-1}$. The second set combined temperatures of $3-13^{\circ}C$ with irradiance of 10, 100, and $200{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Over two separate 4-week trials, in 2014 and again in 2015, we monitored gametogenesis, the early growth stages of the gametophytes, and early sporophyte development of this kelp. Gametophytes grew best at temperatures of $8-13^{\circ}C$ at the lowest irradiance of $10-{\mu}mol\;photons\;m^{-2}\;s^{-1}$. Light had a significant effect on both male and female gametophyte growth only at the higher temperatures. Temperatures of $8-15^{\circ}C$ and irradiance levels of $10-100{\mu}mol\;photons\;m^{-2}\;s^{-1}$ were conditions for the highest sporophyte growth. Sporophyte and male gametophyte growth was reduced at both temperature extremes-the hottest and coldest temperatures tested. S. angustissima is a unique kelp species known only from a very narrow geographic region along the coast of Maine, USA. The coupling of global warming with high light intensity effects might pose stress on the early life-history stages of this kelp, although, as an intertidal species, it could also be better adapted to temperature and light extremes than its subtidal counterpart, Saccharina latissima.

• 한국환경과학회지
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• 제31권12호
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• pp.1079-1087
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• 2022

This study investigated the effect of volcanic materials that erupted from the Nishinoshima volcano, Japan, 1,300 km southeast of the Busan area at the end of July 2020, on the fine particle concentration in the Busan area. Backward trajectory analysis from the HYSPLIT model showed that the air parcel from the Nishinoshima volcano turned clockwise along the edge of the North Pacific high pressure and reached the Busan area. From August 4 to August 5, 2020, the concentration of PM₁₀ and PM_2.5 in Busan started to increase rapidly from 1000 LST on August 4, and showed a high concentration for approximately 13 hours until 2400 LST. The PM_2.5/PM₁₀ ratio showed a relatively high value of 0.7 or more, and the SO₂ concentration also showed a high value at the time when the PM₁₀ and PM_2.5 concentrations were relatively high. The SO₄^2- concentration in PM_2.5 in Busan showed a similar trend to the change in PM₁₀ and PM_2.5 concentrations. It rose sharply from 1300 LST on August 4, at the time where it was expected to have been affected by the Nishinoshima Volcano. This study has shown that the occurrence of high concentration fine particle in Busan in summer has the potential to affect Korea not only due to anthropogenic factors but also from natural causes such as volcanic eruptions in Japan.

• 현장농수산연구지
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• 제21권1호
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• pp.149-157
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• 2019

패류 인공종자생산에서 모패관리의 중요성이 커져가고 있으며 최적의 모패 관리 조건과 원하는 시기에 종자생산을 할 수 있는 성숙유도 조건을 구명하는 하는 것이 매우 중요하기 때문에 본 연구에서는 왕우럭 조개의 모패관리 최적조건과 성숙 촉진을 위한 가온 효과를 조사하였다. 모패관리는 실내사육에 비하여 실외사육이 비만도와 생존율 측면에서 더 효과적인 것으로 나타났으며 관리 측면에서도 인위적인 먹이생물 공급이 없으며 자연환경 조건에서 사육하기 때문에 관리가 수월하다는 장점이 있는 것으로 나타났다. 그리고 동계가온을 통한 성숙촉진 유도는 비만도와 생식소 관찰 등을 통하여 수온 18℃ 이상에서 2개월 정도 사육하였을 경우 성성숙이 이루어지는 것으로 나타나 성숙관리가 다른 패류에 비해 용이하다는 것을 알 수 있었다.

• 생태와환경
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• 제55권4호
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• pp.320-329
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• 2022

Urban areas in watersheds increase the impervious surface, and agricultural areas deteriorate the water quality of rivers due to the use of fertilizers. As such, anthropogenic land use affects the type, intensity and quantity of land use and is closely related to the amount of substances and nutrients discharged to nearby streams. Riparian vegetation reduce the concentration of pollutants entering the watershed and mitigate the negative impacts of land use on rivers. This study analyzes the data through correlation analysis and regression analysis through point data measured twice a year in spring and autumn in 21 selected damaged tributary rivers within the Han River area, and then uses a structural equation model to determine the area land use. In the negative impact on water quality, the mitigation effect of riparian vegetation was estimated. As a result of the correlation analysis, the correlation between the agricultural area and water quality was stronger than that of the urban area, and the area ratio of riparian vegetation showed a negative correlation with water quality. As a result of the regression analysis, it was found that agricultural areas had a negative effect on water quality in all models, but the results were not statistically significant in the case of urban areas. As a result of the model estimated through the structural equation, BOD, COD, TN, and TP showed a mitigation effect due to the accumulation effect of river water quality through riparian vegetation in agricultural areas, but the effect of riparian vegetation through riparian vegetation was found in urban areas. There was no These results were interpreted as having a fairly low distribution rate in urban areas, and in the case of the study area, there was no impact due to riparian forests due to the form of scattered and distributed settlements rather than high-density urbanized areas. The results of this study were judged to be unreasonable to generalize by analyzing the rivers where most of the agricultural areas are distributed, and a follow-up to establish a structural equation model by expanding the watershed variables in urban areas and encompassing the variables of various factors affecting water quality research is required.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.453-460
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• 2018

원유 가격의 상승과 지구온난화로 인하여 재생 가능한 바이오매스를 이용하여 산업적으로 중요한 화합물을 생산하는 연구가 주목받고 있다. 특히, 3세대 바이오매스인 해조류는 비식량 자원, 높은 생산 수율, 온실가스 저감 등 장점을 가지고 있기에 연구 되어야 할 필요가 있다. 본 연구에서는 고체분석 방법을 이용하여 4종의 해조류 중에 미역이 가장 많은 당류를 함유하는 것을 확인하였다. 미역의 효과적인 전처리를 위해 반응표면분석법을 이용하였으며 이를 통해 고체의 부하 및 촉매의 농도 증가가 총 당의 추출률과 관계 있음을 확인하였다. 4종의 락토바실러스 균주에서 미역의 전처리물을 이용하여 젖산 생산 수행하였으며 L. alimentarius와 L. brevis가 해조류 이용한 젖산생산에 적합한 균주임을 확인하였다.

• 한국환경과학회지
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• 제12권6호
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• pp.627-633
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• 2003

2001년 3월부터 2002년 2월까지 부산의 신라대학교 옥상에서 측정한 PM$_{10}$의 질량농도와 화학적 성분을 조사한 결과 다음과 같은 결론을 얻었다. 1) PM$_{10}$의 질량농도는 평균 98.21 $\mu\textrm{g}$/㎥로 나타났으며, 최고농도는 330.56 $\mu\textrm{g}$/㎥로서 연간 기준치인 80 $\mu\textrm{g}$/㎥를 초과하였다. 또한 K(1.23 $\mu\textrm{g}$/㎥)>Ca (1.12 $\mu\textrm{g}$/㎥)>Na(0.79 $\mu\textrm{g}$/㎥))>Al(0.76 $\mu\textrm{g}$/㎥)>Fe (0.75 $\mu\textrm{g}$/㎥) 순으로서 높은 조성을 보였고, Cd (2.72 ng/㎥)이 가장 낮은 질량 농도를 보였다. 2) Cd, Ni, Pb 및 Zn은 평균 지각농축계수가 10이상의 인위적인 기원으로 봄철과 여름철에 비하여 서풍계열의 바람이 우세한 겨울철에 매우 높은 값을 보였으며, 연구 지역의 서쪽에 인접한 사상공단과 서남쪽에 위치한 신평 .장림공단으로부터 서풍계열의 바람을 타고 이동되었음을 알 수 있었다. 또한 이들 중금속은 미세입자의 조성에 많은 영향을 미치는 것으로 나타났으며, 평균 토양입자의 기여율은 9.5%로 나타났다. 3) PM$_{10}$의 조성에 관여하는 금속 원소들은 토양, 해양 및 인위적인 오염물질에 의한 기원을 동시에 포함하고 있으나 해양기원보다는 토양 및 인위적인 기원들 간의 상관성이 우세하게 나타났다.

• 한국대기환경학회지
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• 제22권3호
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• pp.353-360
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• 2006

This study identified a particle size distribution (PSD) of fine particulate matter and emission characteristics of V and Ni by the comparison between anthropogenic sources of oil combustion (industrial boiler, oil power plant, etc.) and lab-scale combustion using a drop-tube furnace. In oil combustion source, the mass fraction of fine particles (less than 2.5 micrometers in diameter) was higher than that of coarse particles (larger than 2.5 micrometers in diameter) in $PM_{10}$ (less than 10 micrometers in diameter) as like in lab-scale oil combustion. In addition to this, it was identified that ultra-fine particles (less than 0.1 micrometers in diameter) had a large distribution in fine particles. Toxic metals like V and Ni had large mass fractions in fine particles, and most of all was distributed in ultra-fine particles. Most of ultra-fine particles containing toxic metals have been emitted into ambient by combustion source because it is hard to control by the existing air pollution control device. Hence, we must be careful on these pollutants because it is obvious that these are associated with adverse health and environmental effect.