Recently, domestic fishing production of Japanese horse mackerel has been continuously decreasing. To achieve sustainable fishing of this species, it is essential to acquire its target strength (TS) for accurate biomass estimation and to study its ecological characteristics. To date, there has been no TS research using a broadband echosounder targeting Japanese horse mackerel. In this study, for the first time, we synchronized an underwater camera with a broadband frequency (nominal center frequency of 200 kHz, range: 160-260 kHz) to measure the TS according to the body size (16.8-35.5 cm) and swimming angle of the species. The relationship between Japanese horse mackerel length and body weight showed a general tendency for body weight to increase as length increased. The pattern of the frequency spectra (average values) by body length exhibited a similar trend regardless of body length, with no significant fluctuations in frequency observed. The lowest TS value was observed at 243 kHz while the highest TS values were recorded at 180 and 257.5 kHz. The frequency spectra for the swimming angles appeared to be flat at angles of –5, 0, 30, 60, 75, and 80° while detecting more general trends of frequency spectra for swimming angle proved challenging. The results of this study can serve as fundamental data for Japanese horse mackerel biomass estimation and ecological research.
산림 식생은 수관층의 종류와 밀도에 의해 하층식생의 발달에 영향을 미치는 것으로 알려져 있다. 본 연구는 산림청 희귀식물로 지정된 꼬리말발도리 개체군의 수관열림도 차이에 따른 개체의 생장(생장량, 엽면적당 질량[Leaf Mass per Area], 엽면적) 및 생리적 특성(SPAD값, 엽록소량, 광합성)을 조사하고, 향후 대체서식지 조성을 위한 기초 자료를 제시하고자 한다. 조사구는 꼬리말발도리 자생지 환경 특성을 고려하여 국립수목원 내 수관열림도 차이가 보이는 3개 조사구(site 1, 2, 3)를 정하고, 꼬리말발도리 자생지(군위)에 1개 조사구(site 4)를 대조구로 하였다. 각 조사구의 광량, 지온 및 온도는 수관열림도와 비례하였으며, 토양습도 및 공중습도는 수관열림도와 반비례하는 경향을 보였다. 조사구별 평균 초장(cm)은 조사구마다 차이를 보였고, 엽면적은 수관열림도가 상대적으로 낮은 조사구에서 높았으며, LMA는 수관열림도가 높은 Site 3에서 높게 나타났다. 도입 개체는 수관열림도 차이에 따라 적절한 광적응 현상을 보이는 것으로 판단된다. 8월에 측정한 엽록소 a+b의 함량은 Site 4에서 가장 높았으며, 엽록소 a/b는 Site 3에서 가장 높았다. 꼬리말발도리의 조사구별 광합성 속도는 Site 2에서 가장 높은 수치를 보였으며, Site 4에서 가장 낮은 수치를 보였다. 그 외 기공전도도, 증산속도 유사한 경향을 보였다. 개체 특성 간 상관 분석 결과, 엽면적과 광량은 강한 음의 상관관계를 보였다. 본 연구는 희귀식물 꼬리말발도리의 대체서식지 조성에 기초 자료를 제시할 것으로 판단된다.
The study was conducted to evaluate the seminal attributes and cryo-banking of Achhami (Bos indicus) bull semen. Of two Achhami bulls, 8 ejaculates from each bull were evaluated for seminal attributes. For semen freezing and cryo-banking, 4 ejaculates (having ≥2 mL semen volume, ≥75% of sperm motility and ≥1,000 × 106 cells/mL of sperm concentration) from each bull were used. Semen samples were diluted in egg-yolk-tris-citrate extender using a two-step dilution protocol, and were frozen in liquid nitrogen (LN2) vapour in a styrofoam box. The mean semen volume, colour, sperm mass activity, motility, viability, concentration, abnormal acrosome, midpiece and tail and, abnormal head of two Achhami bulls were 4.4 ± 0.5 mL vs. 2.5 ± 0.2 mL, 2.5 ± 0.1 vs. 2.4 ± 0.1, 3.5 ± 0.1 vs. 3.5 ± 0.1, 77.0 ± 1.1% vs. 78.3 ± 1.3%, 94.4 ± 0.5% vs. 91.0 ± 0.6%, 1137.7 ± 73.7 × 106 cells/mL vs. 1060.0 ± 44.3 × 106 cells/mL, 10.2 ± 0.5% vs. 10.3 ± 0.5% and 6.7 ± 0.5% vs. 8.2 ± 0.3%, respectively. The post-thawed sperm motility and viability were 53.0 ± 2.0% vs. 50.0 ± 0.0% and 80.2 ± 0.4% vs. 73.2 ± 0.7%, while evaluating by computer-assisted sperm analysis (CASA) system, the percentage of the progressive motility, fast motility, slow motility, local motility and immotile sperm were 75%, 68%, 7.4%, 16.6% and 8.6%, respectively. A total number of 620 doses semen straw were cryo-banked. Due to the acceptable post-thawed sperm motility and viability recorded, cryopreservation of Achhami semen is hereby recommended so as to preserve the Achhami breed. For further validation, the fertility will be observed from the produced frozen semen.
Rockfish was a commercially important fish specie in marine ranching areas in Korea. To estimate density and biomass of rockfish using acoustic method, target strength (TS) information is required on the species. This study measured TS dependence on tilt angle and size on 14 live rockfish individuals at 38, 70, and, 120 kHz by ex-situ measurement (tethered method) and acoustic scattering model (Krichhoff ray mode, KRM). The swimbladdered angle ranged from 18 to 30˚ (mean ± s.d. = 26 ± 4˚ ). The mean TS for all individuals was highest -35.9 dB of tilt angle -17˚ at 38 kHz, -35.4 dB of tilt angle -25˚ at 70 kHz, and -34.9 dB of tilt angle -22˚ at 120 kHz. The ex-situ TS-total length (TL, cm) relationships were TS38kHz = 20log10(TL) - 67.1, TS70kHz = 20log10(TL) - 68.6, and TS120kHz = 20log10(TL) - 69.9, respectively. The model TS-total length (TL, cm) relationships were TS38kHz = 20log10(TL) - 66.4, TS70kHz = 20log10(TL) - 67.0, TS120kHz = 20log10(TL) - 67.0. The two measurements between the ex-situ TS and KRM model for TS-tilt angle and fish size were found to be significantly correlated.
Cobalt was electrodeposited onto chemical vapor deposition (CVD) graphene/Si/SiO2 substrates, during different time intervals, using an electrolyte solution containing a low concentration of cobalt sulfate. The intention was to investigate the details of the deposition process (and the dissolution process) and the resulting magnetic properties of the Co deposits on graphene. During and after electrodeposition, in-situ magnetic measurements were performed using an (AGFM). These were followed by ex situ morphological analysis of the samples with ΔtDEP 30 and 100 s by atomic force microscopy in the non-contact mode on pristine CVD graphene/SiO2/Si. We demonstrate that it is possible to electrodeposit Co onto graphene, and that in-situ magnetic measurements can also help in understanding details of the deposition process itself. The results show that the Co deposits are ferromagnetic with decreasing coercivity (HC) and demonstrate increasing magnetization on saturation (MSAT) and electric signal proportional to remanence (Mr), as a function of the amount of the electrodeposited Co. It was also found that, after the end of the dissolution process, a certain amount of cobalt remains on the graphene in oxide form (this was confirmed by X-ray photoelectron spectroscopy), as suggested by the magnetic measurements. This oxide tends to exhibit a limited asymptotic amount when cycling through the deposition/dissolution process for increasing deposition times, possibly indicating that the oxidation process is similar to the graphene surface chemistry.
Acoustic target strength (TS) measurement and theoretical acoustic scattering models were applied to estimate the TS for assessing the fish biomass. TS measurement was made of ex situ sailfin sandfish Arctoscopus japonicus at 70 and 120 kHz, and then compared to backscatter model prediction. The live sandfish was tethered in seawater using monofilament lines. Measurements were made versus incidence angle, −50° to 50° relative to dorsal aspect directions. Distorted wave Born approximation (DWBA) model was used to calculated TS pattern. The TS values of sandfish (body length: 16.2 cm) at 70 and 120 kHz were ‒66.94 dB and ‒64.45 dB, respectively, and were about 20 dB lower than TS of other fishes in Korea waters. These TS levels were distributed within the range of the theoretical TS. Ex situ measurement and theoretical TS may be applied to improve acoustical detection and biomass estimation of the sandfish, and is necessary to measure with various lengths.
Target strength (TS) information is an important parameter that estimates the detection, distribution, and abundance of Aurelia aurita. In order to investigate the biological TS of jellyfish, some factors such as size (bell diameter), tilt angle, pulsation, and symbion should be known. In the ex situ TS measurements, the tilt angles and pulsation from synchronized swimming behavior of four live A. aurita (bell diameters in the air: 54.2 ~ 94.2 mm) were measured with the acoustic data at 70 kHz. The reduced target strength (RTS) of A. aurita was found to change ranged from 13.4 ~ 16.5 dB according to the incidence angles from –30° to 24°. When the change rate of bell diameter in the water was 0.2, the TS value showed a 7.2 dB change. These results could be utilized as an important data to understand the acoustic characteristic scattering of A. aurita.
본 연구는 희귀특산식물인 섬현삼의 식물 생활사의 전반적인 단계를 종자 발아와 분화재배를 통해 구명하여 현지외 보전의 기초자료를 제공하는데 있다. 종자 발아는 30일간 저온습윤처리하여 증류수에 48시간 침지처리한 종자를 클라스만 상토가 채워진 육묘용 묘판에 파종 후 50% 차광처리시 66%의 최대 발아율을 나타냈다. 분화재배는 유묘크기가 소(초장 2.5 cm, 엽수 4매, 엽폭 1.2 cm, 엽장 1.7 cm)인 식물을 원예용상토가 충진된 분화용기에 이식하여 무차광처리에서 재배시 초장 39 cm, 엽수 29매, 엽폭 9.1 cm, 엽장 5.9 cm, 근장 14.2 cm, 지상/지하부 생중량 및 건중량이 각각 23 / 5.3 g, 4.6 / 1.3g 이상의 우수한 생육특성을 나타내었다. 또한 이 조건에서 94% 이상의 개화율을 나타내었고 모든 개화 개체에서 종자결실을 확인할 수 있었다. 본 연구를 통해 섬현삼의 현지외 보전과 관련된 일련의 과정을 확립하였다. 따라서 증식된 섬현삼 개체에 대해 현지외 보전 뿐만아니라 다양한 연구분야에 적용이 가능하리라 생각된다.
본 연구는 멸종위기식물인 단양쑥부쟁이(Aster altaicus var. uchiyamae)의 개체군을 대상으로 유전다양성을 유지하는데 필요한 최소개체수를 산정하기 위하여 수행되었다. 단양쑥부쟁이가 분포하고 있는 네 지역에서 각각 유전다양성 및 유전적 분화도를 분석하였다. AFLP(amplified fragment length polymorphism) 마커를 이용한 유전적 변이의 분석결과, 총 4개의 프라이머 조합에 대해서 936개의 밴드가 확인되었으며, 그 중 934개의 밴드(99.8%)가 다형성을 보여주었다. 단양쑥부쟁이 개체군 내에서 유전다양성(PPB = 45.3%, h = 0.104, I = 0.168, hs = 0.108)은 높은 수준으로 나타났으며, 개체군 간 유전적 분화도(GST = 0.075, θB = 0.079)는 낮은 수준이었다. AMOVA(Analysis of molecular variance)분석 결과에서도 전체 유전적 변이 중 91%가 개체군 내에서 보이는 반면, 9%는 개체군 간 변이에 기인한 것으로 나타났다. 단양쑥부쟁이 개체군에서 보이는 유전적 특성은 개체군 간의 빈번한 유전자 이동에 기인한 것으로 사료된다. 최대화 전략법에 의하여 경기도 여주일대의 3개 개체군을 대상으로(굴암, 도리섬, 삼합) 개체군 내 최소개체수를 산정한 결과 도리섬개체군에서는 17개체, 삼합개체군에서는 16개체, 굴암개체군에서는 11개체로 파악되었다. 단양쑥부쟁이 개체군의 최소개체수에 대한 정보는 효율적인 현지 외 보전을 위한 가이드라인을 제시해 줄 수 있다.
히어리의 자연집단과 벌채집단간의 비교는 전라남도 순천시 승주읍 접치재, 월등면, 황전면, 경상남도 진주시 명석면, 경기도 포천시 백운산 5곳의 벌채지와 주변 자연림에 분포하는 히어리군락을 대상으로 비교하였다. 100m2당 맹아수와 개체당 평균 맹아수는 벌채 집단에서 자연집단의 것보다 더 높게 나타났다. 반면 맹아수별 수고와 직경은 자연집단에서 더 높게 나타났다. 종조성과 식생상관성은 없으며 벌채집단과 자연집단 모두에서 큰차이 없이 생육하였다. 개괄지인 벌채집단에서 근맹아 뿐만 아니라 실생묘로도 번식하였다. 이처럼 히어리는 환경적응력이 커서 인간이 훼손시킨 벌채집단에서 근맹아와 실생묘로 번식함으로써 종 자체의 소멸은 없고, 오히려 일시적인 교란이후에 개체군 확장을 보였다.
전라남도 순천시 서 면 청소골 일대에 분포하는 히어 리개체군의 분포특성과 개체군 동태를 조사하였다. 히어리개체군은 계곡부와 인접한산림 가장자리를 따라 대상으로 분포하였으며,북사면,북서사면 및 북동사면에만 분포하는 특이성을 보였다. 교목층이 형성된 삼림내에서 아교목층이나 관목층을 이루고 있으며,종조성에 있어서는 히어리가 분포하지 않는 인접지 역 삼림식생과 별다른 차이는 없었다. 25 m2당 평균개체수와 개체당 평균 맹아지는 각각 6.25주 및 3개로서 다른 지 역 에 비해 낮은 밀도를 나타냈으며, 이 지 역의 히어 리개체군이 쇠퇴해가고 있음을 알 수 있었다.
우리나라 특산수종인 히어리 분포지 특성에 대해 현지 조사와 문헌조사를 실시하였다. 히 어리 분포는 전라남도 지역의 보성군, 광양시, 순천시 일대, 고흥군 점암면, 구례군 간전면, 장흥군 천관산, 지리산 노고단 전라북도 남원시 천황산, 지리산 뱀사골과 반야봉, 경상남도 산청군, 하동군, 남해군, 경기도 포천시 백운산에 출현하는 것으로 확인되었으며, 히어리 분포역에서 식물상은 70과 159속 216종 22변종 4품종 총 242종류가 확인되었다 분류군별로는 양치식 물이 5.8%, 나자식물이 3.7%, 단자엽식물이 18.6%, 쌍자엽식물이 71.9%로 분석되었으며, 생활형별 분류에서 1년생이 1.7%, 다년생이 98.3%로 분석 되었다. 생장형 별 비교에서는 초본성이 44.2%, 덩굴성이 12.4%, 관목성이 17.8%, 교목성이 25.6%로 나타났다. 히어리 군락 분포 유형은 전형적으로 북사면, 북동사면, 또는 북서사면이었으며, 전라남도 승주읍 신전리 자생지는 교목상 숲으로 인해 쇠퇴하는 경향을 보였다.
The world-wide capacity of genebanks for ex-situ conservation of crop genetic resources has increased greatly since the 1970s, improving the access of crop breeders to landraces, and wild relatives (Wright, 1997). In south Korea, systematic seed germplasm management was begun at the Rural Development Administration (RDA) in 1985 and consequently genebank system was established in 1988. The RDA genebank, National Agrobiodiversity Center (NAC) of south Korea, preserve 173,217 accessions of plant seed germplasm and 10.7% (18,509 accessions) of whole preserved germplasm is occupied by horticultral PGR by 2011. Horticultural PGR preserved in NAC is composed with 67 genera of crops including pepper (3,817 accessions), tomato (2,040 accessions), cabbages (1,690 accessions) and etc. According to horticultural plant sub-group, fruit-vegetable is the biggest group with 60% of accession share and leafy vegetable (19%), root vegetable (10%), bulb vegetable (8%), and ornamental (3%) follow subsequently. In aspect of PGR status, landrace is dominant part of conserved accession and then developed cultivar, wild relatives, cultivated material, wild, and weedy type follow subsequently. Recently characterization and evaluation of horticultural PGR have been activated for 3 years in NAC, which are useful for breeders and users focused on disease-resistance or active ingredient. It will promote utilization of horticultural PGR and development of horticultural crop breeding program for both human being and sustainable agriculture in near future.
A study on the remediation of heavily Fe ion contaminated soils from abandoned iron mine was carried out, using ex-situ extraction process. Also, oxalic acid as a complex agent was evaluated as a function of concentration, reaction time and mixing ratio of washing agent in order to evaluate Fe removability of the soil contaminated from the abandoned iron mine.
Oxalic acid showed a better extraction performance than 0.1N-HCI, i.e., the concentrations of Fe ion extracted from the abandoned mine for the former at uncontrolled pH and the latter were 1,750 ppm and 1,079 ppm, respectively. The optimum washing condition of oxalic acid was in the ratio of 1:5 and 1:10 between soil and acid solution during 1 hr reaction. The total concentrations of Fe ion by oxalic acid and EDTA at three repeated extraction, were 4,554 ppm and 864 ppm, respectively.
The recovery of Fe ions from washing solution was achieved, forming hydroxide precipitation and metal sulfide under excess of calcium hydroxide and sodium sulfide. In addition, the amounted of sodium sulfide and calcium hydroxide for the optimal recovery of Fe were 15g/ℓ and 5g/ℓ from the oxalic acid complexes, respectively.