• 감성과학
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• 제19권1호
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• pp.61-70
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• 2016

입체 시각 피로는 3D 영상의 확산을 방해하는 가장 주된 요인으로 알려져 있다. 입체 시각 피로는 수렴과 조절의 불일치에 의하여 유발되는 것으로, 이 현상은 양안 시차를 포함하는 영상을 3D 디스플레이로 제시하는 경우 자극에 의하여 유발된 수렴 거리가 물리적인 조절 거리와 불일치하여 발생한다. 이는 실감을 증진시키기 위하여 입체 자극을 사용하는 경우 언제나 입체 시각 피로를 유발할 가능성이 있음을 의미한다. 따라서 입체 시각 피로를 감소시키기 위하여 직접적인 원인을 제거하려는 노력뿐만 아니라 이를 간접적으로 감소시키기 위한 노력 역시 필요하다. 이런 관점에서 본 연구는 입체 시각 피로에 영향을 미칠 가능성이 높은 상대적 시차, 시청 거리, 시청 방위 요인이 주관적 입체 시각 피로에 미치는 영향을 측정하고 입체 시각 피로를 최소화하기 위한 각 요인의 수준을 알아보고자 하였다. 그 결과 참가자들이 입체 시각 피로를 보고하는 경우는 상대적 시차의 교차 시차 크기가 7분 22초를 넘어설 때, 그리고 수직 시야각이 15도 보다 클 때라는 것을 확인하였다.

• 한국토양비료학회지
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• 제22권3호
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• pp.191-196
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• 1989

강원도(江原道)에 위치(位置)한 점봉산(點鳳山)과 오태산(五台山)의 삼림토양(森林土壤)에서 침엽수림(針葉樹林)과 활엽수림(闊葉樹林)으로 나누어 층위별(層位別)로 채취(採取)하여 단당류(單糖類)의 함량(含量)을 분석(分析)하여 조사(調査)한 결과(結果)는 다음과 같다. 1. 단당류(單糖類)의 함량(含量)은 유기층(有機層)에 가장 많았고 심층(深層)으로 내려갈수록 감소(減少)되었는데 이는 유기물함량(有機物含量)과 직접적인 관계가 있었다. 2. Hexose (galactose, glucose, mannose)의 함량(含量)이 절대적으로 많았으며 그 다음으로는 Pentose(arabinose, ribose, xylose)의 순서이었고 deoxyhexoe(furose, rhamnese)의 함량(含量)이 가장 적었다. 單糖類의 함량(含量)은 아래와 같다. glucose>mannose>galactose>arabinose>xylose>rahmnose>fucose>ribose. 3. 침엽수림토양(針葉樹林土壤)의 유기층(有機層)에는 극히 적은 량(量)의 ribose만이 함유(含有)되어 있었으며 활엽수림토양(闊葉樹林土壤)에서는 ribose가 검출되지 않았다. 4. 전토양(全土壤) 유기물(有機物)에 대한 단당류(單糖類)의 비율(比率)은 토양(土壤)의 깊이에 따라 감소(減少)했는데 이는 부식화(腐植化)의 효과(效果)라고 생각된다. 표면유기층(表面有機層)의 단당류(單糖類) 함량(含量)은 유기탄소(有機炭素)에 대해 27~50%, 유기물함량(有機物含量)으로 환산(換算)하면 15.7~29%에 해당하며 이 중에서 hexose는 유기탄소(有機炭素)에 대해 20~30%, 유기물(有機物)에 대해서는 12~22 %의 비율(比率)로 함유(含有)되어 있었다. 5. 각각(各各)의 단당류(單糖類)가 차지하는 비율(比率)은 토양단면(土壤斷面)을 통해 종합해 볼 때 어떤 규칙적인 양상을 보이지 않았다. 이는 토양미생물(土壤微生物)의 활동(活動)이 일정치 않았기 때문이 아닌가 사료된다.

• Geomechanics and Engineering
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• 제36권6호
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• pp.527-543
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• 2024

In the implementation of most civil structures, especially underground, deep excavations with a vertical slope are required. Using flexible retaining walls is applied as one of the ways to stabilize vertical holes. Therefore, it is necessary to know the parameters affecting the performance of such walls in reducing their horizontal movement. In this research, by building a suitable laboratory model, the parameters of the amount of flexibility, the embedment depth of the wall, the type and number of tieback in the wall were investigated for 42 static laboratory models. The purpose of this research is to study the flexible retaining wall with helical tieback compared to simple tieback at different heights, which shows the best performance in terms of reducing horizontal displacement in proportion to increasing or decreasing flexibility. On the other hand, one of the parameters affecting the flexibility of the wall, which is its bending stiffness, was extracted by numerical software outputs and studied on the results such as relative flexibility, stiffness, safety and numerical stability of the wall.The results of this study show that among the parameters, in the first place, the effect of the type of tieback is inhibited and in the second place, the ratio of thickness to wall height is known as the most important parameter. the best performance for walls with the helical tiebacks in reducing their horizontal displacement can be economically, flexibly and stability assigned to a wall that tiebacks is in the range of H2/t to H4/t and its flexibility ratio is 2/3.

• 한국학교보건학회지
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• 제4권2호
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• pp.193-215
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• 1991

This study is aimed at providing basic information applicable to setting up the education programs and strategies to prevent smoking among high school students by analysing smoking behavior and influencing factors. The samples consisted of 814 students, 557 parents and 362 teachers selected randomly from 8 high schools, one from each school district in Seoul. Date Analyses were made through Chi-Square test, Factor Analysis, One Way ANOVA, Multiple Regression, Correlation. SPSS/$PC^+$program was utilized. Smoking behavior (continuous smoking, re-smoking, ex-smoking, never smoking, daily smoking, occasional smoking) were used as dependent variables. Influencing factors (male students, habits, attitudes and knowledge toward smoking, home life, school life, juvenile delinquency, friendship, demographic parent's and teacher's recognition toward male students smoking) were used as in dependent variables. The major findings of the study are as follows : 1. The total smoking rate occupies 41.1% whereas the continuous smoking rate stands at 19.2%, re-smoking rate 9.5%, ex-smoking rate 12.4% and never smoking rate 58.9%. 2. The total smoking rate among high school students is significantly correlated with their monthly expenditures and type of school (p<0.001). The continuous smoking rate also shows the same tendency. As the length of butt get shorter, the current smoking rate increase. The duration of smoking is in proportion to its continuity. The major motive of smoking is curiousity whereas that re-smoking is to follow friend's behavior. The study shows that peer pressure is the most powerful factor influencing smoking behavior of students. Friends and fellow students encourage to pick up smoking and resume smoking even alter one stops smoking. 3. The correlationship between favorable attitudes toward smoking and the current smoking rate and its continuity is statistically significant(p<0.05, p<0.01, p<0.001). 4. The stability and harmony of family life and the current smoking rate show negative correlationship. The daily smoking amount of father is in proportion to the continuity of students' smoking. When parents are in favor of smoking, it is more likely that the experimental smoking rate increase the smoking rate increases, and vice versa. The more acceptable attitudes toward smoking among siblings is also one of the factors to increase the smoking rate and continuity (p<0.001). The more lenient the attitudes of parents toward their children's association with smoking friends, the higher the smoking rate. When students have difficulties in adjusting to school life, it is more likely that the current smoking rate and continuity increase. 5. The continuity of smoking and friendship are significantly correlated (p<0.05, p<0.01, p<0.001). 6. The continuity of smoking and juvenile delinquency are significantly correlated (p<0.001). 7. The difference in attitudes and smoking reasons of parents and students is significantly correlated to different smoking behavior (p<0.01, p<0.001). While smoking knowledge does not significantly influence their smoking behavior, it is noted that in the case of teachers, smoking reason (p<0.05), attitudes (p<0.001) and knowledge (p<0.05) strongly influence their smoking behavior. 8. There is a significantly correlation among the smoking reasons, attitudes and knowledge between students and parents(p<0.001). As for the correlationship between regularity and smoking amount and other influencing factors, the daily smoking amount is in proportion to depth of inhalation and duration of smoking, negative attitudes of parents unstability of family, dissatisfaction of family members, juvenile delinquency, strong smoking reasons and positive attitudes towards smoking. 9. In the case of daily smokers depth of inhalation is significantly correlated to the duration of smoking, juvenile delinquency, acceptability of parents, dissatisfaction of family members and smoking reasons. The duration of smoking motives is significantly correlated to juvenile delinquency, high acceptability of parents, strong smoking motive and positive attitudes toward smoking. 10. It is noted that 40% of parents and 30% of teachers do not recognize the significant correlationship between and the relative influencing factors mentioned above.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.40-49
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• 2004

This work carried out to define the characteristic of Cymbidium kanran habitat at Mt. Halla in Jejudo, Korea from the ecological point of view including geological and topographical features, air and soil temperature, relative humidity, fluctuations of light intensity, habitat vegetation, distribution altitude, area limit, and etc. And another goal of this study consider the conservation counterplan of the cymbidium habitat. Natural distribution areas of the cymbidium were observed more abundantly on the well drained south and east-facing slopes. Soil acidity was ranged from pH 4.1 to 5.3, and electric conductivity was ranged from 176.4 to 299.9 us/cm (average 215.3 us/cm). Base-saturation percentage of the habitat soil was below 50%, bulk density 0.42g/$cm^2$, particle density 2.05g/$cm^2$, humus content 26%, total nitrogen 0.82%, available phosphate 4.2 mg/kg, exchangeable potassium 0.63 Cmol/kg, calcium 0.44 Cmol/kg and magnesium 0.67 Cmol/kg. Annual mean air temperature was $15.4^{\circ}C$, however, air temperature was ranged $11.7{\sim}18.2^{\circ}C$ in spring, $21.2{\sim}23.8^{\circ}C$ in summer, $12.8{\sim}22.0^{\circ}C$ in fall and $5.5{\sim}7.8^{\circ}C$ in winter season. Annual mean soil temperature at depth of 10cm was $13.2^{\circ}C$ And minimum value was recorded $4.7^{\circ}C$ on January, and maximum value $22.5^{\circ}C$ on August. Relative humidity was ranged 90.8~94.7% in summer, 80.8~91.5% in fall and 77.6~84.2% in winter season. Minimum value was 56.5% on December, and maximum value was 100% on July and August. Light intensities were ranged from 400 to 1,800 lux at the greater part of Cymbidium kanran sites in Jejudo. Summer regarded as an lower light intensities was recorded to be range of 500~600 lux; however, autumn and winter were shown higher light regimes ranged from 3,500 to 3,800 lux. Therefore, one must be suprised that the cymbidium grow at the light condition of 6 lux (minimum) or 10,000 lux (maximum). Tree species keeping higher frequency rate and density were Eurya japonica, Camellia japonica, Castanopsis cuspidata, Carpinus laxiflora and Pinus densiflora. Number of trees growing in a 5${\times}$5m quardrat was 35 as an average, and proportion of evergreen versus deciduous was 5:1. Distribution altitude of the orchid habitat was ranged from 120m (low) to 840m (high) from sea level on the south facing slope of Mt. Halla, and was ranged eastern borderline of Gujwaup, Bukjejugun to western boundaries of Jungmundong, Seogwipo city. For the stable conservation of Cymbidium kanran habitat, sunlight regimes must be increased more by means of cutting trees or twigs in the site.

• Journal of Periodontal and Implant Science
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• 제28권1호
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• pp.37-56
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• 1998

The purpose of this study was to evaluate the clinical and microbiological outcomes following the use of 30% minocycline-loaded polycaprolacton film and 2% minocycline-loaded gel that was applied locally into pockets combined with scaling and root planing. 25 human subjects who were non-pregnant, non-lactating, aged 20-50 and diagnosed as moderate to advanced adult periodontitis were enrolled. Subjects were excluded if they had a history of severe acute or chronic systemic disease, if they required antibiotic prophylaxis for dental treatment for any reason, or if they reported a history suggestive of hypersensitivity reactions to minocycline or tetracycline. 4quadrants that had several teeth with a 5-8mm probing pocket depth and radiographic evidence of alveolar bone loss for each patient were selected and divided into test sites and control sites according to the split-mouth design. Scaling and root planing was done for each site at baseline(0week). Test sites received the minocycline gel and strip and control sites had saline irrigation. The patients received both treatments simyltaneously. Subgingival irrigation of sterile saline was applied to the control sites for approximately 30 seconds. Minocycline strip and gel was applied into the periodontal pocket at 1, 2, 3, 4 weeks each after scaling and root planing in the test sites. The clinical and microbiological measurements were made at baseline and at the follow-up visits 6, 10, 14, 20 weeks. The results of this study were as follows; 1. The sulcular bleeding index, probing pocket depth and Periocheck test was significantly reduced and the relative proportions of spirochetes and motile rods were significantly reduced and the proportion of cocci was correspondingly increased, in locally delivered minocycline strip group compared to saline irrigation group. 2. In locally delivered minocycline gel group, The effect was the same with minocycline strip group as compared with saline irrigation therapy. 3. There was no significant differences between minocycline strip group and minocycline gelgroup. In conclusion, minocycline HCl local drug delivery combined with scaling and root planing may provide added improvement of clinical and microbiological responses by inhibiting bacterial recolonization of treated sites. It is suggested that the local administration of minocycline-HCl in the periodontal pocket is effective when combined with subgingival mechanical debridement.

• 대한화장품학회지
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• 제29권2호
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• pp.67-77
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• 2003

Two categories of cosmetic products, cosmetics and quasi-drugs, have been established by the Ministry of Health, Labor and Welfare (MHLW) in Japan. Japanese pharmaceutical law has defined that products categorized as cosmetics do not exhibit any effects on human skin. In fact, cosmetic products are not permitted to claim any efficacy. On the other hand, products in the quasi-drug category can claim several efficacies such as anti-inflammatory effects, whitening/lightning effects, hair growth effects and so on. Unfortunately, the Japanese MHLW has not yet approved the efficacy of anti-aging/anti-wrinkle effects as a claim point. However, the population is aging, and the demand for anti-aging/anti-wrinkle products is increasing year by year. Japanese cosmetic companies have proposed to the MHLW that anti-aging/anti-wrinkle agents be approved as a claim concept of a quasi-drug. However, unified evaluation methods for anti-aging/anti-wrinkle effects have not been established. Currently, each company evaluates the efficacy of products/materials using their own original methods. Thus, to request approval of the MHLW, the establishment of a unified evaluation method is needed. Consequently, the Japan Cosmetic Industry Association (JCIA) has established a task force to develop guidelines for evaluating anti-wrinkle effects in 1998. In conclusion, the JCIA would like to adopt visual and image analysis scales to evaluate the anti-wrinkle effects objectively. Generally, wrinkles are roughly classified into three groups as fine wrinkles, linear deep wrinkles and crow's feet. However, academic societies of dermatology or cosmetics have not yet established a definition of wrinkles in Japan. Thus, in advance of setting up an evaluation method, the definition of wrinkles f3r evaluation must be decided. Wrinkles are defined by the task force of the JCIA as follows; furrows that people can recognize visually and that appear on the forehead, the corners of the eyes and the backs of the neck with aging. In addition, furrows are emphasized by exposure to solar light and by dry conditions. Visual evaluation is the most sensitive method and can be applied to most types of wrinkles. However, visual evaluation is hard to express digitally as results. Besides, in the case of image analysis, comparisons of data obtained from distinct examinations can not be done, because data from image analysis are relative values. Thus, to enhance the reliability of the evaluations, the adoption of an objective scale was required. The principle of the evaluation method is to analyze images taken from silicone replicas of wrinkle areas using several parameters, such as the proportion of the wrinkle $area({\%})$, the mean depth of the wrinkles (mm), the mean depth of the deepest wrinkle (m) and the deepest point on the deepest wrinkle. Lights are shown on the skin replica from an orthogonal direction of the main orientation of the wrinkle, and the resulting shadow images are quantified by the image analysis method. To increase the precision of the data or to allow comparisons of independent examinations, a scale with furrows of several depths, 200, 400, 600, 800, and $1000{\mu}m$, is adapted in the evaluation system. I will explain the guidelines established by the JCIA in the presentation.

• 한국조경학회지
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• 제40권6호
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• pp.190-197
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• 2012

본 연구는 저관리 경량형 옥상녹화의 열수지를 정량화하기 위하여 모의실험을 수행하였다. 콘크리트블록을 이용하여 가로 $1.2m{\times}$세로 $1.2m{\times}$높이 1m의 모의실험구 2개를 제작하여 하나는 한국잔디를 식재한 토심 10cm의 옥상녹화 실험구로 하였으며, 옥상녹화를 실시하지 않은 나머지 하나는 대조구로 하였다. 2012년 6월 6일~7일에 기온, 상대습도, 풍향, 풍속 등 외부 기상환경, 증발산량, 옥상녹화와 대조구인 콘크리트의 표면과 천장면의 온도, 열류량, 열수지를 측정하였다. 6일과 7일의 일최고기온은 각각 $29.4^{\circ}C$와 $30^{\circ}C$로 초여름 날씨로는 매우 무더웠다. 6일과 7일의 일증발산량은 각각 $2,686.1g/m^2$과 $3,312.8g/m^2$이었으며, 일사량이 증가함에 따라 증발산량도 증가하였다. 외부 기온이 가장 높은 시간일 때의 옥상녹화 표면과 대조구 표면의 온도차이를 비교해 보면 대조구 표면이 $5.5^{\circ}C$(6일)와 $2.2^{\circ}C$(7일) 더 높은 것으로 나타났다. 옥상녹화 천장과 대조구 천장의 온도차이를 비교해 보면 $13.1^{\circ}C$(6일)와 $14.2^{\circ}C$(7일)로 나타나 옥상녹화에 의한 실내온도저감효과가 매우 큰 것으로 나타났다. 옥상녹화와 대조구인 콘크리트 표면의 열수지를 분석한 결과, 옥상녹화는 순복사량과 잠열량이 많은 비율을 차지하고 있었으나 대조구는 현열량과 전도열량의 비율이 높았다. 즉, 옥상녹화는 한국잔디와 식재토양에 의한 증발산으로 열을 식혀주는 잠열의 비율이 높은 반면에 대조구인 콘크리트 표면은 식물이 식재되어 있지 않기 때문에 열을 식혀주는 잠열은 $0W/m^2$인 반면에 주위 온도를 증가시키는 현열량과 건물내로 전달되는 전도열량의 비율이 높아 표면과 천장면의 온도를 상승시켰다. 본 연구는 옥상녹화의 온도저감과 열수지 해석을 시도했다는 점에서는 매우 의의가 크다고 할 수 있지만, 옥상녹화는 토심과 토양배합비, 식물종, 계절 등 여러 변수에 따라 온도저감효과가 다르게 나타날 수 있기 때문에 이에 대한 후속연구가 필요하다.

• 생태와환경
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• 제40권1호
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• pp.163-172
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• 2007

본 연구에서, 금강의 작은 지류 하천들인 31개 소하천들을 대상으로 2003년 10월부터 11월까지 어류상, 군집분석 및 하천 형태에 대한 연구를 수행하혔다. 조사된 소하천들은 하폭, 수심, 하상 구성물질, 하천식생 및 주변의 토지 이용도에 따라 산지형, 산지-평지형, 평지형, 농수로형소하천의 4가지 유형으로 구분 대별되었다. 조사기간 중 서식이 확인된 어류는 4과 8종이었으며, 잉어과 어류가 다른 분류군에 비해 가장 높게 나타났고, Rhynchocypris oxycephalus가 419개체로 전체의 73%로 우점종으로 나타났다. R. oxycephalus는 100%산림지역과 연계된 지역이면서 점오염원 및 비점오염원이 전혀 없는 5개의 모든 산지형 소하천(SM)에서 출현한 유일한 종으로 나타났다. 또한, 본 조사대상 소하천들에서 출현한 종들 중R. oxycephalus의 출현비율은 하천의 하상구성 인자 중 모래 (Sand, Sa)와 작은 자갈(Pebble, Pe)로 구성된 하천들 보다 암반(Bedrock, Be)과 큰돌(Boulder, Bo)로 이루어진 하천들에서 양의 상관관계를 갖는 것으로 나타났다(r=0.754, p<0.001, n=31). 2007견 환경부에서 공표한 생물학적 수질기준안에 의거할 때 본 산지형 소하천(SM)지역은 "최적상태"로 나타났다. 이와 같은 결과는 국내 하천들의 최상류역에 서식하는 것으로 알려진 종들의 일반적인 경향과 일치하는 것으로 사료되었다. 유형별로 산지형 소하천(SM)에서 R. oxycephalus 1과 1종, 산지-평지형 소하천(MF)에서 R. oxycephalus등 4과 6종, 평지형 소하천 (FL)에서 R. oxycephalus 등 4과 8종, 농수로형 소하천(AW)에서 R. oxycephalus등 2과 2종의 서식이 확인되었다. 본 연구 결과에 따르면, 오염원이 전혀 없고, 산림으로 둘러 쌓인 하천에서 출현한 R. oxycephalus는 생물학적 수질판정시 1급수 지역에서 최대 값을 보이는 생태지표종 중의 하나로서 사료되었다.

• 해양환경안전학회지
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• 제29권5호
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• pp.417-426
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• 2023

세종기지가 위치한 마리안 소만은 기후 변화로 인한 빙하후퇴로 다량의 융빙수가 유입되고 있다. 이러한 빙하후퇴에 따른 생태계 반응을 예측하기 위해, 해양 환경 변화의 지시자인 식물플랑크톤 생체량 및 크기 구조와 물리, 화학적 매개변수에 대한 현장 조사를 2021년 12월, 2022년 1월 두 차례 수행하였다. 2022년 1월의 수온과 염분은 평균 1.41 ± 0.13 ℃, 33.9 ± 0.10 psu로 2021년 1월의 수온과 염분인 0.87 ± 0.17 ℃, 34.1 ± 0.12 psu보다 상대적으로 고온, 저염의 양상을 보였다. 조사시기 동안 영양염류는 대체로 높은 농도를 보여 식물 플랑크톤의 제한요소로 작용하지 않은 것으로 판단된다. 식물플랑크톤 생체량의 지표인 엽록소는 2021년 12월, 2022년 1월에 각각 1.03 ± 0.64 ㎍ L^-1, 0.66 ± 0.15 ㎍ L^-1로 나타났으며 부유물질은 전체 조사기간 평균 24.9 ± 3.54 mg L^-1로 나타났다. 부유물질의 농도가 높은 소만내측에서 엽록소는 낮은 농도를 보였는데 이는 융빙수로부터 유입되는 고농도의 부유물질로 인해 수층 내 빛이 강하게 제한되어 식물플랑크톤의 성장이 저해된 것으로 판단된다. 또한, 빙벽 주변 정점에서 크기가 작은 미소 식물플랑크톤이 전체 식물플랑크톤 생체량에서 70% 이상 차지하는 것으로 나타났으며 이는 융빙수 유입으로 유발된 저조도 환경에서 미소 식물플랑크톤의 기여도가 증가할 수 있음을 시사한다. 따라서 본 연구는 빙하후퇴 지역에서 유입되는 담수와 부유물질이 식물플랑크톤의 생체량 및 군집구조 조절 요인이 될 수 있음을 시사하며, 결과 자료는 추후 마리안 소만의 탄소순환 변동을 파악하는 기초자료로 활용될 수 있다.