• 융합신호처리학회논문지
• /
• 제19권2호
• /
• pp.35-41
• /
• 2018

The analysis of plankton species distribution in sea or fresh water is very important in preserving marine ecosystem health. Since manual analysis is infeasible, many automatic approaches were proposed. They usually use images from in situ towed underwater imaging sensor or specially designed, lab mounted microscopic imaging system. Normally they assume that only single plankton is present in an image so that, if there is a clumping among multiple plankton of same species (homogeneous clumping) or if there are multiple plankton of different species scattered in an image (heterogeneous interspersion), they have a difficulty in recognition. In this work, we propose a deep learning based method that can detect and recognize individual plankton in images with homogeneous clumping, heterogeneous interspersion, or combination of both.

• Ocean and Polar Research
• /
• 제29권4호
• /
• pp.327-337
• /
• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.

• 수산해양기술연구
• /
• 제48권4호
• /
• pp.495-503
• /
• 2012

An acoustic method for discriminating plankton from fish, in Lake Dom Helvecio of Brazil, is developed. The flow of data from this method is comprised of time varied threshold (TVT), dilation filter, bitmap and mask functions. The TVT can, of itself, precisely explain how to select an appropriate value. The final results of the echogram, which only shows plankton by masking fish signals, is used to examine the acoustic density of plankton by depth and time. The results indicate that the acoustic density of the plankton is at a depth of between 5m to 15m, its density is especially high at 10m to 15m. The results of the acoustic density of plankton by time indicate that May 7 is higher in density than May 8. Future study plans include the use of net samples, environmental datasets to identify the abundance and ecology described by the Chaoborus spp. from other species.

• 한국해양학회지
• /
• 제19권1호
• /
• pp.1-10
• /
• 1984

1975年 12月에서 1976年 5月 사이에 濠洲 Cronulla近海에서 實施한 가다랭이 漁業試驗時 採集한 浮游生物과 가다랭이 胃內容物의 造成 및 量的 相互關係性을 分析硏究 하였다. 가다랭이의 먹이생물의 造成과 豊度는 富裕生物의 그것들과 잘 一致하였으며 그 主要먹이 생물로서는 Nyctiphanes australis, brachyura幼生, 정어리種漁 및 Copepoda등임을 밝혔다. 가장 많은 가다랭이 漁獲은 富裕生物組成上 N. australis와 brachyura유생이 가장 豊富했던 1月과 2月에 있었다. 特히 Copepoda중의 Undinula vulgaris는 가다랭이의 먹이생물中 선택적 기호성먹이로서 가치가 큰 것으로 나타났다.

• 한국환경과학회지
• /
• 제19권4호
• /
• pp.389-397
• /
• 2010

The in vitro toxicities of three crude oils of the Hebei Spirit were examined on laboratory grown plankton, with a focus on the effects of a dispersant. The specific growth rate of phytoplankton and the mortalities of two zooplankton were measured in response to exposure to various concentrations of water accommodated oil, dispersant or both. The effects of the oils varied among the plankton, but were generally low within the range of the oil concentrations used, with little difference in toxicity among the three oils. Such low toxicity appeared to be associated with weathering of the crude oils. Exposure to the dispersant, however, dramatically increased the mortality of zooplankton, with complete inhibition of phytoplankton growth. No synergistic toxic effect was observed with the crude oil and dispersant combination. A better decision making process could be crafted for future application of dispersant in the event of an oil spill in Korean waters to better protect the marine plankton community from the excessive use of dispersant.

• 한국환경과학회지
• /
• 제29권7호
• /
• pp.691-702
• /
• 2020

Carbon biomass of plankton community, Total Organic Carbon (TOC) and Chlorophyll a (chl.a) concentration were examined in the SeoNakdong river from January to December in 2014, to assess composition of phyto- and zoo-plankton variation, to certify the correlation between chl.a and TOC and to determine the level of contribution of plankton carbon content to TOC in the reservoir-river ecosystem. The correlation level between TOC and chl.a was low in the year 2014 but exceptionally was highly correlated only during the period with cyanobacterial bloom. The high level of contribution of plankton carbon content to TOC was attributed to cyanobacterial carbon biomass from May to November and to Cladocera carbon biomass from March to May, November and December despite of its low abundance. These results suggest that there were inter-relationships between phytoplankton, zooplankton and TOC and also subtle consistency of their properties through the year. These patterns should be discussed in relation to the physiochemical and biological characteristics of the environment, as well as to allochthonous organic matters from non-point pollution sources.

• 한국해양학회지
• /
• 제2권1_2호
• /
• pp.13-23
• /
• 1967

Seasonal changes in the primary production of surface water in Suyong Bay, Pusan, were measured using a light-dark bottle method. Gross photosynthesis followed a distinct seasonal change with highest levels in spring and fall. Respiration of plankton community showed its maximum only in the late summer and early fall. Net photosynthesis of plankton community is considerably variable throughout year, but followed a seasonal change similar to gross photosynthesis. Seasonal changes in temperature and salinity are related to the seasonal change in plankton metabolism.

• 생명과학회지
• /
• 제25권5호
• /
• pp.601-606
• /
• 2015

허친슨(Hutchinson)은 동질성이 있고 잘 혼합된 환경에서는 경쟁배타의 원리가 작동하고 있어 많은 종이 공서할 수 없음에도 불구하고 여러 플랑크톤 군집에서 많은 종이 서식하고 있음을 주목하였다. 일부 자원만 공유하면 경쟁배타의 원리가 작용하여 일부 종만이 공존할 수 있다. 그럼에도 불구하고 많은 자연 집단에서 수많은 경쟁관계에 있는 종이 공존하는데 이를 플랑크톤 패러독스라 부른다. 본 연구에서 이 역설에 대한 수많은 견해 중 일부를 소개하였는데 Roy와 Chattopadhyay의 견해를 독성 생성 견해를 포함한 그들의 견해에 따라 기술되었다. 제시된 기작 중 물리적, 생물학적 환경에서 공간적, 시간적 이질성, 외부에서 부과되거나 자기-발생적 공간적 분리, 불완전한 수직 혼합층, 수평적 중간 규모의 소용돌이, 플랑크톤 간 자원경쟁에 의한 동요와 무질서, 자원경쟁에서 변동성 온도에서 안정된 공존과 상보적 역동성을 기술하였다. 본 연구를 통해 플랑크톤과 그 패러독스 연구를 수행하는데 정보가 제공되어 도움이 될 것이다.

• 한국해양학회지
• /
• 제24권4호
• /
• pp.194-205
• /
• 1989

일차생산자의 생물량을 연구하기 위해 천수만에서 1985년 9월부터 1986년 8월까지 월별로 채집된 식물플랑크톤의 체적으로부터 계산한 식물플랑크톤의 탄소량은 $26.7-960.7{\mu}gC/l$의 분포를 보이며 월 평균 탄소량은 $58.6-684.7{\mu}gC/l$(연 평균 $208.5{\mu}gC/l$) 범위의 변화를 보인다. 식물플랑크톤 탄소량과 세포 개체수 및 클로로필 농도의 상호 관계를 분석한 결과, net plankton(> $20{\mu}m$)에서는 탄소량, 개체수 및 클로로필 상호간의 상관 관계가 밀접하게 나타나 이들 상호 관계가 주로 net plankton에 의해 좌우됨을 보여주고 있으며, nanoplankton(< $20{\mu}m$)의 경우, 상관 관계가 낮게 나타났는데 이는 nano-fraction이 제거하지 않은 picoplankton(< $2{\mu}m$)을 상당량 포함하고 있기 때문으로 사료된다. 중회귀 분석 결과 또한 식물플랑크톤 탄소량, 개체수 및 클로로필 상관 관계가 주로 net plankton에 의해 좌우되고 있음을 나타낸다. C/Chl-a 비율은 9.1-100.5의 범위로 변화폭이 큰데 net plankton의 C/Chl-a 평균 비율은 111, nanoplankton의 비율은 6.4로 나타났다. Net plankton의 비율은 높은 시기에는 C/Chl-a값이 높은 반면 nanoplankton비율이 높은 시기에는 기 값이 낮게 나타나는 것으로 보아 C/Chl-a 비율을 변화시키는 주요인은 식물플랑크톤의 크기인 것으로 사료된다. 본 연구 결과 C/Chl-a값의 변화 폭이 크기 때문에 클로로필에 일정 비율을 적용하여 탄소량을 추정하는 방법은 연안생태계에서 적절치 못한 것으로 판단된다.

• Journal of applied mathematics & informatics
• /
• 제27권1_2호
• /
• pp.385-400
• /
• 2009

The adverse effect of harmful plankton on the marine ecosystem is a topic of deep concern. To investigate the role of such phytoplankton, a mathematical model containing distinct dynamical equations for toxic and non-toxic phytoplankton is analyzed. Stability analysis of the resulting three equation model is carried out. A continuous time variation in toxin liberation process is incorporated into the model and a stability analysis of the resulting delay model is performed. The distributed delay model is then extended to include the spatial distribution of plankton and the delay-diffusion model is analyzed with spatial and spatiotemporal kernels. Conditions for diffusion-driven instability in both the cases are derived and compared to explore the significance of these kernels. Numerical studies are performed to justify analytical findings.