• The Korean Journal of Ecology
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• 제8권1호
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• pp.21-29
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• 1985

The physico-chemical properties of sediment, the species composition and biomass of benthic diatoms were investigated in the intertidal zone of Kum river estuary, from July 1983 to May 1984. Sandflat sediment was more oligotrophic than mudflat one. The diatom composition was primarily associated with sediment grain size. The dominant epipelic diatoms belonged to the centric diatoms such as Paralia sulcata and Thalassiosira spp., while the epipsammic diatoms consisted mainly of Achnanthes haukiana and Amphora sabyii. Diatom flora of sandflat was more significantly diverse than that of mudflat. Mean yearly crop of sandflat diatoms was 2.8 times greater than that of mudflat diatoms and peaked at March reflecting the greater availability of ammonia.

• Ocean Science Journal
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• 제43권4호
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• pp.223-232
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• 2008

In order to determine the temporal and spatial variations of nutrient profiles in the shallow pore water columns (upper 30 cm depth) of intertidal sandflats, we measured the salinity and nutrient concentrations in pore water and seawater at various coastal environments along the southern coast of Korea. In the intertidal zone, salinity and nutrient concentrations in pore water showed marked vertical changes with depth, owing to the active exchange between the pore water and overlying seawater, while they are temporally more stable and vertically constant in the sublittoral zone. In some cases, the advective flow of fresh groundwater caused strong vertical gradients of salinity and nutrients in the upper 10 cm depth of surface sediments, indicating the active mixing of the fresher groundwater with overlying seawater. Such upper pore water column profiles clearly signified the temporal fluctuation of lower-salinity and higher-Si seawater intrusion into pore water in an intertidal sandflat near the mouth of an estuary. We also observed a semimonthly fluctuation of pore water nutrients due to spring-neap tide associated recirculation of seawater through the upper sediments. Our study shows that the exchange of water and nutrients between shallow pore water and overlying seawater is most active in the upper 20 cm layer of intertidal sandflats, due to physical forces such as tides, wave set-up, and density-thermal gradient.

• 한국수산과학회지
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• 제45권6호
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• pp.704-715
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• 2012

To examine temporal and spatial variation in salinity and nutrients in the shallow pore water of intertidal sandflats, we measured salinity and nutrient concentrations (dissolved inorganic nitrogen [DIN], phosphorus [DIP], and silicate [DSi]) in pore water of the intertidal zone along the coastline of Jeju Island at two and/or three month intervals from May 2009 to December 2010. Geochemical parameters (grain size, ignition loss [IL], chemical oxygen demand [COD], and acid volatile sulfur [AVS]) in sediment were also investigated. The surface sediments in intertidal sandflats of Jeju Island were mainly composed of sand, slightly gravelly sand and gravelly sand, with a range of mean grain size from 0.5 to 2.5 ${\O}$. Concentrations of IL and COD in sediment were higher along the eastern coast, as compared to the western coast, due to differences in biogenic sediment composition. Salinity and nutrient concentrations in pore water were markedly different across time and space during rainy seasons, whereas concentrations were temporally and spatially more stable during dry seasons. These results suggest that salinity and nutrient concentrations in pore water depend on the advective flow of fresh groundwater. We also observed an imbalance of the DIN/DIP ratio in pore water due to the influence of contaminated sources of DIN. In particular, nutrient concentrations during rainy and dry seasons were characterized by high DIN/DIP ratios (mean-127) and low DIN/DIP ratios (mean-10), respectively, relative to the Redfield ratio (16) in offshore seawater. Such an imbalance of DIN/DIP ratios in pore water can affect the coastal ecosystem and appears to cause outbreaks of benthic seaweed along the coastline of Jeju Island.

• 한국양식학회지
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• 제8권2호
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• pp.99-115
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• 1995

군산연안 조간대의 우점종인 동죽의 소화관 내용물을 1993년 8월부터 1994년 7월까지 조사한 결과를 요약하면 다음과 같다. 동죽의 소화관 내용물에서 관찰된 먹이생물의 종류는 총 60속, 120여종으로 식물성플랑크톤인 규조류가 52속으로 대부분을 차지하고 있으며, 와편모조류가 7속, 황색편모조류가 6속, 남조류가 5속, 녹조류가 3속이었으며, 동물성플랑크톤인 방산충류가 4속, 섬모충류와 갑각류가 2속 출현하였다. 환경수의 우점종과 소화관 내용물에서의 우점종은 일치하지 않았다. 계절에 따른 먹이생물의 출현종수는 3월과 10월에서 Peak를 보였으며, 8월에 가장 적었다. 소화관 내용물의 먹이생물의 크기는 대부분이 단순한 형태를 이루는 소형으로, 둥근형은 $200{\mu}m$이하, 막대형은 지름 $20{\mu}m$ 길이 $500{\mu}m$ 이하의 크기였다.