• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.747-759
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• 2011

The purpose of this study was to compare the trophic structures and the energy flows in the Lake Namyang and the lower reaches of the Nakdong River using the Ecopath model. The sampling and analyses were carried out at 6 sampling sites of the Lake Namyang and the lower reaches of the Nakdong River respectively on March and November in 2007. As a result, the Lake Namyang was consisted of producers(Detritus, Macrophytes, Phytoplankton), primary consumers(Zooplankton, Zoobenthos, Carassius cuvieri, Carassius auratus, Other fishes) and secondary consumer(Cyprinus carpio, Pseudobagrus fulvidraco) and the lower reaches of the Nakdong River was consisted of producers(Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Hemibarbus labeo, Other fishes) and secondary consumer (Micropterus salmoides). The food-chain length of the Lake Namyang was relatively short when compared with the lower reaches of the Nakdong River. The shortness of food-chain length in the Lake Namyang could be attributed to the low biomass of the top predators. The total system throughput of the lake Namyang was estimated at 14.3 kg $m^{-2}\;year^{-1}$ including a consumption of 39.0%, exports of 21.0%, respiratory flows of 12.0% and flows into detritus of 28.0% and the total system throughput of the lower reaches of the Nakdong River was estimated at 2.8 kg $m^{-2}\;year^{-1}$ including a consumption of 52.0%, exports of 9.1%, respiratory flows of 18.0% and flows into detritus of 20.9% in the lower reaches of the Nakdong River.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.275-276
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• 2001

한반도에 자생하는 해산현화식물인 거머리말속 (Zostera, 잘피)의 거머리말 (Zostsra marina), 애기거머리말 (Z. japonica), 수거머리말(Z. caulescens)과 포기거머리말 (Z. caespitosa)들은 연안의 사질과 사니질에 생육하며 생태계에 중요한 역할을 담당한다. 이들 식물의 군집들은 조간대와 조하대에 침수 또는 노출되어 생육하면서 영양염과 중금속 순환에 중요한 역할을 수행한다. 식물체는 유기쇄설물을 먹이연쇄에 공급하는 기능을 하며, 중금속을 고등 영양단계로 수송하는 역할을 한다. (중략)

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.144-150
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• 2016

In southwestern East Sea, we investigated the spatio-temporal distribution characteristics of particulate organic carbon (POC) and nitrogen (PON) in September 2011 (summer), January (winter) and May 2012 (spring). Although cold waters known as the origin upwelling in the surface layer of September were not observed, this periods showed high primary productivity because of high concentrations of chlorophyll, low percentage of non-autotrophic particulate fraction among POC calculated by POC/Chl-a ratio (27%) and low POC/PON ratio (6.2), which means active amino acid and protein synthesis, However, May, 2012 showed low primary productivity because of high percentage of non-autotrophic particulate fractions among POC (66%) and high POC/PON ratio (8.1), Although spring bloom and high primary productivity has been reported in the East Sea, high percentage of non-autotrophic particulate fractions in POC, observed in the East sea during the post 2012 spring, is suggested to be due to the increase of phaeo-pigment during post spring bloom. Thus, composition of particulate organic matter may have sensitively changed by marine environmental factors in spite of same season.

• Korean Journal of Ecology and Environment
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• v.41 no.2
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• pp.144-154
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• 2008

The purpose of this study was to describe quantitatively trophic structures and to analyze energy flows in the Lake Namyang using the Ecopath with ecosim (Walter et al., 1997). The sampling and analyses were carried out at 6 sampling sites of the Lake Namyang during May and November in 2007. A total of 10 groups were considered in this study (detritus, macrophytes, phytoplankton, zooplankton, zoobenthos, Cyprinus carpio, Carassius cuvieri, Carassius auratus, Pseudobagrus fulvidraco and other fishes) to assess the trophic relationship, energy flows and interactions between them. As a result, it was concluded that Lake Namyang was consisted of primary producers (Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Carassius cuvieri, Carassius auratus, Other fishes) and secondary consumer (Pseudobagrus fulvidraco). The total system throughput was estimated at $14.1\;kg\;m^{-1}\;year^{-1}$ including a consumption of 39%, exports of 21%, respiratory flows of 12% and flows into detritus of 28%. MTI analyses indicate that Pseudobagrus fulvidraco have positive impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. On the other hand, other fishes have negative impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. All the functional groups except detritus had a negative impact on themselves and this may show within-group competition for the same resources.

• The Korean Journal of Malacology
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• v.32 no.3
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• pp.165-174
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• 2016

Feeding behaviour of the manila clam Ruditapes philippinarum was qualitatively and quantitatively characterized by comparing the contents composition in digestive tract of the clam and the phytoplankton community in surface sea water in Gomso Bay, west coast of Korea. The contents of digestive tract comprised diatoms (71.5%), dinoflagellates (13.1%), nannoplankton (6.6%), and detritus including mesozooplankton. The abundance of food organisms in digestive tract of the clam was high in winter and spring, while low in summer and autumn. But The biomass of phytoplankton in surface sea water revealed the highest value in autumn. Also, the larger the clam size increases the abundance of food organisms in digestive tract. The dominant species in digestive tract were Paralia sulcata and Navicula arenaria such as benthic diatoms and dinoflagellate cysts, whereas the dominant species in surface sea water were Chaetoceros, Skeletonema, Asterionellopsis such as pelagic diatoms in genus, cryptomonads, and P. sulcata. Analyses of digestive tract revealed that benthic diatoms especially represent an important constituent of food organisms in the malina clam and different of phytoplankton size and morphology explain preference for food selectivity.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1030-1034
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• 2005

The purpose of this study was to clarify the penetration behavior of particulate matters by wave and tidal actions in sandy beach located in enclosed bay and to evaluate the effect of stranded oil on penetration of particulate matters. Experiments were rallied out using a model sandy beach facility. The particulate matters penetrated into saturated sediments by wave action from breaking wave run-up point with a semi-circular forming in low energy beach as enclosed bay. On the other hand, the penetration velocity of the particulate matters was to be faster according to the increase of slope and breaking wave height. The particulate matters by tidal action penetrated into the sediments at an angie of 45 degrees in the direction of porous water flow. The stranded oil completely blocked the penetration of the particulate matters into the sediments. These results indicate that the penetrated oil prevents the penetration of the particulate matters into the sediments and, therefore, results in the reduction in the supply of plankton, bacteria and organic detritus for the benthic organisms in the sandy beach.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.1
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• pp.1-13
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• 2006

A field survey on the spatio-temporal distribution characteristics and origins of organic matter in surface sediments was carried out monthly at six stations in Gamak Bay, South Korea from April 2000 to March 2002. The range of ignition loss(IL) was $4.6{\sim}11.6%(7.1{\pm}1.6%)$, while chemical oxygen demand(CODs) ranged from $12.25{\sim}99.26mgO_2/g-dry(30.98{\pm}19.09mgO_2/g-dry)$, acid volatile sulfide(AVS) went from no detection(ND)${\sim}10.29mgS/g-dry(1.02{\pm}0.58mgS/g-dry)$, and phaeopigment was $6.84{\sim}116.18{\mu}g/g-dry(23.72{\pm}21.16{\mu}g/g-dry)$. The ranges of particulate organic carbon(POC) and particulate organic nitrogen(PON) were $5.45{\sim}23.24 mgC/g-dty(10.34{\pm}4.40C\;mgC/g-dry)$ and $0.71{\sim}2.99mgN/g-dry(1.37{\pm}0.58mgN/g-dry)$, respectively. Water content was in the range of $43.1{\sim}77.6%(55.8{\pm}5.6%)$, and mud content(silt+clay) was higher than 95% at all stations. The spatial distribution of organic matter in surface sediments was greatly divided between the northwestern, central and eastern areas, southern entrance area from the distribution characteristic of their organic matters. The concentrations of almost all items were greater at the northwestern and southern entrance area than at the other areas in Gamak Bay. In particular, sedimentary pollution was very serious at the northwestern area, because the area had an excessive supply of organic matter due to aquaculture activity and the inflow of sewage from the land. These materials stayed longer because of the topographical characteristics of such as basin and the anoxic conditions in the bottom seawater environment caused by thermocline in the summer. The tendency of temporal change was most prominently in the period of high-water temperatures than low-water ones at the northwestern and southern entrance areas. On the other hand, the central and eastern areas did not show a regular trend for changing the concentrations of each item but mainly showed a higher tendency during the low-water temperatures. This was observed for all but AVS concentrations which were higher during the period of high-water temperature at all stations. Especially, the central and eastern areas showed a large temporal increase of AVS concentration during those periods of high-water temperature where the concentration of CODs was in excess of $20mgO_2/g-dry$. The results show that the organic matters in surface sediments in Gamak Bay actually originated from autochthonous organic matters with eight or less in average C/N ratio including the organic matters generated by the use of ocean, rather than terrigenous organic matters. However, the formation of autochthonous organic matter was mainly derived from detritus than living phytoplankton, indicated the results of the POC/phaeopigment ratio. In addition, the CODs/IL ratio results demonstrate that the detritus was the product of artificial activities such as dregs feeding and fecal pellets of farm organisms caused by aquaculture activities rather than the dynamic of natural ocean activities.

• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.292-302
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• 2008

The purpose of this study was to analyze the trophic structures and the energy flows in the lower reaches of the Nakdong River using the Ecopath model (Walter et al., 1997). The sampling and analyses were carried out at 6 sampling sites of the lower reaches of the Nakdong River on May and November in 2007. Total of 9 groups detritus, macrophytes, phytoplankton, zooplankton, zoobenthos, Cyprinus carpio, Hemibarbus labeo, Micropterus salmoides and other fishes were considered to assess the trophic relationship, energy flows and interactions among them in the study. As a result, it was concluded that the lower reaches of the Nakdong River was consisted of producers (Detritus, Macrophytes, Phytoplankton), primary consumers (Zooplankton, Zoobenthos, Cyprinus carpio, Hemibarbus labeo, Other fishes) and secondary consumer (Micropterus salmoides). The total system throughput was estimated at 2.7 kg m$^{-2}$ year$^{-1}$ including a consumption of 52%, exports of 9.1%, respiratory flows of 18.0% and flows into detritus of 20.9%. MTI (mixed trophic impacts) analysis demonstrated that Pseudobagrus fulvidraco had positive impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. On the other hand, other fishes had negative impact on Cyprinus carpio, Carassius cuvieri and Carassius auratus. Also, all the functional groups except detritus had a negative impact on themselves.

• Ocean and Polar Research
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• v.24 no.2
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• pp.153-166
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• 2002

Particle fluxes were measured by using time-series sediment traps in the Bransfield Strait from December 27th, 1999 to December 26th, 2000. Total mass fluxes showed distinct seasonal variations with high fluxes in the austral summer and low fluxes in the austral winter at a 678m water depth in the eastern Bransfield Strait, while they were high only in January and fairly low in other months at a 960m water depth in the central Bransfield Strait. The reason that total mass fluxes occurred only in January at a 960m water depth in the central Bransfield Strait seems to be the strong current in the surface waters, which leads to a substantial amount of terrestrial materials and locally produced organic matter being advected away from the mooring site. Total mass fluxes were very high from January to October at a 1678m water depth in the eastern Bransfield Strait, while they were high only in January and February at a 1860m water depth in the central Bransfield Strait. The fact that total mass fluxes were higher at the deep water in the both sites than at the intermediate water depth may reflect that a substantial amount of terrestrial and organic materials are laterally transported by strong tidal current from the shallow environments to the deep basins.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.4
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• pp.3-11
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• 2001

To know the seawater infiltration into tidal flat sediment in coastal area is very important, because it is significantly correlated with the infiltration and transportation of pollutants in soil, the supply of dissolved oxygen, nutrients and organic matter to benthic organisms for survival of benthic organisms and the seawater purification. So, we set up purpose to clarify the infiltration behavior of seawater by wave action in tidal flat, to clear the effects of slope of tidal flat and breaking wave height on seawater infiltration and to quantify the infiltration volume of seawater. For purpose, the seawater infiltration was studied with visualization method by using coloring tracer and transparent glass beads replaced as natural sediment in model tidal flat. Specific conclusions derived from this study are as follows. The semi-circular type infiltration of seawater by wave action into saturated sediment was a new infiltration behavior that was not considered in previous studies. The infiltration rate of seawater was increased with increasing of breaking wave height and slope of tidal flat. However, the effects of the slope was bigger than that of breaking wave height on seawater infiltration into tidal flat sediments. It was possible to calculate the infiltration volume of seawater by wave action in natural tidal flat sediment and in fields. Therefore, we can point out that wave action play an important role in the supply of dissolved oxygen, nutrients and organic matter to benthic organisms, transportation or diffusion of pollutants and seawater purification. So, we hope to be studied the supply of food to benthic organism, pollutant transport and seawater purification on the base of these results.