• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.138-143
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• 2011

The efficiency of mtCOI amplication after DNA extraction of benthic harpacticoid Tigriopus japonicus s.l. was tested under different conditions depending on fixative (99% Ethanol, or 4% Formalin) and additional chemicals (Ludox or Rose Bengal). Each experimental group by the fixative was subdivided into four groups, respectively: 1) Control (fixative only), 2) processed with Ludox HS40, 3) processed with Rose Bengal, and 4) processed with both Ludox HS40 and Rose Bengal. For the 99% ethanol-fixed sample, overall success rate of amplification by PCR was 96% or above, while for the 4% formalin-fixed one, success rate was much lower than those of ethanol-fixed: 1) Control: 27%, 2) Ludox HS40: 3%, 3) Rose Bengal: 7%, and 4) Ludox HS40 and Rose Bengal: 3%. As a result present study verify that 99% ethanol is a proper fixative for DNA extraction in meiofauna organisms.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.159-171
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• 2001

Community structure, horizontal distribution, density, and ratio between nematodes and benthic harpacticoid copepods of the meiobenthos within the sediments of inner Sihwa Lake were investigated in May 1999 and May 2000. A total of 11 and 8 classes of meiobenthic animals were identified in 1999 and 2000, respectively, which were much lower than other coastal areas. The dominant animals during both sampling periods was the nematodes, followed by sarco-mastigophorans, nauplius of crustaceans, benthic harpacticoid copepods and polychaetes. These five classes of animals comprised more than 90% of total abundance of neiobenthos presented in the samples. In 2000, a lot of polychaete larvae were identified. The most abundant animal were the size that fits in 0.063 mm sieve size. Lower density was observed upper inner part of the Sihwa Lake during both sampling periods, and higher density was observed around the Sihwa floodgates. The average density between those two numbers were observed in the samples collected in the middle of the lake. Lower nematodes to betnhic harpacticoides (N/C) ratio, a relative indicator of environmental pollution, was observed to be lower around the floodgate but higher ratios were observed in the upper inner Sihwa Lake. The present study indicated that inner upper part of the lake becomes unsuitable for the meiobenthos, and the most inner upper lake was considered to be polluted.

• Korean Journal of Environmental Biology
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• v.32 no.2
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• pp.138-152
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• 2014

The objective of the study survey was to determine the effect of marine sand extraction on community composition and rate of recolonization of the meiobenthos following cessation of mining activities. Because of meiobenthic distribution in nature, high abundance, intimate association with sediments, fast reproduction, benthic larva period, sensitivity to pollution and rapid life histories, meiobenthos are widely regarded as ideal organisms to study the potential ecological indicator of natural and anthropogenic stresses. The community structure of meiobenthos was studied at seven stations within sandy tidal and sub tidal zones in Jangbongdo in the Yellow Sea, Korea from Aug. 2006 to Dec. 2007. Meiobenthic samples were collected by three core samples, with a 3.6 cm in diameter, from each sediment sample taken with a Smith-McIntyre Grab. It was found that sand mining often causes complete removal of the sediment and the damage to the habitats of meiobenthos. This study in the effect showed that sand mining resulted in a reduction in total abundance and biomass of meiobenthos in mining area. The finding of this study further showed that initial restoration of abundance and biomass within one year of the cessation of sand mining.

• Korean Journal of Environmental Biology
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• v.18 no.2
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• pp.279-290
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• 2000

To alleviate the harmful effects from contamination, the Sihwa Lake waters have been regularly fluxed out into the ocean to mix and circulate with the oceanic waters, and then allowed to flow back into the lake. In the present study, eco-environmental impacts by the outflowing contaminated lake waters to the benthic communities of the coastal zones along Kyonggi Bay were examined at three separate areas. A total of 22 groups of meiobenthic animals were commonly found in the subtidal zones of the Bay. All groups of the meiobenthic animals on the 1st and 7th days after the outflow were remarkably reduced in numbers from the selected areas examined, as compared to those observed one day before the outflow. It was also found that the community structure of meiobenthos was changed drastically: At the station near the water gate, for example, where the immediate outflow of the lake water was encountered, the benthic harpacticoids, the group observed to be one of the predominant groups before the outflow, were found to have disappeared completely. For an area that was relatively far away from the water gate, the reduction rate of meiobenthos after the outflow events was slower and more gradual than the nearer sites. An area that is the farthest from the water gate, no reduction in any of the meiobenthos group was observed. The ratio between nematodes/copepods (N/C) was remarkably changed by the outflows at the station near the water gate: One day before the outflow, the ratio was 0.7 while the ratio was 19.0 at the station near the water gate. In contrast, at the stations relatively far from the water gate, the ratio decreased one day after the outflow event, but increasing trends were observed one week later. In the tidal flats, Station 1 exhibited the common observed regional values of the ratio whereas Station 2 showed a very high ratio of 191.3. The results suggested that the contaminated lake water outflows directly effect meiobenthos in a relatively short time period and thus the meiobenthos may be a good indicator animal group for examining the effect of pollution. [Lake Sihwa, contaminat water outflow, meiobenthic animals living]

• Ocean and Polar Research
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• v.26 no.2
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• pp.265-272
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• 2004

This study was conducted to investigate the community structure and distributional pattern of meiobenthos in the deep-sea bottom of the Clarion-Clipperton Fracture Zone of northeastern Pacific during July 2001. Examination of sediment samples collected on the eight survey station showed that there were 10 different types of meiobenthos. The most abundant meiobenthic animals were nematodes in all stations. Sarcomastigophorans, benthic harpacticoids were next abundant meiobenthos. Vertical distribution of meiobenthic animals showed the highest individual numbers in the surface sediment layers of 0-1 cm depth and showed more steep decreasing trend as sediment gets deeper on the stations of high latitude located in $16-17^{\circ}N$. Horizontal distribution of meiobenthic animal in the study area within CCFZ showed high densities of meiobenthos at the stations had few manganese nodules on their sediment surface in the site of low latitude. For size distribution analyses showed that animals which fit into the sieve mesh size of 0.063 mm were abundant.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.1
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• pp.42-47
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• 1997

This study was carried out to investigate the faunal composition and distribution pattern of meiobenthic community in the deep sea sediments of northeastern Pacific Ocean. Faunal samples were collected at 10 stations using a multiple corer and a spade type box corer during May 1996. A total of 18 meiofaunal groups were found, and Sarcomastigophora was the most dominant group which accounted for 35.8% of total meiofaunal abundance. Nematoda (30.8%), Nauplius larvae of Crustacea (11.9%), Ciliophora (6.8%) and Harpacticoida (3.0%) which were also important components of the meiofaunal community. All of these five faunal groups comprised more than 90% of total meiofauna. The highest density of 195 ind./10 $cm^2$ was found at St. 4 (4960 m water depth), but the lowest one, 85 ind./10 $cm^2$ at St. 1 (4969 m water depth). The overall mean density of meiofauna was estimated as $1.34{\times}10^5\;ind./m^2$. The abundance of meiofauna showed a slow decreasing trend along the water depth. The highest density was observed in the upper 1 cm and density decreased drastically with increasing depth from the surface.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.1 no.2
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• pp.73-79
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• 1996

This study was conducted to investigate the faunal composition and distribution patterns of macrobenthic community in the deep sea sediments of the KODOS area, the northeastern Pacific Ocean during May 1996. Benthic animals were collected at 25 stations using a spade type box corer. Sediments were sieved through -.3 mm mesh screen. A total of 17 faunal groups in 9 phyla and 363 specimens were identified. Nematoda was the most abundant faunal group which accounted for 30.0% of total abundance. Other dominant faunal groups were foraminiferans (25.1%), harpacticoids (10.2%), xenophyophores (5.2%), and polychaetes (4.7%), Polychaeta was a typically dominant component of macrobenthic community in the study area except traditionally recognized meiofauna taxa. Mean occurrence number of faunal taxa was ca. 6 per 0.01 m$\^$2/, and mean density was estimated as 1,288 indiv./m$\^$2/. The abundance of whole fauna and that of each faunal group was highest at the surface layer of sediment, and decreased monotonously along the sediment depth; 98% of faunal abundance was found within 10 cm depth layer.

• Ocean and Polar Research
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• v.26 no.2
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• pp.255-263
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• 2004

This study was conducted to investigate the community structure and distributional pattern of meiobenthos in the deep-sea bottom of the Clarion-Clipperton Fracture Zone of the northeastern Pacific during July 2003. The samples were collected using the multiple corer at 13 stations along the transects fiom $5^{\circ}N\;to\;17^{\circ}N$. The most abundant meiobenthos was nematodes and followed by sarcomastigophorans; these two taxa comprised more than 70% of the total abundance at all stations. For size distribution analyses showed that animals which fit into the sieve mesh size of 0.063mm were abundant. The maximum density of meiobenthos was $147inds./10cm^2$ at station located in $7^{\circ}N$, and the minimum density was $6 inds./10cm^2$ at station located in $14^{\circ}N$. More than 60% of meiobenthos were distributed at surface sediment layer within 1.0cm, and the peak abundance was found at $0{\sim}0.25cm$ layer. The latitudinal distribution pattern of meiobenthos in the study area seemed to be related with the primary productivity of the surface water that is also connected to the water circulation pattern of the Pacific Ocean near the Equator, diverging at latitude of $8^{\circ}N$ and conversing at $5^{\circ}N$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.307-319
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• 2000

Community structure (seasonal fluctuation), taxon diversity, nematodes/benthic harpacticoids and nematodes/kinorhynchs ratios of meiobenthos were studied in the Gamak Bay, Korea. A series of samplings were carried out from April 1997 to May 1999. Meiobenthic organisms was collected by van Veen grab and three subcores of 34 mm in internal diameter were taken from each sediment sample. The total density of meiobenthos in each seasons was found to be the highest in May 1999, and the lowest in December 1998. Total density of meiobenthos at each station was the highest at Station 9 in May 1999 ($2,218 inds./10 cm^2$) and the lowest at Station 3 in December 1998 ($2 inds./10 cm^2$). The Gamak Bay seemed to have an individual number increased from the inner toward the outer stations. The highest number of meiobenthos was observed on 0.125 and 0.063 mm mesh size. In every season, over $80{\%}$ of the meiobenthos was composed of only four groups: nematodes, benthic harpacticoids, sarcomastigophorans and nauplius larvae of crustaceans. Seasonal fluctuation of meiobenthos was also studied. The nematodes/benthic harpacticoids(nematodes/kinorhynchs) ratios were studied as an index of pollution monitoring for benthic ecosystem at each station in each season. The value of nematodes/benthic harpacticoids ratio was the highest at the inner stations and the lowest at the outer stations in the Gamak Bay. Taxon diversity (H') was the highest at the outer stations and the lowest at the inner stations in the Gamak Bay. The value of nematodes/benthic harpacticoids ratio significantly increased from the outer toward the inner stations, whereas the taxon diversity (H') significantly increased from the inner toward the outer stations in Gamak Bay.

• Ocean and Polar Research
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• v.23 no.2
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• pp.109-119
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• 2001

Meiobenthic community structure of tidal flats near the Yeonggwang Nuclear Power Plant have studied during summer (June) and fall (October) 1997. Examination of sediment samples collected along the transects showed that there were 18 different types of meiobenthos in the study area. The most abundant meiobenthic animals belonged to Phylum Nematoda in both seasons and all transects. However, sediment samples collected near discharge areas, transects A and B, showed relatively lower abundance than other general coastal areas. Another abundant meiobenthic organism is benthic Harpacticoids which is very sensitive to any environmental changes. Polycheats and Ostracods were next abundant meiobenthos which also showed the difference between the study area and other general coastal areas. Only transect C maintained similar meiobenthic abundance and diversity to other coastal areas. Horizontal distribution for transects A and B showed higher densities in upper and mid tidal flat zones. On the other hand, transect C which is located furtherest from the discharges showed an increasing trend in abundance from upper to lower areas. For size distribution analyses showed that animals which fit into the meshsize of 0.125 mm were abundant, Vertical distribution of meiobenthic animals within the sediments for both sampling seasons showed the highest individual numbers in the surface sediment layers of 0-1 cm depth and showed a decreasing trend as sediment gets deeper. Each class of meiobenthos had different vertical profiles. When comparing survey transects A and B with other similar tidal flat areas, this sites seems to a very unstable environment of tidal flats near the Yeonggwang Nuclear Power Plant.