• Journal of Marine Life Science
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• v.2 no.2
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• pp.75-82
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• 2017

Macrobenthos composes the dominant biomass at the mudflat and play an important role in the maintenance of the benthic environments. Organic matter in sedimentary environment affects habitat, feeding behaviors, and survival of benthos. In this study, the relationship between organic matter content in sediment and the distribution of macrobenthos was discussed at two margins (Mokpo and Aphae area) in the mouth of Muan bay. Sediment TOC was higher at Mokpo than at Aphae through the four seasons, and the pollution indicator organism Musculista senhousia was dominant in this area. The macrobenthos distribution was clearly divided into two areas correlated with sediment organic matter content in the mouth of Muan bay.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.143-150
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• 2012

To determine the spatial distribution of marine invertebrate communities in intertidal rocky shore on Dokdo, 10 times investigation was carried out at 7 stations during the year of 2009~2011. The marine invertebrate community can be divided into three different groups based on cluster analysis of Bray-Curtis similarity. As a first group, the pebble beach community, Omphalius rusticus, Monodonta perplexa, and Chlorostoma lischkei which were movable gastropod with dominant occurrence. Secondly, the still rocky shore community, O. rusticus, Serpulorbis imbricatus and Aplysia kurodai occurred dominantly. Finally, the wave-exposed rocky shore community which dominantly occurred by two sessile arthropods, Barnacles, Chthamalus challengeri and Pollicipes mitella. The three groups were likely to be determined by texture of substrate and hydrodynamic conditions of rocky shore in Dokdo. The results indicated that diversity of marine intertidal invertebrate community around Dok do was mainly affected by habitat characteristics and the surrounding physical properties.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.179-188
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• 2020

The influx of marine exotic and alien species is disrupting marine ecosystems and aquaculture. Herdmania momus, reported as an invasive species, is distributed all along the coast of Jeju Island and has been confirmed to be distributed and spread to Busan. The potential habitats and distribution of H. momus were estimated using the maximum entropy (MaxEnt) model, quantum geographic information system (QGIS), and Bio-ocean rasters for analysis of climate and environment(Bio-ORACLE), which can predict the distribution and spread based only on species occurrence data using species distribution model (SDM). Temperature and salinity were selected as environmental variables based on previous literature. Additionally, two different representative concentration pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) were set up to estimate future and potential habitats owing to climate change. The prediction of potential habitats and distribution for H. momus using MaxEnt confirmed maximum temperature as the highest contributor(77.1%), and mean salinity, the lowest (0%). And the potential habitats and distribution of H. momus were the highest on Jeju Island, and no potential habitat or distribution was seen in the Yellow Sea. Different RCP scenarios showed that at RCP 4.5, H. momus would be distributed along the coast of Jeju Island in the year 2050 and that the distribution would expand to parts of the Korea Strait by the year 2100. RCP 8.5, the distribution in 2050 is predicted to be similar to that at RCP 4.5; however, by 2100, the distribution is predicted to expand to parts of the Korea Strait and the East Sea. This study can be utilized as basic data to effectively control the ecological injuries by H. momus by predicting its spread and distribution both at present and in the future.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.194-207
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• 2021

It is necessary to assess and manage the different elements of the marine ecosystem, such as climate change, habitat, primary and secondary production, energy flow, food web, potential yield, and fishing, to maintain the health of the ecosystem as well as support sustainable development of fishery. We set up an ecosystem model around the Korean peninsula to produce scientific predictions necessary for the assessment and management of marine ecosystems and presented the usability of the model with scenario experiments. We used the Atlantis ecosystem model based on the marine food web; Atlantis is a three-dimensional end-to-end model that includes the information and processes within an entire system, from an abiotic environment to human activity. We input the ecological and biological parameters, such as growth, mortality, spawning, recruitment, and migration, to the Atlantis model via functional groups using existing research and local measurements. During the simulation period (2018-2019), we confirmed that the model reproduced the observed data reasonably and reflected the actual ecosystem characteristics appropriately. We thus identified the usability of a marine ecosystem model with experiments on different environmental change scenarios.

• Mycobiology
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• v.48 no.6
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• pp.431-442
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• 2020

Penicillium, the most common genus plays an important ecological role in various terrestrial and marine environments. However, only a few species have been reported from rhizosphere soil. As part of a project to excavate Korean indigenous fungi, we investigated rhizosphere soil of six plants in the forest (terrestrial habitat) and sand dunes (coastal habitat) and focused on discovering Penicillium species. A total of 64 strains were isolated and identified as 26 Penicillium species in nine sections based on morphological characteristics and the sequence analysis of β-tubulin and calmodulin. Although this is a small-scale study in a limited rhizosphere soil, eight unrecorded species and four potential new species have been identified. In addition, most Penicillium species from rhizosphere soil were unique to each plant. Penicillium halotolerans, P. scabrosum, P. samsonianum, P. jejuense, and P. janczewskii were commonly isolated from rhizosphere soil. Eight Penicillium species, P. aurantioviolaceum, P. bissettii, P. cairnsense, P. halotolerans, P. kananaskense, P. ortum, P. radiatolobatum, and P. verhagenii were recorded for the first time in Korea. Here, we provide the detailed morphological description of these unrecorded species.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.198-204
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• 2018

Background: The effective use of habitats is essential for the successful adaptation of a species to the local environment. Although habitats exhibit a hierarchical structure, including macro-, meso-, and microhabitats, the relationships among habitats of differing hierarchy have not been well studied. In this study, we studied the quantitative measures of microhabitat use of Gekko japonicus from three field populations in Japan: one at Tsushima Island, one at Nishi Park, Fukuoka, and one at Ohori Park, Fukuoka. We investigated whether land cover type, a higher hierarchical habitat component, was associated with quantitative microhabitat use, a lower hierarchical component, in these populations. Results: The substrate temperature where we located geckos (SubT) and the distance from the ground to the gecko (Height) were significantly different among the three populations. In particular, SubT on Tsushima Island was lower than it was in the other two populations. Irradiance at gecko location and Height were significantly different among the land cover types. In particular, Height in evergreen needleleaf forest was significantly lower than that in deciduous broadleaf forest. Furthermore, significant interactions between population and land cover type were observed for the SubT and Height variables. Conclusions: The quantitative measures of microhabitat use of G. japonicus varied with population and land cover type, which exhibited significant interaction effects on microhabitat use variables. These results suggest that higher hierarchical habitat components can affect the quantitative measures of lower hierarchical microhabitat use in nocturnal geckos.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.615-625
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• 2021

The coastal areas around Palau Island and Tonga Island, near the Pacific equator, consist of coral reefs, mangrove and seaweed. In particular, understanding the optical properties of sea surface water in coral reef habitats helps improve the accuracy of remote sensing based habitat mapping and identify tropical ecosystem characteristics. Here, we collected spectral characteristics of sea surface water of Palau Island and Tonga Island and analyzed the concentration of suspended matters, absorption coefficient, and remote sensing reflectance to understand the seawater characteristics of the coral reef habitats. Based on the results of the suspended matter concentration analysis, we developed and verified an empirical algorithm to derive the concentration from satellite data using remote sensing reflectance of three bands, 555, 625, 660 nm, showed a high determinant coefficient, 0.98. In conclusion, coral reef habitats in tropical regions are characterized by CASE-I water in terms of the marine optics with oligotrophic properties, and require monitoring using continuous collection and analysis of field data.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.406-425
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• 2019

To observe the seasonal fluctuation of the meiobenthic fauna community around the coastal area of Jeju island, 20 stations were selected and seasonal surveys were conducted. Three-replicate meiobenthic samples were collected from each station in April, July, and November 2017; February, May, August, and November 2018; and February in 2019, in a total of eight months from 2017 to 2019. The total density of meiobenthos at each station ranged from 733 to 2,505 ind. 10 cm^-2. The month in which the highest habitat density appeared in most stations was April 2017 and the month in which the lowest habitat density was seen was February 2019. Nematodes were the most dominant faunal group among the representative 13 meiofaunal groups at all stations. The subdominant groups were benthic harpacticoid copepods and nauplius. The nematode/copepod (N/C) ratio, reflecting the health indices within the ecosystem, varied from 0.02 to 87.40 over the entire season and the average station values ranged from 2.00 to 16.80. The lowest N/C ratio value was found in April 2017 (0.02) and the highest N/C ratio was found at Station 11 in February 2019, which was 87.40, indicating the highest level of pollution. Seasonal and regional meiobenthos community structure similarity was divided into three groups through group analysis and multi-dimensional scaling (MDS) analysis, which showed that the meiobenthos community structure was affected by seasonal variations, rather than by regional differences.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.195-205
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• 2020

Oceanic conditions in walleye pollock habitat in the East Sea have shown decadal fluctuations between warm and cold periods in turn. Specifically, sea surface temperature (SST) has shown a dramatic increase between the late 1980s and the middle 2000s, and abrupt decreasing patterns after the late 2000s. Oceanic conditions in the Dong-han Bay (spawning ground) and middle eastern coastal waters (fishing ground), however, indicated different fluctuation trends in SST, increasing in the Dong-han Bay after the late 1980s, and decreasing after the late 2000s. These fluctuation patterns were especially clear in February and March. Sea surface temperature in the middle eastern coastal waters of Korea soared continuously after the late 1980s, but did not show a distinct decreasing pattern after the late 2000s compared with Dong han Bay, except for February SST values. These long term water temperature changes in both walleye pollock spawning and fishing ground are related to variation in walleye pollock landings. Especially, abrupt changes in spawning ground SST can be one of the factors influencing survival in the early ontogenesis of walleye pollock, including egg and yolk larval stages. During the 1980s, the area of suitable spawning temperature (2-5℃) was wider, and the length of Walleye pollock egg and larval stages greater compared with past and present oceanographic environments. However, such patterns did not correspond with the optimal spawning temperature range and greater length of development of walleye pollock during the late 1980s likely triggering a decline in pollock stock. In conclusion, it has been supposed that the dramatic decrease in walleye pollock landings in the East Sea since the late 1980s was caused by increasing water temperature leading to both early mortality and unsuitable spawning conditions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.25 no.2
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• pp.26-41
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• 2020

In order to culture a life for the physiological and ecological research of the meiofauna, this study aimed to identify the most ideal condition in which the meiofauna can be cultured within a laboratory by setting various environmental conditions. The sediment deposits and seawater were collected from the intertidal zone in Mallipo of the west coast. A aquarium in which the internal environment can be controlled by constantly maintaining the temperature and humidity was fabricated and the culture experiments of the collected meiofauna were conducted together with the sea water and sediment deposits collected. The experiment 1 was conducted after establishing the similar environment as the collecting location. Under the same condition as the experiment 1, the experiment 2 verified a difference between when live foods were supplied and were not. In the experiment 3, the changes in the meiofauna colony were checked according to with or without light and live foods. In the results of culturing experiments, the habitat density and the number of appeared classification groups of the meiofauna colony were relatively higher both in the water tank with supplying the live foods and under the condition of having light in 12-hour cycle than those in the aquarium without live foods and under no light condition. In addition, the habitat density of meiofauna cultured within a laboratory exhibited relatively higher value than that under the natural state.