• Journal of Marine Life Science
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• v.5 no.2
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• pp.58-63
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• 2020

The ascidian Halocynthia aurantium (sea peach), which belongs to the phylum Chordata, is thought to be a valuable organism of aquaculture like H. roretzi (sea pineapple), but its biological characteristics such as development and ecology are not well known. In this study, in order to obtain basic data for H. aurantium farming, the development processes of H. aurantium inhabiting the east coast of Gangwon-do were investigated and compared with those of H. roretzi, a related species. As a result, the morphology and developmental stages of the fertilized eggs, embryos and larvae of H. aurantium were very similar to those of H. roretzi. Fertilized eggs of H. aurantium took about 42.1 hours to hatch at 11℃, almost similar to 40.9 hours of H. roretzi. The time required for larvae to metamorphose into juveniles after hatching was very similar between the two species. The hatched larvae of the two species became juveniles with oral and atrial siphons after 23 days at 11℃. Both types of embryos developed slowly in seawater at low temperatures and rapidly developed at high temperatures. Fertilized eggs of H. aurantium hatched in an average of 62.3 hours at 9℃, 42.1 hours at 11℃, and 36.3 hours at 13℃, whereas those of H. roretzi hatched in an average of 60.4 hours, 40.9 hours, and 35.2 hours. Most of H. aurantium embryos did not develop normally above 15℃, so it is thought that attention is needed in the seed production processes.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.530-538
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• 2023

This study conducted an investigation into the effects of fruit type and cultivation practices (organic and conventional) on soil characteristics and soil arthropod communities within apple, blueberry, grape, peach, and pear orchards. The collection of soil arthropod communities was achieved through the utilization of pitfall traps, with concurrent measurements taken for soil moisture content, electrical conductivity, and temperature. The findings of this study unveiled substantial impacts attributed to fruit type and cultivation practices on soil characteristics. Specifically, within organic apple orchards, discernibly higher levels of soil moisture content, electrical conductivity, and temperature were observed when compared to their conventional counterparts. The investigation into soil arthropod communities yielded a total of 1,527 individuals, classified in to five phyla and 15 orders. The range of abundance, species richness, and diversity indices varied across conventional and organic orchards. Cultivation practices were found not to exert a significant influence on soil arthropod community characteristics. However, Non-metric Multidimensional Scaling (NMDS) analysis indicated a significant differentiation in soil arthropod community structure based on cultivation practices. This study underscores the importance of considering vegetation structure and environmental characteristics that may influence soil arthropod communities comprehensively when assessing the impact of cultivation practices on soil arthropods. Furthermore, it emphasizes the need to account for both the characteristics and structure of soil arthropod communities in understanding the implications of cultivation practices on these organisms.