넙치 Paralichthys olivaceus 의 초기생활사에 미치는 해수 이산화탄소 농도와 수온의 영향

Abstract

Since the industrial revolution, CO2 in atmosphere has been increased rapidly from 280 ppm to 400 ppm. Greenhouse effect caused by enhanced atmospheric CO2 has resulted in global warming, and about one third of CO2 in atmosphere dissolved into the ocean, which causes ocean acidification. Due to the high rate of CO2 increase, therefore, marine ecosystem in world ocean have seriously been influenced by global warming and ocean acidification. Oceanic pH already decreased 0.1 unit compared to the pre-industrial times and these impacts were observed around the ocean. In this study, we investigated the effects of ocean acidification and global warming on the early life stage of marine fishes, olive flounder Paralichthys oliveceus. To figure out biological response to environmental changes, olive flounder were reared from fertilized egg to metamorphosis stage for four weeks in the various carbon dioxide concentration (479, 838, 1422 μatm pCO2) and water temperature (18 and 22℃). The result of this study indicated that total length and wet weight (i. e., growth) had a tendency of increase with inhanced CO2 concentration at 18℃ (p<0.05). However, at 22℃, this tendency reversed. Condition factor (K) was not changed significantly by the various level of CO2 concentration and water temperature. Otolith size was increased with inhanced CO2 concentration. At the present CO2 concentration, total length, wet weight and growth rate display a tendency of increase with temperature increase. At the enhanced CO2 concentration, however, this tendency was weak or reverse. Furthermore, the incidence of skeleton malformation was increased with inhanced CO2 concentration. Also, frequency of malformation was high at both temperature conditions (18 and 22℃). It means that the synergistic impact of high temperature and low pH seems to negative for olive flounder larvae.