Physiological Responses of Gray Mullet Mugil cephalus to Low-pH Water

Abstract

We examined changes in the physiological responses of gray mullet Mugil cephalus exposed to acidic seawater (pH 6.0, 6.5, 7.0) and normal seawater (pH 8.0, control) for 15 days. As pH decreased, survival rate and body weight also decreased. Levels of aminotransferase, total protein and triglycerides also differed significantly with changes in pH, presumably due to stress caused by exposure to acidic water. The level of osmotic pressure was significantly higher in the pH 6.0 group than in other groups. Superoxide dismutase was significantly higher in the pH 6.5 and 7.0 groups than in the pH 8.0 group, and glutathione level was lowest in the pH 6.0 group. We conclude that decreasing the pH level of seawater induces a stress response in fish, damaging their ability to control their hematological and osmotic pressure. Antioxidant enzymes are generally sensitive to osmotic stress; in this study, antioxidant activity significantly changed with pH level. These results indicate that physiological stress induced by exposure to acidification reduces survival rates and inhibits growth in M. cephalus.

A Study on the Impacts of Paste Type Torrefied Wood Flour Coagulants on Water Ecosystem

“…기존 반탄화목재에 대한 연구는 반탄화목분의 용도 확대를 위해 고효율 연료 (Lee et al, 2016)의 개발과 항산화활성 분석 (Nam et al, 2018) (Moon et al, 2017). 또한, 수중의 수소이온농도가 9 이상이 되면 수중생물의 피부의 출혈 등의 피해를 발생시키며, 수소이온농도 6 이하에서는 수중생물의 생육의 곤란 및 어폐류의 사멸 등에 직접적인 영향을 미친다 (Park et al, 2016).…”

“…This is because phytoplankton depletes carbon dioxide in the water during photosynthesis during the day, causing the water to become alkaline. Even slight changes in pH become stressors to marine organisms, causing various physiological effects(Moon et al, 2017). In addition, if the concentration of hydrogen ion in water is more than 9, it causes damage such as skin bleeding of aquatic organisms, and, if below 6, directly affects them, causing difficulty in growth of aquatic organisms and even death of fish and shellfish(Park et al, 2016).…”