제주에 서식하는 Ulva pertusa Kjellman의 환경적 요인에 따른 유기물 및 무기물 함량의 계절적 변화

Abstract

The enormous flow of nutrients into seawater has frequently led to massive blooms of the intertidal algae Ulva pertusa. Intertidal algae experience a variety of stressful environmental conditions that can stimulate or inhibit their biosynthesis. For this reason, intertidal algae can be used as an indicator of the state of the nutrient cycling system in coastal water. Therefore, to both understand the ecological features of U. pertusa and to evaluate the condition of ecosystems in Jeju, we analyzed the levels of the organic and inorganic components of U. pertusa alongside various environmental factors over a 2-year period, through the use of Pearson’s multiple range tests at p < 0.05 (SPSS version 12.0). Environmental factors such as air and water temperatures, salinity, and rainfall displayed a clear seasonal variation and the greatest fluctuation was observed during the summer-autumn seasons (June to October). The environmental factors were significantly related (p < 0.05). Organic and inorganic components of U. pertusa displayed strong seasonal variability. Organic components (e.g., proteins, lipids and amino acids) displayed significant seasonal variation (p < 0.05) and these components had strong positive correlations with carbon (C), nitrogen (N), and phosphorus (P) (p < 0.05). Inorganic components (e.g., ash, Ca, Fe, Cu, and Zn displayed significant seasonal variation (p < 0.05), and these components had a strong negative correlation with C and N (p < 0.05). Our results also revealed that carbohydrate levels were affected by decreasing mineral concentrations, particularly Ca, Fe, Cu and Zn. (p < 0.05). These minerals acted inversely with carbohydrate and were all significantly affected by N and C levels. U. pertusa had a C:N ratio higher than 9.6 and the values were higher in 2011 than in 2010. A C:N ratio higher than 9.6 is an indication of nitrogen limitation. Accordingly, our study suggests that U. pertusa experienced more nitrogen limited conditions in 2011 than in 2010. In this study, an ecological significance was identified between the various environmental factors and biochemical components of U. pertusa. Our findings improve our understanding and evaluation of not only the biochemical features of U. pertusa but also the nutrient conditions of coastal water in Jeju.