碩士 / 國立中興大學 / 生命科學系所 / 106 / Since the Industrial Revolution, the concentration of carbon dioxide (CO2) in the atmosphere has risen rapidly, resulting in ocean acidification (OA) and warming, which has threatened coastal ecosystems. Highly productive seagrasses usually live adjacent to or among coral reefs and can absorb CO2 in seawater, regulate the pH and the aragonite saturation state (ΩAr). The purpose of this study was to use coral reefs mesocosms to examine the effects of seagrasses on coral reef ecosystems under OA and warming. The net ecosystem production (NEP) was used to determine the functioning of the mesocosms. Three mesocosms without seagrass and three mesocosms with seagrass were designed to conduct four stages of OA and warming experiments. A non-acidified CO2 partial pressure of 400 ppm was used as control and 800 ppm was used as the OA scenario. The first stage was unacidified and 25˚C; the second stage was OA and 25˚C; the third stage was OA and warmed up to 28˚C; the fourth stage was OA and the temperature was raised to 31˚C. The results showed that under the OA scenario, the coral calcification rates with seagrasses were higher in OA (25˚C) and OA (28˚C) than without seagrasses. In addition, the OA scenario proliferated the macroalgae, and the growth rate of macroalgae without seagrasses was higher than that with seagrasses. Therefore, OA (25˚C) significantly increased the NEP of the mesocosms without seagrasses, but OA had no effect on the NEP of the mesocosms with seagrasses. Ecosystem respiration (ER) increased gradually with increasing temperature under the scenario of OA, but gross primary production (GPP) in OA (28˚C) reached the maximum, then dropped in OA (31˚C). Due to the high temperature environment of 31 ̊C, the growth rate of macroalgae reduced and the mortality increased. The mesocosms without seagrasses dropped sharply at OA (31˚C) by 0.93±0.22 g O2 m-2 d-1, while the mesocosms with seagrasses decreased moderately by 0.68±0.13 g O2 m-2 d-1. Under the condition of OA and warming in the future, seagrasses can maintain the calcification rate of corals. Seagrasses can inhibit the growth of macroalgae, caused the magnitude of NEP declined less and maintain the stability of coral reef ecosystems at a high temperature of 31˚C.
| Identifer | oai:union.ndltd.org:TW/106NCHU5105051 |
| Date | January 2018 |
| Creators | Shin-Jing Ang, 洪靜 |
| Contributors | Hsing-Juh Lin, Pi-Jen Liu, 林幸助, 劉弼仁 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 99 |
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