碩士 / 國立臺灣大學 / 海洋研究所 / 105 / Sexual reproduction is considered as a key factor for the maintenance of broadcast spawning scleractinian coral populations and genetic diversity. In the process of reproduction, gametogenesis pattern and spawning time are the two fundamental stages which do not only influence fertilization but also larval survival. However, suffering from increasing anthropogenic and climatic disturbances, gametogenesis pattern (fecundity and oocytes size) and spawning time of corals are highly influenced, this may lead to a reduction of fertilization success. In this study, we carried out reciprocal transplantation experiment to examine how coral gametogenesis pattern and spawning time change under hyper-thermal and highly variable environment conditions. Two sites in Kenting, Taiwan, with contrasting thermal environments: Outlet of the Nuclear Power Plant (OL) with higher daily mean temperature and daily temperature fluctuation (30.5°C ~ 23.4°C ± 2.1~2.5 °C), and Wanlitung (WLT) with a relatively stable temperature environment (29.7°C ~ 22.6°C ± 1.1~1.2°C), were chosen as the study sites. At each site, five colonies of coral Platygyra verweyi were sampled and separated into three group: maternal colonies, control group (making into nubbins) and transplantation group (making into nubbins and transplanting to another site). Results of fecundity were different from three groups and site. Downsizing and transplantation led to a great number of reduction in fecundity (1/3 or less oocytes per polyp) in the transplantation groups compared to maternal colonies in both sites. Furthermore, fecundity of samples from maternal and control groups in WLT were higher than those in OL, respectively. Fecundity of transplantation groups in both site was lower than maternal colonies and control groups but both transplantation groups were not different from each other. Unlike fecundity, oocyte size was larger in all groups in OL compared to WLT, respectively. However, downsizing had little but not significant impact on oocyte size. Spawning time of downsized nubbins were advanced in control groups in both sites. But spawning time of transplantation groups were the same as maternal colonies in the sites where they have been transplanted. In general, this study showed that downsizing has impacts on fecundity and spawning time which might because of energy re-allocation to growth or regeneration. Besides, temperature anomalies do have effects on oocyte size and spawning time, under extreme environment, corals tend to increase single offspring fitness and sharply define the spawning time in order to increase fertilization success.
| Identifer | oai:union.ndltd.org:TW/105NTU05279001 |
| Date | January 2016 |
| Creators | Ching-Hsin Tsao, 曹景昕 |
| Contributors | Chao-Lun Chen, 陳昭倫 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 55 |
Page generated in 0.0146 seconds