Effects of thermal stress on fertilization and early embryogenesis in coral species from the Great Barrier Reef and Japan

Favites chinensis colonies were collected from the reef flat off Sesoko Island, Okinawa and transported to aquaria at Sesoko Station. After spawning, sperm and eggs were separated and then used in fertilization experiments at 7 temperatures (25.5, 26.4, 27.0, 27.8, 28.9, 30.2 and 31.6°C). Early fertilization (first and second cleavage) was assessed after 3 hours using a dissecting microscope.Acropora millepora were collected from Davies Reef on the Great Barrier Reef and transported to aquaria at the Australian Institute of Marine Science. Similar fertilization experiments were carried out at 28.3, 30.4, 31.8, 32.8 and 34.1°C. Embryos were sampled at 2 and 4 hours, fixed in Bouins solution and later assessed for fertilization success and gamete quality.Acropora millepora, Favites abdita and Mycedium elephantotus, were collected from Davies Reef. In this experiment, eggs and sperm were separately pre-exposed to temperatures of 26, 28, 30 and 32°C for 30 minutes prior to fertilization at these tempertures. The embryos were sampled and fixed at 2 and 4 hours and assessed for fertilization success, abnormal embryo development and cell cleavage rates.
This research was undertaken to examine the influence of seawater temperature on fertilization success and early embryogenesis of reef-building corals, in different families, from the Great Barrier Reef and Japan. Gametes were subjected to temperatures ranging from 2°C below average temperatures during the spawning period at each location to 5-6°C above average, which encompasses the range of increases that might be expected under climate change scenarios.

中华扁脑珊瑚（Favites chinensis）群体采集于冲绳县濑户岬岛附近的礁坪，并转运至濑户岬站的水族箱中。产卵后，精子与卵子分离，随后用于7个温度（25.5、26.4、27.0、27.8、28.9、30.2及31.6°C）下的受精实验。3小时后，使用解剖显微镜评估早期受精情况（第一次和第二次卵裂）。鹿角杯形珊瑚（Acropora millepora）采集于大堡礁的戴维斯礁，转运至澳大利亚海洋科学研究所的水族箱中。类似的受精实验在28.3、30.4、31.8、32.8及34.1°C下进行。胚胎在2小时和4小时时取样，用布恩氏液固定，随后评估受精成功率和配子质量。鹿角杯形珊瑚（Acropora millepora）、隐伏扁脑珊瑚（Favites abdita）及象耳滨珊瑚（Mycedium elephantotus）采集于戴维斯礁。本实验中，卵子与精子在受精前分别于26、28、30及32°C温度下预暴露30分钟，随后在相同温度下受精。胚胎在2小时和4小时时取样固定，评估指标包括受精成功率、胚胎发育异常情况及细胞卵裂速率。
本研究旨在探究海水温度对来自大堡礁及日本的不同科造礁珊瑚受精成功率及早期胚胎发生的影响。配子所暴露的温度范围为各地点产卵期平均温度以下2°C至以上5-6°C，该范围涵盖了气候变化情景下预期的温度升高区间。