Study on skeletal records of coral bleaching and past high seawater temperature events

珊瑚白化和过去高海水温度事件的骨骼记录研究

• 批准号: 16540433
• 负责人: SUZUKI Atsushi
• 金额: $ 2.37万
• 依托单位: National Institute of Advanced Industrial Science and Technology (AIST)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540433/
• 关键词: Coral; skeleton; coral bleaching; Global warming; seawater temperature; oxygen isotope ratio

Frequent coral bleaching has been observed in tropical and subtropical seas during the last three decades. These recurrent coral bleaching events may be a response to global warming. The influence of bleaching on the isotopic composition of coral skeletons has been controversial. Some studies reported clear changes associated with bleaching events, while these changes remained less evident in other reports. Since bleaching can result in a substantial decrease in skeletogenesis, a very fine sampling technique would be needed to detect the corresponding isotopic changes in the coral skeleton. We introduce a recent progress achieved by a high-resolution skeletal isotope microprofiling technique. Using the technique, bleached corals from Pandora Reef, Great Barrier Reef and Ishigaki Island, Japan showed a dramatic decrease in skeletogenesis, together with a reduction in the carbon isotopic composition, coincident with the worldwide severe bleaching event in 1997/98. Such changes are consistent with the hypothesis that reduced photosynthesis acts to decrease the carbon isotopic composition of the skeleton. However, the drastic reduction in growth would lead to an increase in carbon isotope ratios and may have resulted in subduing the ^<13>C-response to bleaching. The results indicate that isotopic microprofiling may be the key to identifying gaps in coral growth that are diagnositic of past bleaching events.

过去三十年来，在热带和亚热带海域观察到珊瑚频繁白化。这些反复发生的珊瑚白化事件可能是对全球变暖的反应。白化对珊瑚骨骼同位素组成的影响一直存在争议。一些研究报告了与漂白事件相关的明显变化，而在其他报告中这些变化仍然不太明显。由于白化会导致骨骼生成大幅减少，因此需要非常精细的采样技术来检测珊瑚骨骼中相应的同位素变化。我们介绍了高分辨率骨骼同位素显微分析技术最近取得的进展。使用该技术，来自潘多拉礁、大堡礁和日本石垣岛的白化珊瑚显示出骨骼生成显着减少，碳同位素成分也减少，与 1997/98 年全球严重白化事件同时发生。这些变化与光合作用减少会降低骨架碳同位素组成的假设是一致的。然而，生长的急剧减少将导致碳同位素比率的增加并且可能导致减弱对漂白的 13 C-响应。结果表明，同位素微分析可能是识别珊瑚生长间隙的关键，从而诊断过去的白化事件。

项目成果

Skeletal oxygen and carbon isotope records of coral bleaching.

珊瑚白化的骨骼氧和碳同位素记录。

• 发表时间: 2004
• 期刊: Chikyukagaku (Geochemistry) 38
• 作者: Suzuki;A.;Kawahata H.
• 通讯作者: Kawahata H.