- 期刊
- OpenAccess
利用人工養殖珊瑚評估珊瑚骨骼化學組成作為古環境代用指標之應用
A Feasibility Evaluation of Using Coral Chemical Compositions as Climate Proxies: Tank Study
摘要
珊瑚骨骼的化學組成，被視為是回推古氣候的重要工具，為了解各種環境因子對珊瑚骨骼化學與同位素組成的影響，進而評估其用於古氣候重建的可靠性，本研究在實驗水箱中養殖珊瑚，取得在特定溫度及光度下所生長的微孔珊瑚骨骼，並配合各式電極及資料截取設備連續監測水箱中溫度、光度、溶氧量、pH等變化，同時利用硼同位素及有機染色等方法對實驗期間所生長之珊瑚骨骼進行標定。雷射剝蝕感應耦合電漿質譜儀分析結果顯示，在相同溫度下生長的珊瑚骨骼。其鍶及鋇等微量元素，在空間分布上的不均勻性極高，鍶/鈣變化可達200%。意味在微觀尺度下，溫度並非影響珊瑚骨骼鍶/鈣變化的唯一變因。鋇的濃度僅在骨骼表面珊瑚組織生長處有急遽升高的現象，顯示鋇的分布與有機質密切相關。水箱培養的珊瑚骨骼，其同位素值為千分之26.3到千分之24.1之間，且與生長溫度呈負相關，可能係導因於珊瑚呼吸作用與共生藻光合作用改變水中pC0_2。同一珊瑚群體在相同生長條件下，不同生長位置的骨骼，其氧阿同位素差異達千分之1.2，碳同位素差異可達千分之2.5。綜合珊瑚骨骼，海水化學組成及連續監測之環境參數，可系統性評估珊瑚骨骼環境代用指標的基本機制，為環境變遷研究提供重要資訊。
並列摘要
The chemical compositions of coral skeleton have been used as one of the most important tools to reconstruct the paleo-climatic condition in the past ocean. To evaluate the feasibility of using coral chemical compositions as climatic proxies, Porites were cultured under various temperature in controlled tanks. The temperature, light intensity, dissolved oxygen and pH of these tanks was continuously monitored. The quantitative analyses of Sf and Ba concentration in Porites skeleton were carried by rep-MS. Our results show that the chemical compositions in high spatial resolutions coral skeleton are extremely heterogeneous, with more than 200% Sr/Ca variations on sub-mm scale. Large deviations from theoretic trend of B. C and O isotope also were observed. These results suggest that temperature may not be the dominated factor influencing trance element distribution of coral in short-time scale.