- 學位論文
北臺灣殼狀珊瑚藻所紀錄之環境變遷與成長驗證
Environmental change and growth validation recorded in crustose coralline algae along north coast of Taiwan
摘要
海岸藻礁生態系為潮間帶生物提供結構複雜的棲地，其碳酸鈣礁體也儲存了長時間尺度之環境變遷過程。本研究探討臺灣殼狀珊瑚藻所紀錄之穩定性氮同位素值（δ15N）變化，結果發現約1400年前成長於桃園與北海岸麟山鼻的殼狀珊瑚藻，其δ15N值約為2-3‰，明顯低於現生殼狀珊瑚藻的δ15N值，分別約為10.2 ± 1.2‰（桃園）與5.6 ± 0.9‰（麟山鼻）。此外，生物群聚之δ15N值，於桃園藻礁介於8-20‰，也明顯高於麟山鼻生物群聚之δ15N值（4-11‰），顯示人為汙染已明顯改變藻礁生態系食物鏈之δ15N基礎值，並且以桃園藻礁受到汙染程度較為嚴重。另外，鈣化藻類的碳酸鹽中的氧（δ18O）同位素值可用於建構古海洋之溫度變化，然而前人的研究利用高溫去除藻體有機物的方法，可能會造成鈣化藻類之δ18O值產生分化，而改變原始組成。為瞭解碳酸鹽去除有機物的方法對鈣化藻類之影響，本研究透過四種去有機處理法（無處理、雙氧水分解法、常壓高溫加熱、真空高溫加熱）來移除殼狀珊瑚藻碳酸鹽的有機物質，結果顯示高溫加熱確實會降低殼狀珊瑚藻δ18O值，無處理與雙氧水分解法則不會造成δ18O再分化。這證實了過去的文獻中所提及鈣化藻類的δ18O值不平衡是由於高溫的製備方式所產生之分化。此外，桃園藻礁在過去被證實其年代長達7600年，然而在臺灣的殼狀珊瑚藻之生長速度仍欠缺明確的數據，因此本研究也量測了臺灣現生殼狀珊瑚藻的垂直與水平生長速率，以瞭解該藻體在藻礁生態系中的成長、入添與再生能力。本研究係將附著於鵝卵石上的殼狀珊瑚藻以茜素紅染色並放置於海水缸養殖6－8個月，殼狀珊瑚藻的垂直生長速率約為0.708 μm/day，生長在養殖缸壁上的新生殼狀珊瑚藻水平生長速率，則高達約0.11 mm/day。該結果指出臺灣的殼狀珊瑚藻的增厚速度緩慢，但是在環境適宜的條件下，殼狀紅藻幼體具有良好的入添與生長能力。
並列摘要
Coastal algal reef ecosystem not only provide complex habitats for diverse marine organisms, the calcified reef structured but also storage the long-term environmental information. In this study, I analyzed stable isotopic compositions of the marine organisms in the crustose coralline algae (CCA) ecosystem to elucidate the sewage pollutions. The δ15N values of the CCA collected from Taoyuan coast recently showed significant higher than the CCA grown about 1400 years ago (2-3‰). Besides, the δ15N values of marine organisms in Taoyuan algal reef (8-20‰) were also much higher than the counter parts collected in the Linshanbi algal reef (4-11‰). This disparity in δ15N values reflected that algal reef ecosystems in the water pollutions in the coasts of Taiwan have increased δ15N baseline, especially in the Taoyuan coasts receiving more severe pollution and resulting in overall the highest δ15N values. In addition, the δ18O value of algal carbonate was used to reconstruct ancient water temperature. However, the previous study which used high temperature treatment to remove organic matter from calcareous algae, might cause the re-equilibrium of CCA δ18O values. To prove this artifact, our study used four treatments (no-treatment, H2O2, heating in 1 atm, heating in vaccum) to remove organic matter from dead CCA in algal reef, and the results indicate that heating treatment would cause lower δ18O values compared with no-treatment and H2O2 groups. This result suggests that the isotope disequilibrium of δ18O values in the CCA in the previous study was due to high temperature treatment. Besides, this study also quantified the growth rate and evaluated the resilience of CCA. We dyed the CCA growing on the cobbles with alizarin red and cultivated in seawater tank for 8 months. The vertical growth rate of CCA have a mean value of approximately 0.708 μm/day, however the horizontal growth rate of CCA is much higher at around 0.11 mm/day. The results indicate a high ecological resilience of the CCA in north western Taiwan, which can recruit and colonize in suitable environment by recruitment of CCA seedlings.
並列關鍵字
crustose coralline algae ； CCA ； algal reef ； stable isotope ； CCA growth rate ； coastal pollution參考文獻
延伸閱讀
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