Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/53741
標題: 利用中觀生態池探討沉積物對珊瑚礁生態系影響
Effects of Sedimentation on Coral Reef Ecosystems-A Mesocosm Experiment
作者: 林幸助
樊同雲
關鍵字: 基礎研究;Macroalgal dominance;生物科學類;藻類優勢;海葵優勢;食藻動物;食海葵魚類;沉積物;Sea-anemone dominance;Herbivory;Sea-anemone feeding fish;Sedimentation
摘要: 
本計畫總體目標在於了解造成珊瑚礁相變為藻類優勢及海葵優勢的過程與機制,並探討可行復育策略。台灣南部墾丁珊瑚礁部分地區相變為藻類或海葵優勢的事件屢有所聞。墾丁長期生態研究(KT-LTER)結果顯示,墾丁珊瑚礁的相變現況並非單一因子所能造成,可能是由過漁所導致之食藻或食海葵動物過少、大量沉積物輸入之棲地破壞、營養鹽污水排放及不明原因之珊瑚大量死亡等因素之共同作用。本計畫為釐清這些影響因素,在2005年成功建構了6個5噸,全球非常少見之開放式珊瑚礁中觀生態池系統,內含墾丁珊瑚礁主要生物功能群。第一年(2006-2007年)進行因過漁導致珊瑚礁動物過少狀況下之營養鹽添加實驗,分為添加營養鹽之實驗組與不添加之對照組,各3重複。對照組與野外未受污染之墾丁珊瑚礁類似。但在實驗組,松藻及其他大型綠藻在一個月後開始藻華,覆蓋珊瑚並相變為藻類優勢,三個月後造成珊瑚光效能降低而白化。同時也發現營養鹽會促進珊瑚與海葵生長,然而海葵會主動攻擊珊瑚導致白化的面積擴大,但是海葵卻會躲避藻華的大型藻類。此結果顯示我們已在實驗室成功複製墾丁珊瑚礁相變為藻類優勢之過程,但海葵、藻類與珊瑚之間的交互作用遠比我們了解的更複雜。目前正進行第二年(2007-2008年)之食藻動物的控制實驗。我們發現鸚哥魚數量多時會有效減少大型藻類數量,而馬糞海膽對叢藻和松藻具有較佳的控制能力。雖然食藻魚類與無脊椎動物都具有控制藻類藻華的潛力,但是食藻魚類的攝食習性遠比我們預期複雜。我們擬再申請第三年計畫經費(2008~2009年),也是本系列珊瑚礁中觀生態池實驗的最後一年,探討另一項重要因子-沉積物對墾丁珊瑚礁的影響機制,釐清沉積物與營養鹽以及食藻或食海葵動物之間的交互作用。實驗設計將分為沉積物之有無添加2種處理,在添加營養鹽之狀況下有無遮光2種處理,以及在海葵優勢之珊瑚礁有無食海葵魚類2種處理。沉積物取自於墾丁海域沉積物主要來源之保力溪上游沿岸土壤。每次進行2種處理,各3個重複。每次實驗預計進行1-2個月,於冬天與夏天各至少進行一次。我們擬藉由添加陸源沉積物模擬暴雨過後,檢驗沉積物懸浮沉降是否會導致海葵優勢。我們期望藉由遮光實驗,檢驗沉積物的遮光效應是否是相變為海葵優勢的主要原因。藉由操控食海葵魚類之數量,我們擬探討食海葵魚類是否可以提升珊瑚礁相變為海葵優勢之抗逆能力。本計畫不僅提供具體的科學數據,提供最適的管理策略與珊瑚礁復育策略給墾丁國家公園或海洋國家公園管理處參考,同時亦可提供往後進一步建立大尺度之珊瑚礁環境生態模式的重要參數。

This proposal is aimed to reveal the processes and mechanisms of phase shifts of coral reefs and to explore restoration strategies by mesocosm experiments. The coral reefs at Kenting National Park in southern Taiwan are well known by the abundant and diverse communities. However, the coral reef ecosystem is degrading in the past two decades. Many coral reefs have been reported to shift to macroalgae-dominated or sea-anemone-dominated systems. The results of KT-LTER suggested that low herbivory or carnivory resulted from overfishing, habitat destruction caused by sedimentation and eutrophication by sewage discharge were the main causes of the phase shifts. In 2005, we successfully constructed 6 coral reef opened mesocosm facilities for experiments. In the first year (2006-2007), we conducted mesocosm experiments to examine responses of macroalgae, sea-anemone, and corals to nutrient enrichment with reduced herbivory. Prolific green algae were observed in the 3 enriched tanks, but not in the 3 controls. Photosynthetical efficiencies of the coral and the green alga and the asexual reproduction of the sea anemone were enhanced in the enriched tanks. Sea anemones were observed to attack corals in both the enriched tanks and controls, but kill corals in the enriched tanks. In the enriched tanks, the stimulated macroalga was found to cover corals and affect their maximum quantum yields. In conclusion, combined effects of reduced herbivory and nutrient enrichment are the most likely causes of the observed phase shifts. However, the interactions among sea anemones, corals and macroalgae are more complex than we expected. In the second year (2007~2008), we are conducting grazing experiments to hypothesize that herbivory would increase resilience of coral reefs to shift to macroalgal dominance. We are determining the relative effect of herbivorous fish and invertebrates in controlling macroalgal blooms. Here, we propose sedimentation experiments for the third year study (2008~2009) by adding terrestrial sediments to test whether sedimentation induce the shifts to sea-anemone dominance and whether shading is the main reason. We propose to examine whether shading is the main factor for the shift to sea anemone and whether sea-anemone feeding fish is the main factor for the resilience. Eventually, this study would be able to provide science-based information regarding the mechanisms of phase shifts, management and restoration of coral reefs.
URI: http://hdl.handle.net/11455/53741
其他識別: NSC97-2621-B005-001
Appears in Collections:生命科學系所

Show full item record
 

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.