Top-down vs. Bottom-up control on the competitive interactions between hard coral, sea anemone and macroalga

• Main Authors: Yu-Jen Chang, 張又仁
• Other Authors: Hsing-Juh Lin
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/2v4367

碩士 === 國立中興大學 === 生命科學系所 === 98 === A mesocosm experiment was carried out to examine the interactive effects of grazing (fish and sea urchins) and nutrient enrichment on competitive interactions between the macroalga Codium edule, the sea anemone Mesactinia ganesis, and the scleractian coral Acropora muricata in Kenting, southern Taiwan. The results showed that the macroalga in the controls and enriched tanks declined 90% by grazing within a week. Corals in the enrich tanks showed better photosynthetic efficiency, greater cell number of zooxanthellae, higher chlorophyll a and total protein contents than those in the controls. Cell number of zooxanthellae in sea anemone in the enriched tanks was about 2-fold of that in the controls. Sea anemones grew better in the enriched tanks or with corals, but the biomass decreased when growing with the macroalga. Conclusively, macroalgal biomass was controlled by the grazing in enriched tanks. However, coral was hurt by the attacks of sea anemone. Nutrient enrichment appears to increase the resistance of coral to the attacks.