Phase shift of coral reefs:The change of branching Acropora coral, sea anemone, and algae dominance

• Main Authors: Nai-Cheng Lin, 林乃正
• Other Authors: Tung-Yung Fan
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/ad278q

碩士 === 國立東華大學 === 海洋生物多樣性及演化研究所 === 95 === The outbreaks of some marine organisms result in phase shift of community structure and degradation of ecosystem function. However, the process, reason, and mechanism for these changes in community composition are not yet known. On the coral reefs of southern Taiwan, specifically in two locations in Nanwan Bay, solitary sea anemones (Mesactinia genesis) and macroalgae have replaced branching Acropora corals and become the dominant benthic groups. Ecological monitoring, field transplantation experiments, and a controlled environment laboratory experiment were used to investigate these phase shifts. Ecological monitoring using permanent transects and water quality assessment was conducted at Taioshi and at the Inlet of the power plant from 2003 to 2007. At Taioshi, the mean cover of hard corals ranged between 1-12%, while macroalgae was 11.4% in 2004 and increased significantly to 67.5%, becoming dominant in 2007. The mean cover of the sea anemone Condylactis sp. was 20.1% in 2003 and decreased to 0.02% in 2007, while Turf algae ranged from 55.6 to 71.6% in 2004-2006, and significantly decreased to 28.5% in 2007. The seawater was eutrophicated with the highest concentration of sediment, nitrate, and phosphate at 132.9 mg cm-2 d-1, 4.35