Assessing the Influence of a New Entrance to a Fishing Harbor on Coastal Phytoplankton Dynamics Using Principal Component Analysis and Structural Equation Modeling

以主成份分析及結構方程模式探討安平漁港新建航道對鄰近海域浮游植物的影響

周偉融(Wei-Rung Chou) ； 方力行(Lee-Shing Fang) ； 王維賢(Wei-Hsien Wang) ； 張桂祥(Kwee Siong Tew)

《Platax》 2010卷7期 (2010/12) Pp. 41-55

https://doi.org/10.29926/PLATAX.201012.0004

摘要

本研究使用主成分分析釐清安平漁港附近海域的環境變動因素，以及航道挖通對海域浮游植物產生的影響，再以結構方程模式建構海域環境變動因素與葉綠素a之間的關係。PCA的結果顯示「矽、磷營養鹽」、「河川注入」、「重金屬污染」、「海域溶氧」及「硝酸鹽類」等五個潛在變項是影響本海域環境變動的主要因素。SEM模式則顯示河川注入是影響浮游植物變動的首要因素(0.79)，硝酸鹽類次之(0.08)。至於重金屬污染及矽、磷營養鹽對浮游植物的影響則不顯著。浮游植物正向的影響海域溶氧，而河川注入則爲負向。整體而言，PCA結果能釐清安平漁港附近海域環境變動的原因，而SEM則能辨別各因素對本海域浮游植物變動的相對重要性。

關鍵字

主成份分析 ； 結構方程模式 ； 浮游植物

並列摘要

Principal Component Analysis (PCA) was used to analyze the physico-chemical variables in Anping Fishing Harbor and its adjacent area, and Structural Equation Modeling (SEM) was used to investigate the influence of the variables on phytoplankton dynamics. The PCA result revealed five important latent variables affecting the area: phosphate and silicate nutrients, river input, heavy metal pollution, dissolved oxygen (DO), and nitrates. SEM results further revealed that river input significantly affected phytoplankton in the area, followed by nitrate concentration. The effect of heavy metals, phosphate, and silicate on phytoplankton was not significant. DO was positively affected by phytoplankton and negatively affected by freshwater river input in the area. In a complex system with anthropogenic and natural impacts, PCA helps to reveal the sources of influence on phytoplankton dynamics in the area, whereas SEM provides a simple ecological model revealing the direct and indirect, as well as the relative importance of each influence.

並列關鍵字

Principal Component Analysis ； Structural Equation Modeling ； phytoplankton