新山水庫藻類生態模擬及改善優養化工法之初步探討

The Algal Ecological Modeling in Hsin-shan Reservoir and Preliminary Study in Eutrophication Control

許嘉珍(Chia-Chen Hsu)

指導教授 ： 吳先琪

國立臺灣大學/工學院/環境工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00757

摘要

本研究藉著不同月份的採樣收集新山水庫在近八個月的水質資料，並利用零維模式模擬藻類在其中的消長情形。為精確描述水體不同層間的藻相變化，模式將表水至水深十公尺處分為三層，並考慮由溫度變化造成的層間混合效果。由於影響藻類生存的因子相當多，本模式利用採樣所得之水質及水文資料做為環境條件，以作為模式校正根據，找出適用在新山水庫的模式參數。
本研究以各藻種之生理特性將總藻分為四類，以模擬此四種藻在各層水體之體積變化。由實測結果能顯示藻類在各季節的消長情形，而隱球藻雖在各季節皆是最多數量的藻種，但因體積小，使得冬季出現頻率增加的矽藻及金黃藻因體積較大便轉變為優勢藻種，優勢藻會改變的原因是水溫變化引起的環境變動造成不同藻的適應能力有差異。
由於水庫優養化問題在台灣數座重要水庫已引起關切，若有害藻種存在水庫水體，對於飲用水便是一大危機。而新山水庫在每年五月有嚴重藻華現象發生，本研究欲針對此問題提出一解決方法，並欲證實以混合力量打破水體分層能有效抑制微囊藻在表層的生長，因此在水庫安裝一模廠設施，藉由沉水馬達造成的混合力量，將表水附近之藻類帶至水深八公尺處，實驗結果發現微囊藻並未因離開表層而消失，推測水深八公尺處之光線或環境仍適合藻類生存，且混合力量未足以打破新山水庫在夏季約兩公尺的分層現象，需加強混合力量或以其他工法代替以達成目的。

關鍵字

優養化 ； 動態模擬 ； 水體分層 ； 限制因子 ； 混合係數

並列摘要

Hsin shan reservoir is located in Keelung, Taiwan. By sampling during last year, we collected the water quality data of this reservoir, including algae phase and nutrient such as ammonia nitrogen, nitrate and phosphate. These data were used in developing an algae dynamic model which is zero dimension. From surface to ten meters down to the water, we divided three levels to simulate the growth situation of different kinds of algae. The measured data showed that there was a phenomenon about algae succession happened in this reservoir. The physical characteristics of different kind algae and the environmental condition controlled which kind of algae would be the widely distributed species. Take Hsin Shan reservoir for example, Cyanophyta had a wide distribution in summer, but in fall, Bacillariophyta and Chrysophyta replaced it.
After calculating all parameters of this model, other data were needed to verify the model. This model can also be used for environmental management, and to predict when bloom will happen in reservoirs.
Eutrophication is a serious problem in reservoirs, and Hsin shan reservoir was examined beyond standard in 2003 with Carlson Index. In order to correct this, we established a pilot in this reservoir. In the pilot, mixing was thought to destratify the stable condition of water. In the end of the experiment, the goal species, Microcystis, didn’t leave the water body. The possible reason was that the environment below the surface water was also suitable for it, and there might be enough light and nutrient for its growth. More powerful mixing or other artificial methods are needed to alleviate the bloom happened in Hsin shan reservoir.

並列關鍵字

eutrophication ； algae succession ； dynamic modeling ； water stratification ； limiting factor ； mixing coefficient

參考文獻

台灣地區水庫浮游藻類圖鑑，1996，行政院環境保護署環境檢驗所。

林明郁(2004)，翡翠水庫藻類族群結構分析及分層系統動態模擬，碩士論文，國立台灣大學環境工程學研究所。

簡鈺晴(2005)，翡翠水庫藻類多樣性之分析及消長動態之模擬，碩士論文，國立台灣大學環境工程學研究所。

Droop, M. R. (1973) Some thoughts on nutrient limitation in algae. J. Phycol. 9: 264-272.

Falkowski, P. G. (1984) Physiological responses of phytoplankton to natural light regimes. J. Plankton. Res. 6: 295-307.