碳酸鈣之多型態結晶探討

An investigation on the polymorphism of calcium carbonate crystallization

李政學(Cheng-Hsueh Li)

指導教授 ： 陳恕行

崑山科技大學/工程學院/機械工程研究所/碩士(2009年)

https://doi.org/10.6828/KSU.2009.00078

摘要

碳酸鈣跟許多固體都能形成多型態結晶，也就是相同的成份能形成原子排列方式不同的晶體。常見的碳酸鈣結晶有方解石及霰石，鈣化生物能控制這兩種結晶各別的成長率，這兩者在水中有不同的溶解度。人類活動所排出的二氧化碳使海水酸化，加上的硫酸根及硝酸根的排放，對生活在近海的鈣化生物影響很大。鈣化生物負責建構棲息地同時也是食物鏈上重要的一環，鈣化生物消失將引起很嚴重的生態後果。本研究以養殖的貝類為研究對象，可以發現貝殼內不同結晶型態會隨水質條件而改變。研究方法是以非生物式的產生碳酸鈣結晶，探討不同型態結晶的性質。
細胞利用主動運輸將鈣離子排除，排除過程需要消耗能量，所以鈣化生物會設計使鈣化更容易進行。這些設計包括用薄膜產生離子梯度並將碳酸鈣飽和溶液存在一個密閉空間。還有一項設計是利用殼內的毛細管網絡將飽和碳酸鈣溶液輸送至殼最前緣。這項研究有助於瞭解對抗持續酸化環境的功效。

關鍵字

多型態結晶 ； 溶解度 ； 酸化

並列摘要

Calcium carbonate as well as many other crystalline materials is polymorphic, which means that it has more than one crystal structures. Two common types of calcium carbonate crystal are calcite and aragonite. Many calcifying organisms are able to control the respective growth of these two crystal types which have different solubilities. Ocean chemistry is becoming more unfavorable for calcification due to the vast emission of carbon dioxide. The situation is more severe coastal waters as precipitation containing nitric acid and sulfuric acid further increase the acidity. Life of calcifying organisms which are not only important in the food chain but are also responsible for reef building is threatened. Under the same condition, the two types have different saturation state within water. This work studies clams cultured. The ratio between different crystal structures change in different water conditions. The investigation method is to conduct abiogenic calcifying experiments to understand the properties of different crystal types.

Extruding calcium, through an energy consuming process, from cytoplasm is an important routine for survive. A certain number of designs exist for reducing energy consumption. Those designs include using a membrane to generate ion gradient and help store saturated calcium carbonate fluid within a compartment. Another design is to use the capillary network to transport the fluid to farthest location. Understanding those designs is conducive to endeavor for neutralizing the negative effect of global acidification.

並列關鍵字

polymorphic ； solubilities ； acidification

參考文獻

[12] An-Chin Lee, The Effect of Temperature and Components of Artificial Seawater on Digging Ability of Hard Clam (Meretrix lusoria), J. Fish. Soc. Taiwan, 31(4): (2004), 251-262.

[1]Colin Brownlee, Alison R Taylor, Algal Calcification and Silification, ENCYCLOPEDIA OF LIFE SCIENCES, (2002), 1-6.

[2]T.A. McConnaughey, J.F. Whelan, Calcification generates protons for nutrient and bicarbonate uptake, Earth-Science Reviews 42 (1997), 95-117

[3]Allegra M. Small, Walter H. Adey, Reef corals, zooxanthellae and free-living algae: a microcosm study that demonstrates synergy between calcification and primary production, Ecological Engineering 16 (2001), 443–457

[4]Kleypas, JA et al. Geochemical Consequence of Increased Atmospheric Carbon Dioxide on Coral Reefs. Science (1999), 284-118。