碩士 / 國立臺灣海洋大學 / 環境生物與漁業科學學系 / 103 / Natural tags, i.e., trace elements and stable isotopes, bioaccumulated in a consumer’s tissues via ingestion of diet and absorption from water. It can be used to biomonitor the seasonal variation of environment conditions through consumers. The objectives of this study is to analyse the natural tags in the tissues of swordtip squids (Uroteuthis edulis), for the purposes (1) to determine if the concentrations of elements in the tissues varied according to abotic environment; (2) to understand if the levels of natural tags effected by ontogenetic stages; (3) to examine the temporal variation in natural tags, and finally to discuss the possible factors influenced. Samples of squids were collected monthly from June 2010 to December 2012 and August 2013 to June 2014 from Waimu Shan fishing harbor, and seawater samples were collected monthly from August 2013 to June 2014 from the waters off northern Taiwan. Concentrations of sodium (Na), magnesium (Mg), potassium (K), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), strontium (Sr), cadmium (Cd), barium (Ba), lead (Pb) of the tissues, including mantle, digestive gland and gill, and seawater were measured by using the solution based inductivity couple plasma mass spectrometry (ICP-MS). Stable isotope ratios of carbon and nitrogen in mantle muscle were analyzed with an elemental analyser coupled to isotope-ratio mass spectrometer (EA-IRMS). A total 210 of squids were analyzed. The result of PCA analyses showed that the elements composition in mantle and gill were similar to water. However, the elements composition in digestive gland were different that representing the source of elements accumulated in digestive gland may origined from food. The levels of Fe, Ba and Pb decrease with increasing body size, and a dilution effect might exist during the rapid growth stage. A significant difference in concentrations of Fe, Ba and Pb were higher in immature squid than those of maturing and mature squids. At the immature stage, the accumulation occurs through the dissolved pathway by tegumental and gill absorption through directly contact with seawater. However, the concentration of Cd in maturing and mature squids was higher than immature squids. This may be related to this dietary bioaccumulation with growth. The values of δ13C and δ15N were not significantly correlated. There were variation of δ13C and δ15N ratio in mantle of squid which may relate to migration and the prey composition difference. The results of PCA analyses showed that the composition of natural tags varied by ontogenetic differences and seasons. There were differences in the natural tags in digestive gland and gill at different maturity and also in different season. The results implied that the seasonal variation in the composition of natural tags in tissues of Uroteuthis edulis were causing by the environmental conditions that influenced by currents and food web.
| Identifer | oai:union.ndltd.org:TW/103NTOU5451013 |
| Date | January 2015 |
| Creators | Tzu-Hua, 王姿樺 |
| Contributors | Wang, Chia-Hui, 王佳惠 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 97 |
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