No periodic patterns of temporal variations in the metal levels in U. lactuca or in other seven common seaweed species from Ping Chau were observed from 1999 to 2000. Cu levels were generally negatively correlated with other metals in seaweeds. / Spore production of U. lactuca was significantly reduced by the elevation of copper and nickel levels in the seaweed samples. The reproductive frequency of U. lactuca generally increased from January and February to the maxima in March and April. Copper, nickel and nitrate levels showed significant negative correlations with these reproductive frequencies. / The metal abundance in 24 seaweeds showed the following trend: Fe > Mn, Zn > Cu, Ni, Pb, Cr > Cd. U. lactuca and Padina australis showed relatively high mean and large range values of metal levels. Principal component analysis summarized the overall metal loadings in these 24 seaweed species. The variations in Pb, Fe, Mn and Cr levels in the seaweeds varied greatly. / There were significant spatial variations of different metal levels in the extensive study of U. lactuca from various intertidal waters in Hong Kong from 1999 to 2001. In general, metal levels in U. lactuca increased from January to March or April and then dropped in the following months. No periodic patterns or temporal trends of variations of metal levels in U. lactuca were found. Different metal levels in U. lactuca were comparatively lower than those in other studies in other countries and in past studies in Hong Kong. / There were significantly differences in various metal levels in different structures of Sargassum hemiphyllum, generally decreased in the following order: receptacles > vesicles > leaves > branches. / This thesis research involves biomonitoring levels of eight metal species (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in seaweed and the effects of these metals on the reproduction of Ulva lactuca. The study started from September 1999 and ended in June 2001, covering 40 intertidal sites in Hong Kong and 24 seaweed species. Environmental data on pH, salinity and nutrient levels (ammonia, nitrite, nitrate and phosphate) in seawater from these sites were also monitored. / Wong Tai Choi Richard. / "April 2005." / Advisers: P. C. K. Cheung; P. O. Ang, Jr. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0159. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 371-401). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_343602 |
| Date | January 2005 |
| Contributors | Wong, Tai Choi Richard., Chinese University of Hong Kong Graduate School. Division of Biology. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xliii, 401 p. : ill., maps) |
| Coverage | China, Hong Kong, China, Hong Kong, China, Hong Kong |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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