Title page for etd-0809114-100747


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URN etd-0809114-100747
Author Zhi-ling Huang
Author's Email Address No Public.
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Department Marine Biotechnology and Resources
Year 2013
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Spatiotemporal distribution of siphonophores and hydromedusae in relation to hydrography in the Dongsha Atoll
Date of Defense 2014-07-30
Page Count 101
Keyword
  • distribution
  • assemblage
  • Dongsha Atoll
  • siphonophores
  • hydromedusae
  • Abstract This study investigated the seasonal and spatial distribution in species composition and abundance of siphonophore and hydromedusa communities in relation to the hydrography conditions in Dongsha atoll, a tropical lagoon in the northern South China Sea, from February (winter) to October (autumn) of 2011. Dongsha atoll, surrounded by the water mass of South China Sea all year arround, has significant seasonal variations in hydrography, warm in summer and cold in winter, and salinity was significantly affected by rainfall in autumn, and the difference of each stations within a season is not significant. In total, 49 siphonophore and 42 hydromedusa taxa were identified during the study period, with the average abundance of 596 ± 201 ind/ 1000 m3 and 635 ± 234 ind/ 1000 m3 respectively. Two species of calycophoran siphonophores, Chelophyes contorta and Eudoxoides spiralis, were very common in all seasons, while the composition of other predominant species changed seasonally. The hydrological stations group for each season showed no clear relationship with the distribution of shiphonophores and hydromedusea in the study area. The abundance of siphonophores was higher in winter and spring than in summer and autumn, while the abundance of hydromedusae was higher in spring and summer than in winter and autumn, low abundance in autumn may be caused by the typhoons. Result of cluster analysis, based on species with more than 1% of the total catch, showed that the distribution pattern of jellyfish (both siphonophores and hydromedusae) in Dongsha atoll can be divided into two assemblages, the outer of atoll that was mainly influenced by the South China Sea and the inner of atoll in which the main species may have polyps pouplations inhabit. The jellyfish abundance, species number and species diversity showed a significant negative correlation with chlorophyll a. Most dominant species of jellyfish were negatively correlated with chlorophyll a concentration, temperature, salinity, and positively correlated with dissolved oxygen concentrations. Overall, the factors affecting the distribution of jellyfish assemblages in Dongsha atoll were not only hydrological factors, the impact of the typhoon was also an important factor.
    Advisory Committee
  • Chang-tai Shih - chair
  • Kwee-siong Tew - co-chair
  • Hung-yen Hsieh - co-chair
  • Wen-tseng Lo - advisor
  • Files
  • etd-0809114-100747.pdf
  • Indicate in-campus at 1 year and off-campus access at 2 year.
    Date of Submission 2014-09-12

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