| Summary: | 博士 === 國立臺灣海洋大學 === 海洋生物研究所 === 105 === Pelagic tunicates are receiving increasing attention worldwide. Their ecology and role in the marine environment has been underestimated in the past. Major research efforts worldwide have focused on the growth of pelagic tunicates, their suspension feeding and clearance rates, reproduction and life cycles, transport of organic matter and vertical migration, and several different studies on their abundance and distribution. In Taiwan, only a few studies were focusing on these exclusively marine invertebrates. The aim of my Ph.D. thesis is to analyze the taxonomic composition, abundance and distribution of pelagic tunicates in the waters of Taiwan, focusing on different areas (in the waters off the NPPI and NPPII, in the waters around the island of Taiwan such as Dongsha Island National Park, and Kueishantao, Turtle Island). My survey is mainly based on taxonomic work. My research started with sample collection from ship-board in the different areas and continued in the laboratory in order to recognize the different organisms at their species level as well as focusing on their abundance and distribution, together with the dominant species according to the area. I included data from different seasons and even longer time periods in order to understand the temporal variation of the presence/occurence of pelagic tunicates. The most abundant species for larvaceans was Oikopleura dioica, in every area and season. The most abundant species measured for thaliaceans was Doliolum denticulatum. Finally, I carried out statistical models with the aim of finding the connections between environmental factors (chl-a, temperature, salinity) and the abundance and distribution of marine zooplankton. The main factor influencing the patterns of distribution and abundance of larvaceans and thaliaceans turned out to be the availability of food (chl-a). Temperature, stimulating the algal blooms, also played an important role as an indirect influence. This analysis could provide the reasons for tunicates sometimes occuring in significant aggregations and their contributionse to different phenomena in the water column and deeper water layers of the ocean. My study could be a starting point for further research. It provides an overview on Taiwanese waters biodiversity and a deeper understanding of this group of organisms.
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