碩士 / 國立臺灣大學 / 地質科學研究所 / 104 / Abstract
Benthic foraminifera are the most abundant eukaryotes and play an important role in the cycling of organic matter in deep sea environments. However, their ecology in cold seep environments, one of the most unusual seafloor habitats, is just beginning to be revealed. This study employed multiple multivariate statistical approaches to investigate the benthic foraminiferal community composition and the controlling environmental factors in the cold seep region on the Four Way Closure Ridge, offshore SW Taiwan. Sediment cores were retrieved from three sites (seep, transition, and reference) using video-guided sampling equipment. Faunal analysis based on the size class >250 um showed that the three sites shared the same feature of having abundant agglutinated benthic foraminifera (>50%) in the topmost sediment, probably as a result of the low carbonate saturation state in the overlying and pore waters. The cold seep communities had the lowest biodiversity, but cluster analysis indicated substantial similarity in community composition shared between the seep and transition sites. Indicator species analysis suggested Haplophramoides bradyi niigataensis, an agglutinated species, to be the dominant indicator of the seepage hotspot, whereas Bulimina aculeata and Cassidulinoides differens were the dominant indicator species in the broadly defined cold seep region. Canonical correspondence analysis showed that the concentration of sulfate and dissolved oxygen in the pore water were the most significant biogeochemical factors explaining the community variance. The patterns delineated objectively and quantitatively by these numerical ecology tools offered a basic understanding of the benthic foraminiferal ecology in modern cold seeps developed on accretionary wedges.
| Identifer | oai:union.ndltd.org:TW/104NTU05138002 |
| Date | January 2016 |
| Creators | Meng-Ting Chiang, 蔣孟庭 |
| Contributors | 魏國彥 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
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