Abstract
The primary objective of this study was to determine the isotopic variation
of the sedimentary organic carbon (£_13Corg) in the sediment samples of the
gravity core 17950-2. The core was retrieved from the northern South China
Sea during ¡§Monitoring Monsoon¡¨ cruise onboard R/V Sonne in 1994. The
£_13Corg data were further compared with other proxies, such as foraminiferal
£_18O and £_13C, TOC wt%, and CaCO3 wt% to decipher the late Quaternary
evolution of climate change from the South China Sea for the last 200 ky. Prior
to 65 ka, the £_13Corg, calibrated TOC wt% (TOC ex wt%), and Terrestrial wt%
fluctuated synchronously. The increased TOC ex wt% and Terrestrial wt% were
consistent with the enriched £_13Corg, implying the enhanced productivity due to
the increased terrestrial input. The enhanced glacial productivity could have
been caused by the increase in terrestrial input and mixed layer by wind-driven
upwelling. The South China Sea, however, is a nitrogen-limited basin. The
enhanced nitrogen fixation induced by increased dust input can also be a
potential candidate that is responsible for the elevated productivity during
glacials.
Theoretically, the £_13Corg is utilized as a powerful tool to determine the
carbon ratio between marine and terrestrial origin in the shelf area and
reconstruct the pCO2 history of the low-productivity open ocean. According to
TOC ex wt%, the productivity of the northern South China Sea were
significantly higher in glacials than interglacials. Therefore, the variation of
pCO2 of the northern South China Sea can not be reconstructed properly based
on £_13Corg record solely .
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0729102-161926 |
| Date | 29 July 2002 |
| Creators | Yu, Chih-Chian |
| Contributors | Chung-Ho Wang, Kuo-Yen Wei, Hui-Ling Lin |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0729102-161926 |
| Rights | unrestricted, Copyright information available at source archive |
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