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| Ren, Haojia; Sigman, Daniel M.; Chen, Min-te; Kao, Shuh-ji. |
| We report a new foraminifera-bound delta N-15 (FB-delta N-15) record from the South China Sea (SCS) extending back to 42 ka. This record shows a similar to 1.2 parts per thousand glacial-to-interglacial delta N-15 decrease, with a deglacial delta N-15 maximum similar to that observed in many bulk sedimentary delta N-15 records and in a Caribbean FB-delta N-15 record. The glacial-to-interglacial delta N-15 decrease is smaller than in the Caribbean record, indicating that at least half of the Caribbean delta N-15 decrease into the Holocene was regional, not global, supporting the interpretation of a Holocene increase in Atlantic nitrogen fixation. At the same time, the glacial-to-interglacial delta N-15 decrease observed in the SCS may also be explained as a... |
| Tipo: Text |
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| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37670/36834.pdf |
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| Zheng, Li-wei; Hsiao, Silver Sung-yun; Ding, Xiao-dong; Li, Dawei; Chang, Yuan-pin; Kao, Shuh-ji. |
| Total organic carbon to total nitrogen ratios (C/N) and their isotopic compositions (δ13CTOC and δ15NTN) are oft-applied proxies to discern terrigenous from marine-sourced organics and to unravel ancient environmental information. In high depositional Asian marginal seas, the inclusion of N-bearing minerals in the bulk sediment dilutes or masks signals sought after in δ15N and δ13C analyses, thus leading to incorrect and even contradictory interpretations. We used KOH-KOBr to separate operationally defined total organic matter into oxidizable (labile) and residual fractions for content and isotope measurements. In a sediment core in the Okinawa Trough, significant amounts of carbon and nitrogen existed in the residual phase, in which the C/N ratio was ~9,... |
| Tipo: Text |
Palavras-chave: Carbon; Nitrogen; Isotope; Okinawa Trough; Sediment; Total organic carbon. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40584/39503.pdf |
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| Chang, Yuan-pin; Chen, Min-te; Yokoyama, Yusuke; Matsuzaki, Hiroyuki; Thompson, William G.; Kao, Shuh-ji; Kawahata, Hodaka. |
| We analyzed the high-resolution foraminifer isotope records, total organic carbon (TOC), and opal content from an Okinawa Trough core MD012404 in order to estimate the monsoon hydrography and productivity changes in the East China Sea (ECS) of the tropical western Pacific over the past 100,000 years. The variability shown in the records on orbital time scales indicates that high TOC intervals coincide with the increases of boreal May-September insolation driven by precession cycles (similar to 21 ka), implying a strong connection to the variations in monsoons. We also observed possibly nearly synchronous, millennial-scale changes of the ECS surface hydrography (mainly driven by salinity changes but also by temperature effects) and productivity coincident... |
| Tipo: Text |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32929/31435.pdf |
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