Time variations of d15N of organic nitrogen in deep western subarctic Pacific sediment over the last 145 ka
[1] We present d15N data of organic nitrogen (d15NON) from a deep western subarctic Pacific (WSAP) sediment core over the last 145 ka. To remove the effect of inorganic nitrogen (IN) on bulk nitrogen (BN), we used the contents of IN and BN, and the isotopic ratios of IN (d15NIN) and BN (d 15NBN). Th...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.656.8327 http://geos.ees.hokudai.ac.jp/yywata/paperfiles/Shigemitsu2008.pdf |
| Summary: | [1] We present d15N data of organic nitrogen (d15NON) from a deep western subarctic Pacific (WSAP) sediment core over the last 145 ka. To remove the effect of inorganic nitrogen (IN) on bulk nitrogen (BN), we used the contents of IN and BN, and the isotopic ratios of IN (d15NIN) and BN (d 15NBN). The contribution of IN to BN was largest 59 % and d15NIN had lower values than d 15NBN. However, the large contributions of IN to BN and the distinct isotopic values did not largely change any variability associated with d15NON in the d 15NBN. Thus, it is possible to use d 15NBN in carrying out paleoceanographic research with d15N at least in the open WSAP. The d15NON values have been affected by long-term diagenesis making the values lower with depth in the sediment, but the values during less productive colder periods were generally lower compared to those during neighboring productive warmer periods. The results might indicate that d15NON during the less productive colder periods (i.e., glacial periods) were lower than that during the productive warmer periods (i.e., interglacial periods). Previous studies have reported that the |
|---|