Data Entry: Please note that the research database will be replaced by UNIverse by the end of October 2023. Please enter your data into the system https://universe-intern.unibas.ch. Thanks

Login for users with Unibas email account...

Login for registered users without Unibas email account...

 
A mid-Holocene transition in the nitrogen dynamics of the western equatorial Pacific : evidence of a deepening thermocline?
JournalArticle (Originalarbeit in einer wissenschaftlichen Zeitschrift)
 
ID 57322
Author(s) Kienast, M.; Lehmann, M. F.; Timmermann, A.; Galbraith, E.; Bolliet, T.; Holboum, A.; Normandeau, C.; Laj, C.
Author(s) at UniBasel Lehmann, Moritz
Year 2008
Title A mid-Holocene transition in the nitrogen dynamics of the western equatorial Pacific : evidence of a deepening thermocline?
Journal Geophysical research letters
Volume 35
Number 23
Abstract Sedimentary delta N-15 records from the oligotrophic western equatorial Pacific (WEP) off Mindanao show that late Holocene sedimentary delta N-15 is substantially lower than that of the early Holocene, following a gradual >3 parts per thousand decrease that occurred between 7 and 3 kyrs ago. Analyses of modem day nitrate isotope profiles from the same region indicate the sensitivity of the WEP N pools towards (1) the advection of N-15-enriched nitrate from the Eastern Equatorial Pacific (EEP) by the North Equatorial Current (NEC) and the Mindanao Current in subsurface waters and, (2) at shallow depths, the input of new and N-15-depleted nitrate through N, fixation. We suggest that the Holocene decrease in sedimentary delta N-15 reflects a diminished relative input of N-15-enriched nitrate to the surface biota, either through an increase of regional nitrogen fixation, a change in nitrate consumption along the advective path of nitrate supply, or a decrease in the vertical Supply Of N-15-enriched nitrate from the NEC. The latter mechanism is consistent with a Holocene deepening of the WEP nitracline/thermocline. Citation: Kienast, M., M. F. Lehmann, A. Timmermann, E. Galbraith, T. Bolliet, A. Holboum, C. Normandeau, and C. Laj (2008), A mid-Holocene transition in the nitrogen dynamics of the western equatorial Pacific: Evidence of a deepening thermocline?, Geophys. Res. Lett,, 35, L23610, doi: 10.1029/2008GL035464.
Publisher American Geophysical Union
ISSN/ISBN 0094-8276
edoc-URL http://edoc.unibas.ch/dok/A5249290
Full Text on edoc No
Digital Object Identifier DOI 10.1029/2008GL035464
ISI-Number WOS:000261668700001
Document type (ISI) Article
 
   

MCSS v5.8 PRO. 0.339 sec, queries - 0.000 sec ©Universität Basel  |  Impressum   |    
29/03/2024