Alkenone temperature and carbon isotope records: Temporal resolution, offsets, and regionality

Authors
Citation
R. Schneider, Alkenone temperature and carbon isotope records: Temporal resolution, offsets, and regionality, GEOCH GEO G, 2, 2001, pp. NIL_1-NIL_14
Citations number
62
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
ISSN journal
1525-2027 → ACNP
Volume
2
Year of publication
2001
Pages
NIL_1 - NIL_14
Database
ISI
SICI code
1525-2027(20010103)2:<NIL_1:ATACIR>2.0.ZU;2-H
Abstract
Over the last decade the number of paleoceanographic studies presenting and discussing alkenone-derived sea surface temperature (SST) records and carb on isotope ratios of alkenones (delta C-13(alkenones)) has increased rapidl y. This short review paper summarizes the state of knowledge about SST vari ability determined by alkenone paleothermometry in sediment trap studies an d investigations of marine sediments for timescales of single to millions o f years. In particular from the evaluation of Quaternary records, character istic temperature pattern have emerged that mismatch with SST curves estima ted by other methods, e.g., foraminiferal stable oxygen isotopes and transf er functions. In future studies the spatial distribution of such variance p atterns typically observed in alkenone SST curves should be checked in orde r to better understand their meaning for ocean circulation changes and a po ssible relationship to global climate change. On the other hand, certain ph ysical and biological processes have the potential to put the reliability o f alkenone SST curves into question. Accordingly, examples for possible eff ects of bioturbational mixing, lateral transport of remote alkenones, diagn etic alteration and degradation of alkenone composition, biogeographic and temporal diversity changes in alkenone-producing algae, as well as the infl uence of changes in salinity and nutrient conditions on the alkenone paleot emperature signal, are briefly mentioned, highlighting the need for more de tailed future studies on these issues. Finally, a short summary on the stat us of the use of the delta C-13(alkenones) signal as a proxy for past varia tions in the carbon dioxide pressure (PCO2) in ocean surface waters and rel ated problems is given.