TY - JOUR
T1 - Alkenones as paleoceanographic proxies
AU - Sachs, Julian P.
AU - Schneider, Ralph R.
AU - Eglinton, Timothy I.
AU - Freeman, Katherine H.
AU - Ganssen, Gerald
AU - McManus, Jerry F.
AU - Oppo, Delia W.
N1 - Publisher Copyright:
© 2000 by the American Geophysical Union.
PY - 2000/11/1
Y1 - 2000/11/1
N2 - Alkenone-derived estimates of temperature and CO2 are contributing to our understanding of Earth's climate history. In order to increase confidence in alkenone-based climate proxies we recommend the following actions. First, the sedimentary component or fraction containing alkenones should be identified in order to assess the impact of horizontal advection and vertical mixing on alkenone-derived temperature and CO2 estimates. Second, differential mixing rates of alkenone-containing particles and sand-sized foraminifera should be quantified by independent dating of the two phases. Until that is accomplished, apparent temporal offsets of climate proxies in the two phases should be interpreted cautiously. Third, the stability of the unsaturation ratio and carbon isotopic compositions of alkenones during all phases of diagenesis should be confirmed. Both field and laboratory observations are required. Fourth, future alkenone investigations should be coupled with other paleoclimate proxy measurements at high-deposition-rate-sites in a variety of oceanographic settings. In upwelling regions and in the vicinity of river plumes, salinity and nutrient proxies should be measured since changes in these parameters may affect alkenone biosynthesis.
AB - Alkenone-derived estimates of temperature and CO2 are contributing to our understanding of Earth's climate history. In order to increase confidence in alkenone-based climate proxies we recommend the following actions. First, the sedimentary component or fraction containing alkenones should be identified in order to assess the impact of horizontal advection and vertical mixing on alkenone-derived temperature and CO2 estimates. Second, differential mixing rates of alkenone-containing particles and sand-sized foraminifera should be quantified by independent dating of the two phases. Until that is accomplished, apparent temporal offsets of climate proxies in the two phases should be interpreted cautiously. Third, the stability of the unsaturation ratio and carbon isotopic compositions of alkenones during all phases of diagenesis should be confirmed. Both field and laboratory observations are required. Fourth, future alkenone investigations should be coupled with other paleoclimate proxy measurements at high-deposition-rate-sites in a variety of oceanographic settings. In upwelling regions and in the vicinity of river plumes, salinity and nutrient proxies should be measured since changes in these parameters may affect alkenone biosynthesis.
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U2 - 10.1029/2000GC000059
DO - 10.1029/2000GC000059
M3 - Article
AN - SCOPUS:0003277208
SN - 1525-2027
VL - 1
JO - Geochemistry, Geophysics, Geosystems
JF - Geochemistry, Geophysics, Geosystems
IS - 11
ER -