Holocene and Eemian sea surface temperature trends as revealed by alkenone and Mg/Ca paleothermometry
In this study we review a global set of alkenone- and foraminiferal Mg/Ca-derived sea surface temperatures (SST) records from the Holocene and compare them with a suite of published Eemian SST records based on the same approach For the Holocene, the alkenone SST records belong to the actualized GHOST database (Kim, J.-H Schneider R.R., (2004) GHOST global database for alkenone-derived Holocene sea-surface temperature records. Available from. http.//www pangaea de/Projects/GHOST.), while the Mg/Ca-derived SST database represents a new compilation The actualized GHOST database not only confirms the SST changes previously described but also documents the Holocene temperature evolution in new oceanic regions such as the Northwestern Atlantic, the eastern equatorial Pacific, and the Southern Ocean A comparison of Holocene SST records stemming front the two commonly applied paleothermometry methods reveals contrasting - sometimes divergent - SST evolution, particularly at low latitudes where SST records are abundant enough to infer systematic discrepancies at a regional scale Opposite SST trends at particular locations could be explained by out-of-phase trends in seasonal Insolation during the Holocene. This hypothesis assumes that a strong contrast in the ecological responses of coccolithophores and planktonic foraminifera to winter and summer oceanographic conditions is the ultimate reason for seasonal differences in the origin of the temperature signal provided by these organisms. As a simple test for this hypothesis, Eemian SST records are considered because the Holocene and Eemian time periods experienced comparable changes in orbital configurations, but had a higher magnitude in Insolation variance during the Eemian For several regions, SST changes during both interglacials were of a similar sign, but with higher magnitudes during the Eemian as compared to the Holocene This observation suggests that the ecological mechanism shaping SST trends during the Holocene was comparable during the penultimate interglacial period Although this "ecology hypothesis" fails to explain all of the available results, we argue that any other mechanism would fail to satisfactorily explain the observed SST discrepancies among proxies.
Leduc G., Schneider R., Kim J. -H., Lohmann G. (2010). Holocene and Eemian sea surface temperature trends as revealed by alkenone and Mg/Ca paleothermometry. Quaternary Science Reviews. 29 (7-8). 989-1004. https://doi.org/10.1016/j.quascirev.2010.01.004, https://archimer.ifremer.fr/doc/00231/34229/
Leduc, Guillaume, Schneider, Ralph R, Kim, Jung-Hyun, Lohmann, Gerrit (2010). Mg/Ca-derived Holocene Sea Surface Temperature database. PANGAEA. https://doi.org/10.1594/PANGAEA.736946
Leduc, Guillaume, Schneider, Ralph R, Kim, Jung-Hyun, Lohmann, Gerrit (2010). Sea surface temperature reconstruction from sediment core 108-658C using alkenones. PANGAEA. https://doi.org/10.1594/PANGAEA.737190
Leduc, Guillaume, Schneider, Ralph R, Kim, Jung-Hyun, Lohmann, Gerrit (2010). Summary of sea surface temperature trends reconstructed from Mg/Ca ratios for the Holocene. PANGAEA. https://doi.org/10.1594/PANGAEA.735777
Leduc, Guillaume, Schneider, Ralph R, Kim, Jung-Hyun, Lohmann, Gerrit (2010). Summary of sea surface temperature trends reconstructed from alkenones for the Holocene. PANGAEA. https://doi.org/10.1594/PANGAEA.735805
Leduc, Guillaume, Schneider, Ralph R, Kim, Jung-Hyun, Lohmann, Gerrit (2010). Sea surface temperature reconstruction from sediment core MD97-2120 using alkenones. PANGAEA. https://doi.org/10.1594/PANGAEA.737254