Open AccessA study of the TEX 86 paleothermometer in the water column and sediments of the Santa Barbara Basin, California
Author(s) -
Huguet Carme,
Schimmelmann Arndt,
Thunell Robert,
Lourens Lucas J.,
Sinninghe Damsté Jaap S.,
Schouten Stefan
Publication year - 2007
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/2006pa001310
Subject(s) - sediment trap , water column , sediment , structural basin , geology , oceanography , sea surface temperature , temperature record , particulates , hydrology (agriculture) , environmental science , holocene , geomorphology , chemistry , geotechnical engineering , organic chemistry
Particulate organic matter collected during a 2‐year period, as part of an ongoing sediment trap study, and a high‐resolution sediment record from 1850 to 1987 A.D. from the Santa Barbara Basin were analyzed for TEX 86 , a temperature proxy based on marine crenarchaeotal membrane lipids. Highest fluxes of crenarchaeotal lipids in the water column were found in May–June 1996 and from October 1996 to January 1997 and, in general, showed a good correlation with mass fluxes. TEX 86 reconstructed temperatures from the sediment trap series ranged from 8 to 11°C and were usually substantially lower than sea surface temperatures (SST), indicating that unlike in previous studies, the TEX 86 corresponds to subsurface temperatures, likely between 100 and 150 m. TEX 86 temperature variations observed in trap samples were not coupled to changes in SST or deep‐water temperatures and only to some degree with crenarchaeotal lipid fluxes. This suggests that a complex combination of different depth origins and seasonal growth periods of Crenarchaeota contributed to the variations in TEX 86 signal during the annual cycle. TEX 86 temperatures in the two sediment cores studied (8–13°C) were also substantially lower than those of instrumental SST records (14–17.5°C) confirming that TEX 86 records a subsurface temperature signal in the Santa Barbara Basin. This result highlights the importance of performing calibration studies using sediment traps and core tops before applying the TEX 86 temperature proxy in a given study area.