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| Sicre, Ma; Bard, E; Ezat, U; Rostek, F. |
| The C(37)-C(39) alkenones were quantified in suspended particulate matter obtained from the surface waters of the North Atlantic, including the Nordic seas, over a temperature range of 4degrees20 C. U(37)(K') values were linearly correlated to temperature over the entire range covered by our data set, i.e., 420 C (U(37)(K') = 0.027T + 0.036, r(2) = 0.97). The compilation of water column data from the Atlantic, Pacific, and Southern Ocean and Mediterranean Sea suggests that the linear model may not be the best function for fitting U(37)(K') and in situ temperature values. It also shows that suspended matter data from warm waters (T >20degreesC) are still needed to constrain the equation of the global curve. High abundances of C(37: 4) were found in the... |
| Tipo: Text |
Palavras-chave: Alkenones; Paleotemperature; Calibration; Atlantic Ocean; Plankton; Geochemistry; Marine geochemistry; Global change; Biogeochemical processes (4805); Oceanography; Paleoceanography. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33393/31866.pdf |
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| Sicre, Ma; Ternois, Y; Miquel, Jc; Marty, Jc. |
| C-37 alkenone fluxes were measured with sediment traps at 200 m depth over the years 1989/1990 and 1993/1994 to assess the interannual variability of the alkenone flux from the surface waters of the Mediterranean Sea. Fall and spring were identified as the high flux periods. SST estimates derived from the U-37(K) index indicated 50 m and 30 m as major production depths in spring and fall, respectively. Althought interannual variation of alkenone fluxes was notable, the seasonality and depth of production appeared to be recurrent features of the coccolithophorid cycle of production. Alkenone fluxes at 1000 m measured over the year 1993/1994 were about 5 times lower than at 200 m and show no evidence of preferential preservation relative to the organic... |
| Tipo: Text |
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| Ano: 1999 |
URL: https://archimer.ifremer.fr/doc/00239/35059/34599.pdf |
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| Conte, Mh; Sicre, Ma; Ruhlemann, C; Weber, Jc; Schulte, S; Schulz-bull, D; Blanz, T. |
| [1] In this paper, we compile the current surface seawater C(37) alkenone unsaturation (U(37)(K')) measurements ( n = 629, - 1 to 30 degrees C temperature range) to derive a global, field-based calibration of U(37)(K') with alkenone production temperature. A single nonlinear "global'' surface water calibration of U(37)(K') accurately predicts alkenone production temperatures over the diversity of modern-day oceanic environments and alkenone-synthesizing populations (T = - 0.957 + 54.293(U(37)(K')) - 52.894(U(37)(K'))(2) + 28.321(U(37)(K'))(3), r(2) = 0.97, n = 567). The mean standard error of estimation is 1.2 degrees C with insignificant bias in estimated production temperature among the different ocean regions sampled. An exception to these trends is... |
| Tipo: Text |
Palavras-chave: Alkenones; Paleoproxies; Sea surface temperature; UK ' 37. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00239/34978/33474.pdf |
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| Sikes, El; Sicre, Ma. |
| This study assesses the relationship to salinity and temperature of the levels of the tetra-unsaturated 37-carbon methyl alkenone (C-37:4) in the surface ocean. U-37(K'), a measure of the relative abundances of the C-37:2 and the C-37:3 alkenones, has a well constrained linear relationship to temperature in the open ocean [Prahl and Wakeham, 1987] and is a well-established technique for estimating past sea surface temperatures in the sediments (e. g. [Muller et al., 1998]). Unlike the di- and tri-unsaturated C-37 alkenones, the temperature response of the tetra-unsaturated C-37 alkenone is less certain [Sikes et al., 1997], and recent work has suggested a relationship to salinity instead [Rosell-Mele, 1998; Schulz et al., 2000]. Our study examined 106... |
| Tipo: Text |
Palavras-chave: Alkenones; Paleosalinity; Marine organic geochemistry; Organic geochemistry; Paleoceanography; Organic marine chemistry. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33414/31886.pdf |
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