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... |