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Abstract: Recent coccoliths from 74 surface sediment samples recovered from the southeastern Pacific off Chile were examined quantitatively to investigate modern regional gradients of sea surface productivity and temperature. All findings are based on coccolith accumulation rates. Therefore an approach was designed to estimate recent sedimentation rates based on 210Pb and bulk chemistry analyses of the same set of surface samples. Highest total coccolith accumulation rates were found off north-central Chile, where seasonal upwelling takes place. Based on a multiple linear regression between calculated coccolith accumulation rates and World Ocean Atlas derived sea surface temperatures, a calibration model to reconstruct annual average temperatures of the uppermost 75m of the water column is provided. The model was cross-validated and the SST estimates were compared with SST observed and SST estimates based on diatoms and planktonic foraminifera, showing a good correlation. [Copyright &y& Elsevier]

The scanning Electron Microscope (SEM) and the Petrographic Microscope (Light Microscope, LM) are devices which both are used in routine analysis of coccolithophore assemblages, but comparisons and/or combinations of quantitative data from both sources are difficult. In this paper a comparison is made between the results obtained with the Flores and Sierro settling technique (1997) for LM and the Andruleit filtration technique (1996) for SEM, considering their advantages and drawbacks. Twenty-six surface sediment samples from the South Atlantic and Southeast Pacific were studied. All the taxa distinguished were reduced to fourteen groups accounting for 100%. The biogeographical patterns of coccolithophorid species and species groups determined using both techniques are highly comparable, although the trends in relative and absolute numbers are not always identical. In particular, the numbers of coccoliths per gram of sediment are higher in the case of the filtration technique/SEM-technique than for the settling technique/LM technique and an approach is introduced to estimate LM values using SEM counts with a linear regression equation. The results obtained allow different methodologies to be compared for the study of current coccolithophore biogeography. [ABSTRACT FROM AUTHOR]