|Over the past decade I have worked to develop and
to estimate past sea surface temperature (SST). When the technique was
proposed in the mid 1980’s it still needed to be calibrated, its
sources determined, and the stability of the resulting temperature
record assessed before it could be reliably applied world-wide to
paleoceanographic questions. My development work on C37 alkenones addressed each of these issues. By
to paleotemperature estimation, my multi-proxy work helped to establish
that alkenone-based temperature estimates are robust and produce late
Quaternary temperature records in the Atlantic, Pacific, and Southern
Oceans. Recent studies have shown the radiocarbon ages of alkenones and
foraminifera in sediments differ, suggesting that post depositional
lateral transport of the organic fraction may be important in some
locations. Presently, I am funded to re-examine the veracity of the
alkenone record in the sediments by determining the 14C ages of sedimentary alkenones in areas of varying flow regimes on the sea floor.
I continue to work with alkenone temperature estimation in modern samples to elucidate the controls on temperature proxies as they are produced. I am comparing the relative timing of the fluxes and the temperature estimates of UK'37 with foraminiferal-based techniques (assemblages and δ18O), along with additional biomarkers and bulk fluxes in sediment traps. My results show that the differences between the responses of each of these biologically based estimates suggests that the organisms responds differently to their environment and this impacts temperature reconstructions across climatic shifts. We are presently applying our new understanding of these productivity differences to down-core paleo-studies to better interpret the offsets in timing between different proxies and their impacts on paleoclimatic records.