Organic Compounds as Proxy-Indicators of Sea Surface Palaeotemperature: The Uk 37 Index

Abstract

The Uk37 index is a proxy-indicator of sea surface temperature (SST). It is derived from the relative abundance of two organic compounds (long-chain alkenones) which are commonly found in Quaternary marine sediments. These compounds are biosynthesized by some species of algae of the Class Prymnesiophyceae, which includes the coccolithophorids. Uk37 stratigraphy in ocean cores can provide time series records of local SST in the photic zone. Despite several biological and geochemical questions which constrain its applicability as a palaeothermometer, it has been successfully used in the study of temperature records over several glacial/interglacial transitions, and has increased the current understanding on the evolution of upwelling areas, el Nino events and rates of climatic change produced over hundreds, thousands or tens of thousands of years.