Paleoproductivity and climate evolution in the Kuroshio mainstream area over the past millennium

Abstract

A variety of biomarkers of sediment core KET-1 were studied to reconstruct both paleoproductivity and phytoplankton community structure variations and to reflect the local climate change of Kuroshio mainstream of east Taiwan over the past millennium. The results showed that sterols in sediments derived from the mixed terrestrial and marine inputs, with the riverine input from eastern Taiwan as the main terrestrial sterol source. The upward increase of terrestrial organic matter over the past millennium suggested the increasing riverine input of eastern Taiwan. The variation of the marine primary productivity was mainly influenced by the nutrient supplements from the riverine input. The changes of brassicasterol to dinosterol ratio indicated a phytoplankton community shift from dinoflagellate-dominated to diatom-dominated since 1500 CE. The increasing terrestrial inputs and the change of phytoplankton community change over time were related to “dry-humid” climate change.

Keywords

• Sterols
• Paleoproductivity
• Phytoplankton community structure
• Climate changes
• Kuroshio mainstream