Progresses in the study of organic lipid molecules for reconstruction of paleo-sea temperature

Temperature is a very sensitive and crucial factor in climate change, and an indispensable boundary condition in climate modelling. The reconstruction of paleotemperature is of great significance for understanding paleoclimate system such as the evolution of atmospheric circulation, and ocean currents strength and path, as well as for making more accurate predictions of future climate changes. Along with the development of new analytical techniques, organic temperature proxies have been highly valued as an important tool in paleoclimate research and widely applied in temperature reconstruction globally. In this paper, six organic thermometers are reviewed, i.e. \rm U^\rm K_37 , TEX₈₆, RI-OH, LDI, NL₅, and RAN₁₃, including lipid structural characteristics, biological sources, and mechanism in their responds to temperature. The development history, basic principles, application status, and limitations of each index are also elucidated. Multi-index combination is believed necessary and recommended for reliable reconstruction of paleotemperature, which is significant for the progress of paleoclimate study.