Diatom-based paleoproductivity and climate change record of the Gulf of Tehuantepec (Eastern Tropical Pacific) during the last similar to 500 years

Changes in marine productivity of the last five centuries in the Gulf of Tehuantepec were investigated using a high-resolution record of diatoms, organic carbon (C-org), total nitrogen (TN), Ni/Al, and Cu/Al. The laminated sediments were dated by using Pb-210 and C-14, with a bayesian age model providing a new Delta R = 247 +/- 30 years for the bulk sediment. The Little Ice Age (LIA) (similar to 1500 to similar to 1858 CE) was characterized by the predominance of cold-water and high productivity diatoms (Chaetoceros spores, Thalassionema nitzschioides, Lioloma pacificum, Thalassiosira nanolineata, and Rhizossolenia setigera) and high values of geochemical productivity proxies. A transition period (similar to 1860 to similar to 1919 CE) toward warmer conditions related to the end of the LIA and the beginning of the Current Warm Period (CWP), was indicated by the appearance of warm-water diatoms (Neodelphineis pelagica, Thalassiosira tenera, and Rhizossolenia bergonii), as well as lower values of C-org, TN, Ni/Al, and Cu/Al. The most recent period of the CWP (similar to 1920 CE to today) was characterized by the increased abundance warm-water taxa (N. pelagica, Cymatodiscus planetophorus, T. tenera, Plagiogramma minus, Nitzschia interruptestriata, and R. bergonii), and by the prevalence of low values of C-org, TN, Ni/Al, and Cu/Al. These changes in productivity during the LIA and CWP were likely driven by changes in solar irradiance and the migration of the Intertropical Convergence Zone. This study highlights the spatial extent of the LIA in the Eastern Tropical North Pacific and contributes to the knowledge of the productivity response to climate in tropical regions.