Organic paleotemperature proxies in suspended particulate matter and sediment core tops from continatal slope off Newfoundland during Maria S. Merian Expedition MSM39 in June 2014

• Main Author: Schukies, Julian
• Format: Dataset
• Language: English
• Published: PANGAEA 2018
• Subjects: Newfoundland; north atlantic current; North Atlantic; Northwest Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.894308; https://doi.org/10.1594/PANGAEA.894308

TEX86 (tetraether index of 86 carbon atoms) is an organic paleotemperatureproxy based on the relative abundances of thaumarcheal isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs). The calibration is based on global core top sediments. The global core top calibrations of TEX86 are often not reliable for reconstructions of watertemperatures in regions with distinct hydrographic conditions. In the area of the continental edge of Newfoundland (Northwest Atlantic), hydrographic conditions are mainly determined by the Labrador- and the North Atlantic Current. Thus, the region differs from the global ocean. In this study the accuracy of temperature estimations of TEX86 was tested at the realm of the continental edge off Newfoundland. For this purpose, GDGT distribution in suspended particulate matter of water surface and core top sediments was analysed. Based on the GDGT composition, the influence of the regional environmental factors on the TEX86 proxy was investigated. Based on TEX-signals of the samples, temperatures were estimated, using various global core top calibrations (for the surface sediments: TEX86, BAYSPAR (for sea surface temperature (SST), for subsurface temperature (SubT0-200 m)), TEX86L, TEX86L0-200 m / for the suspended solids samples: TEX86, BAYSPAR (SST), TEX86L). Using the global core top TEX86-calibration for sedimentary signals, the annual mean (am) SST were estimated. However, due to the large standard error, reliability is uncertain. Statistical analyses show strong relations of the sedimentary TEX86L-values to the mean temperatures of summer season (June, July, August) below the water surface (average temperature of 10 and 15 m water depth). A sedimentary temperature signal of the summer months could be explained by a combination of the maximum abundance of the regional Thaumarchaeota and the iGDGT export by fecal pallets of a local copepod population in the summer season. The temperatures derived from TEX-signals of suspended particulate matter results in an overestimation of the in ...