This dataset contains temperature data acquired with a 70 m long thermistor chain (50 m equipped with sensors, 20 m of cable to the monitoring station), deployed on the EMSO-Azores observatory from September 2020 to May 2021. Each thermometer is separated by 50 cm for a total of 100 temperature points. Data consist in 70 963 measurements acquired every 15 minutes. The chain is connected to the SEAMON East environmental monitoring node and measures temperatures on different faunal assemblages and substratum on the active Tour Eiffel edifice at 1695 m depth. The raw file contains all data acquired by the sensors. The corrected file was processed to remove outliers that included values below background seawater temperature (4°C), values above 30°C that corresponded to simultaneous periods of high/homogeneous temperature values recorded on all sensors. Unique outliers were then removed after screening of the graph. If extreme values lasted at least three consecutive step, they were kept. Removed values were replaced by NAs. Location of the Eiffel Tower edifice : N 37°17.33 - W 32° 16.53