One Slocum glider owned by GEOMAR (ifm12) was used during the cruise M156 to intensify the survey of the 18°W, 18.5°N cyclonic eddy. The glider was deployed on 24-Jul-2019 at 18°05'W, 18°35'N. It conducted an eastward transect along 18°42'N from the core to the periphery of the cyclonic eddy and was recovered on 28-Jul-2019 at 17°W, 18°42'N. The glider was equipped with temperature, conductivity, pressure, chlorophyll (chl-a), turbidity and optode oxygen sensors. An optical nitrate sensor (SUNA, Satlantic) was mounted to the glider's top as a self-contained sensor package.