[en] The Canary Basin, which encloses the subtropical eastern North Atlantic, is dominated in surface waters by the presence of the Azores Current, the Canary Current and the Canary Upwelling Current. Although extensive work has been done in the area to understand the local dynamics, some oceanographical phenomena remain partially unexplained. Following specific events of unusually high sea surface temperature recorded in the Canary Basin during 2017, the causes of this anomaly have been investigated. Here, the starting point is a long-term mooring, the European Station for Time series in the Ocean Canary Islands (ESTOC) which is found north of the Canary Islands. With moored ADCP, surface current velocities, among others, parameters are measured. In this work, a time series from April to September 2017 is used. The observations are analyzed and compared to a climatology based on the Simple Ocean Data Assimilation (SODA) reanalysis. The principal finding is an anomalous northeastward flow, sustained from late April to late September. This flow was found to be in opposition to the usual southwestward Canary Current dominating the open ocean around the Canary Islands. The temperature recorded also showed anomalous maximum values during early summer. Those two anomalies combined are reported as an explanation for the unprecedent bloom of cyanobacteria Trichodesmium spp. Around the Canary Islands during 2017. In future studies, it would be very important to study the long- term recurrence of this king of events, due to the strong ecological and social impact of the anomalies recorded.

[es] La Cuenca de Canarias corresponde a la frontera este del giro subtropical del Atlántico Norte. La dinámica general superficial se encuentra dominada por la presencia de la corriente de Azores, la corriente de Canarias y la corriente Canaria de Upwelling. A pesar de las extensas investigaciones realizadas en el área, algunos acontecimientos específicos no han sido completamente explicados. Unos eventos de anomalía positiva de la temperatura superficial del mar (TSM) durante la primavera 2017 en las Islas Canarias están siendo investigados. En este estudio se propone un evento de circulación superficial anómala como posible causa de la anomalía de TSM. La Estación Europea de Series Temporales Oceánicas de Canarias (ESTOC) proporciona medidas de la velocidad de la corriente en capas superficiales (entre 20 y 100 m de profundidad) durante el periodo de tiempo abril-septiembre 2017. Las medidas tomadas de velocidad y dirección de corriente son comparadas con una climatología oceánica realizada a partir del reanalysis SODA (Simple Ocean Data Assimilation). El principal resultado es una anomalía de circulación en las aguas superficiales (20-100 m) sostenida durante el periodo de tiempo estudiado. Se observó una corriente de dirección noreste, en completa oposición con la dirección de corriente dominante mostrada por la climatología (sursuroeste). Por último, se discute de la posible relación entre la anomalía de corriente y el bloom de cianobacterias Trichodesmium spp. acontecido en las Islas Canarias ese mismo año. De cara al futuro, es importante resaltar la necesidad de extensivos estudios para optimizar la comprensión de las causas y frecuencias de estos eventos anómalos de circulación y TSM, ya que podrían presentar un importante impacto ecológico y social si se demuestra su relación con el bloom de cianobacterias.