BGC processes from gliders in the se bay of biscay

Abstract

He marine biogeochemical (BGC) processes support the base of the trophic chain and thus affect the whole ocean ecosystem. Therefore, the monitoring of BGC variables and the understanding of BGC processes are crucial for the proper management of marine areas. Despite the existing observatories in the SE Bay of Biscay (SE-BoB) which monitor the BGC and physical estate of the ocean, there are still knowledge and observational gaps. The recent acquirement of 2 gliders by AZTI and the conducted glider missions aim to fill this observational gap. A glider mission run in November 2023 monitored the Adour River plume and its marked westward spreading for 5 days. In the final part of that mission, the glider revisited the area initially affected by the plume, observing the evolution of the water column conditions. Besides, the recently launched BIGFIS project aims to characterize the effect of ocean circulation in the BGC cycle by joining glider-based BGC observations with high-frequency radar and satellite-based observations in the SE-BoB. It also aims to optimally complement the information provided by current observatories in the area. In addition, the suitability of BGC models available in the area to resolve BGC-physical processes will be tested. In the frame of this project, 2 gliders were launched in September 2024 to collect hydrographic and BGC data, which are currently being analyzed.