Applications of ocean gliders for climate change monitoring of Essential Ocean Variables (EOVs) in the Northeast Atlantic

Primary productivity and respiration form the foundation of the ocean's food web and life and drive oxygen's biogeochemical cycling. Oxygen and phytoplankton abundance are two essential ocean variables (EOV) in monitoring the state of the ocean and in the study of the impact of climate change on the marine ecosystem. To estimate primary productivity and respiration in the sea, ocean gliders deployed in the Northeast Atlantic are equipped with oxygen optodes and chlorophyll fluorescence sensors to obtain critical data in the upper water column at a much larger spatial and temporal scale than is possible with research vessels.

During the first missions near the ESTOC Station in the Canary Islands led by PLOCAN, oxygen, turbidity and chlorophyll fluorescence data was measured with sensors installed on SeaExplorer gliders. We used this dataset to provide estimates of primary productivity and respiration in the medium term. Short deployments of Slocum Gliders with the Marine Institute in the Celtic Sea and along the continental shelf provide much higher temporal resolution data of the phytoplankton diel cycle. This also allowed for the study of the potential for gliders to detect phytoplankton thin layers and/or vertical migration of HAB species as part of an integrated operational oceanography platform for the early warning system for HABs.