POSEIDON POS469

The POSEIDON cruise P469 to the submarine volcanic gas discharge sites off Panarea (Aeolian Islands, South Italy) is conducted within the framework of the ECO2 project (EU) and the Helmholtz-Alliance "ROBEX – Robotic Exploration of Extreme Environments". The Panarea gas vents represent a unique environment as carbon dioxide (CO2), methane (CH4), hydrogen (H2), nitrogen (N2), helium (He) as well as hydrogen sulfide (H2S) is simultaneously emitted into the water column. This and the different source strengths of gas discharge render the Panarea area an ideal test bed for the study of the dynamics of gas discharge and associated plume formation.

The major aim of the cruise is to quantitatively understand the dynamics of plume formation and its effects on the distribution of different gases dissolved in the ambient seawater applying appropriate plume models that enable the determination of the source strength of the respective gas discharge site. Under consideration of bubble rise velocity and bubble size, the models will be parameterized and validated by gas measurements of pCO2, CH4, H2S, N2, oxygen (O2), and argon (ar) conducted in the surrounding of gas discharge. Gases will be simultaneously measured using the prototype of a novel Underwater Membrane Inlet Mass Spectrometer. Investigations will be conducted along transects across discharge sites using the ROV PHOCA and a towed video-guided pump CTD. In parallel to these ship based deployments, measurements will be conducted by divers at the shallow gas vents off Panarea Island.