It was the image that everyone had been waiting for: out of the darkness, lit up by ROV Kiel 6000’s floodlights, the ghostly shape of a hydrothermal chimney appeared, shimmering in the hot fluids spewing out into the cold Atlantic.
After a miraculously short search based on data collected during a previous mission, the IceAGE3 mission successfully located this previously unknown (but long-suspected) hydrothermal vent field on the Reykjanes Ridge. Geological assumptions would place these features at regular intervals along the ridge but they have proved inexplicably hard to find – this new discovery is only the second vent field to have been found on this northern portion of the Mid-Atlantic Ridge between the Charlie Gibbs Fracture Zone and Iceland, in a setting where geologists would expect to fall over them at least once every 100 km.
The science team on board RV Sonne, led by Chief Scientist Saskia Brix from the Senckenberg Institute, have been treated to some spectacular sights in the past two weeks – from the murky depths of the deep Norwegian Basin to the rainbow colours of the cold-water coral reefs at Lóndsjúp to the east of Iceland. But this otherworldly seascape of piles of globule-like pillow lavas splattered with white bacterial mats and topped by craggy yet fragile chimneys churning out 300º C mineralised fluids from deep in the ocean crust was truly an unforgettable experience for all on board. Those of us following remotely via the live camera feed were given a tantalising snapshot of the discovery before the satellite link blinked out, but the follow-up dives over the next two days were well worth waiting for. Giant halibut, delicate pink anemones and multitudes of corals (both dead and alive) obligingly revealed themselves to the ROV cameras too.
Located some 700m deep, this new hydrothermal vent field has yet to be named but its discovery will allow scientists to investigate all manner of questions about how these northerly vent ecosystems are related to their cousins further south on the Mid-Atlantic Ridge, and how the highly specialised fauna living on and around the vent chimneys interact with other ecosystems living on the surrounding rocky slopes of the ridge, and with those in deeper waters in the surrounding basins.
The IceAGE3 mission now leaves the Reykjanes Ridge and sails to the deep waters of the Western European and Iceland Basins, where the team will investigate the megafauna living on the abyssal plains in water depths of 3400 m. Using the ROV Kiel 6000 once again, the team will sample the ecosystems here and in gradually shallower locations in the Iceland Basin, in order to compare them to their counterparts surveyed in the Northern Sea north of Iceland.