CE11009 Vents and Reefs (VENTuRE campaign) Survey

Vents and Reefs deep-sea ecosystem study of the 45o North MAR hydrothermal vent field and the cold-water coral Moira Mounds, Porcupine Seabight . This survey took place on board the R.V. Celtic Explorer in July/Augyst 2011 along the mid-Atlantic ridge, led by University College Cork and focuses on two distinct deep-water biogeological systems - hydrothermal vents and cold-water coral reefs. Hydrothermal vents play a key role in replenishing depleted elements in the oceans, supporting unique chemosynthetic ecosystems and depositing ore-grade metal sulphides. Cold-water coral reefs are biodiversity hotspots on continental margins and preserve a unique high resolution geological record of intermediate water depth environmental and climate change. This was a discovery and exploration cruise to document previously undiscovered examples of these important bio-geological systems. Surveys were conducted using the ROV Holland 1. In order to determine the location of high-temperature hydrothermal venting on the seafloor and subsequently obtain water samples for plume studies, 14 CTD deployments were undertaken. Reef areas were mapped with high resolution multibeam. Two geological settings were sampled: ROV based sampling of the active vent site sulphides and surrounding mafic rocks, and dredge based sampling of two flat-topped seamounts. Specific objectives: Our programme has the following specific objectives: 1) Verify the status of reef growth and coral health in the Moira Mound extension field. 2) To study the off-reef and within-reef sedimentary environment to provide evidence for current flow and sediment transport affecting reef development. 3) To study cold-water coral reef biodiversity and sample fauna for ongoing biodiscovery research. 4) To locate the source of active high-temperature hydrothermal fluid venting on the Mid-Atlantic Ridge at 45°N and hence discover the first deep-water hydrothermal vent between the Azores and Iceland 5) To determine and map the geological setting, geochemistry and history of hydrothermal activity of the vent field at 45°N. 6) To characterise MAR macrofaunal communities at the study site by visual, morphological and molecular means, to identify new taxa and establish a sample reference collection. 7) To establish the phylogenetic, phylogeographic or population genetic affinities of the fauna at 45°N, revealing the influences of hydrography, geological history and isolation on vent biogeography. 8) To test whether the vent community at 45°N belongs to a new biogeographic province of chemosynthetic fauna; 9) To elucidate the consequences of isolation on the life-history biologies of taxa shared between 45°N and other known vents, through analysis of their gametogenic development; 10) Isotopic analyses of biomass dominant taxa to elucidate trophic structure; 11) To collect samples of potentially novel organisms for the marine biotechnology community/biodiscovery programme.