A Preliminary Study of Macrofaunal Communities at the Novel Hydrothermal Vent Field “Dymond” Near the Base of Axial Seamount

Hydrothermal vents occur along all mid-ocean ridge spreading centers and are one of the most extreme environments on Earth, supporting novel life forms in the absence of sunlight. Here, remarkable microbial communities form the base of the food chain to sustain rich macrofaunal assemblages. In 2011, an unusual hydrothermal vent field was discovered, during an NSF-funded Ocean Observatories Regional Cabled Array cruise, the “Dymond field” at a water depth of ~1990 meters, near the base of Axial Seamount on the Juan de Fuca ridge. It is underlain by a secondary magma chamber residing ~ 16 km southwest of an extensive chamber underlying Axial Caldera, 1500 m below sea level. The largest hydrothermally active, complex edifice in Dymond rises ~60 m above the seafloor. It hosts multiple pinnacles and numerous vents that are notably different from those within Axial Caldera. Rare, small orifices emit particle-free fluids with chimlets and surrounding deposits covered in extremely thick orange microbial mats and oxidized substrate. These unique microbial mats support a diverse macrofaunal ecosystem. This preliminary work provides the first description of macrofaunal communities at Dymond, which includes Rattail fish (Coryphaenoides acrolepis), Ridgeia tubeworms (Ridgeia piscesae), sea pigs (Scotoplanes globosa), Fathead sculpins (Psychrolutes phrictus), and Juan de Fuca limpets (Lepetodrilus fucensis).

Presentation Preference: Poster

Primary Presenter: Morrigan Havely, University of Washington (mhavely@outlook.com)

Authors:

Morrigan Havely, University of Washington  (mhavely@uw.edu)

Deb Kelley, University of Washington  (dskelley@uw.edu)

Mike Vardaro, University of Washington  (mvardaro@uw.edu)