Spatial Variability and Structure of Hydrothermal Ecosystems at the Tempus Fugit Vent on the Galápagos Spreading Center
Nicole Raineault1, Clara Smart2, Leigh Marsh3, Timothy M Shank4, Charles R Fisher5 and Robert D. Ballard1, (1)Ocean Exploration Trust, Narragansett, RI, United States, (2)University of Rhode Island, Graduate School of Oceanography, Narragansett, RI, United States, (3)University of Southampton, Southampton, United Kingdom, (4)WHOI, Woods Hole, MA, United States, (5)Pennsylvania State University, State College, PA, United States
Abstract:
Our early understanding of hydrothermal vent ecology originated from the historic vent sites along the Galápagos Spreading Center (GSC). In 1977, images of these newly discovered chemosynthetic environments changed the way scientists viewed life at depths beyond which sunlight could penetrate. Since the initial discovery, large-scale disturbances as a result of eruptive and tectonic activity have both destroyed and created vent habitats along the GSC. Four years ago, visual observations during the discovery of the active Tempus Fugit vent site at 86°W revealed a large peripheral field of dead vesicomyid clams, indicative of the persistence of hydrothermal activity at this field, likely for more than 20 years. From our knowledge of succession at these vent communities, the occurrence of juvenile clams amongst mature live clams, bathymodiolus mussels and siboglinid tubeworms indicates that there have been multiple colonization events. Riftia tubeworms only observed in nascent stages of growth in 2011 now have have tubes almost 4 m in length in some cases.
In 2015 the E/V Nautilus mapped an area of diffuse flow in the Tempus Fugit field (100 m x 150 m) at centimeter level resolution using the standard ROV Hercules imaging suite, comprised of stereo cameras and a structured light laser sensor. This system, along with ROV HD video, samples, and environmental sensors, documented hydrothermal activity and biological community structure (e.g., Riftia tubeworms only observed in nascent stages of growth in 2011 now, in 2015, have tubes almost 4 m in length). Analysis of the resulting high-resolution photo mosaic and samples will address questions regarding distribution of species surrounding hydrothermal activity. This large-scale cohesive imagery provides us with information about the community structure associated with these ecosystems at a moment in time, while the assessment of fluid flow and associated faunal assemblages will provide a proxy for the temporal and spatial variability of venting activity at the Tempus Fugit site.
