HR: 0800h
AN: T31A-0472 INVITED     [Abstracts]
TI: Overview of the Ridge 2000 Integrated Studies Sites
AU: * Fisher, C
EM: cfisher@psu.edu
AF: Penn State University, Department of Biology, 208 Mueller Lab, University Park, PA 16802 United States
AB: The Ridge 2000 program is in its fourth year and fieldwork at each of the Integrated Studies Sites (ISS) is in full swing. Multidisciplinary monitoring continues at the EPR ISS with seismic, temperature, and current data being continuously recorded. Long-term fluid sampling programs aimed at furthering our understanding of temporal variations in the chemistry of high-temperature hydrothermal vents are continuing. In situ fluid chemistry monitors have been deployed for weeks, and longer deployments are planned as the technology matures. Nested within these monitoring studies are experiments addressing larval dispersal and changes in microbial and macrobiological communities. In early 2006, geodetic monitoring will begin, with an array of pressure gauges as well as a detailed compliance study. By early 2007, a 3-D multichannel seismic survey will have provided unprecedented details of the crustal structure at 9°50'N. Together these studies provide a strong framework for an interdisciplinary understanding of the links between the forces that produce a mid-ocean ridge spreading center and their manifestation on the seafloor. Fieldwork on the Endeavour segment of the Juan de Fuca ridge in 2005 also included a balance of monitoring, experimental, and sampling programs across a wide range of disciplines. Four interdisciplinary field programs were conducted to maintain and expand ongoing Ridge 2000 and proto-NEPTUNE experiments. These research programs continued development and testing in situ chemical and microbial sensors, conducted co-registered sampling of fluids, fauna, and chimney material, and recovered moorings that measured heat and chemical fluxes at the segment scale. High-resolution mapping was also completed at this site, which has been chosen for one of the two initial NEPTUNE Canada nodes to prepare the way for the collaborative, cabled observatory projects. The mapping cruise included 5 secondary school teachers as part of the REVEL outreach and education program. Live transmission of high-definition video from the seafloor to land stations provided an exciting preview of the potential of high-bandwidth communication with the seafloor. The first round of fieldwork at the East Lau Spreading Center ISS was completed in 2005. Building upon the two R2K-funded cruises in 2004, three cruises in 2005 sampled 7 hydrothermal vent sites. Four of these sites were discovered by the collaborative efforts of R2K scientists, working together across cruises, and one site by Japanese colleagues collaborating with R2K scientists in 2004. Another of the sites was discovered during the first R2K cruise of 2005. The SM2000 mounted on Jason II in 2005 was used to create fine-scale bathymetric maps of six of the sites and high-resolution imagery was collected for photomosaics of selected areas of hydrothermal activity within the sites. These maps and imagery guided even finer scale surveys, equipment deployments and sampling of basalt, hydrothermal deposits, vent fluids, microbial mats, and benthic organisms. Some of the fauna collected are still alive and under study in pressure vessels in R2K-supported laboratories. Results from these cruises have improved our understanding of this back-arc spreading center, "from mantle to microbe," and are invaluable for selection of the focus area, or bull's eye, for the next generation of integrated, interdisciplinary studies in this region.
UR: http://www.Ridge2000.org
DE: 3001 Back-arc basin processes
DE: 3017 Hydrothermal systems (0450, 1034, 3616, 4832, 8135, 8424)
DE: 3025 Marine seismics (0935, 7294)
DE: 3035 Midocean ridge processes
DE: 3045 Seafloor morphology, geology, and geophysics
SC: Tectonophysics [T]
MN: Fall Meeting 2005