A simple proto-type device for measuring fluid flux in black smokers and diffuse flow. Here it is deployed from ALVIN at Bio 9 on the East Pacific Rise 9°50' N. Analysis of particle movements from high resolution video is used to determine fluid velocity. Advective heat output is determined from this velocity measurement, together with fluid flux area and fluid temperature (from Ramondenc et al., 2006).

2. BRIEF REVIEW OF THE FIRST PHASE OF THE PROGRAM (2002-2007)

The Ridge 2000 (R2K) program has broken new ground in three areas that stand out relative to 'business as usual' OCE research: Integrated Studies, Time Critical Studies, and Education/Outreach. Peer-reviewed publications (Appendix 1) provide the most in-depth record of scientific results to date. R2K Newsletters and Workshop Reports (http://ridge2000.org/science/meetings/index.php) also provide a considerable amount of information on then-current results and planning. Here we provide a brief review of first-phase activities within the main research Program components. More detail on a given project is available in the individual PI Summaries in Appendix 4.

R2K began with three initial Integrated Studies Sites (ISS): The Endeavour Segment of the Juan de Fuca Ridge; 8°–11° N on the East Pacific Rise; and a back-arc spreading center in the Lau Basin. Progress at all three ISS has been significant, underscoring the strength of many aspects of the initial Community Education efforts (Long Beach Mtg 2002; Boulder Mtg, 2003; Table 1) and development of community-consensus Implementation Plans at each site (Albuquerque Workshop 2002, Table 1), as the Program got underway. The advances differ between the sites but each ISS has revealed new insights into spreading center and/or hydrothermal ecosystem processes. Successful acquisition of a rich suite of multi-disciplinary data has been encouraging, and integration of results has begun in earnest in the past couple years. The field results and findings from onshore modeling/laboratory studies have become sufficient for some interdisciplinary patterns to emerge. Recent and future community-wide (Vancouver 2005; Fall AGU 2006; Portland 2008; Table 1) and focus-site (EPR April 2006, Lau June 2006, Endeavour July 2006, Table 1) workshops have been designed with the aim of optimizing dissemination of current results and provided forums, not only for planning, but also for discussing integration of results that can illuminate interplay between components of the ridge system(s).

Theoretical Institutes sponsored by R2K emphasize a subset of spreading/hydrothermal processes, with short courses designed for non-specialists and intensive workshops that aim to propel 20-30 investigators into a next stage of in-depth research (Table 2). Field schools (Iceland, Cyprus, Table 2) introduce students and non-specialist researchers to onshore exposures of crustal and hydrothermal systems that are analogs to the oceanic axial systems emphasized by R2K. These theoretical institutes and field schools also serve to help entrain new scientists and students by giving them a good introduction to aspects of the R2K program, and allowing them to interact with current R2K researchers.

Rapid response capabilities have improved notably with the emphasis placed on Time Critical Studies in R2K. Key improvements are the development (and continued assessment) of criteria for when to respond via seagoing mapping/sampling or not, for a given axial event, and the significant reduction in the time needed to have a well-equipped team ready to conduct a response cruise. Response time at the Endeavour ISS is now less than a week. In the case of the recent 2005/2006 eruption at the EPR, a response cruise was mobilized and on site within 3 weeks of the initial discovery that a recent or ongoing eruption was likely.

Education and public outreach efforts (Section 4) have grown from individual programs initiated by researchers throughout the community to include a series of specific projects that are designed to provide R2K researchers with effective ways to contribute to outreach without having to create or fund the complete effort. Current projects are reaching not only students and public audiences here in the U.S., but also international audiences through new partnerships with other groups and programs. R2K efficiently provides a continuous presence on the web of high-quality and up-to-date mid-ocean ridge science.

2.1 Integrated Studies

RIDGE research at the East Pacific Rise and Juan de Fuca Ridge, prior to the start of R2K, provided a useful framework for integrated research at the 8°–11°N and Endeavour segment ISS, respectively. In contrast, the envisioned Lau ISS was in a reconnaissance stage at the beginning of the Program. Focus areas (the "bull's eye" of the ISS, where 1-10's-m-scale studies at specific vents are co-located) were selected at the time the Implementation Plans for EPR and Endeavour were drawn up. For Lau, a series of coordinated cruises was laid out in the Implementation Plan, successfully funded and carried out, and at the Vancouver 2005 meeting, the focus area of the ISS was selected.

EPR 8-11°N. There have been more than a dozen cruises to the EPR (see Table 3) since the start of R2K, including two rapid response cruises after the discovery of a 2005/2006 eruption. A majority had multidisciplinary science parties onboard (biologists, chemists, geologists/geophysicists). The scope of these studies ranged from mantle imaging (seismic, electro-magnetic) and crustal processes (geodetic, inversions for properties), through seafloor mapping (sonar, video) and sampling (rock, fluid, biological), to hydrothermal fluid characterization (water samples, in-situ electro-chemistry measurements), macrofaunal distribution/evolution and microbial sampling, and recently included oceanographic current and larval dispersal measurements. Continuous, multiple-year monitoring of both seismicity and temperature (T) at high and low T vents was achieved for the first time (2003-2006). Repeat visits (~annual) allowed vent fluid chemistry to be linked to evolution in chimney and biological community structure as well as to hypothesized changes in subsurface magmatic activity (Von Damm and Lilley, 2004). EPR advances not already mentioned in Section 1 include recognition that upper mantle structure does not directly follow current-day plate boundary geometry (Key and Constable, 2002; Toomey et al., 2007) although relationships between uppermost mantle structure (few km sub-Moho), ridge segmentation, and surface morphologies are apparent (White, et al., 2002; Fornari et al., 2004; Soule et al, 2005; Escartin et al., 2007; Ferrini et al., 2007). Indications of the depth extent of hydrothermal system connectivity are suggested, based on which fluid/biological properties show tidal modulation, which do not (Larson et al., 2007), and on local microseismicity patterns along the axis (Tolstoy, in press). The selection of the 9° 50'N area as the focus site proved quite fruitful when instruments deployed for early R2K studies were in place prior to, during, and following an eruption in 2005/2006 (R2K Newsletter, 2006; Tolstoy et al., 2006; Cowen et al., 2007; Soule et al., 2007). Several axial instruments were lost to the lava flow but some were recovered and had captured behavior indicating the nature of and nearby hydrothermal responses to the seismo-magmatic activity. Polonium isotope dating methods (Rubin et al., Fall AGU 2006) provide independent information on lava age for comparison to seismic signatures of the activity and evolutions seen in vent fluid temperature recordings. Previously-scheduled cruises throughout essentially the whole 06/07 field season were adjusted to take advantage of the excellent opportunity to document evolution of the axial system following this eruption. Three of 4 upcoming cruises involve follow-up studies that were begun in prior years (vent fluid chemistry, laval dispersal, subsurface microbiology) and the fourth will conduct long-awaited 3-D multi-channel seismic measurements of crustal structure.

Endeavour Segment. The Endeavour ISS has benefited from significant involvement of colleagues and funding associated with other programs (W.M. Keck Foundation, NOAA/Vents, NURP, MBARI, Canadian DFO and NSERC). Keck support resulted in significant advancement in sensor development and installation at the site. Investigators from NOAA and Canada have played an integral role in scientific and technological advances while, at the same time, leverage of the long-term RIDGE/R2K work at the site has furthered the aims of these other programs. Detailed observations at the Endeavour vent fields began in the late 1980's. By the 90's, approximately annual repeat mapping/sampling visits to at least some of the sites were being carried out and the hypothesis that the segment's hydrothermal system was near steady state was put forward. Much of the segment has now been mapped at meter-scale resolution, and detailed geological maps have been completed on two of the fields (Glickson et al., 2007). As R2K got underway, the US Navy hydrophone system documented a number of seismic events along the Juan de Fuca ridge, and some of these events were found to be associated with changes in venting at Main Endeavour vent field (MEF) (Wilcock and Kelley, R2K Events 2007). The evolution of the hydrothermal system as well as new biological and geological mapping/sampling have been the focus of over twenty cruises that included work at Endeavour ISS since 2000. The 2003-2006 deployment of the Keck seismic and hydrothermal networks provide data to determine detailed relationships between seismicity and venting systems (Wilcock and Kelley, R2K Events 2007). First of their kind microbial incubators were installed in chimney walls to document gradients in temperature, chemistry and corresponding microbial communities on the time frame of months to a year (Wilcock and Kelley, R2K Events 2007). Ongoing biological studies aim to interrogate the upper temperature limits of life, both for metazoans and microbes. R2K studies are underway to document the geochemical heterogeneity of basalt and sulfide samples and to link these to tectonic and magmatic evolution of the axial valley and to the present-day gradients in fluid chemistry The axial valley morphology of the segment is conducive for studying overall axial heat flux and the influence of currents on distributing this input to the broader ocean (Thompson et al., 2003, and Viers et al., 2006).

The long-term desire to construct a continuous, real-time remote presence at an oceanic spreading center is being realized currently, with the establishment of NEPTUNE Canada, a cabled observatory that will have an instrumented node at the MEF and Mothra field. Several R2K scientists have been involved in design and planning for NEPTUNE and instruments recovered in 2007 are being readied for hook-up to the system for initial data streaming, targeted for 2008. This is an exciting opportunity expected to produce important deep-sea observatory results, both scientific discoveries and technological advances. An example of how the efforts of the R2K program can impact study of an area is the fact that after decades of local studies focused largely in the narrow axial zone, and commonly at previously known vent fields, three recent programs now provide contextual information on regional scale structure and crustal/mantle chemistry. Both multi-channel seismic (Canales et al., 2005; Carbotte et al, 2006 Nedimovic et al., 2005) and petrological studies (Gill et al., Fall AGU 2006) obtained results that challenged prior models of subsurface processes/structure. An upcoming seismic tomography experiment (Table 3) funded through R2K will investigate 3-D relationships between crustal structure, melt distribution and known seismicity/venting characteristics.

Eastern Lau Spreading Center. All but 1 of the initial Lau Implementation Plan goals were achieved by 2005. This dramatic pace (compared to decades to achieve similar systematic overviews at the other ISS) highlights the advantages that R2K Program coordination can bring to interdisciplinary study of a site, as well as exemplifying the role of recent conceptual and technological developments. The initial series of four R2K, and 2 non-R2K, cruises took place in 2004 and 2005. Many hydrothermal vent fields were discovered via plume signatures in the overlying ocean, a few were mapped and sampled at an initial level, and comparison between these sites was well underway by June 2006. Differences in axial morphology and fault patterns, crustal properties (Martinez et al., 2006; Jacobs et al., 2007), vent chemistry, and local ecosystems were tied to along-strike changes in host rock chemistry. Noting a major change in most characteristics from ABE vent field southwards along the eastern Lau spreading center, this was chosen as the focus area for the ISS. Kilo Moana field, to the north, was designated for comparative work, to document the influences of its basaltic crust versus the andesitic crust at ABE field. Unique chemistry and fauna at Mariner field was included for some additional comparisons. Second phase studies began in 2006 and 4 projects have been recommended for funding with the expectation that data acquisition will occur in the 2008-2009 period. Interaction with Tongan, Japanese, and Chinese scientists also investigating spreading centers in the Lau Basin is a fundamental part of R2K coordination at this ISS.

Modeling and Laboratory Experiments. Modeling and laboratory experiments are a key way to advance understanding of the interplay between geological and hydrological processes or chemical and biological reactions. During the first phase of R2K numerical models of crustal structure, magmatic diking events, heat exchange, and brine layer control on black smokers have been pursued (Fontaine & Wilcock, 2006; Fontaine et al., 2007; Buck, 2005; Ramondenc et al., 2006). Calculations of energy available for microbial usage have been updated to include H oxidation effects (Shock and Holland, 2004). Experiments on methods for determining Fischer-Tropsch reactions versus other modes of organic compound formation have provided new understanding (McCollum and Seewald, 2006). And, a role of sulfide clusters in metal release rates, and therefore availability for biological speciation, has been determined (Hsu-Kim, submitted). New geochemical techniques for measuring U-Pa disequilibria have been developed and applied to assess the subsurface melting processes at the EPR (Sims et al., 2002). Current onshore projects address a range of topics from mantle flow and the role of water during melting, methods for dating young basalts, fluid-rock interaction, sources of organic compounds, and microbial genomics (Table 4).

2.2 Time Critical Studies

The dramatic yet unpredictable and intermittent nature of magmatic and tectonic processes at spreading centers makes TCS an exceedingly challenging, but ultimately rewarding endeavor. Since 1993 when NOAA-Pacific Marine Environmental Lab first gained access to the U. S. Navy's Sound Surveillance System (SOSUS) data for real-time monitoring of seismicity along the Juan de Fuca and Gorda Ridges in the Northeast Pacific, seven major seismic events have been recorded. All three earthquake swarms detected since 2000 have been followed by a rapid response (notes from throughout one of these cruises provide a flavor of the intensity and excitement of searching for plume/seafloor signals that would confirm the seismicity was associated with new magma or cracking that affected hydrothermal circulation http://ridge2000.org/science/tcs/news_endv_rrc.php). There is no real-time access to information at EPR, but in 2006 a serendipitous discovery of very recent axial activity was obtained (http://ridge2000.org/science/tcs/epr06activity.php) and two response cruises were conducted. Important results from R2K TCS work include detection and location of eruptions (in real time at the NE Pacific ridges). Earthquake swarms have been correlated with dike intrusions, eruptions, and venting. Fine-scale lava chemistry and flow morphology have been documented. Altered vent field activity associated with eruptions has been monitored. Enhanced (and unusual) microbial populations have been observed and sampled. In-situ seafloor measurements have been made during an eruption. And there have been opportunities for monitoring of post-eruption physical, chemical, and biological changes in the hydrothermal environment (on the seafloor and in the water column).

2.3 Program Database- the R2K Data Portal

The Program database provides an excellent example of how the R2K community is able to embrace a concept in support of interdisciplinary science, obtain community input on a variety of approaches, elicit a successful proposal for implementation, and develop/maintain a system in a mode that is responsive to users. The R2K Data Portal was established in Fall 2003 in response to a program call for a dedicated data system to facilitate open and timely exchange of data in support of the interdisciplinary science goals of the program. The R2K Data Portal, part of the Marine Geoscience Data System (http://www.marine-geo.org/), which provides uniform access to a broad suite of data from the global oceans, has been built with the primary goal of providing full cataloging, open access, and long-term preservation of data collected throughout R2K. Cruise and data acquisition information, navigation and the majority of shipboard field data from all R2K cruises conducted to date are available online via the Data Portal. Development of the portal revealed a number of issues of inadequate data documentation and has contributed to development of improved data documentation at sea. R2K scientists have strongly embraced the database as evidenced both by the excellent level of compliance in data submissions and in the significant use of the Portal data holdings (Section 6.2).