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CITATION Fornari, D.J., S.E. Beaulieu, J.F. Holden, L.S. Mullineaux, and M. Tolstoy. 2012. Introduction to the special issue: From RIDGE to Ridge 2000. Oceanography 25(1):12–17, http://dx.doi.org/10.5670/ oceanog.2012.01.

DOI http://dx.doi.org/10.5670/oceanog.2012.01

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Introduction to the Special Issue From RIDGE to Ridge 2000

By Daniel J. Fornari, Stace E. Beaulieu, James F. Holden, Lauren S. Mullineaux, and Maya Tolstoy

Articles in this special issue of the following quote from H.H. Hess nature of volcanically-driven submarine Oceanography represent a compendium (1962) in his essay on “geopoetry” and hot springs and their attendant chemo- of research that spans the disciplinary commentary on J.H.F. Umbgrove’s synthetically-based animal communities and thematic breadth of the National (1947) comprehensive summary of Earth underscore the fact that the seafloor/ Science Foundation’s Ridge 2000 and ocean history: ridge crest environment represents one Program, as well as its geographic focal The birth of the oceans is a matter of of the current frontiers in the explora- points. The mid-ocean ridge (MOR) conjecture, the subsequent history is tion and understanding of our planet. crest is where much of Earth’s volcanism obscure, and the present structure is just The global spreading center network may is focused and where most submarine beginning to be understood. Fascinating be viewed as a single system of focused volcanic activity occurs. If we could speculation on these subjects has been energy flow from the earth’s interior to the look down from space at our planet plentiful, but not much of it predating the lithosphere, hydrosphere and biosphere. with the ocean drained, the MOR’s last decade [the 1950s] holds water. Viewed in this manner it becomes evident topography and shape, along with that the processes involved in generation its intervening fracture zones, would The discovery of deep-sea hydro- of oceanic lithosphere are strongly inter- resemble the seams on a baseball, with thermal vents in the late 1970s, and connected and that an interdisciplinary the ocean basins dominating our plan- the overwhelming evidence that approach will be necessary to achieve etary panorama. The volcanic seafloor seafloor spreading and volcanism major strides in our understanding is hidden beneath the green-blue waters exerted fundamental controls on of the role lithosphere genesis plays of the world’s ocean, yet therein lie myriad Earth processes spanning the in planetary evolution. fundamental clues to how our planet geo- and biosciences, led to an Ocean works and has evolved over billions of Studies Board (1988) workshop that This statement, derived from the years, something that was not clearly reported the following: expansive deliberations of over 80 ocean understood 65 years ago—witness Recent discoveries of the widespread and Earth scientists immersed in the

12 Oceanography | Vol. 25, No. 1 early spring mists of Salishan Lodge associated with hydrothermal venting, animals; and exploration of the role of along the Oregon coast, served as including seafloor chimney distributions, larval dispersal in population dynamics the overarching unifying objective sulfide mineral and fluid chemistry, and maintenance. The results of these of the Ridge Interdisciplinary Global relationships to local- and regional-scale decade-long multidisciplinary efforts Experiments (RIDGE) Initiative funded volcanic and tectonic processes, and the on a wide range of field, laboratory, by the National Science Foundation’s physics and chemistry of hydrothermal and modeling studies laid the essential Ocean Sciences Division. That guiding plumes that carry the effluent into the groundwork for future MOR research. principle focused research efforts global hydrosphere. Biological objectives The RIDGE Program capitalized through the 1990s to explore all facets included a focus on chemoautotrophy on the use of new, innovative tech- of global MOR phenomena, yielding a and how it fuels deep communities at nologies, including both tethered and profound expansion of our knowledge of vents; characterization of diversity, gene autonomous robotic vehicle systems, oceanic spreading center processes. flow, and global distribution of vent as well as traditional human-occupied The RIDGE geographic purview species; investigation of metabolic and submersibles, and also improvements was global, with scientific imperatives physiological capabilities of microbes and in near-bottom sonar and imaging ranging from understanding mantle dynamics using a variety of geophysical Daniel J. Fornari ([email protected]) is Senior Scientist, Geology and Geophysics techniques and modeling, to along-strike Department, Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA, USA. characterization of MOR lava vari- Stace E. Beaulieu is Research Specialist, Biology Department, WHOI, Woods Hole, MA, ability and correlation to mantle melting USA. James F. Holden is Associate Professor, Department of Microbiology, University processes. A key RIDGE objective was to of Massachusetts, Amherst, MA, USA. Lauren S. Mullineaux is Senior Scientist, Biology better resolve the nature and influence Department, WHOI, Woods Hole, MA, USA. Maya Tolstoy is Associate Professor, of MOR segmentation and spreading- Department of Earth and Environmental Sciences, Lamont-Doherty Earth Observatory of rate variability on a host of processes Columbia University, Palisades, NY, USA.

Oceanography | March 2012 13 Figure 1. Locations of the three Ridge 2000 Integrated Study Sites plotted on the global bathymetric tile set available through Virtual Ocean (http:// www.virtualocean.org; Ryan et al., 2009). EPR = East Pacific Rise. END = Endeavour Segment of the Juan de Fuca Ridge. LAU = Eastern Lau Spreading Center.

hardware and software that provided microbial processes and the techniques et al., 2009; http://www.marine-geo.org/ ever-increasing resolution of seafloor to study them. portals/ridge2000). The MOR commu- features and processes. During the During 2000–2002, the US oceano- nity chose three focus areas as Integrated Ridge 2000 Program, implementation graphic community gathered to evaluate Study Sites (ISSs) where coordinated and use of robotic and autonomous the RIDGE Program’s previous decade experiments would be conducted—the vehicles became routine, and a wide of findings and to outline priorities East Pacific Rise (EPR) from 8°N to range of new, specialized sensors and for the next decade. The Ridge 2000 11°N, the Endeavour Segment of the sampling devices were developed to Program formally began in 2002 with Juan de Fuca Ridge, and the Eastern Lau capture various physical and biogeo- new proposal solicitation guidelines Spreading Center (see Figure 1). chemical characteristics of hydrothermal for the types of research activities that The articles in this special issue of fluids. Much of the new technology would be the focus of the new program. Oceanography highlight the wealth of was designed to operate in situ, thereby The next steps required coordinated and interdisciplinary research on oceanic making the measurements more accurate focused studies that included exploring spreading centers accomplished over the and relevant to interactions between both temporal and spatial associations past decade of Ridge 2000 field, labora- vent macro- and microfauna and the among diverse processes involved in tory, and modeling studies. Many of the chemistry of fluids that bathe them. A the transfer of mantle-derived heat and articles were conceived during detailed significant development during the past chemical energy to the seafloor and into discussions in various working groups few decades of spreading-center research the biosphere through hydrothermal at the Ridge 2000 meeting in Portland, was the first recognition of the associa- circulation. Part of this effort involved Oregon, in 2010, and in follow-up efforts tion between H2, S, and Fe oxidizing a dedicated approach toward data and since then (see Rubin and Fornari, 2011). microbes and seafloor volcanic erup- metadata archiving and accessibility in These research endeavors represent tions, which led to an explosion in the order to facilitate and enhance scientific not an “end” but rather a beginning of recognition and importance of deep-sea discovery (Carbotte et al., 2004; Ryan a vibrant next phase of global research

14 Oceanography | Vol. 25, No. 1 on oceanic spreading centers that Program, we chose to start the research for the last 60 years. Two articles, will continue to explore myriad links review articles with the geophysics and by Carbotte et al. and Canales et al., between causal processes in both spatial petrology of the lithosphere. Gregg present some of the latest results from and temporal domains. et al. focus on mantle processes and multichannel seismic studies at the EPR This issue is organized both themati- melting, which are key to delivering and Endeavour ISSs, and discuss the cally and topically, beginning with the heat that drives crustal processes sophisticated technology used to acquire overarching presentations of integrated beneath spreading centers. Perfit et al. those geophysical data. Dziak et al. focus research accomplished at each of the ISSs report on the geochemical compositions on innovative hydroacoustic methods (Fornari et al., Kelley et al., and Tivey of extruded lavas at the EPR based on that provide greatly expanded coverage et al.), and then focusing on various the largest data set of MORB samples of the global system of spreading centers. disciplinary research efforts, beginning spanning several second- to fourth- That work complements other regional at the base of the MOR system—the order ridge segments, and relate them geophysical studies, providing insights mantle—and moving upward into the to crustal formation processes. Smith into MOR seismicity and volcanic/ water column. Throughout the issue, et al. provide an overview of slow to tectonic episodicity. we provide complementary illustra- ultraslow spreading centers where core We then move into geological, tions and captions that touch on key complexes and long-lived detachment geochemical, and microbial processes elements involved in Ridge 2000 faulting dominate the tectonic histories occurring within, on, and above the research, and photographs that show of those ridges, in contrast to the more seafloor, starting with a discussion of some of the investigators and students normal accretionary processes associated hydrothermal discharges by Baker et al. who have worked on this exciting science with the Ridge 2000 ISSs. Geophysical and extrusive volcanism by Rubin et al. over the past decade. measurements and experiments have during submarine eruptions. Lowell In keeping with the “mantle to been crucial to understanding the et al. provide an integrated magma- microbe” concept of the Ridge 2000 structure of oceanic spreading centers hydrothermal model for the EPR ISS.

Oceanography | March 2012 15 Di Iorio et al. detail measurements of discovered at vents, including a compre- physical oceanography at the EPR ISS, heat flux from high-temperature vents, hensive list of species in culture, and with new implications for the impor- and Thurnherr and St. Laurent provide molecular approaches for understanding tance of ridge topography in structuring a snapshot of new measurements of their in situ function. flows that transport larvae and hydro- turbulence in a buoyant plume. Bemis The special issue continues with thermal plumes. Speer and Thurnherr et al. further review the modeling of articles related to vent fauna at the discuss a seven-year time series of the partitioning of heat and chemical seafloor and in the water column and Lagrangian measurements of flow in fluxes from diffuse-flow hydrothermal the physical oceanographic processes the Lau Basin, with implications for the discharges relative to high-temperature that are important in larval and chemical transport of larvae between vents on discharges, and Hautala et al. describe dispersal. Luther et al. describe a unique back-arc spreading centers. We conclude measurements of these discharges into data set that compares in situ chem- the issue with an article by Goehring the bottom boundary layer. Holden et al. istry and controls on vent fauna at Lau et al. highlighting a variety of education summarize the biogeochemical processes and EPR sites. Govenar’s article links and public outreach projects conducted enabled by microbial use of the reduced the energy transfer from microbial during the Ridge 2000 Program. hydrothermal fluids and mineral precipi- chemosynthesis to higher trophic levels tates. Toner et al. highlight, in particular, through symbiosis or grazing. Adams Acknowledgements microbial use of iron transported in et al. discuss life-history processes of Many of the articles presented in this hydrothermal plumes, and Girguis vent fauna, including larval dispersal, special issue benefitted from discussions and Holden examine two potential settlement, and recruitment. Burd with a broad cross section of researchers biotechnological applications of micro- and Thomson describe surveys of during several Ridge 2000 community bial energy and primary production at zooplankton in the proximity of the meetings and workshops. We thank our vents. Sievert and Vetriani review the Endeavour ISS. Lavelle et al. summarize many collaborators who contributed diversity of chemoautotrophic microbes observational and modeling studies of to the field and laboratory programs

16 Oceanography | Vol. 25, No. 1 that helped develop the ideas presented Oceanographic Laboratory System References in these articles and in our numerous (UNOLS) and the marine facility Carbotte, S.M., R. Arko, D.N. Chayes, W. Haxby, K. Lehnert, S. O’Hara, W.B.F. Ryan, joint publications over the years. The and vehicle operators throughout the R.A. Weissel, T. Shipley, L. Gahagan, and Ridge 2000 Program has benefitted academic fleet. others. 2004. New integrated data manage- ment system for Ridge2000 and MARGINS from committed support over the past Compiling this type of synthesis research. Eos, Transactions American decade by program managers at the requires dedication by the authors as Geophysical Union 85(51):553, http:// dx.doi.org/10.1029/2004EO510002. National Science Foundation in the well as the many named and anony- Hess, H.H. 1962. History of ocean basins. Ocean Sciences Division, primarily the mous reviewers who gave their time Pp. 599–620 in Petrologic Studies: A Volume Biological Oceanography and Marine to improving the materials presented. in Honor of A.F. Buddington. A.E.J. Engel, H.L. James, and B.F. Leonard, eds, Geological Geology & Geophysics Programs. We are indebted to them for their hard Society of America, New York. Specifically, we thank David Epp, Rodey work and commitment to seeing the Ocean Studies Board. 1988. The Mid-Oceanic Ridge: A Dynamic Global System. Proceedings Batiza, Phil Taylor, Barbara Ransom, seminal results of Ridge 2000 presented of a Workshop. National Academy Press, Dave Garrison, Adam Schultz, Rick in this compendium. We also are very Washington, D.C. Rubin, K.S., and D.J. Fornari. 2011. Carlson, Ian Ridley, and Bilal Haq grateful to Ellen Kappel, Vicky Cullen, Multidisciplinary collaborations in mid-ocean for their programmatic assistance Johanna Adams, and Jenny Ramarui ridge research. Eos, Transactions American throughout the decade of Ridge 2000 of The Oceanography Society for their Geophysical Union 92:141–142, http://dx.doi. org/10.1029/2011EO170002. Program activities. We also thank Dolly patience and dedication to producing Ryan, W.B.F., S.M. Carbotte, J. Coplan, S. O’Hara, Dieter, Linda Goad, and Brian Midson the work represented in this special A. Melkonian, R. Arko, R.A. Weissel, V. Ferrini, A. Goodwillie, F. Nitsche, and others. 2009. at NSF for their support in funding and issue. This special issue was funded by Global multi-resolution topography (GMRT) scheduling ships and deep-submergence a supplement to the Ridge 2000 Office synthesis data set. Geochemistry Geophysics Geosystems 10, Q03014, http://dx.doi. vehicle assets to accomplish the field- grant at the Woods Hole Oceanographic org/10.1029/2008GC002332. work at the Ridge 2000 Integrated Study Institution (NSF-OCE-0838923). Umbgrove, J.H.F. 1947. The Pulse of the Earth. Sites, along with the University-National Martinus Nijhoff, The Hague, 358 pp.

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