Collaborative Research: The Basalt-Hosted Biosphere at North Pond, A Subseafloor Mid-Atlantic Ridge-Flank Microbial Observatory

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Intellectual MeritNorth Pond, the target for drilling based on IODP 677-Full in 2011, is a shallow sediment pondon the western flank of the mid Atlantic ridge. Prior drilling and study of North Pond revealed youngocean crust (7-8 m.y.) with active, low temperature fluids vigorously advecting through basement. Thethermal and hydrologic state of North Pond are characteristic of large portions of the global ridge flank system, where a significant fraction of lithospheric heat is lost via hydrothermal processes, and theassociated fluid-rock reactions significantly alter the composition of ocean and crust. Petrographicobservations of certain textural features in the alteration rind of basaltic glass that have been retrieved at many (other) sites suggest that microbes may play an important role in alteration of ocean crust in ridge flank settings. However, this hypothesis has not been confirmed and indeed, we lack robust molecular, biochemical, or physiological data that might inform our understanding of the very nature of microbes in the lithosphere. The principal motivation for the North Pond project is to address these questions through systematic empirical and experimental study. The fundamental scientific questions that motivate the drilling and observatory program at North Pond include: 1) What is the nature of microbial communities harbored in young ridge flanks and what is their role in ocean crust alteration? 2) Are these communities unique, particularly incomparison with seafloor and sedimentary communities? 3) Where do deep-seated microbial communities come from (sediment, rock, seawater?)? While some of these questions can be addressed through sampling with ?typical? IODP recovery and analysis of sediment and rock, progress at the heart of questions that relate to active processes such as crustal alteration, microbial colonization, fluid dynamics, and transience, require time-series observation and experiments, coupled with contextual data concerning chemical, physical, and hydrodynamics of the system as a whole. In a sense, this is taking an Earth systems science approach to solving problems in the environmental life sciences. To achieve this approach IODP will establish three long-term subseafloor microbial observatories in North Pond in order to identify indigenous ridge flank microbes and delineate the role that they play in oxidative alteration. A major portion of the infrastructural needs for this project have already been supported, enabling preparations, which are now well underway for deployment in 2011 with the IODP. This includes the design, fabrication, and purchasing of hardware, down hole samplers, instruments, and experimental materials. This proposal requests ROV dives shortly after the IODP expedition to initiate the observatory and populate it with a variety of samplers and experiments and to collect supporting material (sediments,water, rocks) from the surround area to elucidate sources for the subsurface biome that will be sampled within borehole observatories. We also seek ROV time one year later to monitor how fast these boreholes recover from drilling operations and gauge future operations and direction. The experiments at North Pond will also provide an excellent comparison for ongoing studies on the eastern flank of the Juan de Fuca Ridge, which is chemically, thermally, and hydrologically distinct.Broader ImpactsWe propose to bring three professionals (videographers and science writers) on board the IODP cruise and the two cruises proposed herein. These individuals will work with ship-board scientists and shore-based liaisons associated with COSSEE-West and Ocean Leadership. Our objectives are to link teachers and classrooms with these liaisons in real-time, establish new educational programs in drilling related science, and create new products for broader public outreach. For example, through the creation of a variety of media products, from blogs, vignettes, and online media, we will develop a documentary that focuses on life below the bottom of the ocean. Another important broader impact of this project is in the establishment of long-term infrastructure for community wide study of this environment. Observatories are a community resource, and over the next decade many dozens of diverse researchers will participate in scientific study at North Pond. Indeed, scientists have recognized the importance of this site as a key reference system and have engaged in scientific study of it since the mid 1970?s. This project marks the beginning of a new era of observing science for the community at North Pond, through the establishment of a 3-D array of instrumented modern borehole observatories.