Current projects

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Past projects




 

 

 

Upper ocean biogeochemistry

Ocean chemistry of the greenhouse gases
Lead Scientist/Project Manager: Peter Brewer
Lead Engineer: George Malby


Colleagues: Keith Kvenvolden (USGS/MBARI), Bob Kleinberg (Schlumberger),Bill Kirkwood, Gernot Friederich, Edward Peltzer, Mario Tamburri.

We seek to continue work on the deep ocean chemistry of the principal greenhouse gases, CO2 and CH4, with a focus on their ability to form hydrates, and the productive use of MBARIís ROV technologies to carry out novel experiments. In 1999 we took three distinct approaches to this problem, each of which we seek to continue into 2000.

  • Field work on natural exposures. We will examine gas hydrate decomposition and distribution in the Eel River Basin, and the evolving chemical signatures of a gas plume in the Santa Barbara Basin. We have collaborated on a study of the unique organic geochemical signatures, and microbial phylogenetic sequences, at a hydrate site. We seek to take part in a R/V Western Flyer cruise to Hydrate Ridge, Cascadia in summer 2000. The focus will be on imaging new and existing vents, sampling and recovering hydrates, computing the phase boundary for the unique compositions at the site, and sampling the changing chemistry of the rising gas plumes both by ROV gas sampling, hydrocasts and ROV water sampling, and use of a new in situ solid state CH4 sensor. 
  • Advanced Instrumentation. We are now in the late stages of planning a novel deep-sea nuclear magnetic resonance (NMR) experiment with colleagues from Schlumberger and the Naval Research Laboratory (NRL), using the Schlumberger CMR well logging tool and ROV Tiburon. The purpose of the experiment is to interrogate the processes occurring during hydrate formation in porous media by examining the changing pattern of liquid water in the sample. A substantial body of theory on the preferential formation of hydrates in the larger pores exists, which we may test. In addition it may be possible to directly "see" the gas protons at depths below 2000m, where the proton density of the gas approaches that of liquid water. This knowledge may well lead to tools which enable interrogation of the fundamental characteristics of hydrate sites around the world by the ocean science community. In anticipation of success in 1999 we are proposing a follow-on experiment in Fall 2000. 
  • Ocean CO2 disposal. We seek to repeat of our 3600m experiment with Tiburon to examine the rate of disappearance of the dense CO2 hydrate formed. We seek to develop new tools for examining formation of saturated CO2 solutions at shallow depths, thereby avoiding some of the complexity of hydrate formation, with subsequent deep disposal. We seek to extend our work on biological responses, and plan for advanced geochemical studies by novel spectroscopic means.

In addition, we have initiated a time sequence CH4 hydrate study at shallow depth which may be greatly enhanced by the MOOS concept and associated instrumentation. We will complete the construction of equipment for dissolved organic carbon (DOC) measurement.