Progress Report

**Note** This document and the above items are available and updated on the World Wide Web at URL: http://ocean.washington.edu/people/grads/scottv/nasa/progress.html

The ocean is capacious and completely full of wonder. To have learned only this in my first year as a NASA Earth System Science fellow would have been enough, but after diving to the sea floor hydrothermal vent system 2200 meters below the Pacific surface, we ascended from the voluminous, living sea, and I climbed out of the submersible with a logbook full of enthusiasm for oceanic grandeur.

That charge from the depth has been sustained and reinforced over the last year. A challenging series of geology, geophysics, and math classes has repeatedly motivated me to consider how to interpret the water-column and deep-sea current data that I helped to collect while at sea last summer. I was energized by the advances in ridge-crest system science and human understanding of global change which were demonstrated at the December, 1995, meeting of the American Geophysical Union. And as I continued to build an analytic foundation through my core courses this winter, a seminar addressing long-term climate change with attention to global tectonics, ocean circulation, and evolution exposed me to new examples of the interconnected nature of diverse Earth system processes: from Heinrich events and Bond cycles to the assumptions underlying oxygen isotope records and the Wilson cycle.

In following the graduate curriculum in Marine Geology and Geophysics at the University of Washington, I have initiated my training in the fundamentals of heat and mass transport as a basis for understanding the geological and processes within the marine environment. The sequence of classes I will have completed by June, 1995, will be ideal preparation for my summer research goals, and I anticipate that the summer's insights will, in turn, segue neatly into the more general core courses in chemical, and physical oceanography I plan to attend in autumn.

As summer nears, I will be well-positioned to thoroughly investigate one of the primary issues outlined in my proposal: whether hydrothermal plumes result in sea surface expressions that are detectable by satellite. Last summer I helped to conduct a survey of hydrothermal activity over the Endeavour segment of the Juan de Fuca Ridge; the resulting data set is unprecedented in its spatial and temporal resolution and continuity. It contains navigated temperature, salinity, and transmissivity anomalies recorded above one of the most thoroughly studied spreading centers on the planet and is complimented by the simultaneous measurements of two deep sea current meters. I am confident that the combined data sets will elucidate the too-often confounding nature of hydrothermal plumes: their magnitude, transience, advection by and interaction with bottom currents, and ultimately their influence on the surrounding environment and ecology.

Although my spring will be primarily devoted to coursework, I am already looking forward to the chance to begin data analysis this summer. With constant attention to the potential implications for global change outlined in my proposal, and with continued exposure to interdisciplinary contemplation of Earth system dynamics through seminars and collaborations, I anticipate contributing to the explication of some of the voluminous seas' multitudinous wonders.

In addition to the progress I have made at sea and in school during the last year, there have been a number of developments which promise an increasingly rich field of research opportunities in theme with my proposal. Most exciting is the recent detection of an earthquake swarm on the Gorda Ridge (also off the Northwest coast) and the subsequent deployment of a fast-response scientific team to the site. Because the 1986 event plumes (which initially propelled me into ridge-crest research) were formed in association with a nearly identical seismic signature, the present Gorda activity was expected to generate event plumes. Indeed, extensive plumes have been detected only days ago! From my perspective, every observations of massive water-column anomalies represent groundtruth that will be crucial in assessing the utility of satellite sensors (like the Topex-Poseidon altimeter) in detecting sea surface expressions of ridge-crest phenomena. Needless to say, I am tremendously gratified that we are beginning to detect patterns and predict dynamics with such success.