I teach marine science in a high school on the coast of New Hampshire. My students will be fascinated with the NOVA/Into the Abyss. Your excellent videos expose them to many career opportunities. They always want to know what eduacation and training is necessary to work on the research vessels, ROV's and to work for NOVA.

Catherine F. Silver
South Hampton, NH
cfsilver@nh.ultranet.com

With the extreme variations in temperature, volatility of chemicals at high temperature, and a pH of 2.8, is there any corrosion or deformation to the titanium shell of ROPOS? With the same hazardous conditions, does the lubricant degrade on the diamond-imbedded chainsaw? Assuming it requires a lubricant. If not, what are the mechanisms under which it operates?

In regards to life originating at hydrothermal vents, have the 5% of species known to science been classified, and what are they? Have there been any paleontological studies done on transects perpendicular to spreading centers, or in mountain-producing seismic zones of oceanic origin? Are there any fossils that indicate evolutionary evidence anytime between the Cambrian and Quaternary periods, and which periods do those fossils span? Could these organisms belong to the same phylum or genus as the fossils of the Burgess Shales?

Due to the quantity and purity of the minerals collected within hydrothermal vents, has it been suggested that the vents be 'mined' for economic purposes? (Ferro-manganese nodules are considered as a potential source, albeit an expensive one with present methods of collection.)

I enjoyed the opportunity to experience the Juan de Fuca Ridge project. The Web page is well organized, very informative, with a wonderful sense of humor.

Leslie Anne Zednai
Vancouver, British Columbia, CND
annez@unixg.ubc.ca

Regarding your question about ROPOS, its titanium housings do not corrode, even very close to the vents. Its aluminum frame would show signs of corrosion if left in or very close to a hydrothermal plume for, say, two weeks, but in the short space of time the robot approaches vents, there is no damage. Some protection is afforded by sacrificial zinc anodes attached to the frame.

More than 300 species of animal and hundreds of species of microbes from hydrothermal vents have been classified, but not all of them live exclusively in vents. See Resources for books that give lists and thorough descriptions of these species. So far, paleontological work on vent systems has been restricted to ancient vent structures that have been forced onto land via plate-tectonic movement. The oldest vent life dates back about 350 million years, which would make it too young for the Precambrian fossils of the Burgess Shale.

Ever since hydrothermal vents were first discovered in the late 1970s, people have talked about exploiting them for their minerals. The cost is prohibitive, but recently one company began mining minerals in a relatively shallow vent system off the island of New Guinea. Concerns about such activities and the effects they might have on the living communities in vents now has the Canadian government, for one, considering protecting part of the Endeavour Segment of the Juan de Fuca Ridge as a marine reserve.

To the ENTIRE crew (researchers, correspondent, ship crew, and NOVA) for putting this documentary together, I and my eight-year-old son extend our thanks. This has been a really wonderful experience for us as you uncover some of the mysteries of the sea and "black smokers."

It is our hope that NOVA continues to participate in this sort of excellent adventure with such outstanding correspondents.

Be well.

Jerry O. Holloway
Niles, MI
joholloway@cbd.net