Mars Water, Odd Surface Features Tied to Life.
By Leonard David
Senior Space Writer
posted: 07:30 am ET
28 March 2003
"Data gleaned by Odyssey has shown tremendous water ice deposits, Boynton said.
"It really is changing the way we think of how the ice formed," Boynton told SPACE.com . The idea that water vapor eked down to depths deep enough and cold enough to condense out does not seem to account for the vast amounts of water ice detected, he said.
"There's no telling how deep the ice might extend just below surface on Mars, Boynton said. It could be several hundreds of feet to well over a mile in depth.
"All of a sudden you're starting to talk about a pretty significant amount of water," Boynton said. "It looks like the Viking 2 landing site was actually right on top of this ice. If its robot arm had dug just a little bit deeper they would have found it," he said.
"As for life being preserved in the ice or still kicking today, Boynton said that, with reasonable confidence he believes there's loads of ice on Mars. "If there is something that is happy living in ice…it is going to be very happy there," he said."
http://space.com/scienceastronomy/mars_streaks_030328.html

This large amount of ice could be evidence of a former ocean in the northern plains of Mars, perhaps ice covered. There conceivably could STILL be an ice covered ocean on Mars beneath the sedimentary cover.
The ground penetrating radars to be sent on Mars Express 2003 and Mars Reconnaissance Orbiter 2005 should be able to detect them if such large subsurface bodies of water exist there:

Europe Searching for Underground Water on Mars
August 28, 2001 07:00 CDT
http://www.cosmiverse.com/space08280103.html

It is also interesting that Boynton mentions that the Viking 2 lander just missed the large amount of water in the northern plains of Mars. My view is that the validity of the water measurements at the Viking lander sites is in doubt since there is no way of knowing how much of the samples were delivered to the detection instruments. This means the validity of the organic measurements are also in doubt. In other words, the assertion that there are no organics on Mars may be incorrect due simply to an unexpectedly small of amount of sample being delivered to the detection instruments:

From: Robert Clark (rgregoryclark@yahoo.com)
Subject: Mars Odyssey lecture and water on Mars.
Newsgroups: sci.astro, alt.sci.planetary, rec.arts.sf.science, sci.astro.seti
Date: 2002-05-11 20:57:54 PST
http://groups.google.com/groups?th=9eeea294caf8b074

Bob Clark