Show Date: March 2, 2005

OCEANS ON EARTH AND IN SPACE
Pam Eastlick for the Marianas Variety

Greetings and welcome to The Deep column and the deepest radio show on Earth. The Deep is the science talk radio program that takes you from the depths of the ocean to the farthest reaches of the universe. This week on The Deep hosted by Jim Sullivan and aired at 6:00 this evening on K-57, we’ll talk about the deepest subject: oceans. We’ll learn about some continuing dangers to Earth’s ocean and then discover that Earth may not have the only ocean. We’ll also have some expedition calls and our science news updates as well as taking your phone calls. Tune in tonight! And don’t forget to log on to www.thedeepradioshow.com for all the latest and deepest news!

HOW MANY PEOPLE DOES AN EMPTY OCEAN FEED?

Global warming is not the only problem for the world’s oceans. Humans are seriously over-fishing many types of fish and destroying unknown riches in their greed for rich fish hauls. In an attempt to curb some of this destruction, the U.N. General Assembly has called for a temporary ban on high seas bottom trawling. But according to many scientists, this isn’t enough. They want an immediate end to this destructive practice.

Bottom trawlers rake giant nets equipped with wheels, chains and metal doors across the sea floor to scoop up fish. These contraptions bulldoze everything in their path, shattering corals and churning up huge clouds of sediment that choke any life that escapes. Their main targets are the teeming deep-sea mountains called seamounts, home to thousands of species of corals and fish, some of which have never been identified. Unfortunately, most seamounts are in international waters.

Environmental groups say bottom trawling is killing little known species and entire coral ecosystems, and should be stopped immediately so these remote areas can be studied. An area twice the size of Europe has already been destroyed. Among the leading opponents of this ban were Japan and Iceland. They aretwo of 11 countries whose fisheries accounted for 95 percent of the high seas bottom trawling catch in 2001, according to the Deep Sea Conservation Coalition.

And bottom trawlers aren’t the only problem. Scientists speaking at the annual meeting of the American Association of the Advancement of Science say that we're also fishing in ways that destroy the potential for recovery of fish populations.

Studies show that current fishing practices - catching the biggest and oldest fish and leaving the younger fish to grow - may be damaging. The larvae produced by older fish, such as the commercially valuable rockfish, grow three times faster than larvae produced by younger fish and older fish spawn earlier in the season. In essence, the older fish give their young a better chance for survival.

And not only fish are at risk from bad fishing practices. British and French fishing boats may be killing more than 2,000 dolphins a year, environmental scientists have warned. Campaigners renewed calls for a halt to pair-trawling for bass after a report highlighted the growing number of dolphins caught in nets in the English Channel. Pair-trawlers, which tow large nets between two boats, have been blamed for killing hundreds of dolphins and there are fears that the species could become extinct in the Channel. Will the human greed for fish empty our oceans of all life? Tune in tonight on The Deep when we discuss these controversial practices.

FINDING OTHER OCEANS
We’ve known for a long time that two and possibly three of Jupiter’s moons may contain liquid water oceans. Europa and Ganymede, the solar system’s largest moon (bigger than Mercury & Pluto!) both have solidly frozen surfaces of water ice. Both moons wobble as they revolve around Jupiter, strongly suggesting that their interiors may contain liquid water with a solid rock in the middle. Europa is about the same size as our moon and its surface is covered with cracks and streaks. It may contain a liquid sea of water that’s at least 30 miles deep. Ganymede could contain an ocean that’s at least 300 miles deep.
Scientists have long been intrigued by Enceladus, one of Saturn’s moons. Enceladus is the most reflective moon in the solar system; it’s the color of new fallen snow. The space probe Cassini, in orbit around Saturn, has just taken new close-up pictures of this frozen snowball and revealed a fascinating, tortured world of ice.

Since NASA's Voyager spacecraft flew past Enceladus in 1980 and 1981, planetary scientists have been fascinated by the moon's wrinkled terrain and smooth plains, some of which seemed to be relatively free of impact craters. Smooth, crater-free surfaces on moons and planets indicate the surface is geologically young, while wrinkles could indicate volcanism. The new close-up photos reveal that Enceladus has similarities to both Europa and Ganymede.

This picture is a high-resolution mosaic showing complex systems of fractures and resurfaced terrain. There are very few craters, indicating that something is changing the surface and erasing the impact marks.

The data gathered by Cassini’s spectrometer show the surface of Enceladus is pure water ice, with no other compounds detected. Scientists expected to see ammonia or ammonium compounds and carbon dioxide but none were detected. One Cassini scientist said the spectra looked like ice made in a laboratory, it was so pure and free from contaminants. Cassini will conduct an even closer flyby of Enceladus next Wednesday, March 9, coming within approximately 310 miles of its surface.

Tune in tonight to K-57 at 6:00 p.m. and join us on The Deep when we’ll talk about oceans; the health of Earth’s world ocean and oceans in space. And don’t forget to log on to www.thedeepradioshow.com for all the latest Deep News!