Show Date: November 30, 2005  
Pam Eastlick for THE DEEP on line

GLOBAL WARMING
PROOF FROM ICE
AND
DANGEROUS FISH

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, aired at 6:00 this evening on K-57, we’ll talk about pollution; a couple of different kinds. Then we’ll have some expedition calls. We’ll also have some science news updates and we’ll be taking your phone calls. Tune in tonight and join host Jim Sullivan, Pam Eastlick and our expedition coordinator Peter Melyan for the latest in scientific news! Then log on to www.thedeepradioshow.com for more information on all the latest and deepest news!

MAKING ICE
Do you make ice cubes at home? If you do (or if you have some purchased ice in the freezer) go fill a clear glass with water and drop a few cubes into it. Now, hold it up and have a look at the ice. If the ice is clear, you’ll see little bubbles trapped inside. Those bubbles are full of air.

When water freezes, it undergoes a state change that is virtually unique. When most substances go from liquid to solid, they form orderly, densely packed crystals. Since the solid form is much denser than the liquid form, the solid immediately sinks to the bottom.

Water is a polar molecule. The oxygen ‘side’ of the water molecule carries a partial negative charge; the hydrogen sides carry partial positive charges. This means that as water cools down toward its freezing point, the charges attract and repel each other and the solid that forms has no crystalline structure. Solid water is chaotic, just like liquid water. Since the oxygen molecules repel each other, the structure that forms is open, irregular, and most importantly less dense than liquid water. This means something miraculous. Solid water FLOATS on liquid water.

Why is this miraculous? Because the single little two word sentence “Ice floats.” is what makes life possible on Earth. If ice didn’t float; the oceans would have frozen solid from the bottom up, leaving no liquid in which life could develop. We are here today simply because ice floats.

That open structure also causes air molecules to be trapped in the ice as it freezes. Those little dots and blemishes in your ice cubes are full of the air you breathe every day. If your air has pollutants in it, they will be trapped in the air bubbles in the ice cubes. And that air will remain trapped in there until the ice melts which in the case of your ice cubes will happen in a matter of weeks or months.

But there’s a place on Earth where the ice hasn’t melted in hundreds of thousands of years. That place is Antarctica, the vast continent at Earth’s south pole. Snow has been falling over Antarctica ever since the land mass wandered over the south pole several million years ago. It hasn’t melted; it’s just turned to ice. Most of the Antarctica continent is covered with an ice sheet that’s miles thick.

The ice at the bottom of that sheet was formed hundreds of thousands of years ago and the bubbles frozen in that ice tell an interesting tale. Scientists have been drilling deep holes in Antarctica’s ice for many years now and removing the ice plugs from them. These plugs are made from tens of thousands of layers of fallen snow and air bubbles that become compressed over time. The chemistry of the ice reveals what temperatures were in the distant past, while the air bubbles within the ice are tiny time capsules that hold samples of our air as it existed hundreds of thousands of years ago.

Scientists have recently pulled the longest ice plug ever extracted from the Antarctic ice. It’s almost two miles long and it was drilled by the European Project for Ice Coring in Antarctica from a high plateau in East Antarctica called Dome 2. The ice at the bottom of this core was trapped there over 650,000 years ago. The previous record was a core drilled by the Russians at Vostok Station, which contained air samples that were 440,000 years old. This new core confirms what environmental researchers have suspected all along. Today’s carbon dioxide levels are not part of a ‘normal’ cycle. Today's still rising level of carbon dioxide is 27 percent higher than any other peak in 650,000 years.

The ice core tip

Carbon dioxide is a so-called ‘greenhouse gas’. The air inside a greenhouse is warmer than the air outside because the glass allows light in, but doesn’t let heat back out. Carbon dioxide works the same way in Earth’s atmosphere, trapping heat and causing Earth’s average temperature to rise.

Methane is another greenhouse gas and the new core shows that atmospheric methane levels are currently 130 percent higher than any peak in the last 650,000 years.

This measurement also reduces some uncertainty about the Ice Age cycles since it contains records for the last eight Ice Ages. The Vostok sample had four. The Vostok sample also showed that warm interglacial periods lasted about 10,000 years. Because our current interglacial period has lasted about 12,000 years, many scientists speculated the planet was overdue for an ice age.

But the new core shows that the interglacial period of 440,000 years ago, when Earth's position relative to the sun was very similar to what it is today, lasted nearly 30,000 years and was not ended by natural decreases in carbon dioxide, This research indicates that the next Ice Age is about 15,000 years away.

Warm, warm, warm. Or should that be warn, warn, warn? Tune in to The Deep tonight as we return of one of our favorite subjects.

HEAVY METAL
You thought from looking at the title “Dangerous Fish” that we were going to talk about sharks again, didn’t you? No, today we’re talking about far more dangerous fish than sharks; fish that kill and cripple many, many more people than the tiny number that are killed and crippled by sharks each year. We’re talking about swordfish and mackerel and tuna. Wait a minute, you say, those fish aren’t dangerous. Well, they can be if you eat them and they are becoming more dangerous each year. The culprit? Mercury contamination.

Mercury is one of the ‘heavy metals’ like lead and cadmium that play havoc with the human body if ingested. Mercury is particularly deadly to the nervous system and its interactions with the muscles. The most notorious case of mass mercury poisoning was in the Japanese village of Minamata where a factory that made plastics spewed toxic mercury into the bay where the local villagers gathered the fish and shellfish that were virtually their only protein source.

First, the village cats began to ‘dance’ and then commit suicide by jumping into the bay. Then, one by one, the people began to have fits and babble incoherently as their muscles twisted their bodies into bizarre shapes. Then the children began to be born with the same symptoms. The people of Minamata still suffer today from the effects of this irresponsible pollution of the environment but the fish that you eat doesn’t have nearly the levels of mercury that they ingested. However, mercury levels in fish and shellfish are on the rise all over the world and top-drawer predators like swordfish and tuna concentrate the mercury levels in the entire food chain.

Minamata victim of mercury poisoning

Just how dangerous is the fish you eat and what can you do about it? Tune into The Deep tonight to find out.
Whether we’re learning about heat pollution or mercury pollution, The Deep, hosted by Jim Sullivan with Pam Eastlick and Peter Melyan is the place to be on K-57 tonight at 6:00 p.m. Don’t miss it!