Oceanography (Great Courses) DVD Review

Oceanography: Exploring Earth’s Final Wilderness

It’s been almost 50 years since I took an oceanography course, so I ordered this course as a refresher. It was a refresher all right, and not just of what I remembered of oceanography — this course covers everything from the history of the Earth to modern-day pollution. As one of my old colleagues at the Geophysical Institute says, “It’s not Planet Earth, it’s planet Cloud-Ocean.”  And this course was a marvelous refresher of the whole of geophysics, core to tropopause, and some biology with the whole thing straightforward enough to be understandable to almost anyone.

It started out conventionally enough, with an overview of the history of oceanic exploration. But many of the observations of the ocean basins demanded explanation. Why did the mid-Atlantic ridge exist, for instance? The Challenger Deep? For that matter, why were island arcs so often paralleled by trenches and home to volcanoes and earthquakes? What were the magnetic stripes discovered during World War II? How was it that the sea floor, which should have been receiving sediments from the continents throughout geologic history, had astonishingly young bedrock when drills began to penetrate those sediments? Some of these questions were touched on 50 years ago, some were hastily swept under the rug, and some (such as the puzzlingly young age of the seafloor bedrock) had not even been discovered yet.

These questions eventually led to the theory of plate tectonics, and several lectures on these DVDs are devoted to explaining this theory and how it came about. But that’s a small part of the first two discs in this set of six.

The physics and chemistry of water take up several lectures. Waves, rogue waves, tsunamis, and tides are covered, along with some of the physics of water. For something so familiar (oxygen and hydrogen are two of the most common reactive elements in the universe) water has some astonishing properties. Not only does it have an extraordinarily high heat capacity and is it very nearly the universal solvent, it is one of the few compounds in which the solid phase is less dense than the liquid. In other words, ice floats! We’re so used to this we don’t even think about it, but the world would be very different if ice sank, as most solids do in their own melts.

Life in the seas is interesting in itself and also critical to feeding our global population. Food webs, plankton, jellyfish, fish, marine mammals and birds and whales all get their moments of exposure, along with fish farming.

Then the course moves on to coasts: estuaries, deltas, beaches and sea cliffs. Life is here, too, from sea grasses and mangroves to coral reefs.

The lectures then cover storms, the deep ocean circulation, and the effects of climate change and pollution.

As a meteorologist I would of course like to have seen more on the role of the oceans in influencing weather. Not only are the oceans the great flywheel of climate, and their slow response one of the problems in climate modeling, they provide much of the water vapor that transports energy around the globe. Still, 36 half hour lectures can’t cover everything. Professor Tobin certainly tried, though, and for a single course succeeded brilliantly.

The El Nino Carol

Another parody carol, to be sung to the tune of “Greensleeves.”

What child is this, who stops the wind
And changes weather globally,
Who paints the boats of fishermen
And drives their prey to the Arctic.

This, this is El Nino who
Brings thunder to the desert shore.
Whose arms hold a child so wild?
Ah, who but my lady ENSO.

He brings wild storms to the western coasts
And batters California,
Sends drought and floods to Africa
And halts the monsoon in India.

This, this is El Nino who
Brings drought to islands across the sea.
Whose arms hold a child so wild?
Ah, who but my lady ENSO.

So tuna sport in Alaskan seas,
And clouds boil high over desert sands,
And crops are battered or blown to dust
As the child feeds on global warming.

This, this is El Nino who
Brings warmth and rain to Alaska.
Whose arms hold a child so wild?
Ah, who but my lady ENSO.

If you’re not familiar with this aspect of meteorology, El Nino refers to the periodic reversal of winds in the equatorial Pacific, associated with changes in the sea surface temperature field. It got its name from the fact that it was first recognized along the west coast of South America where it hits around Christmas time, hence the name, El Nino (the Christ-child.) It was also called “The Painter,” because the mass die-offs of fish when the water warmed produced quantities of hydrogen sulfide, which in turn affected the color of fishermen’s boats. It is now recognized as a part of the ENSO (El-Nino Southern Oscillation) cycle, which has worldwide effects on climate.