We would like to invite you into a unique little world unseen and largely unknown by most people—that of the ocean research ship at work. When most people think of ocean research, marine biology comes to mind, whales and coral reefs, fish. But this is different. This is physical oceanography. While marine biologists study the organisms that live in the water, physical oceanographers study the water itself, how it moves and why and how its movement affects climate. We're still not quite used to thinking about the ocean as an active participant in the climate system. And we're unused to thinking about great streams of water, some warm and some cold, coursing through the body of the ocean on its surface and in its opaque depths as if they were blood vessels in the human body. By transporting huge quantities of heat from where there is too much to where there is too little, and vice versa, ocean currents moderate our climate on a global scale. The Agulhas is one of the largest and fastest ocean currents in the world. That's why we're out here to study it.
Understanding how and why and to what affect the Agulhas flows will reveal an elegant and beautiful natural system that, by the sheer chance of physics, makes our world a more comfortable place to live than it would otherwise be.
The Agulhas Current is the Indian Ocean's version of the Gulf Stream. Originating in the tropics, both sprint along the west sides of their respective ocean basins transporting warm, salty water away from the tropics toward the poles. Both are therefore called Western Boundary Currents; but because their respective oceans lie in opposite hemispheres, the Gulf Stream flows toward the North Pole, while the Agulhas flows toward the South Pole. The Gulf Stream has been sounded, plumbed, probed and measured for over two centuries, since the very birth of oceanography as an independent science. Though it is equally important to world-ocean circulation and to climate, far less time, attention, and technology have been applied to the Agulhas Current. That's beginning to change, and Dr. Lisa Beal's Agulhas Current Timeseries falls in the vanguard of the new effort to understand its ways and means.
But measuring ocean currents requires a purpose-built research vessel like Melville or Knorr. As a matter our course, research vessels need to do things commercial vessels never do, stopping, for instance, and remaining over a precise spot in the open ocean. But the ship alone is not enough. Oceanography isn't like, say, biology or botany. The oceanographer can't see her subject, except for an unrevealing sliver of the surface from the bridge of the ship—the Agulhas is hundreds of kilometers long and over 2,000 meters deep.
Therefore, highly specialized electronic instruments are required to serve as surrogate eyes, and deploying them requires highly skilled technicians comfortable doing precise work on a pitching afterdeck in 35 knots of wind. On these cruises, Mark and Robert, at sea together for 25 years, make it look easy, but it's not. It's complex, demanding, dangerous, and fascinating to watch. If you choose to join us, we'll take you out on the afterdeck as the guys retrieve moorings two miles long bristling with high-tech instruments that have remained in the water collecting data since we put them there in April 2010. We'll take you into the shipboard labs and onto the bridge to see how scientists and sailors collaborate to understand the ocean. And we'll introduce you to the day-to-day life aboard world-class research ships. It's an isolated little microcosm with its own rules, mores, language, and dangers. There are lots of ways to get hurt. When she's rolling in a beam sea, just going down the stairs ("ladder" in nautical lingo) to your cabin can be an adventure. Quarters are close. Scientists, techs, officers and crew, we all eat in the same room; our workspace and our living space are only one deck apart. Watch on watch off, work proceeds 24 hours a day in all weathers.
If you bring to the science of the ocean just enough imagination to visualize that which you cannot see, the science will reveal a depth of wonder unimagined by most people. The world ocean is alive with motion. The Agulhas Current is only a single, if large, arc in the circle of motion. But understanding how and why and to what effect the Agulhas flows will reveal an elegant and beautiful natural system that, by the sheer chance of physics, makes our world a more comfortable place to live than it would otherwise be. The wonder of the ocean thus revealed reaches out and grabs some of us by the head and heart and never lets go. I can vouch for that; I'm one of them.