Dive and Discover : Expedition 12 : Daily Update, January 2, 2008

Today's Weather
Partly sunny
Lat: 05°03’S
Long: 26°03’W
Air Temp: 79.6°F
Bar Pressure: 1009.7 mbar
Sea Temp: 80.6°F
Sea State: 5 to 8 ft
Swell Height: less than 7 ft, ESE
Wind: SSE; 11 to 16 knots
Visibility: Unlimited

RV Knorr
RV Knorr, a 279-foot (84.5-meter) vessel, can stay at sea for up to eight weeks. It is equipped with sophisticated navigation and communication systems and can accommodate a wide variety of scientific projects. Learn more »

As the R/V Knorr slices through the deep blue sea toward our study location at the Mid-Atlantic Ridge

, its main lab—the size of an average ranch-style home—buzzes with activity in seemingly every inch of its 1,300 square feet. The science team members—mostly from the United States but some from as far away as Japan—work like elves, checking and double-checking a slew of electronics, and navigation and communication programs designed for the mission.

Outside, the hangar has been buzzing nonstop since yesterday. It seems more like a pre-marathon warm-up station than just a garage used to house the high-tech “cats” on board. The robotic vehicle Jaguar has been running in the hangar since yesterday, its propellers turning lazily while a constant stream of water from a nearby hose flows over the main electronics housing, like cool rags over an athlete. This housing is like its outer “body,” and serves to keep seawater out of Jaguar’s computer “brains” once it is put in the ocean. Close by, Puma waited patiently like the Scarecrow in Oz until its “brains” were installed today. After testing, both will be ready for a dunk in the ocean so the team can check their ballast and ensure all systems are “go.”

Since the engineering preparations are in full swing, we can get down to the business of selecting a work site that’s more specific than “between 2 and 8 degrees South latitude”—an area about 420 miles long!

In addition to testing the new navigation and communications technology, we also want to hunt for hydrothermal vents. Where should we go?

“We would like to go to a place that no one has been before–and one that might be a bit different from the rest,” said marine geophysicist Rob Reves-Sohn. Scientists have studied the northern reaches of the Mid-Atlantic Ridge (MAR) for decades, he explained, but the southern MAR, where we are, is a treasure chest waiting to be opened. It’s the perfect spot (and not only because of the balmy weather!). Here’s what we know about vents along the southern MAR to date.

It’s only been six years since British scientists first found evidence for vents in the form of hydrothermal plumes

on the southern Mid-Atlantic Ridge. Since then, expeditions from England and Germany involving British, German, and US scientists have discovered vent sites at two different locations along the southern sweet spot. And it seems they had some fun naming them!

At about 5°S latitude, they found three so-called “black smoker”

hydrothermal sites emitting some of the hottest fluids ever measured: 340 to 407°C (644 to 766°F)! They named these sites Red Lion, Turtle Pits, and Comfortless Cove. Another more lukewarm field by comparison was christened Wideawake Field. And near 8 to 9°S, scientists named a black smoker Drachenschlund (“Dragon Throat” in German). A low-temperature site was named Lilliput because the mussels found living there were small compared to most. Lilliput was one of the places in the novel “Gulliver’s Travels” where tiny people lived.

A team of German scientists will be visiting some of these sites again in about a week, though they’re far enough away that we probably won’t see them.

So where will we go? For our engineering tests, we need to go to a place where we believe we can pretty quickly nail down a vent site. Ideally, the vent would have a strong hydrothermal plume

—like a cloud of smoke above a campsite—and the team will be able to locate it first by using the cylinder-shaped instrument called a CTD

and other sensors that measure water properties. Then we’ll unleash Puma to map and zero in on the site. Jaguar will be hovering by, ready to fly in closer to capture images of the vents and any animals living around them.

It won’t be easy, but we think we have a chance. During the previous expeditions, scientists detected signs of a strong hydrothermal plume in the water column near latitude 4°S. However, time can be your enemy when you have a lot to accomplish during your short time at sea, and the team ran out of time on that expedition, so the site remains ripe for further investigation.

This site could be exciting for another reason, too. It's a weird one in the vent-hunting business: While most vents are found near the middle of the segments along the Mid-Atlantic Ridge, this one is found between segments. What’s more, whereas most hydrothermal vents occur in volcanic rocks that make up the upper layer of the ocean crust

, we may find rocks here that are from the mantle

! How will these vents look compared to the other ones we’ve seen along other parts of the Mid-Atlantic Ridge? We can only guess. We hope you’ll join us to find out.

Until then, we have to keep working on our equipment and plans so that we arrive at the study site, sometime on Saturday, like finely tuned athletes raring to go.