Crew Log 216 – Fishing for Answers

April 12, 2010 – At Sea, 11º 48’N, 090º 18’W
By Herb McCormick

Just moments after I’d come on watch early this morning, with a fresh cup of coffee in hand that had not yet begun to work its magic, out of the corner of my eye I caught what appeared to be a glistening, wet rock. Java or no, as we were at least a hundred miles off the coast of Nicaragua, I realized this was impossible.

“What’s that?” I said.

At the helm, skipper Mark Schrader glanced around and happily affirmed that I wasn’t still dreaming. As he disengaged the autopilot and spun the wheel around, he replied, “Let’s go have a look.”

As it turned out, what we’d spied was the shell a big sea turtle, basking in the morning sun, maybe even enjoying a snooze on the flat, windless sea. As the day progressed, we’d eventually see at least another dozen big turtles, wallowing on the surface just like this guy. We all had a look as Mark took a second pass, but I noticed that our resident scientist, oceanographer Michael Reynolds, seemed more than a little preoccupied, which is saying something. Soon enough, I realized what was on his mind.

“Are we going to do a cast?” he wondered aloud.

No, Michael wasn’t interested in fishing for turtle (though later in the day, mate Dave Logan would land a gorgeous yellow-fin tuna on his trolling rig astern). Nope, as usual with Dr. Reynolds, he was fishing for answers regarding the wide, blue ocean around him.

Moments later, with the boat at a virtual standstill and aided by the captain, Michael lowered his latest “toy” – a roughly two-foot long probe capable of recording and storing valuable data on temperature, salinity and pH factors – into the sea. It’s one impressive “dipstick” and it’s already gathering important information on the significant 2009-2010 El Niño event in which scientists and researchers are just beginning to gain a firm grasp.

Today on Ocean Watch, after a rough and tumble start to their leg from Costa Rica to Puerto Vallarta, Mexico, the crew is enjoying a respite from lashing winds and lumpy waters. Though the beginning of the passage was indeed lively, it was also fast, giving the team a fine head start on the 1,400-nautical mile leg northward. Some 36 hours into the passage, however, the breeze died and OW once again reverted to a combination of sail and motor to maintain a steady pace. For Michael, the calm conditions were perfect for once again, literally and figuratively, taking the temperature of the vast North Pacific.

When Mark purchased the boat for the Around the Americas expedition, it was already equipped with a powerful crane on the aft deck for hoisting aboard a hard-bottomed inflatable dinghy and a large outboard engine. In the 23,000 miles of voyaging since we left Seattle, we’d used it precisely once: to lift a large, abandoned weather buoy onto the boat that we retrieved in the Arctic. It was such a cumbersome exercise – and the crew of Ocean Watch such a fit, rugged lot – that we haven’t had cause to use it since…we just grunt and groan to get heavy stuff on deck! That is, until Michael and his new gear returned to the boat.

Once mate Logan helped rig a fresh tackle system to the crane, it proved to be the perfect vehicle to manhandle the new instrument around, which weighs a solid fifteen pounds once clear of the drink. Actually, the sensor Michael deploys into the ocean is just one of two new oceanographic instruments he’s brought onboard; both have been supplied by Sea-Bird Electronics, based in Bellevue, Washington, and one of the world’s premier manufacturers of high-seas scientific instrumentation.

(The other instrument, a “thermosalinograph,” provides a continuous record of surface temperature and salinity, and runs in concert with our existing SeaKeeper 1000 gear to provide validation and a cross-reference to that set of data.)

But the CTD unit (the letters stand for conductivity-temperature-depth, but the one aboard OW has also been fitted with a pH sensor to evaluate ocean acidification, as well) that’s actually “cast” into the ocean performs a different task; basically, it helps scientists like Michael define and record the structure of the surface waters through which we sail. And since the effects of an El Niño episode are crucially linked to the temperatures in the varying layers and depths of the sea, the data the CTD provides is invaluable input.

“What oceanographers want to know is not just the temperature at the surface but also at varying depths,” said Michael. “To get this, they rely on instruments they can lower from ships. They’re looking for a variety of information, but the most important things to measure are the temperature, the depth and the salinity. You measure salinity – the saltiness of the water – by measuring conductivity, and from that you can figure out how much salt exists. Once you lower down the sensor – and that’s why depth is important – you get a running profile, like capturing a photograph, of the ocean at whatever depth you make your cast.”

Each cast takes about two minutes to complete, and during that interval the CTD unit records samples roughly four times a second on its journey towards the bottom; on OW, a cast is limited to about 40 meters. (“I may try to talk to Mark about that,” said Michael. Good luck, mate.)

Michael has been aboard just two days but he’s already seen evidence that the current El Niño is far from over. “What we’re trying to do – what everyone who does this work tries to do – is create profiles,” he said. “In an El Niño you have very warm El Niño water on top of a layer of cold water. So far on this voyage, we’re seeing a warm layer that’s about 20-30 meters deep. Normally, the deep, colder water would come up towards the surface and turn over a great distance from shore. So what we’re seeing is that the El Niño still exists. As we move further north, we should move out of this pattern.”

El Niño events, of course, are complicated matters, but Michael has done a fine job of breaking down both the science and history of El Niño episodes in a story we’ll post on our website in the next few days. Stay tuned.

In the meantime, at least twice a day as we continue north, Ocean Watch will come to a halt, the crew will scramble aft, and the CTD sensor will go back to work. After all, whenever you go fishing, the only way to catch something worthwhile – either dinner or solutions – is to keep casting the gear back into the sea.

-Herb McCormick with photographs by David Thoreson

*This crew log submitted by Iridium OpenPort and Stratos

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