Sargasso Sea: Monitoring Climate Change in the Ocean’s ‘Most Studied Spot’


Bryan Walsh, writing for Time magazine, looks at the scientists of the Bermuda Institute of Ocean Sciences and their contributions to the modeling of climate change.

“The thing about oceanography is that it is a very collegial profession.” So says Tony Knapp, director of the Bermuda Institute of Ocean Sciences (BIOS), and given the backdrop — aboard BIOS’s multimillion-dollar research ship the HSBC Atlantic Explorer, with the sun shining and the Atlantic Ocean rolling behind him — it’s hard to argue. It’s also one of the few scientific professions where motion sickness is a real risk, as I’m learning aboard the ship, which is buffeted by the advance wind and sea swells of Tropical Storm Fiona. But beyond the fresh air and occasional seasick research assistant, what sets apart the oceanography done at BIOS from other disciplines is its importance — the institute’s work is fundamental to our ability to model the ocean’s role in climate change, among other areas — and its rarity. BIOS is one of just a handful of institutes worldwide that regularly monitor the ocean for physical and chemical changes. “We just have not invested in understanding ocean chemistry,” says Knapp. And when it comes to ocean science, what we don’t know may be hurting us.

The scientists at BIOS are trying to change that. Founded in 1903, BIOS is one of the few marine-research stations actually situated in the middle of the ocean — the Atlantic, in the waters surrounding the isolated island of Bermuda. That base has given BIOS scientists the ability to reach, in just a few hours’ sail, the deep water — Bermuda sits on a seamount, and within a few miles of its reef-shielded coasts, the ocean can be more than 10,000 feet deep. For decades, BIOS researchers have been sailing to the same spot in the Atlantic — Hydrostation “S,” 15 nautical miles southeast of Bermuda — where they take water samples from the surface all the way down to just above the ocean floor. Since the program began in 1954, BIOS ships have visited the “S” more than 1,100 times. (There’s nothing special about the location of “S”; it’s simply a convenient deep-water spot near the island.) Researchers in Hawaii carry out a similar program in the Pacific, but they’ve taken fewer samples over a smaller amount of time. “This is the single most studied spot in the ocean,” says Knapp. (See pictures of the world’s most polluted places.)

Together with the oceanographer and environmentalist Sylvia Earle, I was with Knapp last week for the Atlantic Explorer‘s 1,160th trip to Hydrostation “S.” Knapp has been with BIOS for more than 30 years — long enough to remember when the trips were done on a much smaller boat (one that sank three separate times at the dock) and when scientists had to cater their own meals. Now the lunch is excellent, provided you haven’t just been seasick, and the new ship, remodeled a few years ago, practically gleams. Knapp, who spent his summers as a kid crewing merchant ships and who still sails in his free time, isn’t shy about showing pride in the Atlantic Explorer, which is funded primarily with money from the U.S. National Science Foundation. On this trip to “S,” like the other 1,159 trips before it, BIOS will record the ocean’s temperature, salinity and dissolved oxygen levels. “It’s a checkup for the deep ocean,” says Knapp.

See “Are We Destroying the Oceans?”

What BIOS is doing, in effect, is fishing for water. When the Atlantic Explorer reaches “S,” researchers prepare the CTD rosette (Conductivity, Temperature, Depth recorder), which holds 24 cylindrical bottles called Niskins in an array that looks like the bullet chamber of a very large revolver. A fishing lure connected to thousands of feet of cable, the CTD is lowered over the side of the ship and into the water. At regular intervals between the surface and more than 9,000 feet below, bottles open up and capture water at a particular depth. Sensors on the CTD record temperature and other data as the rosette is reeled out and then reeled back in, but once it’s onboard, BIOS researchers will still take samples from every bottle, to confirm the computer readings. It’s painstaking, laborious work — and it’s expensive, since the Atlantic Explorer costs about $22,000 a day to operate.

But such trips are the only way we can build up a meaningful history of the ocean, a data set big enough to let us really know if the ocean is changing — just as the Mauna Loa Observatory in Hawaii has kept a record of changing atmospheric CO2 concentrations for decades. And just as carbon levels have been rising in the atmosphere, thanks largely to man-made greenhouse-gas emissions, CO2 levels are on the rise in the ocean as it warms as well. Ocean data matters — the oceans hold far more energy than the atmosphere. “This will tell us how the ocean is changing over time,” says Knapp. “Climate change is all about the oceans, not the atmosphere.” The difference is that we know a lot more about the atmosphere and land than we do about the ocean — especially the deep. Science has only really been able to regularly look beneath the surface of the ocean — which covers more than 70% of the planet — for a little more than half a century, and the reality is that our understanding of the deep is still surprisingly rudimentary. That’s true whether we’re talking about the species of the deep, many of which haven’t even been named, or the ocean chemistry that drives much of our weather and climate. What data does exist isn’t shared as well as it could be, making it difficult to understand how different parts of the ocean interact. We may know the story of Hydrostation “S,” but most of the blue spots on the map are still blank to us.

The answer would be a truly global ocean-monitoring system, one that could provide enough linked data from around the planets to helps scientists construct a holistic picture of the oceans. We’re taking small steps toward that goal — in addition to long-running data sets like the ones that belong to BIOS, there are thousands of small, drifting “Argo” probes around the world that measure depth, temperature and salinity. But a global monitoring system would need far more probes, along with more satellites covering the oceans, robotic and manned submarines that could explore the far depths — even geotagging of marine species. It wouldn’t be cheap; such a system would likely cost in the billions. But as Sylvia Earle says, “What’s really expensive is not knowing.”

For now, the day we might properly understand the entire ocean system — and predict how it might change — is still to come. In the meantime, the Atlantic Explorer will keep giving us pieces of the ocean puzzle, providing clues to the enormous changes humanity is bringing about in the deep, through everything from carbon emissions to overfishing. “The ocean has a memory,” Knapp says on the way back to Bermuda, where the samples will be analyzed and logged. We just need to read it.

For the original article go to,8599,2016556,00.html?xid=newsletter-daily

Image: “Beneath the Sargasso Sea” by Henry Power at

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