Farewell, Oceanus!

I knew thee, a little bit. So I was a little sad when I got a notice that after 500 voyages, the Oceanus is being retired from the US oceanographic fleet. It’s actually owned by the National Science Foundation, but after 36 years, the powers that be decided it was time for retirement.

Woods Hole Research Vessel Oceanus

Last cruise for the WHOI research vessel Oceanus

Yes, in March, 1997, I spent two weeks on the Oceanus as an onboard journalist and deck hand (on a 177-foot long boat, there are no free rides, everybody works), on its 300th voyage, with Dr. Peter Wiebe as chief scientist. We cruised to Georges Bank and back as part of the US Globec Georges Bank program.The researchers — Peter Wiebe, David Mountain and David Townsend, were trying to figure out the population dynamics of cod and haddock and how this related to these little zooplankton, Calanus and Pseudocalanus. An interesting scientific question, but also on of great interest to local fishermen, who at the time were on year three of a series of restrictions and fishing grounds closures, including for Georges Bank.

Here’s a video tribute, from Woods Hole: Farewell Oceanus

And here’s what it looks like staring down at the deck were we deployed all our equipment and nets:

Woods Hole Oceanographic Institute RV Oceanus

Batten the hatches, matey! Looks like rough sailing ahead.

We worked 8-12 and then 4 to midnight every day (this is known as the “day” shift”) deploying the MOC 10, this gigantic series of 10 meter squared nets that each opened at a specific depth, Bongo nets, CTD measurments, and Reeve nets. We did a lot of hauling things up and down, dumping cod ends of nets into buckets so that the contents could be pickled and examined at a later day, and then we had to rinse everything. Wet, grueling work, but fascinating.

We actually did have one pretty big storm where we had to heave to, as they say, and the bosun, a tight lipped fellow named Jeff Stolp, literally went around the entire ship and closed the portholes and tightened down the thumbscrews — yep, battening down the hatches!
WHOI RV OceanusI should probably write a followup to this research — I just dug out my three reporters notebooks, filled with very detailed notes — but since they were in the thick of things during the cruise they didn’t really have any findings.
For me, the cruise was an important peek into this mysterious world of oceanographic research. I got a sense of the difficulties that oceanographers face in trying to tell us something about what is happening in the ocean. It is incredibly hard physical labor collecting tons and tons of data, but when you look at the immensity of the problem which were never enough even though it seemed like there was so much.
Thanks, Oceanus and Woods Hole, for cruise #300 — an experience of a lifetime.






Virtual oceanography — north, to the Denmark Strait

A team of researchers from Iceland, the US and Norway have spent the last month exploring the chilly waters between Iceland and Greenland in search of a relatively new southbound current called the North Icelandic Jet. The current is “new” in that two of the researchers on the cruise, Drs. Steingrímur Jonsson and Hedinn Valdimarsson from the Marine Research Institute, Iceland, found it in 2004.
They, along with Bob Pickart, from the Woods Hole Oceanographic Institution in the US, Kjetil Våge, from the University of Bergen in Norway, and Laura de Steur, from the Royal Netherlands Institute for Sea Research have been trying to further document the characteristics of this current (which they did) during the cruise.
So why do we care? The bottom line is that this new southbound current may mean that the Atlantic Meridional Overturning Current, the AMOC, may be less sensitive to climate change than was previously thought. No “Day after Tomorrow” scenarios where the AMOC stops and basically halts the redistribution of heat from the equator to the poles.
Here’s a nice graphic, courtesy of the cruise website, that shows where researchers went to monitor this new current:

Researchers on a Sept. 2011 cruise took ocean measurements all along the northern part of Iceland to successfully document the existence and behavior of the North Icelandic Jet

You can also read about the underpinnings of their research findings in a recent article in Nature Geoscience.
From my perspective, one of the most impressive aspects of the cruise was the tremendous effort made to bring the science as it happens, to the public — there were writers, photographers, videographers — even a Norwegian journalist who wrote blog posts in Norwegian.
I’ve spent time on another WHOI boat, the Oceanus, and I have to say I quite enjoyed the feeling of being virtually there that the website gives you. Check out this video about just being on board the ship:

Life aboard from Benjamin Harden on Vimeo.

Hats off to all involved — great science and great outreach.

A current at the bottom of the world

A recent paper published in Nature by Lisa Beal, of the Rosenstiel School of Marine and Atmospheric Science at the University of Miami, has some surprising news about the Agulhas (pronounced Ah- gul’- us) system, a western boundary current that “leaks”  warm, salty water from the Indo-Pacific Ocean into the Atlantic.

Here’s what it looks like in a graphic from Beal’s paper, courtesy of the University of Miami:

The news is that this leakage may get stronger as the climate warms, which would strengthen Atlantic Ocean circulation just at a time when climate change is expected to actually weaken circulation in the Atlantic.

From the UMiami press release:

“This could mean that current IPCC model predictions for the next century are wrong and there will be no cooling in the North Atlantic to partially offset the effects of global climate change over North America and Europe,” said Beal, “Instead, increasing Agulhas leakage could stabilize the oceanic heat transport carried by the Atlantic overturning circulation.”

There is also paleoceanographic data to suggest that dramatic peaks in Agulhas leakage over the past 500,000 years may have triggered the end of glacial cycles. This serves as further evidence that the Agulhas system and its leakage play an important role in the planet’s climate.

Curiouser and curiouser!

And here’s a link to Beal herself explaining how this little known system and its leaks are vitally important to predicting future climate.

Finally, if you want to know more about the Agulhas system, check out this great page Beal has put together for school kids to help them follow her scientific work.

Warmest Atlantic water in 2000 years

An international team of researchers studying ocean sediment cores taken off of Svalbard, an arctic island archipelago at 79 degrees North latitude, has found that the North Atlantic Drift, the northern extension of the Gulf Stream, is the warmest it has been in the last 2000 years.

The average temperature of the warm ocean current has been roughly 3.5 degrees C, but in the last 30 years, that average has jumped roughly 2 degrees C. Their findings have been published in the 28 January issue of Science magazine under the title “Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water”

What is that cross-section picture in my header?

This very cool snippet of an image is from hand-drawn figures from:

“Report on Norwegian Fishery and Marine-Investigations Vol. 11 1909 No. 2 :THE NORWEGIAN SEA, ITS PHYSICAL OCEANOGRAPHY

From Helland-Hansen and Nansen, The Norwegian Sea

But what is it?
It shows a cross section of one of the transects that the Norwegian scientists Helland-Hansen and Nansen studied in the Norwegian Sea. The basic idea was  to get a better handle on how currents were moving in the waters off of Norway. It was thought that this information would be helpful in fisheries management, which at the time was a critical part of Norway’s economy. The two collaborated on a voluminous manuscript whose basic observations remain important today, as we try to figure out what the Atlantic Ocean’s currents are doing in response to warmer ocean temperatures and changing salinities. The two could not have know this when they wrote the following in their preface:

We hope, however, that we are not too immodest, if we say that the great observation-material at our disposal has led us to a number of discoveries, which are important in several respects, and which give great promise for the future. We may mention the new views on the movements of the water in the sea mentioned in Chapters VI, VII, VIII, IX, and X, the discovery of the formation, distribution, and uniformity of the bottom-water, Chap. XI, etc. But of more general interest are perhaps the annual variations in the currents (the Atlantic Current, Chap. VII, and the Coast Current, Chap. VIII), and their relations to the variations in the climate of Norway, the variations in the fisheries, and also the variations in the harvests of Norway, the growth of the forests, etc. We have also been able to trace a certain relation between these variations and cosmic causes. We think that these discoveries give us the right to hope that by continued investigations it will be possible to predict the character of climate, fisheries, and harvests, months or even years in advance.

If only they knew.

You can see the whole manuscript on a webpage maintained by Svein Østerhus, a physical oceanographer at the Bjerknes Centre for Climate Research.

Learning about the future from looking at the past

Every school child learns that the Earth’s oceans cover roughly 3/4 of the planet’s surface, but what most of us don’t realize is that just 8 percent of that area covers the continental shelves — and that area provides 75 percent of all global fish catches — this I just learned from Callum Roberts’ excellent book, “The Unnatural History of the Sea,” which documents how we’ve been busily depleting fish stocks since our ancestors climbed down from the trees and figured out how to make hooks and toss them into the water. The whole book is an eye opener about how looking at past fisheries data tells us how much we have lost — and how we have to work even harder to protect what we have.

But the real reason I wanted to post this post was to observe, as Roberts does, that 87 percent of the area of the ocean is more than 1,000 meters deep — and for oceanographers interested in understanding how changing climate will change currents, this is where a lot -but not all — of the action is. And like the sleuthing that’s reported in Callum Roberts’ book,  scientists are piecing together how the ocean’s currents will work in a warmer world by looking at the past.

Andreas Born, a German who has just defended his PhD at the University of Bergen in Norway,  been looking at what has happened in the Eemian interglacial 126,000 years ago, before last ice age. It was warm then, and some scientists say this might be an example of the kind of  warmer climate we can expect. But unlike now, the Earth overall was cooling, especially in the Arctic, as the ice age came on. Long story short, the northern extension of the Gulf Stream, the North Atlantic Current, shifted farther north and carried warmer subtropical waters to northern Europe. So while the Arctic overall was cooling (and those glaciers were starting to rumble out of northern Canada towards the US) the warm currents kept Scandinavia ice sheet free for several millennia.

A warmer Arctic

So what happens if the Arctic is actually warmer? Born predicts that as the sea ice cover shrinks, circulation in the subpolar region, called the subpolar gyre, will strengthen. That will essentially block the North Atlantic Current from bringing its warm waters up to Scandinavia.

Surface waters or deep waters?

What’s interesting about this prediction is that Born is essentially saying that surface currents will control the transport of warm Atlantic water into the Arctic — which is a little different than what a whole slew of researchers are looking at when they look at the Atlantic Meridional Overturning Circulation, which is a big conveyor belt of water that moves north on the surface of the Atlantic  until it reaches the Arctic, then cools, plunges and heads south as deep water. One of Born’s colleagues at the Bjerknes Centre, Svein Østerhus, is looking at the movement of this deep water, as I described in a piece on ScientificAmerican.com.  His pursuits include looking at the formation of the deepest coldest water in the world, in the Antarctic in the Weddell Sea. But more about that in a subsequent post.

Geoengineering won’t touch sea level rise

This just in on the geoengineering front in the battle to grapple with climate change: At least as far as controlling sea level rise, it won’t work. A study just published in the Proceedings of the National Academy of Sciences warns that we’re in for at least 30 cm of sea level rise by 2100 “despite all but the most aggressive geoengineering under all except the most stringent greenhouse gas emissions scenarios.”

Aggressive geoengineering, in this case, means injecting sulfur dioxide into the atmosphere at a rate comparable to a Mount Pinatubo eruption every 18 months (!) or building an ever expanding fleet of giant space mirrors.

The “business as usual” scenario has sea-levels rising by 1 meter by 2100 — enough to flood out 150 million people and swallow roughly 10 percent of the “global gross world product.”

The graphic of the Greenland Ice Sheet melt is courtesy of Konrad Steffen and Russell Huff, CIRES, University of Colorado at Boulder. They have done some chilling work (pardon the pun) on the melting of this enormous ice sheet.

What is this AMOC thing?

One of the things that really got me interested in the question of how ocean currents will affect future climate is a report by the US Global Change Research Program (USGCRP*), called Abrupt Climate Change. One of my sources told me to read Ch. 4, entitled “The Potential for Abrupt Change in the Atlantic Meridional Overturning Circulation.” For those of us who like to state things dramatically, this is kind of stuff that Hollywood loves — yep, think, “The Day After Tomorrow”:

Now, anyone reading this blog probably knows that this movie took a couple of scientific facts and blew them way out of proportion. As George Monbiot says in The Guardian, “it was a great movie and lousy science.” Nevertheless, it did bring attention to the idea that changing ocean currents could and will affect our climate.

But first, what is the Atlantic Meridional Overturning Circulation — abbreviated AMOC — anyway? It’s not, as many people have said, the Gulf Stream (which is mainly wind driven, as it happens). But it is a kind of giant conveyor belt of heat and salt that cycles in the Atlantic, with a northward flow of warm salty water in the upper layers of the Atlantic, traveling from the Equator to the poles, and then a southward flow of colder water in the deep Atlantic.

One important feature of this circulation is the warm water that comes up to the Arctic and cools off, releasing heat. As the water gets colder, it gets denser and then sinks. It then flows south towards the Equator. That sinking helps pull the warm water up from the Equator. It’s kind of like a perpetual motion machine in the ocean, driven by imbalance between the heat of the sun coming in at the Equator compared to the relative coolness at the poles. Simple, right?

Here’s a picture from Wikipedia that shows how it works:

There are many things that are interesting about this movement of the ocean’s currents, one of which is that scientists still aren’t completely sure about the relative importance of all the physical forces that makes it work. (!)

Yes, it’s winds, and tides, and the buoyancy of warm salty water that then becomes cold dense water, with a dash of heat added at the bottom of the ocean by from the warmth of the earth’s core, but essentially, we don’t really know how if we change one component (for example, if the poles get warmer), how ocean currents will react.

So that brings me back to the Potential for Abrupt Climate Change and the Atlantic’s circulation.
First of all, while we don’t know exactly how all the forces that drive the Atlantic’s circulation work, we do know that doing anything to change the circulation will have a big effect.

We know because we have pretty solid evidence for this in paleoclimate records. These changes include “changes in African and Indian monsoon rainfall, atmospheric circulation of relevance to hurricanes, and climate over North America and Western Europe,” according to Ch. 4 of the USGCRP report.

Based on this, the report goes on to say that scientists don’t think that it will stop, although it will slow down. Here’s science speak for that “No current comprehensive climate model projects that the AMOC will abruptly weaken or collapse in the 21st century.” Whew, so Hollywood DID get it wrong — no icebergs in the East River after all!

But wait… if the Atlantic’s circulation were to collapse, forget about icebergs in the East River, we’re talking almost three feet of sea level rise, and to quote the report, this 80 cm of sea level rise would be in addition to “what would be expected from broad-scale warming of the global ocean and changes in land-based ice sheet due to rising CO2, changes in atmospheric circulation conditions that influence hurricane activity, a southward shift of tropical rainfall belts with resulting agricultural impacts, and disruptions to marine ecosystems.” What would 80 cm of sea level rise look like in Manhattan? Found this great image on geology.com:

Looks like Wall Street gets wet feet.

But as the report writers state, this is very unlikely.

Of course, what is very unlikely? That’s the kicker, I think. And you have to wade through quite a bit of this report until you find out that very unlikely is 10 percent. TEN PERCENT.

And that is why there are some two dozen monitoring efforts across the Atlantic, trying to get a handle on how the AMOC works, and why scientists are pushing to set up a comprehensive, coordinated international program to figure it all out. More about that next time.

*Since this is a blog, I get to interject all kinds of personal observations, like this one: Am I the only person out there who looks at this acronym and thinks immediately of the CRP and the Watergate Plumbers? I know it’s not exactly the same, and I guess I am showing my age, but I can’t help but see that acronym and think about Nixon.

Mapping the Barents Sea –the MAREANO project

With the shrinking of the polar ice caps, places like the Arctic Ocean and the Barents Sea are attracting more attention from shippers, oil companies and the like. In recognition of this (and partly to explore the region to let out oil and gas leases on the Norwegian Continental Shelf), the Norwegian government has been funding this enormous mapping and exploration project in the Barents Sea, called the MAREANO project.

Since their first mapping year in 2006, the project has discovered cold water coral reefs,
photographed marine life at a depth of 2700 meters and documented the effects of trawling on marine life on the Barents Sea bottom.

There’s an impressive collection of pictures on this site, which should disabuse anyone of the idea that the cold waters of the Barents Sea are barren. They’re not. The shrimp pictured at the top of this post is from 2700 meters, and then there’s this jellyfish that no one has ever identified before from 1000 meters. You can also create your own maps showing areas where there are vulnerable natural resources and the like.

All of this info feeds into the Norwegian Management Plan for the Barents Sea, and may also play a role in future CO2 management — one study of the North Sea, the Norwegian Sea and in the Southern Barents Sea estimated the storage capacity of these areas, in the depth interval 0.8-4 km below sea level, at about 13 Gt (that’s 13 000 000 000 tons for people like me who don’t think in gigatons) CO2 in geological traps (outside hydrocarbon fields), while the storage
capacity in aquifers not confined to traps is estimated to be at least 280 Gt CO2.