There once was the Langseth, a ship
Over wave and trough did she skip.
Many instruments aboard
To always record
Depth, gravity, mag – every blip.
There once was the Langseth, a vessel
Where in their bunks scientists nestled.
‘Til called to their shifts
Their heads they must lift
For with errors and logs they must wrestle.
There once was the Langseth, a boat
On her airguns the crew they would dote.
Oft while in a turn
Guns were brought up astern
To ensure best acoustical note.
There once was the Langseth, seacraft.
Where we launched XBTs down a shaft.
With each probe descent
To the lab data went
So that temperature-depth could be graphed.
There once was the Langseth, a fine tub!
Where the galley crew made us good grub.
But when seas ran high
Up in knots stomachs tied
And to keep the food down, there’s the rub.
There once was the Langseth, fair barge.
To collect seismic data her charge.
Streamer 8-km long
And four gun strings strong
She’s the fleet’s seismic dreadnaught at large!
-Tanya Blacic, aboard the R/V Marcus. G. Langseth
Time series of deployment and recovery. Photo Credit: Ernie Aaron.~Ernie
It takes a team of people to get the OBS in the water and back out again. To illustrate the process of deploying a WHOI or SIO OBS, Gary Linkevich has created a time lapse video. The first part of the video captures two WHOI OBS deployments with Peter, Dave, Dylan, Gary, and Kate. The WHOI OBS are the peanut shaped yellow capsules that appear in the background next to the railing. After the WHOI OBS is in the water, we capture an SIO OBS deployment with Mark, Dylan, Gary and Kate. The SIO OBS are the rectangles with a yellow top and white base. Right after we deploy the SIO OBS, we start putting together a new one for deployment. The assembly process involves an instrument test and then attachment of the metal weight, floatation devices, light, and radio together. The deployment of this SIO OBS happened during the midnight crew shift which includes Ernie, Pamela, Afshin and Jenny. Once they pick her up and put her in, they start the assembly process all over again!
Thanks Gary for putting together this time lapse!
See you Later,
Kate Volk aboard the R/V Endeavor
One of our assistant engineer, Kurt Rethorn, gave us a tour of the engine room. Here's what we learned:
Kurt is an awesome tour guide!
Water quality (Photo credit: Kate Volk)Sea water temperatures in the Gulf Stream are pretty warm (Photo credit: Kate Volk)
Tropical mountain ranges erode quickly, as heavy year-round rains feed raging rivers and trigger huge, fast-moving landslides. Rapid erosion produces rugged terrain, with steep rivers running through deep valleys. However, in a number of tropical mountain ranges, landscapes with deep, steep valleys transition quickly into landscapes with low-sloping streams and gentle slopes at high elevations. This topographic contrast between high and low elevations poses a problem for geologists. Though heavy rains fall throughout the mountain range, erosion seems to sculpt parts of the mountain differently from others.
Mount Chirripó, Costa Rica’s highest peak, bears exactly this type of terrain, with flat valleys at high elevation capping rugged valleys below. The beveled summit of Mount Chirripó bears striking resemblance to summits as far away as Taiwan, Papua New Guinea and Uganda. Some geologists think that tectonic forces deep below earth’s surface pushed Chirripó into its flat-topped form about 2.5 million years ago. Others think glaciers did the work, sculpting the peak in over hundreds of thousands of years.
Max Cunningham, a graduate student at Columbia University’s Lamont-Doherty Earth Observatory, traveled to Chirripó this past summer to test the idea that mountain glaciers carved the summit we see today. Working with his adviser Colin Stark, a geomorphologist, and Michael Kaplan, a geochemist, both at Lamont-Doherty, Cunningham chiseled away samples of glacial debris to take home for analysis. The researchers hope to eventually pin down when the high-elevation valleys capping Mount Chirripó’s summit eroded into their current form. Read more about their work in the above slideshow.
Photos by Max Cunningham unless otherwise credited.
It was nearing time to launch the next expendable bathythermograph probe, or XBT. The software was readied and two scientists headed out of the lab, radio in hand. They donned lifejackets that had once been bright orange but were now closer to a dull rust color from long and dirty use on the deck and selected a T-5 probe from the box.
Out on the deck they were alone, perched partway up the stack of levels in the stern of the ship, the gun deck below them and the paravane deck above. It seemed that the others working the graveyard shift were all inside, perhaps wrestling with some mechanical puzzle or else simply keeping watch to make sure all was well, sipping strong coffee, playing cards to pass the time. The scientists snapped the probe into the gun-shaped launcher. They removed the plastic end cap from the black cylinder that housed the probe and its spool of fine copper wire.
“We’re in position.”
There was a pause, then the radio crackled back, “Launch probe.”
In a moment the probe was sliding down the long tube that extended out and downward from the starboard side. With a small splash it plunged from the end of the tube into the inky deep. Now to wait while it made its journey towards the bottom, more than 4000 meters below. Despite the very late (or very early, depending on your point of view) hour, it was warm. The air was muggy – not exactly a welcome change from the air-conditioned lab, although the tinge of diesel fumes was less out here in the relative open. There was little wind and the seas were calm. Standing on the moving island of light that was the ship the sea quickly disappeared into the surrounding void. What surface that could be seen appeared to rise disturbingly close up alongside them, like a churning wall of water. It was only visible at all by the few swirls of foam formed by the ship’s passage and a reflection here and there off the constantly moving face of the black oily-looking water. They waited for the go ahead to terminate the probe.
Down in the lab, there was a strange blip on the screen showing the multibeam bathymetry data, but no one noticed as they were too busy entering in location data for the XBT or scrutinizing the movement of the streamer birds that regulated the depth of the hydrophone streamer. There were, after all, 36 other monitor screens to watch.
Outside there was a louder than usual splash. The two scientists peered into the gloom.
“Dolphin?” one wondered out loud.
“While we’re shooting? I hope not,” the other replied, “We’ll end up having to interrupt the line.”
Was there something just under the water surface? A pale sinuous shape at the very edge of the ship’s halo of light? No, it must be a trick of the light and the weird perspective engendered by the lack of any sense of distance. Perhaps more coffee was in order when they got back inside.
The radio crackled again, “Terminate probe.”
The scientists broke the wire that was still spooling out to the probe that was now falling behind them. “Probe terminated,” they reported. They were just turning to leave when it emerged.
At first it looked like a whale back, though pale milky green in color rather than the expected grey. As it lifted free from the surface it became clear that it was much longer than an orca or even a grey whale, more like an ancient marble column turned soft and rubbery. It tapered as more of its length was exposed until the tip broke free of the clinging water. One side of the enormous snake-like shape was covered with round suckers the size of dinner plates in a poisonous green color. The cyclopean tentacle towered out of the water, waving gently with a sickening sort of grace ten meters or more above the uppermost deck. Here and there along its length were clots of a coppery tangled substance, almost like seaweed wrapped around it. “The XBT wire,” one of the scientists realized from the midst of her fascinated horror.
The tentacle hovered for another movement before swooping down with surprising swiftness. The two scientists were neatly plucked from the ship in the blink of an eye. With a clatter, the radio fell to the deck. They were held above the water for a long moment, crushed together so tightly they couldn’t speak and could barely draw breath. Then, slowly, the tentacle disappeared beneath the smoothly rolling waves.
Two hundred and sixty-seven shots until the next XBT.
-by Tanya Blacic aboard the R/V Langseth (with a wink to H. P. Lovecraft)
Our small ship is in a state of endless motion with pitch, roll, yaw, and heave. We continuously experience a feeling of fluctuating gravity at sea, as one minute we are several pounds heavier and the next we are several pounds less. We’re tossed about endlessly like riders at the fair. It’s a feeling that can turn the stomach of the saltiest of sailors, but more often disturbs the newbies the most. At sea there is also no such thing as silence. Out here the engines are always running, hydraulic pumps are always droning, and ships operations occur around the clock. From my bunk I can feel us lurch forward and lean into a turn to starboard, or port, and then they reverse the pitch of the propeller as if applying an emergency brake to slow the ships forward motion. This reverse pitch causes a shudder in the hull that shakes us like a cheap hotel vibrating bed and it chatters every moveable thing. From my bunk I can also hear the acoustic pings emanating from the hull-mounted transducers. Speaking to me in code, they tell me if OBS operations are going well. Based on the ping styles I can also discern the acoustic techniques used by WHOI and Scripps, so that I know which instrument type is being talked to. All of this information creates a movie in my mind that plays out until I fall asleep. Life on a ship is a constant immersion in all that is going on and for 30-days there will be no escape.
Kara and Matt are entranced by velocity analysis
Perspective view of seafloor depth from MGDS across the continental slope overlain by a higher resolution swath of bathymetric data that we acquired along our transect, which is also shown projected onto the seafloor.
Preliminary image of a salt diapir in seismic reflection data near the base of the continental slope. The y-axis shows the time it takes for a sound wave to travel down in the earth and back again. This images shows about ~5 km down into the earth below the seafloor. Donna Shillington aboard the R/V Langseth
Today was the first day of the onshore deployment of the RT130s through southern Virginia and North Carolina. My partner, Yanjun Hao, and I, were just one of five teams working to deploy instruments along the two survey lines. We deployed the first two instruments at West Harnett Middle School and South Hartnett Elementary School, both outside of Lillington, NC. In both case, the fifth and sixth graders were very interested in learning about what we were doing and eager to participate. I explained to them the basic concept of P and S-waves and then asked the children to jump so that we could test that each of the channels on the sensors was working correctly. They very much enjoyed getting to see on the clié exactly what the signal they generated looked like. At both schools, I was surprised how much the children, and the teachers, knew about earthquake seismology and the intelligent questions they asked. A teacher asked whether they would detect the explosives detonated at nearby Fort Bragg, and a sixth grader named Gauge blew me away when he asked if the sensors would be able to record the sound waves generated by the planes or nearby explosions! In total, we probably spoke to 100 kids about the project today. It was a very encouraging to see how excited and interested they all were in the science. When we first arrived and explained that we would be installing a seismometer, a 5th grade teacher looked at us with wide eyed and asked "Are you seismologists?!" I nodded yes and she was so excited she started jumping up and down. Despite some rain and GPS trouble later in the day, the excitement that the elementary and middle schoolers showed about seismology was enough to make it a great start to the deployment.
Posted by Christopher Novitsky
Posted by Beatrice Magnani
See ya'll later,
For those of you following at home, it might be a bit confusing on which ship is doing what and where. I've made a little cartoon timeline that will hopefully illuminate our progress so far.
There are two ships currently in the Atlantic: the OBS deploying R/V Endeavor and the seismic shooting R/V Langseth. The R/V Endeavor has been putting OBS down and picking them back up again on lines 2, 3, and 4 while the R/V Langseth has shot seismic along line 2 and 3, and is going to head over to shoot on line 4 soon.
See you later,
Kate Volk aboard the R/V Endeavor
Well we have finished deploying OBS on line four and are now transiting back to the beginning of line 3 to start picking OBS back up again. At this point, we've all fallen into our jobs and are working like a well oiled machine. Each shift was able to deploy around 9 or 10 OBS in 12 hours time, moving smoothly from one site to the next. To celebrate our progress so far, I've got some group photos to share.
The science party from left to right: Gary, Dylan, Afshin, Harm, Brandon, Pamela, Jenny, and Kate (Photo credit: Dave DuBois, edited by Gary Linkevich)
The WHOI and SIO OBS technicians from left to right: Ernie, Peter, Mark, and Dave (Photo credit: Gary Linkevich)
The whole science group (Photo credit: Ethan, edited by Gary Linkevich)
The science group in the WHOI van with the WHOI OBS (photo credit: Dave DuBois)See you later,
Kate Volk aboard the R/V Endeavor
No one ever leaves the field the same way they entered it. Yes there is a new layer of mud on equipment, the expected wear and tear on your personal gear and your physical being, but that is not what I am referring to. I am acknowledging the intangible shift in perspective from a deepened understanding and a broadened vision that has been provided by the experience and beyond that the questions that drive the next field campaign.
The end of any field campaign is bittersweet. The adrenaline rush of the data collection phase slows to a more normal rhythm of daily life. There is a change from an unwavering focus on the many details of the project with a hard push day after day to extract as much out of the field time as possible, to a position of intense reflection. Was the campaign a success? Were we able to accomplish what we had hoped? Did we come away with the data we wanted? What did we learn? Should this project be repeated? or adjusted? perhaps expanded?
Our Reflections –
Our fledgling partnership has shown there is both a willingness and an interest among the local Greenlandic to work with scientists in collecting measurements. There is an aptitude for working with the instruments and a desire by them for the collected data on temperatures at depth in their local fjords to build a broader understanding of their environment. Both the science team and the Greenlandic fishermen see this data as important to planning for the future. They are hopeful it will provide them insights to direct their fishing practices, which in this traditional community remains their main livelihood. We are hopeful it will provide evidence of processes driving change in the Greenland tidewater glaciers.
The Kullorsuaq fishermen have told and showed us that they will adapt to change in the north. We can help them adapt by providing them information that assists their choices and adjustments.
When we arrived in this small community there were no water temperature measurements inside the fjords for this area of Greenland. We hoped to collect water column data that would tell us if this northwest corner of Greenland was being affected in the same way as other parts of Greenland, with warm Atlantic Water flowing in at depth. Bathymetry (bottom depth) measurements did not exist in this section of Greenland’s coastline and it turned out the area was much deeper than we had expected. When we planned the project the little data that is available showed depths of 400m, yet we lowered our instrument approximately 500 meters and only three of our casts reached bottom. The Kullorsuoq fishermen told us that in front of the glacier it is over twice this depth which they have learned from lowering their fishing line.
While we were not able to get data the full extent of the water column the measurements we collected confirmed that, as in other areas of Greenland, warm surface water (>4°C) is layered on top of colder fresh Polar Water (<-1.5°C), and below this, from about 200 m (700 ft.) and below, flows warmer Atlantic Water. As our equipment didn’t allow us to go the full water depth we don’t know how warm it gets, but we know it exceeded 1.7°C and was still rising at the depth of the cast. This warm deep water is affecting glaciers like Alison that sit in deep fjord troughs by melting the ice at the base of the glacier, causing weakening and retreat.
Our sampling plan was adjusted to deal with the ice conditions in the field. We had to shift our collection points to work around the mélange in front of glacier. We focused the first day (shown in red) on getting as close to the ice front as possible, collecting a ‘transect’ or line of measurements, and surveying the smaller channels. Day 2 (shown in green) we extended the transect from day 1, tested for pathways to the outer shelf, and tested one of Hayes Glacier (just north of Alison) outlets paths, and collected some repeat measurements from Day 1 to see how conditions vary with time and tides.
We have plenty of data to analyze but in the future collecting data in other seasons and locations would be beneficial. According to our Greenlandic partners getting winter measurements in Kullorsuaq is possible using their dog sledges to move the instrument. Early spring would offer interesting conditions as well. The local fishermen are anxious to continue to work with us, and we hope to be able to continue and build on this partnership.
Qujanoq (kwee-yan-ok) to our new Greenlandic friends – Thank you.
Project Information: Dave Porter and Margie Turrin were in northwest Greenland working with local community members to collect water column temperature profiles. The Leveraging Local Knowledgeproject will work with members of local Greenlandic communities to collect water measurements in the fjords. This will assist in determining if warming Atlantic Ocean water is circulating up through Baffin Bay where it enters the fjords to lap against the frozen glacier footholds, causing them to loosen their hold on the rock below. Alison Glacier (74.37N and 56.08W) is selected as the project focus. Emptying into Melville Bay to the east of Kullorsuaq Island and has been undergoing dramatic change over the last decade.
The project is funded by the Lamont Climate Center with support from the NASA Interdisciplinary Program and logistical support from NSF.