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In Ethiopian Desert, a Window into Rifting of Africa

A new study in the journal Nature provides fresh insight into deep-earth processes driving apart huge sections of the earth’s crust. The process, called rifting, mostly takes place on seabeds, but can be seen in a few places on land—nowhere more visibly than in the Afar region of northern Ethiopia. (See the slideshow below.) Here, earthquakes and volcanoes have rent the surface over some 30 million years, forming part of Africa’s Great Rift Valley. What causes this, and does it resemble the processes on the seafloor, as many geologists think?

The study suggests that conventional ideas may be wrong. Past calculations done by scientists predict that the solid rock under the Afar should be stretching and thinning substantially as the continent tears apart; thus molten rock should not have far to travel to the surface. Led by David Ferguson, a postdoctoral researcher at Columbia University’s Lamont-Doherty Earth Observatory, researchers analyzed the chemical makeup of lava chunks they collected from the Afar. They showed that magmas actually came from quite deep–greater than 80 kilometers, or 45 miles, within the earth’s mantle–and formed under extraordinarily high temperatures, above 1,450 degrees C, or 2,600 F.

This implies that magmas are generated by a long-lasting plume of mantle heat. It also indicates that magma must make its way up through a surprisingly thick lid of solid rock, called the lithosphere. This idea has been supported by some seismic images of the Afar subsurface.

Rifting here is fairly slow—one or two centimeters a year, or 0.4 to 0.8 inches, and this may partly explain why so much solid rock persists. As the lithosphere is pulled apart, it does stretch, crack and thin. However, because the process in this region takes so long, the base of the lithosphere has time to cool down by losing heat to the colder rock above. This keeps the relatively cold, brittle lithosphere thicker than would be expected, and counteracts stretching. Sometimes, though, magma suddenly spurts long distances to the surface, and the earth visibly cracks and pulls apart during spectacular rifting events. That includes a series of events that started in 2005, and was closely observed by scientists.

Parts of the rift have already sunk below sea level. In the distant future–maybe 10 million years from now–the process will advance so far that the Red Sea will break through and flood the region. A new sea will open up, whether or not there is anyone around to name it.

In East Africa, earth’s crust is stretching and cracking, in a process called rifting. Here in the Afar region of northern Ethiopia, hundreds of faults and fissures have formed over time.In East Africa, earth’s crust is stretching and cracking, in a process called rifting. Here in the Afar region of northern Ethiopia, hundreds of faults and fissures have formed over time. (David Ferguson)

 

An important force driving the rifting is magma created beneath earth’s rocky outer shell, which has forced its way upward to push apart the crust. This eruption happened in the Afar in June 2009. (David Ferguson)An important force driving the rifting is magma created beneath earth’s rocky outer shell, which has forced its way upward to push apart the crust. This eruption happened in the Afar in June 2009. (David Ferguson)

 

This crevice opened in a matter of hours, during a sequence of very large earthquakes in September 2005. It formed in response to magma being injected into the shallow crust, and is still emitting volcanic gases. This injection of magma was the largest event of its kind to be observed by scientists. (Lorraine Field)

This crevice opened in a matter of hours, during a sequence of very large earthquakes in September 2005. It formed in response to magma being injected into the shallow crust, and is still emitting volcanic gases. This injection of magma was the largest event of its kind to be observed by scientists. (Lorraine Field)

 

Fresh lava erupted onto the desert floor preserves fragile surface textures, formed as the viscous molten rock cooled and hardened. Over time, these sharp features will erode away. (David Pyle)

Fresh lava erupted onto the desert floor preserves fragile surface textures, formed as the viscous molten rock cooled and hardened. Over time, these sharp features will erode away. (David Pyle)

 

A remote field site within the rift. Afar is one of the hottest and most sparsely populated regions on the planet. (David Pyle)

A remote field site within the rift. Afar is one of the hottest and most sparsely populated regions on the planet. (David Pyle)

 

In a region that is vast, largely roadless and dominated by armed tribes, scientists depend on helicopters to get around, and on local people to act as guides and security guards. The climate necessitates large amounts of portable drinking water. (David Ferguson)

In a region that is vast, largely roadless and dominated by armed tribes, scientists depend on helicopters to get around, and on local people to act as guides and security guards. The climate necessitates large amounts of portable drinking water. (David Ferguson)

 

ethiopia-7

Lavas forming the rift surface cracked apart during an earthquake in 2005 to form this fault. The horizontal boundary between the light and dark area marks the pre-2005 ground surface, and shows that the area in the foreground dropped several meters during the quake. The geology of Afar provides many clues to the tectonic and magmatic process operating beneath our feet. (David Pyle)

The highs of hump day and the lows of engine failure…

Mapping the Galicia Rift off Spain - Mon, 06/24/2013 - 11:00

June 22 was officially hump day – we were halfway through our 43-day cruise. Happily, we were also about halfway through our data collection; we had just finished acquiring the primary lines in the southern part of our survey area, which was a major milestone.  The data are looking very nice (stay tuned for an upcoming post with some of the first images of features below the seafloor here from our new data!).  Now that we have been out for a while and the survey was proceeding smoothly, everyone had settled into their shifts and routines, and the science party was consumed with onboard processing and archival of the incoming data stream. Funny enough, hump day and the near completion of half of our survey almost coincided with the summer solstice and a very full moon!  It seemed like the convergence of many lucky omens.
Alas, it was not so. In the wee hours of the morning on June 24, the port engine failed as we were steaming along collecting data.  The ship has two engines (partially in case of just such an event!).  Fixing things at sea is obviously more complicated than fixing them on land, and the engineers onboard determined that the damage was significant and not quickly repaired. While we have the parts onboard to replace most of the known broken pieces, making the repairs and assessing the full extent of the damage is best done dockside. Thus we decided to pick up all our seismic gear and head back to Vigo to make the repairs.  It took us >3 days to deploy all of the streamers, paravanes, and associated kit, but only about 12 hours to recover them! Now we are limping back to Vigo through relatively rough (3-4 m) seas powered by one engine.  Once the damage and remedies for the port engine can be fully assessed, we can figure out our next move. Wish us luck!

Donna Shillington
LDEO

How to launch an XBT

Mapping the Galicia Rift off Spain - Thu, 06/20/2013 - 20:09

All of us on the science team have had our turn being indoctrinated in the "perils" of XBT deployment. In this video, Luke demonstrates the proper technique for launching an XBT.

Ship Tour – The Mess

Mapping the Galicia Rift off Spain - Thu, 06/20/2013 - 09:49
We’re starting a new series of posts here on the Galicia 3D blog to give our readers a piecemeal tour of our home away from home, the R/V Marcus G. Langseth. Every few days or so, you will see new parts of the ship with detailed descriptions and hopefully a few interesting stories to go with them. Today we focus on the mess and galley (dining area and kitchen), arguably the most important area of the ship, but stay tuned for the engine room, bridge, the rack, main lab, aft decks, gym, steel beach, the ping pong table and more! 

Prior to boarding the Langseth, my expectations of the food on board were clouded with visions of elementary school cafeteria slop doled out in aluminum trays and eaten with sporks and a side of plastic bag infused with milk. Little did I know that the folks on board take their food quite seriously. The three meals prepared each day are easily the most anticipated events of a crews’ day.

The galley (a.k.a. the kitchen in land dweller speak) is manned by a cook and steward who are responsible for sustaining the morale for the 53 people on board. The mess is regularly stocked with snacks like crackers, raisins, peanuts, dried prunes (yuck!), popcorn, cold cereal, microwave pasta, deli meats and cheeses, an assortment of milks and juices, coffee, tea, ice cream, and “fresh” fruits and vegetables (which will slowly be replaced with canned fruits and vegetables as the days go by). Cookies and pastries are also available at select times during the day if one is lucky enough to get there before they’ve all been consumed.



Between snacking times are the three glorious meals. Breakfast has the most stable menu of all the meals with a selection of eggs, potatoes, hot cereal, pancakes, French toast, bacon, sausage, ham, and a fruit platter that is now transitioning from fresh to canned fruits. Lunch generally consists of a type of sandwich, soup, French fries and/or onion rings, hot vegetables, rice, and other unpredictable delights. Supper has been quite intriguing as of late. We’ve been blessed with several kinds of steak, beef tenderloin, meatloaf, spaghetti, and many other varieties of taste bud tantalizing foods. For those who sleep during dinner and require a stomach recharge at 3am (yours truly and a good number of the crew on the midnight to noon shift), the galley staff save plates of dinner for “breakfast” that can be eaten during off times – I like to call this meal “brupper”, but am having difficulty getting the name to stick.


Lunch at the mess with Luke, Sarah, and Tyler.
It has been entertaining to watch our young British colleagues become exposed to American cuisine for the first time with foods like peanut butter and jelly sandwiches, meatloaf (although they’ve been informed that it’s never as good as my mom’s – love you mom!), French toast, sausage in patty form, and Hershey’s chocolate syrup. It is also quite obvious that a 2,000 mile pond provides for the generation of different mealtime habits. For example, Luke was quite disgusted that I would dip a chocolate-chip cookie in a cold glass of milk; I shared his disgust when he spiced his French toast (sans-syrup) with salt and pepper and ate it like a normal piece of toast (apparently this was his first French toast experience). I’m guessing there will be some sort of payback if we ever meet in England sometime.

Well folks, speaking of the devil, I’m off to the mess for a warm breakfast. I hope you enjoyed the tour and stay tuned for the next one!

Brian Jordan
Rice University

Calm after the storm

Mapping the Galicia Rift off Spain - Tue, 06/18/2013 - 06:46

We made it! According to the 30 minute log, which is one of the duties that we are given while on watch, we sustained up to 40 knot (74 km/hr, 46 mph) winds and ~7m (23 ft) seas for a few hours last night. That said, and aside from a relative lack of sleep, most of us seem to be no worse for wear. We also managed to travel north of our next sail line by almost an entire degree of latitude, which translates to ~111km (69 miles). We have now turned around, and are heading back to the survey area while working on streamer one. We will then re-deploy the air guns, and re-engage the survey in a couple of hours. 

Same view taken this morning.
James Gibson
Lamont-Doherty

Preparations for the storm

Mapping the Galicia Rift off Spain - Mon, 06/17/2013 - 01:08
As a follow up to Donna's post, we are making individual preparations, which include taking the motion sickness medicine of choice or default depending on where you come from.
Spanish, English, and American motion sickness remedies.
 We are also securing (tying down) our stuff and preparing our beds, which includes a new to us method coined "tacoing." To "taco" a bed means to use whatever you can find e.g. dirty clothes, luggage, random foam (Luke found some foam in the bird lab) in order to form a taco shape between your mattress and the wall. This way the roll has less of an affect on you as you try to get some sleep.. At least that's the theory.
My laptop's ready!
Brian in a reasonably "taco'd" bed... And Luke's version.

Will update from the other side of the storm.

James Gibson
Lamont-Doherty

Storm a Comin'

Mapping the Galicia Rift off Spain - Sun, 06/16/2013 - 21:06
For the last week, we have been enjoying relatively calm seas.  Swells rolled in from distant storms, but the local weather was quite enjoyable. Now the storm that pummeled the east coast of the US last week is headed our way. This storm is expected to give us winds up to ~36 knots and ~7-8 m (~21-24 ft) waves!  This is too rough for the more vulnerable components of our gear such as the airguns, which are dangling beneath floats behind the ship.  Additionally, our data quality suffers when the weather worsens. When the winds pick up to ~25 knots, we’ll pull in some of our gear, and then turn around to face the storm and ride it out.  In the meantime, we are preparing by strapping things down in the main lab and stowing loose items that might roll around and fall over once the ship really starts to roll.
Wish us luck!
Donna Shillington
17th June
Map of forecast wave heights posted in the main lab. The big bulls-eye is right over our field area...

Hello, sunshine

Mapping the Galicia Rift off Spain - Thu, 06/13/2013 - 04:31

We have been at sea for nearly two weeks, and during this time we have seen many things… the hints of exciting geologic structures under the seafloor in our data, waves, whales, gear going off the stern. But we have seen very little of the sun, until today.  Most days have been overcast and grey. Now that all the equipment is deployed, there is nothing requiring us to be outside except for the occasional XBT launch, so it’s easy for a day or two to go by without going outside at all. It is even possible to be totally unaware of the weather for long stretches of time since the main lab, where we spend most of our time, is windowless and below the water line. Instead of windows, we have monitors showing what is happening out on various decks from a series of cameras around the ship.  Today they showed bright sunshine reflecting off the water behind the ship.  After spending a few minutes out in the sun on the deck, my unaccustomed eyes are still seeing spots…. Back to the lab!
Bern and James are on watch, so they can only watch the sun on TV from the lab.
 Donna Shillington
13th June

Miracle workers of the Langseth overcome the curse of the Costa da Morte

Mapping the Galicia Rift off Spain - Mon, 06/10/2013 - 14:28
After days of uneventful and productive data acquisition, a pall fell over the R/V Langseth. Early Sunday morning, one of the streamers began to report communication errors and soon failed to communicate at all.  A series of tests over the ensuing hours revealed that the problem was not on the ship but in the equipment out in the water.  Recovering and repairing seismic gear is not a quick task. To access this streamer, we had to undo many of the steps required to put it out to begin with: recover the port paravane, shift Streamer 3 starboard and out of the way, and then reel in part of Streamer 4. After hours of troubleshooting, the technical staff of the Langseth brought Streamer 4 back to life.  All of the equipment on the Langseth is… not new, and this certainly applies to the seismic streamers. The technical staff on the ship are pros at keeping this equipment alive (and many cases bringing it back from the dead). Twelve hours after the problems with Streamer 4 began, it was back in the water, and we were ready to start collecting data again. 
But no sooner had one problem been solved, another appeared. This time the trouble arose from the failure of a piece of equipment on the ship that is at the heart of our acquisition system – the real time navigation unit (or RTNU, for those in the know). This component gathers satellite and other navigational information from the seismic equipment and delivers it to the navigation software on the ship so that we can determine the positions of all of our equipment in the water, and where and when we need to be shooting.  Once again, the dedicated technical staff of the Langseth came to the rescue.  Painstaking checking and double-checking of each component in the RTNU began last night and continued into the early hours of the morning. In the wee hours, it’s easy to get a little superstitious.  Did all these problems arise because Tim Reston and I each accidentally drew in lines on our chart indicating that we’d completed lines in our 3D box before we actually had? Or was it the curse of Costa da Morte (Coast of Death)? This part of the Galician coast is known for its shipwrecks and nicknamed accordingly. Of course, the real culprit was the non-newness of the gear in question. Once again, the Langseth’s miracle workers saved the day by assembling the working parts of various old RTNU’s into one working unit.  Thanks to their efforts, we are up and running again….

RTNU carnage on a table in the main lab.
Donna Shillington
10th June

Poseidon Visits (and Seismic Oceanography)

Mapping the Galicia Rift off Spain - Mon, 06/10/2013 - 13:41
One of the secondary activities on the cruise has been the deployment of XBTs off the stern. XBTs are a standard oceanographic tool designed to measure the variation of water temperature with depth, providing information on mixing processes within the water column. As temperature is one of two primary controls on velocity of sound in water (the other being salinity), it is also of interest in the processing of our bathymetric data.

Poseidon's Zodiak on the way over to exchange supplies.
A few years ago, it was realised that seismic provides a method of directly observing the mixing processes, as the different water layers have sufficiently different seismic velocity and salinity for reflections to be generated at their boundaries: we have already seen reflections in the water column of our data, probably from boundaries between North Atlantic water and warmer, more saline Mediterranean water. However there have been relatively few studies of these processes using traditional oceanographic and seismic techniques, a deficiency being rectified by the deployment of XBTs at regular intervals during our cruise.

A successful exchange on medium-high seas!!
In addition to deploying ocean bottom seismometers to record our seismic shots, the German research vessel F.S. Poseidon has been carrying out oceanographic measurements, mainly using CTD casts (conductivity-temperature-depth), which provide more information than XBTs. As a result they had several XBTs left over. These they transferred to us this morning: Poseidon came within about 1 km of the Langseth and sent the XBTs over in a small boat. A real bumpy ride!

Goodbye, until we meet in Vigo!Tim Reston
University of Birmingham

Poseidon: OBS deployment update

Mapping the Galicia Rift off Spain - Sat, 06/08/2013 - 08:13
On 5th of June, Poseidon deployed her last three OBH instruments. The crew then spent the next two days doing CTD ("conductivity, temperature, depth") measurements of the water column. They typically recovered good measurements of conductivity and temperature for depths down to 1000 m. These measurements can be used to monitor mixing of different water bodies (such as warmer Mediterranean waters with the cold Atlantic) and to calculate variations in velocity within the water column to compare with seismic reflections we observe within the water column. Rough seas for the last 1.5 days have made the CTD measurements challenging.

Today the Poseidon is recovering eight OBH to download the data they recorded and redeploy them elsewhere within the 3-D box. It will be exciting to see the first OBH data! We won't see the rest of the data until the remaining OBS and OBH are recovered in August and September.

Despite being in the same area, here on the Langseth the science party hasn't seen the Poseidon since our first day passing them on the way out to sea from Vigo. However, this may be because we are all busy below deck in the main lab (with no windows) processing data!

Marianne Karplus
8th June


Underway and beginning to collect data

Mapping the Galicia Rift off Spain - Sat, 06/08/2013 - 00:43
For the last couple of days, we have been slowly (very slowly) steaming along at 4 knots (~4.6 miles an hour) towing all of the gear behind the ship and collecting seismic data. A lot of data! Each of the four seismic streamers behind the ship records returning sounds waves on 468 channels. Every time one of our air gun arrays fires, we collect 60 Mb of data.  Repeat that every 16 seconds for a few days, and it adds up.  Even though we have only been at it for a few days, we have already generated 405 Gb of raw seismic data, and that does not include all of the other types of marine geophysical data that we collect (bathymetry, magnetics, etc). Nonetheless, there are many reminders that we still have a long ways to go.  For example, a large map on a table in the main lab shows all 56 profiles that we plan to acquire during this cruise in our target area for 3D imaging (black horizontal lines in the image below). As we complete them, we draw a green line along the profile on the map. Four down, fifty-two to go! 

Donna Shillington
8th June

Map in the main lab showing planned profiles. The ones we've already completed are in green
*Follow our progress on the "Survey Area" page as we update the sail lines every ~4 days.

The Source

Mapping the Galicia Rift off Spain - Thu, 06/06/2013 - 07:07
Our fourth (and final) gun array was deployed last night!! This means that all of the hard work that the crew has performed (with our help, of course) will begin to pay off as the data streams in while we traverse east along the western most extension.


Marine reflection seismology involves actively generating soundwaves (rather than waiting for earthquakes as in many other types of seismology). The ideal seismic source is as close to a “spike” as possible. Sound waves from the source travel into the Earth, where they reflect off sedimentary layers as well as hard-rock surfaces. The returning reflections are recorded by over a thousand hydrophones (underwater microphones that gauge pressure changes created by the reflected seismic waves) in the streamers that we have been deploying for the last four days.



The source consists of a series of air guns of varying sizes, which are hung at a depth of 9m (~30 feet) below large inflatable tubes. The tubes are 60m (~200 feet) long and each has 9 active air guns (10 with one to spare). In our case there are two sets of air guns being towed 150m (~500 feet) behind the ship, that alternately fire. To create a strong source that is as spike-like as possible, the guns are carefully arranged and fire almost simultaneously. The air is released from the chamber of the air gun, creating a 3300 cubic inch bubble pulse, which collapses to create the sound waves.
Orientation of the streamer and gun arrays being towed by R/V Langseth.
The red circles indicate the location of the gun arrays.
We are making sound in the ocean, where many mammals use sound to communicate and hunt for food. In order to ensure we are operating responsibly and minimizing our impact on mammals, we have five Protected Species Observers (PSO’s) onboard who both watch and listen for (from the observation deck in Donna’s previous post) any marine mammal that comes close to the ship. If any are spotted or heard within a specified radius around the ship, we power down the guns until they leave the area.

James Gibson
Lamont-Doherty

Langseth: The paravanes are out!

Mapping the Galicia Rift off Spain - Tue, 06/04/2013 - 00:24
Most of the science team came out on deck this afternoon to watch the starboard-side paravane deployed in relatively calm waters under partly cloudy skies. The technical and engineering crew proceeded slowly and carefully through the deployment procedure, and after about a couple of hours the paravane and attached streamer were over 300 m off the starboard side of the Langseth.

The second paravane went in the water at 22:00 this evening, and streamer 2 is currently being uncoiled into the water behind the ship. Despite a few delays, we are making good progress!

Marianne Karplus
4th June





A Tale of Sea Ice, Algae and the Arctic

Arctic Sea Ice Ecology - Wed, 05/29/2013 - 16:12
Andy Juhl measures and creates a temperature profile for each core drilled from the ice.

Andy Juhl measures and creates a temperature profile for each core drilled from the ice.

I returned to New York on Monday, but Lamont-Doherty Earth Observatory scientists Andy Juhl and Craig Aumack remain working in Barrow, Alaska for another week. They’ll continue to collect data and samples in a race against deteriorating Arctic sea ice conditions as the onset of summer causes the ice to thin and break up. Even in the two weeks I stayed in Barrow the ice changed dramatically, shifting from a snow-covered ice pack to a nearly snow-free ice pack, covered in cracks and increasingly large melt ponds. An animation from the May 23 Barrow sea ice radar reveals just how quickly shorefast sea ice can change. Soon the ice will be deemed unsafe for travel by snow machine and spring fieldwork conducted on the ice will end.

Our team’s research in Barrow is just one part in the long process of studying and answering questions about algae growing in and under Arctic sea ice and its role in the marine ecosystem. And, it’s a process that does not necessarily have a defined end — investigating the natural world always leads to more questions. From fieldwork, where observations are made and data gathered, new questions arise, new hypotheses are put forward and new ways of collecting data are developed. This work leads to further experiments where new data and samples are collected, observations are made, analyses performed and results interpreted. Some of the findings will challenge existing hypotheses, leading to their modification, which starts the research process over again.

The algae-filled bottom section of an ice core, ready to return to the lab.

The algae-filled bottom section of an ice core, ready to return to the lab.

Fieldwork gives scientists the opportunity to observe systems in a holistic way, leading to new insight and further research questions; each piece of data causes a rethinking of ideas and expectations for future results. “Fieldwork is inspiring and it’s critical to the creative process for environmental science because you often see things that you don’t necessarily see in your data,” said Andy. “There are subtleties and patterns that you can pick on if you pay attention to observe the natural world. You can’t do that in the lab or by looking at numbers.”

Some people may be disappointed to learn that we don’t have many immediate answers about sea ice algae and the Arctic ecosystem based on our month of Barrow fieldwork. But, scientists don’t set out to study things that are already understood or to answer questions that already have answers, and it takes time to unravel Earth’s mysteries. On this trip, project scientists discovered and collected lots of algae, observed novel behavior by marine organisms in the water column and on the seafloor, and gathered lots of data. The next steps in this project are to analyze the samples and data collected in Barrow, interpret these, write up findings and report these in journals and at scientific meetings. And, in 2014, Andy and Craig will return to Barrow to continue their study of sea ice algae, armed with new understanding of the algae, as well as new research questions to explore.

Our team at work in the Arctic.

Our team at work in the Arctic.

The goal of our project is to understand how ice algae functions and its role in the marine ecosystem, but we’ve received many questions about how ice algae, the residents of Barrow and the rest of life in the Arctic will be affected by a climate that is undoubtedly and irrevocably changing. The answer is that we don’t know, but our research may contribute to future understanding of these issues. Though the Arctic is changing faster than anywhere else on the planet, with temperature increasing and ice volume decreasing, it is still one of the least explored places on Earth. In order to know how climate change will impact this region, the basic oceanographic and ecological processes must first be understood.

As our project progresses, we’ll continue to provide updates and look forward to sharing a video of our time in Barrow that’s being produced by our friends at Climate Science TV. For more information on this research project, visit http://lifeintheice.wordpress.com. Our colleagues at Lamont-Doherty Earth Observatory also travel the world exploring our planet; to keep up with more interesting Earth science research and reports from the field, follow Lamont-Doherty on Twitter and Facebook.

And thanks to everyone who followed our expedition, we enjoyed sharing it with you!

Science, Creativity and Isopods

Arctic Sea Ice Ecology - Mon, 05/27/2013 - 03:12

It’s near midnight and Lamont-Doherty Earth Observatory researchers Andy Juhl and Craig Aumack, and Arizona State’s Kyle Kinzler are gathered around a table in their lab at the Barrow Arctic Research Consortium discussing the best way to catch an isopod. When scientists do fieldwork, they enter into it with specific questions and science goals in mind, but one of the joys of exploring the world through scientific research is solving challenges and devising new ways to collect data.

Andy Juhl readies ROV Brinson for a trip into the Arctic Ocean.

Andy Juhl readies ROV Brinson for a trip into the Arctic Ocean.

Meet Brinson. He’s a remotely operated vehicle (ROV) along on our Arctic expedition and named in honor of a foundation that provided Andy funding to build him. Brinson, originally designed and built by engineer Bob Martin, and modified by Andy, is the result of an idea that evolved over several years of Arctic fieldwork.

“We were deploying just this ice fishing camera, but were frustrated by the fact that there was always something just beyond our range that we wanted to see,” said Andy. “So we wanted mobility and once we got that we were frustrated by the fact that we didn’t know how big things were, and that’s when we decided we needed the laser pointers to provide scale. So Brinson has been a multi-step evolution into a simple, but well-equipped ROV.”

Brinson now consists of a GoPro camera and a standard ice fishing camera attached to a frame made of PVC pipe that can be lowered into a hole in the ice. On the ice surface, the ice fishing camera’s live video feed shows what Brinson sees as he travels through the water. Brinson is equipped with small bilge pumps that act as motors, which enable him to be maneuvered forward, up, down and side to side via his tethered remote control. When Brinson is below the ice, Craig monitors the video feed and describes to Andy what he sees on the screen. When something of interest appears, Craig tells Andy which way to maneuver Brinson, so they can continue to get footage of the organism.

Brinson recently saw small crustaceans called isopods roaming around the ocean floor. Andy and Craig were excited about this find and very curious to learn more about what isopods might eat and their role may be in Arctic the marine food web. Once Brinson, and Andy and Craig, saw the isopods, it was decided that our team should catch some, but we had no trap or means of doing so.

Scientists need to bring absolutely everything they need, and think they might need, with them on research expeditions, especially those to remote areas like Alaska’s North Slope. So, when, for example, you decide you must build an isopod trap late at night in Barrow, you’re pretty much limited to what you have on hand: a plastic buckets, plastic window screening, electrical tape, rocks, string.

Craig displays his catch.

Craig displays his catch.

With these materials, a little ingenuity and their limited knowledge of isopod behavior, Craig and Kyle constructed isopod traps. The guys hypothesized that isopods might like chicken, so baited their traps with chicken bones saved from our dinner. The traps were attached to eight meters of string and dropped to the sea floor. Kyle’s trap sat overnight and caught two isopods; Craig’s trap sat on the ocean bottom for several days and contained at least 20 isopods when it was pulled up.

The beauty of the isopod traps is that they worked and project scientists will get valuable data about the Arctic marine food web as a result. “From the underwater videos shot by Brinson, it looks like the activity of the isopods increases after the ice algae exports,” Andy explained. “We think there’s a plausible connection there: the ice algae could be a food source for isopods. We never would have posed that as a hypothesis unless we had the opportunity to observe them and make these connections.”

Fieldwork is, in part, a pattern of observing and questioning, and responding to these with new theories, methods and experiments. It’s also part of a larger creative process that involves improvisation and unconventional thinking. Said Andy, “In the field, we make a lot of stuff out of duct tape and epoxy.”

For more information on this research project, visit http://lifeintheice.wordpress.com or follow Lamont-Doherty Earth Observatory and the hashtag #LDEOarctic on Twitter.

Ctene Sensations of the Arctic Ocean

Arctic Sea Ice Ecology - Thu, 05/23/2013 - 01:40

One of the goals of Andy Juhl’s and Craig Aumack’s Arctic research is to determine the role of ice algae as a source of nutrition for food webs existing in the water column and at the bottom of the Arctic ocean. During their fieldwork these Lamont-Doherty Earth Observatory scientists are deploying a plankton net, a common tool used by ocean scientists to catch tiny marine plants and animals in the water column, to collect live plankton for identification and examination in the lab. They’re hoping to determine the different kinds of organisms active in this part of the Arctic Ocean and their food web feeding connections, or who’s eating whom by testing the organisms to see if they contain algae in their guts and muscle tissues.

This information is important because it will provide a baseline understanding of the connection between the algal community in the sea ice and the underlying ecosystem, and how it functions. Once this is understood, scientists may be able to better understand and predict changes that could occur in the marine food web as Arctic snow and ice cover changes.

A few days ago we caught the comb jellies in this video near shore at a depth of about four meters. Though comb jellies have the same type of gelatinous body as a jellyfish, they belong to a completely different phylum called ctenophores. Known for being vicious carnivorous predators, ctenophores use rows of comb-like cilia to propel themselves through the top of the water column and prey on smaller organisms, such as zooplankton. Ctenophores are found throughout the world’s oceans, including Arctic waters — quite a few of appeared in the holes we’ve bored into the ice this week.

These two comb jellies were filmed under a microscope in our lab. Each one is just a few millimeters long, though they can grow to be about 10 cm, sometimes larger. You can also see small copepods, a type of zooplankton and favorite food of ctenophores, zipping around the screen. Seeing a lot of ctenophores in the upper water column is a good indicator that they are feeding extensively on copepod larvae, who in turn are feeding on ice algae. This is an example of a few of the connections that make up the foundation of the food web in this fragile, yet biologically productive ecosystem.

Click here to view the embedded video.

On Wednesday Andy and Craig answered responded to questions about their research during a Reddit “Ask Me Anything” session. While the event is over, the session remains on Reddit and we encourage you to check it out to learn about our research and life in Barrow, Alaska.

For even more information on our project, visit http://lifeintheice.wordpress.com or follow Lamont-Doherty Earth Observatory and the hashtag #LDEOarctic on Twitter.

Collecting Core Data About Arctic Ecosystems

Arctic Sea Ice Ecology - Mon, 05/20/2013 - 13:53
Andy Juhl collects temperature data from a core, while Craig Aumack drills another.

Andy Juhl collects temperature data from a core, while Craig Aumack drills another.

Our team spent most of Friday on the Arctic sea ice, drilling and sampling ice cores at our main field site. For each core collected, Lamont-Doherty Earth Observatory scientists Andy Juhl and Craig Aumack take a number of different physical, chemical and biological measurements that characterize the ice and the organisms living inside it. Some of these measurements are recorded right away in the field, others will be taken later using pieces of the cores that we bring back to the lab.

Two of the physical measurements Andy and Craig record are the temperature and salinity of the ice. “Temperature is a critical parameter that controls the rate of almost all biological processes in the ice — almost everything happens slower when it’s colder, and parts of the ice can be colder than others. And if you know the temperature and the bulk salinity of the ice you can calculate how much brine volume there is within a given layer in the ice,” Andy explained.

Brine volume is an important measurement because algae live in brine channels in the ice. As ice gets colder, there’s less brine volume within it, meaning there’s less room for algae to grow. Andy and Craig also measure the concentrations of plant nutrients in the ice cores, including nitrate, ammonia, phosphate and silicate – some of the same elements that plants growing on land need. And, as with terrestrial plants, nutrient availability in sea ice is a factor that controls the growth of algae inside the ice.

 the objects of our affection. The brown areas are the bottom of the cores and indicate the presence of algae in the ice.

Ice cores: the objects of our affection. The brown areas are the bottom of the cores and indicate the presence of algae in the ice.

Other measurements, such as particulate organic carbon (POC) and dissolved organic carbon (DOC), Andy and Craig take in the lab will reveal the amount of carbon, or organic material in the ice. In addition to algae, carbon found in the ice comes in the form of non-living materials, such as bits of organic detritus from the tundra that become trapped in the ice. Finally, samples are collected for microscope work so that project scientists can identify the different types of organisms found throughout the ice.

All of this information varies in any single ice core from the top to the bottom, and based on where it is drilled. By taking consistent measurements from each ice core in different locations, project scientists can develop an in-depth understanding of the dynamics of the Arctic algal ice ecosystem – and how it may be changing.

Our group spent Saturday and Sunday in the lab processing samples from last week and preparing equipment, including mounting a camera system on our small remotely operated vehicle (ROV). We’re heading back onto the ice early Monday morning with the ROV and are looking forward to working in temperatures that may reach 35F.

For more information on our project, visit http://lifeintheice.wordpress.com or follow Lamont-Doherty Earth Observatory and the hashtag #LDEOarctic on Twitter.

What Lies Beneath Arctic Ice?

Arctic Sea Ice Ecology - Sun, 05/19/2013 - 03:38

On Thursday we lowered a camera into an ice borehole to get a look at the underside of the ice. In the following video, you can clearly see the algae living in the bottom of the ice due to their pigments, which they use to harvest light.

These organisms are not frozen into the ice; they’re living creatures that grow and thrive in tiny pockets of brine inside the ice. You might notice in the video that the underside of the ice is not flat, this is probably a reflection of variability in physical conditions in and above the ice, such as snow cover thickness.

Click here to view the embedded video.

While watching this video, Andy Juhl and I discussed how cool it is that there are vibrant communities growing in extreme environments. “One of the lessons that research in polar regions has taught us is that we need to broaden our definition of where life exists and thrives. In the Arctic, we have life growing inside ice, at below freezing temperatures. This means that we know to look in more unusual places for science of life and that’s one of the interesting things we learn by doing this kind of work,” Andy said. “Ice is not necessarily an inhospitable habitat, and on other planets where we see ice, that’s a place where we should probably look for signs of life.”

The second film shows a bit of life on the seafloor. This video was shot near shore where the water depth is about 8 meters, so it’s fairly shallow; water temperature here is -2C. The bottom consists of soft mud and it looks like there are deposits of algae that probably came from the ice on the surface of the bottom (those are the darker areas). There’s a variety of bottom dwelling organisms that live in the mud, such as the isopod that wanders across the mud in this clip. We don’t yet know how large the isopods are or what they eat; scientists on our team are trying to figure out a way to measure an isopod in situ or capture one to examine in the lab.

Click here to view the embedded video.

As our work in Barrow progresses, we’ll continue to post more videos so that you can get a sense of the life that makes up this fascinating ecosystem.

For more information on our project, visit http://lifeintheice.wordpress.com or follow Lamont-Doherty Earth Observatory and the hashtag #LDEOarctic on Twitter.

 

Ice Capades

Arctic Sea Ice Ecology - Fri, 05/17/2013 - 06:24
Scientist Andy Juhl makes notes at our first field site about snow depth and distribution.

Scientist Andy Juhl makes notes at our first field site about snow depth and distribution.

Fieldwork is exciting and inspiring, leading scientists to new ideas, places and observations about how the world works. Spring on Alaska’s North Slope provides an especially productive environment for fieldwork. When the sun never sets, it’s easy to linger in the field and the lab long into the well-lit night.

Our team spent about six hours on the Arctic sea ice Thursday, enjoying blue skies and temperatures in the low teens, while making observations, maintaining sampling sites and taking measurements. Most of our time was spent at two different field sites Andy and Craig established near Point Barrow, a narrow spit of land that’s the northernmost point in the United States. Traveling to these sites involves loading up two sleds with all of the sampling equipment, hitching the sleds to snowmobiles and carefully traversing the sea ice on said snowmobiles, which, I discovered today, is extremely fun.

Andy, Kyle and Craig prepare to finish drilling a hole in the ice.

Andy, Kyle and Craig prepare to finish drilling a hole in the ice.

One of the research questions Andy and Craig are exploring in Barrow is how the amount of snow covering sea ice might affect the diverse species of algae living in and just below the ice. A thin snow cover allows more sunlight to reach the algae; a thicker snow cover creates a darker environment. As in any ecosystem, many different species are competing for light and nutrients. For this study, Andy and Craig want to see how changing one factor in the Arctic sea ice ecosystem – the amount of available light – might allow some organisms to grow better and become more prevalent than others.

Last week Andy and Craig set up an artificial snow gradient at our first field site, where different snow depths cover the ice in a small, isolated area. Ice cores were drilled here on their first day and Andy and Craig will repeat this same exercise later in May. Collecting data over these specific time intervals will enable them to see how snow depth and distribution affect the community of organisms living in the ice. This information will provide an idea of what might happen to the entire ecosystem if more light is introduced via less snow cover in the future.

At the second field site, scientists used an auger to drill a hole in the ice, which is currently about four feet thick. Then a camera was lowered into the hole, with a live feed to a computer so we could see what was happening in the sea directly below us. A thick layer of algae covered the underside of the sea ice and once lowered eight meters to the sea floor, the camera revealed isopods (small crustaceans), jellyfish and a few unrecognizable members of the Arctic marine ecosystem.

Lowering the camera into the -2F sea.

Lowering the camera into the -2C sea.

“We do the camera work because there’s no substitute for seeing the ecosystem intact. We need to get cores in order to collect samples, but you get a really different impression of the ecosystem with the camera,“ Andy explained.

Later in the afternoon we searched the ice for a sampling station Andy and Craig used last year, but were unable to find it. The area had become covered with huge pressure ridges, large fragments of ice that pile up when sheets of ice collide, which are hard to cross on a snowmobile. At one point fresh polar bear tracks meandered among the ridges, but we never caught sight of the bear who made them.

For more information on this project, visit http://lifeintheice.wordpress.com or follow Lamont-Doherty Earth Observatory and the hashtag #LDEOarctic on Twitter.

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