While I arrived in Barrow, Alaska on Tuesday, Lamont-Doherty Earth Observatory scientists Andy Juhl and Craig Aumack, and graduate student Kyle Kinzler from Arizona State University, got here one week ago. They took a few days to unpack and set up their lab (everything they need to work here must be shipped to Barrow in advance), scout locations for sampling on the ice and ensure that their tools and equipment are working properly before they begin their fieldwork.
Our team alternates days in the lab and days on the ice. The lab space we’re using is a bit north of town at the Barrow Arctic Research Center (BARC), a newly constructed facility where the National Science Foundation leases space for its researchers. Scientists wishing to work in and around Barrow can use BARC as their home base. At the moment the building is fairly quiet as the only other occupants are a group of international graduate students being trained on how to conduct sea ice research.
Today was a lab day, where recently collected samples were processed, experiments performed and preliminary data analyzed. Fieldwork is just the beginning of a research process that can take several years. The majority of the samples and data collected here won’t be examined until scientists are back at their respective institutes, where it can take months or longer to analyze all of their samples and data and then write up the results. But, to ensure that their research is on the right track, a few experiments and analyses are done while in Barrow.
This afternoon I spent time in a zero degree walk-in freezer talking with Craig Aumack, who’s conducting experiments to learn more about the organisms living in Arctic sea ice. Each year, as soon as any light is available, algae start growing in the ice and continue to bloom through the onset of spring and the Arctic’s long summer days. Algae prefer to live in the bottom of the ice, because, like all plants, they need light and nutrients, and these are plentiful at the sea-ice interface.
Craig’s experiments are called settling experiments, and these help him learn what happens to the organic materials and organisms living in the sea ice when they’re released into the ocean. Craig wants to determine the rate at which these particles sink down through the water column; this information reveals whether particles are more likely to be consumed while falling through the water column or once they accumulate on the seafloor. Particles that sink slowly are more likely to be eaten by zooplankton, tiny marine animals, while those that fall to the bottom will be consumed by worms, crustaceans and mollusks.
Settling experiments must be done in a freezer because organisms that call ice home would quickly die if exposed to a 70-degree temperature difference. Though extreme temperatures can also cause humans to become a bit uncomfortable, we’re able to don parkas and puffy jackets to protect us; algae don’t have this luxury. So, Craig replicates the conditions in which ice algae thrive, and bundled up, works in a frigid environment.
Andy Juhl was happy to explain this experiment and their research further, fortunately outside of the freezer. “There’s a whole ecosystem living inside the ice. Ultimately, we want to know what the dynamics of this special ecosystem are and how this is connected to the rest of Arctic ecosystem,” he said.
“We know the Arctic is changing very rapidly in terms of ice cover, duration of ice cover and extent of ice cover. One of the things we need to understand if we’re going to try to predict what will happen to the Arctic in the future is the ice ecosystem and its importance to the functioning of the entire Arctic,” Andy said.
Tomorrow, Thursday, we head out onto the ice to sample. This afternoon I received my land use permit from the Ukpeaġvik Iñupiat Corporation, the organization that owns the land we’ll be working on, and successfully completed my snowmobile training, so I’m officially ready for fieldwork.
Andy Juhl and Craig Aumack, microbiologists from Columbia University’s Lamont-Doherty Earth Observatory, are spending a month in Barrow, Alaska studying algae in and below sea ice, and how our warming climate may impact these important organisms. They’re investigating the factors that control the growth of algae inside of sea ice, how these algal communities are connected to other Arctic marine organisms and what happens to the organic matter that builds up inside sea ice. I’ve joined them to document and tell stories about their research, how it’s done, why and what they’re learning.
Barrow is the northernmost point in the United States and is situated where the Chukchi Sea meets the Beaufort Sea. Throughout the long winter, these waters are covered with a thick layer of ice. This ice is home to many different microscopic algae, which form the base of the polar food web.
During late winter and spring, large communities of these algae flourish, or bloom, inside and on the undersurface of the sea ice. As the ice melts, algae are released into the nutrient rich waters, feeding plankton and higher trophic levels, including fish, whales and seals.
The Arctic is warming faster than any other place on the planet, shortening winter and causing pack ice to thin and break up earlier and earlier each year. How will these changes impact the Arctic marine food web? Answering this question and understanding how the ice algae respond to our warming climate will inform resource managers and policymakers, as well as local residents, of how the larger Arctic marine ecosystem may be impacted.
Andy and Craig hope to learn how our fast-warming climate and the resulting dissipation of sea ice affect the entire marine food web. This knowledge is essential to assessing the value of the ice community in the Arctic and is paramount to predicting ecosystem-wide consequences to rapidly changing Arctic environments.
We’re based at the UMIAQ field station in Barrow, which provides logistics support for NSF-funded scientists conducting research in the area. From Barrow, we’ll travel across the sea ice by snowmobile to nearby Point Barrow, where we’ll establish sampling stations and drill and remove cores of ice. Samples will be analyzed back in the lab to investigate the flux of the algal organisms and organic matter from the sea ice to the water column during the spring melt.
Over the next few weeks we’ll share stories from the ice about our research, the role sea ice algae play in Arctic ecosystems and how that’s changing, and what’s it’s like to live at the top of the planet. And, if we’re lucky, a few pictures of whales and polar bears.
The Lamont IcePod team is a blended mix of engineers and scientists learning from each other through the design and testing of this new instrument. With a range of talents and backgrounds, the project mixes seasoned field workers with those new to field work; experienced instrument developers with those newly learning this end of engineering; and scientists with countless hours spent pouring over Greenland ice sheet data with those exploring the ice sheet for the first time. It is the opportunity for mentoring and development that comes from this mix of early career with experienced personnel that has made the IcePod Instrument Development Project a good fit for its American Recovery and Reinvestment Act funding.
So who makes up the IcePod engineering and science team? As we work through data and examine the products collected in the first part of our field season there is an opportunity to introduce members of the team and the data and instruments they operate.
Chris Bertinato trained as an aerospace engineer before joining the IcePod team. In the air he is the team’s connection to the flight decisions made by the crew. Like the members of the flight crew he dons a headset as soon as aircraft begins its warm up. The headsets are connected into the plane electronics through lengthy cabling that trails behind each set. The cabling necessitates a threading and weaving between the crew as they move about the aircraft, testing and checking equipment and switches. Watching them work one can imagine a class devoted to practicing safe maneuvering about the plane while tethered to the electronics system – something like a Maypole dance!
Chris is a main operator of the equipment rack and has responsibility for the Laser Imaging Detection And Ranging (LIDAR) system part of the optical package in the pod taking constant measurements to find the surface elevation, and the inertial navigation system (INS) used to locate or “georeference” the data. The INS is a critical navigation aid that employs several accelerometers (motion sensors) and gyroscopes (rotations sensors) to continuously calculate the position, orientation, direction and speed of the plane as it moves through space. INS were first developed for rockets, but have become essential instruments for collecting referenced data in an aircraft, since the pitch, roll and yaw of the plane (see drawing) as it moves through the air can make it difficult to correctly locate and orient the data for processing. For those of us used to flying on commercial airliners, movies and music can provide enough of a distraction that we don’t notice the regular rolling of the aircraft as it responds to buffeting by the air around it.
The cylindrical housing for the laser sits snugly in one of the pod bays with the INS sitting atop in the small grey box. The laser focuses down through a clear panel, and scans back and forth in a swath that at 3000 ft. of altitude swings approximately 3000 ft. wide collecting elevation information. The data is then fed through a processor that turns it into elevation data.
The image above shows a swath of laser data over the airbase, and can be used to help explain the instrument. The color in the image shows the reflectance of different surfaces to the laser. You will see three of the LC130 aircraft lined up across the front of the airfield, cleaned from snow and clearly outlined in the data. There are two additional aircraft positioned in the middle of the image that are still surrounded by snow and therefore remain somewhat obscured. Trees, roads and other features in the adjacent area are clearly imaged.
In Greenland Lidar will be used to assist with locating features of interest in the ice sheet. The image above of meltwater channels in Greenland will be important to track during the summer season as these channels can reactivate seasonally, becoming a blue stripe on the otherwise white landscape. These darkened blue sections will absorb more heat energy from the sun due to their altered reflectivity (albedo) encouraging additional surface melt. In an upcoming post we will discuss how the infrared camera carried in the pod will allow us to track the heat energy in the channel both in its current state, and as it begins to melt later in the season.
Lidar will also be used to detect openings in the ice sheet (crevasses). Many of the crevasses are deep yet not wide, making them difficult to detect without the assistance of instruments. Detecting crevasses is important as they pose danger for pilots attempting to land and deliver support to ground crews, can be deadly for overland traverses that are carry scientists and support staff across the ice, and can provide us with critical information on changes in the ice sheet. Lidar data collected in our IcePod flights can be used to help in all of these situations.
For more on the IcePod project: http://www.ldeo.columbia.edu/icepod
By Ana Camila Gonzalez
When we walked into the Sheraton in Springfield, Massachusetts we were greeted by none other than a wall full of cross sections from trees perfectly sanded to reveal the rings.
“No way” I say. “I forgot the camera!” says Neil.
We were just walking into the Northeast Natural History Conference, along with Dario and Jackie from the Tree Ring Lab. When I pictured my freshman year of college last summer, I pictured a lot of things. I did not picture getting to go to a conference to present a poster on my own research.
On the first day we listened to talks given by people who dealt with everything from conservation science to birds and berries and beetles. I’ve gone to multiple talks at Lamont, but those talks are mostly geared towards graduate students, so I’m always the slightest bit lost listening to them. This conference seemed to be geared towards a wider audience: I could actually understand the talks. I couldn’t believe it at first. After the first day I knew a little more about a wide range of topics: I can now tell you about the reproductive cycle of a lobster, what kind of fruits allow birds to fly farther during migration and even the life cycle of an Emerald Ash Borer in a tree.
I also learned more about the research process, since many people were presenting research projects that we weren’t already familiar with. I thought there was only a specific set of proxies for climate, but I found that people are continually finding more and more. I listened as someone described how they were using a mountainside as a proxy for climate change, and I realized that one of the great things about environmental science is that you can use the world as your lab, in many cases literally.
That afternoon during lunch we were told to make sure our GPS systems were safely hidden in our car. We were warned that we had to realize that we were now in a “big city.” We joked at our table—all being from New York—about how Springfield didn’t seem like a big city at all. I liked the thought, however, of a field of science where so many people are able to work in small rural towns that they do see Springfield as a big city. Want to know a secret? As much as I like school in the Big Apple, and I see myself living the city life for a while after school, I don’t see myself living anywhere with a population over five thousand after that.
Everyone in the lab was scheduled to present the next day. I was scheduled to give a poster, but Jackie, a Senior undergrad at Columbia, was scheduled to give a talk: we were both freaking out in the hotel room that night, but she probably had more justification. That night Jackie, Neil and Dario went through their talks while I made a big deal over how to cut my poster. Jackie ended up cutting it for me; my hands were too shaky. I must have asked a million questions to prepare that no one ever actually asked me, but by the end of that night I felt ready. “At least I’m not giving a talk!” That didn’t really calm Jackie’s nerves.
The next morning we had an awesome breakfast, I bought a piece of flan for no apparent reason, and we headed to the conference. I set up my poster and less than a half hour later sat to watch Jackie, Dario and Neil give their talks back to back. They were all wonderful, and some questions were asked that sparked some good conversation. Someone made a comment about baldcypress, and my ears turned up at the corners. She was mentioning how incredibly sensitive it was to drought, and I have to admit I got a little too excited. I talked to her afterwards: “That makes so much sense! I’ve been trying to cross-date this batch of baldcypress for so long, and it seems like every drought year thus far has produced either a narrow, missing or micro ring, and yeah, like you mentioned, isn’t it crazy that they’re so sensitive…” yeah, I was a little over-excited. It worked out well, because I had to go stand by my poster directly afterwards.
This is it. I’m standing by my poster. Someone comes up to me. THEY’RE GOING TO ASK ME SOMETHING I CAN’T ANSWER… THEY’RE GOING TO… “Hey, so can you tell me a bit about what you did?”
Wait. Really? I can do that!
The rest of the poster session went well. I was asked more than “can you tell me about your poster,” but it wasn’t half as bad as I had imagined. There were many questions I could answer, and there were many that I couldn’t. I ended up liking the questions I couldn’t answer more, however, because they told me what to do next. The same scientist who I had talked to previously about the baldcypress caught me off guard when she told me she’d look forward to reading about my findings in a paper. I hadn’t thought about it before, but I guess that’s my next step: take the unanswerables and answer them.
All in all, I learned more than I ever thought I could at the North East Natural History Conference, and walked away with much more than just natural history. I’m more excited than ever for what’s to come.
Ana Camila Gonzalez is finally out of the woods. She has, essentially, completed her first-year as a student in environmental science and creative writing at the Tree Ring Laboratory of Columbia University and Lamont-Doherty Earth Observatory. She has completed her blogging on the process of tree-ring analysis, from field work to scientific presentations…for now. We are happy to announce that she will be working with us for Summer 2013.
When we left Stratton Air Field almost two weeks ago, I recall smiling when a mechanical issue temporarily pulled us from the aircraft and the woman shepherding us back into the waiting area remarked, “Don’t worry, we keep doing it until we get it right!” Today we are faced with just that type of day. Testing a new system is all about running through the same set of operations “until you get it right.” For our team, this means flying the same patterns over the same locations looking for repeat targets to test and retest our instruments.
The aircrew arrives each morning ready to fly the patterns and routes we have selected. They are willing to redirect if the weather changes, or if our priorities shift, but we have stayed fairly consistent in our requests. Of course, being in Greenland, we talk about varying our plan and picking some of our science team’s favorite targets. It seems almost unfair to be here and not venture off to the fast changing Jakobshavn or Petermann glaciers. But we are a disciplined group with a specific mission…we need to do it “until we get it right.” The navigator programs the plans into his system and we are ready to fly.
We are lucky. No matter how many times we fly over the Sondrestrom Fjord, it always looks stunning: the water a deep blue, the ice pieces feathered along the edge where the floating tongue ends. Once we move over the deeper ice in the center of the glacier, we still marvel at the twisting, refrozen meltwater streams that wind across the ice face.
Over the rocky edges of the landmass it is still fascinating to see the twisting rolls of collapsing ice that pile and swirl along the brim of the flat-topped frozen lakes. The mountains themselves look like painted rocks with their smooth and shiny surfaces.
It is hard to believe one could ever tire of these flights. Each area we fly over is more stunning than the next. Today our flight is cut short. Engine trouble brings us back to the base, but we’re hoping that tomorrow we’ll be back up in the air trying one more time, “until we get it right.”
For more on this project: http://www.ldeo.columbia.edu
Holidays vary around the world with their dates and traditions, so it should have come as no surprise that we would find a holiday in our scheduled Greenland visit. Today, April 26, is “Store Bededag,” which translates as “Great Prayer Day,” brought by the Danish to Greenland when they ventured to this island from their homeland. Kangerlussuaq, and other populated areas of Greenland, are a mix of Danish and Greenlandic in people, language, food and tradition. The holiday does not stop our survey flights today, but a snow storm with low-visibility has brought us to the ground. In the end it is a good day to focus on data.
Prior to today we have completed several flights, each with a tightly designed purpose, and there is plenty of data to be gone through. With our newly designed system, each instrument must be tested individually for operational capability and range, and then assessed for the enhancement that comes from aligning the results with the data from the other instrumentation. Calibration runs are also required for some of the instruments. In the end, each flight ends with a stack of data disks which need to be reviewed in detail.
Each flight has a list of priorities designed around specific target locations and weather availability. Yesterday our target instruments were the visible and infrared cameras, the laser system and the deep ice radar system. For the two cameras we would fly down Sondrestrom Fjord building a set of matching images.
The Bobcat, our visible image camera, showed a wide swath of surface imagery, noting where fast moving ice had crumpled into bands of ridges, as well as where it had thinned, cracked, and showed evidence of refrozen melt water streams.
The Infrared Camera operates at a higher frame capture than the Bobcat, and collects temperature differences from the places where the ice has thinned or opened. The colder the surface, the blacker the infrared image; warmer surfaces show as white. The tongue of the fjord is an excellent testing area for this.
The Deep Ice Radar was being fine-tuned on this flight. Following the first Greenland test flight, the system was adjusted and the team was anxious to see the results. We headed up Russell Glacier to get to enough ice depth to receive the radar returns, but with the weather worsening and the winds kicking up, we didn’t go any further than needed.
The LIDAR (Laser Imaging Detection And Ranging) testing was our last test of the day. Designed to give us surface elevation, with repeat use it can show change in ice surface elevation over time. In order to show small change in ice elevation, a very tight accuracy is needed, on the order of 10 cms. The LIDAR calibration was designed as a gridded pattern of 4 by 4 lines flown at 170 knots of air speed. Calibration flights can be bumpy and twisty, as the plane will roll with the turns needed to create the pattern. The 20-knot headwinds cause some additional turbulence, but the full eight passes are completed before a return to the airfield.
For more on Icepod: http://www.ldeo.columbia.edu/icepod
Half of the people lining the walls of the Kangerlussuaq International Science Support (KISS) building are waiting to go north to the top of the ice sheet at Summit Camp, and the other half are waiting to go east to the top of the ice sheet at Raven Camp. The science and support teams have been ready and waiting for several days now, hoping for a break in the weather up on the ice sheet.
Ice sheets are large enough that they can create their own weather. Large mountains of ice several miles thick, they stretch into higher elevations and gather the clouds around them. The sunny but cold weather (-21 to -9 degrees C) is a tease to the group ready each morning and waiting for clearance, day after day.
For the Icepod team the waiting is just as difficult. A series of flight options have been drafted, but with the target of getting equipment and teams out to the camps, our flights are shifted for the moment to “piggybacks” with other flight missions. Piggybacks are actually an excellent opportunity for the project to show how the pod might work once the full system is tested and ready for science use. The project design is for the pod to be fully integrated into the guard’s NSF Operation Deep Freeze mission of supporting science in the polar-regions. In the future, as the LC130’s deliver cargo and personnel to the polar science camps, the pod can be switched on by the loadmaster to gather data as the aircraft transits.
Word comes mid-morning that the first flight of carpenters and materials will head to Raven Camp. There is not room for us but we are set for the second flight. The runway at Raven Camp is a groomed strip on the ice sheet, so the pod will make its first ice landing.
The first morning flight and ice landing go well for the pod, but one aircraft engine is causing some concern. The aircraft is looked over and the engine is cleared for us to take off late in the day with the second cargo delivery. We will fly out at high altitude before we stop at camp to install a temporary GPS for an Icepod GPS calibration. A forklift is used to load two large pallets of cargo onto the metal tracks that run the length of the aircraft and that assist the quick release of the supplies. The delivery at Raven Camp will be a “combat offload” with the cargo unstrapped and the plane moving forward on the ice so that the load slides out the back.The pod team is loaded and ready to head out.
Cargo Combat Offload
“Combat Offload at Camp Raven April 23, 2013 with the Icepod project. (credit Matt Patmore)”
With the cargo delivered, several of us exit the aircraft to install a GPS base station on the ice sheet so that the pod can complete its GPS calibration. A cloverleaf design will be flown with 20 to 30 degree turns closing the loops and straight lines between, while the GPS tracks the changes in direction and the movement in the air. In the pod design an array of GPS’s were mounted, one on the aircraft hatch and several on the pod itself, in order to determine the best location for “seeing” the satellites and yet be close to the instruments. The GPS is critical to all the data, used to tie back to a specific point on Earth. One station is set up back at Kangerlussuaq, and the second set up at Raven Camp will provide us a closure point so that we can tie together and adjust all the points in between.
The station is set to operate. The team returns to the aircraft from the ice sheet and the calibration is flown. A follow-up flight to Raven Camp over the next few days will retrieve the GPS station. Once completed, the team heads for home over the ice sheet for a 9 p.m. touchdown. Although the aircraft loses an engine in the return transit, the day is determined a success with the completed piggyback flights, ice ramp landings and the GPS instrument calibration.
For More on Icepod: http://www.ldeo.columbia.edu/icepod
Ravens dominate the Kangerlussuaq landscape. Perhaps it is their deep ebony color and solid frame, or perhaps it is the white stillness of winter with little else but humans moving about, but whatever the cause the ravens are a recognized presence. The towering black hill rising above the glacially carved fjord is aptly named Raven Hill and boasts a steady circling of the mythical black winged creatures calling out in their raspy voices. With ravens being much a part of the region, it seems only fitting that our first flight would be to Raven Camp in search of deep enough ice to test the Deep Ice Radar system or “D-Ice” as it is referred to.
The day starts out a bit hazy and the weather is forecast to deteriorate during the day. Most flights have been cancelled, but the Icepod team has been cleared for flight if we can manage a departure by noon and return to base by 2 p.m. Sensor and equipment adjustments keep the team busy until mid morning, and weather maps are continually being consulted for updates. Several times the planning team reconfigures the flight lines looking for the optimal plan to maximize the testing of the equipment with available time and weather considerations. Our NYANG partners are as anxious for the flight to go as the Icepod team, but if there are any weather concerns, caution must override enthusiasm. With the camp being at a higher elevation than Kangerlussuaq, the weather can vary considerably from the base.
Raven Camp lies at close to 2000 meters (~6800 ft.) elevation, where the glacial ice is approximately 1800 meters thick. “Noise” in the radar system drops after 1200-1500 meters of ice thickness, so although the weather is poor, we are hoping to get to this ice thickness to run a first real test of the D-Ice. Unlike our optical systems, the radar is not affected by poor visibility, so this is the right decision for the flight today. The plane is loaded with cold weather emergency gear, standard protocol when flying in the polar regions, and we take off down Sondrestrom fjord, making the noon flight departure time.
This series of flights is designed for instrument testing, so the science team is troubleshooting as they fly. Every instrument is tested in the short two-hour flight, and procedures are reviewed. The sound in the aircraft is deafening and earplugs are mandatory, which makes communicating challenging, but communicating is an essential part of the testing.
The plane reached the edge of the deep ice and the aircraft lowers to a survey elevation of 900 meters (3000 ft.) above the surface flying along the ice contour. The radar system is up and recording. In too short a time, the plane has reached Raven Camp, but the poor weather conditions limit our ability to see the camp below. The aircraft turns and we head back to base. In our post-flight debrief, reviewing data takes a top priority for tomorrow. With a limited number of flight hours available, every flight is precious, so we need to be sure that assessment and adjustment is made to the instruments as we go.
For more on this program see: http://www.ldeo.columbia.edu/icepod
Icepod joined the first large wave of science teams headed to Greenland via the NYANG LC130 transport system. Four LC130 aircraft were packed to bursting with pallets of equipment, supplies and science teams anxious to get to their designated research locations. Planes one and three were designated for cargo load, plane two would carry the bulk of the science personnel, including half the Icepod team, and plane four would carry Icepod with its skeletal engineering support team. 5:00 a.m. pick-ups for the science members set up the planes for staggered departures every 30 minutes starting at 8:00 a.m. With a flight time of seven hours from Schenectady NY to Kangerlussuaq Greenland, an early departure facilitates moving through customs and getting settled with the science support staff that awaits the group in Greenland.
All the aircraft were packed from end to end with either cargo or personnel. While we waited for the pallets of cargo to be loaded onto the planes the science teams’ discussion focused on how Greenland’s ice will be dissected and examined in the upcoming season. One group will look at ice surface processes using ground penetrating radar and shallow ice cores starting at the Dye 2 location, another will drop into the high elevation Summit camp to start an overland traverse examining the ice (although we learned that nighttime temperatures are running at -50 degrees C, a bit too low currently for set up). A third group will examine the firn layer (that section in the ice that is just starting to compress) over Jakonbshavn glacier, and the Icepod team will be doing their first set of instrument test flights in polar conditions looking at the ice from the bed up to the ice surface.
The science personnel were finally loaded into Plane two, which had been divided across the middle of the main cabin, to accommodate cargo aft and science teams foreward packed knee to knee in two sets of facing rows. With this heavy load the aircraft would need to stop to refuel in Goose Bay, in Labrador, Newfoundland, Canada. Goose Bay Air Base, affectionately known by many as “The Goose”, was once home to Strategic Air Command’s 95th Strategic Wing. The ice cream served to the visitors of the airfield has become part of the travel lore of the teams en route to Greenland, so by the time the wheels touched down, everyone’s thoughts had moved from polar ice to ice cream. Two baskets full of assorted Good Humor truck style ice cream were quickly dispensed and we were back up in the air and underway for the last half of the journey.
When the west coast of Greenland came into view the sun was just peaking through the clouds lying low along the tops of the coastal mountains. The shadowy ridgeline just visible through the mist was a welcome sight after seven hours of flight. Tomorrow will be a day of setting up base stations and reviewing some of the transit data, then the Icepod project will launch into its first set of Greenland test flights.
For more information on the IcePod project: http:www.ldeo.columbia.edu/icepod
By Ana Camila Gonzalez
“You can do math on excel?” I ask. I immediately imagine a face-palm response, but Dario, one of my advisors, is nice enough to hide it. I’ve collected tree core samples, I’ve prepared them and cross-dated them. Now what?
Oh, right. The Science.
I guess I never really understood there could be so much involved in answering a question. When I imagine the scientific method I’ve learned since the sixth grade, I somehow imagine a question that can be answered with a yes or no. If I let go of this apple, will it fall to the ground? Hypothesis: yes, it will. Experiment: yes, it does. Conclusion: yes, it will. To the credit of my high school science teachers, it’s not that they didn’t make it perfectly clear that the why and the how are just as important as the yes or the no. I just couldn’t imagine that you’d have to explain why the apple falls with four different figures: haven’t you seen an apple fall too?
Dario is helping me understand how to analyze the data from the black oak samples I have already been working with for some time now. I know these samples. Or at least I think I know these samples. I’m learning there’s more to know about them than I initially thought.
We’re analyzing the climate response, which proves to be exactly what it sounds like. We have recorded measurements of climate (precipitation records, temperature records) and a proxy for tree growth (our ring width measurements!) and by comparing those we can see how a tree population responds to a range of climactic conditions. Alright. I can do this. I’ve made graphs before.
“So we’re going to find correlations,” says Dario.
“Click on an empty cell.” I start to make a scatter plot; I think what we’re going to do is look at the slope of a line of best fit.
“So we’re going to see if the correlation is positive or negative?” I ask.
“Yes, but we also have to see if the correlations are significant.” Isn’t any correlation higher than a zero significant? They’re showing a relationship.
Dario continues, “Any correlation above a 0.2 or so is significant for the hundred years of ring width and climate that you have for this analysis.” I learn how to use the =correl function to compare the populations to temperature and I have to say I’m disappointed. I thought 0.2 sounded so low, but some of my data is showing a much lower correlation, and the data that is significant only ranges from about really close to 0.2 to 0.38 or so. I wanted to see a 0.5 correlation like I did between tree samples within a species as I was cross-dating. Comparing precipitation to ring width gives me slightly higher correlations, a few in the 0.3 range, but I’m still feeling underwhelmed.
“No, but it’s still significant! It matters!” Dario tells me to make a scatter plot comparing precipitation to ring-width measurements over time at both sites. At first it looks like a ball of yarn, but as I mask the plot out I can see why those 0.3 correlations are significant. I follow each curve, visually skateboarding up and down the peaks and valleys and noticing that I’m going up and down a lot of very similar hills as I do so. What’s most rewarding is looking for years I know are drought years (1966 and 1954 were big droughts) and seeing relatively low measures of precipitation and ring width during those years. I knew while I was cross-dating that those years were important when I saw how small the rings were, but now I can prove it. Like the apple falling, I can’t just say that because I see the rings are small those were dry years. I have to compare it to precipitation records, temperature records, and, dare I say it, the Palmer Drought Severity Index (I have to admit I don’t entirely understand the mechanics behind the index, but I understand that dryness is a composite of precipitation and temperature forcings).
Dario, over multiple days, teaches me a few more nuances of Excel and helps me understand the ARSTAN program and how we use it to make our ring-width measurements more effective as proxies for tree growth. He mentions this would all be easier if I knew how to use R. I make a mental note: learning R is the next step. If I thought that was scary, now I have to put this information on a poster. That real people will see. At a real conference.
Neil shows me a few poster examples, and the message is clear. Show your data instead of describing it in words. That also means I’ll have to explain my data by actually… talking… about it. Gulp. The North East Natural History Conference is next weekend, but I feel like I’m ready. I understand the why and how after analyzing my data. At least I understand it enough to give an answer better than yes or no.
Ana Camila Gonzalez is a first-year environmental science and creative writing student at Columbia University at the Tree Ring Laboratory of Lamont-Doherty Earth Observatory. She will be blogging on the process of tree-ring analysis, from field work to scientific presentations.
By Ana Camila Gonzalez
Ever since I’ve started learning to cross-date tree core samples, I’ve learned I have a type. I prefer my tree cores to be black oaks, middle-aged, with some nice big rings to show me. Alright, fine, I can deal with some smaller rings every now and then. As long as they’re some nice marker rings.
Unfortunately, the trees don’t seem to be trying to impress me.
I was told on a fifth grade field trip that you could tell the age of a tree by chopping it down and counting from the ring on the outside, which represents the current year, to the inside ring, which represents the year it started to grow. I’m coming to learn at the Tree Ring Laboratory of Lamont-Doherty Earth Observatory that there are a few problems with that statement.
Primarily, you don’t have to chop the tree down. I learned while doing fieldwork that coring a tree does not damage it at all. More importantly however, you can’t always find the exact age of a tree by simply counting the rings backwards. One has to verify the years you assigned to each ring against other samples, and, occasionally, against known climatic or ecological events. Sometimes a ring can be missing, possibly from either a very dry year or insect defoliation that causes a lack of growth on the side of the tree you’re looking at. Sometimes a ring is there, but it’s tiny; so small you need a microscope to see it: a micro ring. And this is where cross dating comes in.
I sit down to cross date my first batch of samples, black oaks from 2003, with rings I can see without using a microscope. I use the microscope regardless, of course, because sometimes what looks like a ring from far away can actually be a false ring: an “extra” late wood growth caused by an early freeze, early warming, or some disruption to ‘normal’ seasonal weather. The microscope helps me see whether these bands have defined edges or seem to fade, and I’ll know that only the truly defined ones are rings.
I seem to be lucky, however, as none of the Black Oaks seem to have any false rings. I’m actually eager to find some missing rings and micro rings, but I don’t find any of those either; missing rings in oak are so rare that you’ll likely be able to plant your own oak forest and watch it grow to maturity before you find one. This is so easy, I think. I feel like I have it in the bag.
I finish measuring the rings on my samples and labeling them with the years I assigned hypothetically to each ring from my cross dating. Now I’m ready to run the measurements through COFECHA, a program that gives me the correlations between individual samples and finally the correlation between all of the samples. When I first run the program with every sample, I’m told something between 0.5 and 0.6 is the expected correlation for ‘good’ black oaks (in other words, there is a 50 to 60 percent chance that given the ring-width measurements on one sample, you’d be able to predict the measurements on a second sample from the same batch). I get a 0.3 correlation. What could I have possibly done wrong?
I soon find that although Black Oaks don’t usually produce missing rings, micro rings or false rings, it is still a possibility, for reasons I didn’t understand at that time. There is also the possibility of human error resulting from mounting the samples incorrectly, missing pieces of the sample after coring and so on. (Editor’s note: one of the biggest issues dating oaks is jumping from one side of a ray to another while moving down an increment core. Sometimes the rings that are aligned across this division are not!).
What I was doing up until this point was just writing down the years where I found narrow and wider rings as marker rings and trying to find a pattern with everything I wrote down. It was helpful, but I needed to learn more about cross dating to make a few problem samples correlate with the population.
First, I was told I could take a step back and get my nose off of the microscope. By holding up a problem sample to one with a good correlation, I could try and find where patterns aligned visually, and this was usually more helpful than just trying to find the patterns in a sea of numbers I had written down. Second, I was focusing too much on individual samples and not remembering that multiple cores are often taken from the same tree: before a sample can correlate well with an entire forest it is easier to make sure it correlates against the others from the same tree. Finally, I learned that some trees—the very young, the very old, and the trees that constantly get outcompeted for resources—just don’t conform: the rebels, the grumpy old men, the proud nerds. Very suppressed rings won’t correlate well with a series, and neither will very wide rings that signal a release from competition from neighboring giants. Sometimes a 0.3 or a 0.4 correlation is the best you can get for a sample, and I had to learn how to know whether to accept that or keep trying further.
That first batch took me a week and a half to finally cross-date. You should’ve seen the look on my face when I saw my first correlation in the 0.5 range.
And that was just the black oak.
I decided to continue coming to the Tree Ring Lab over winter break, and at first it was incredibly peaceful. A few days of sanding and stabilizing some pines really put me in the Christmas spirit. And then I met Baldcypress, which made me more of a Grinch.
At first, baldcypress and I were really only going to be a one-time thing. I was only told to measure three or four batches from the 80s as a side project, but after I logged all the measurements the COFECHA results were cringe-worthy. I was told I had to try my hand at cross dating the cypress.
If I thought the black oak population had trouble samples, I reconsidered. While Quercus velutina hardly ever displays missing rings, false rings or micro rings, Taxodium distichum seems to want to flaunt them. My first batch had mostly been false rings, but I also learned what a micro ring actually looked like.
I remember staring at a set of what should have been ten rings for 20 minutes, but only seeing nine. I finally asked my advisor and then watched as Neil marked a band relatively darker than its surroundings a cell wide as a ring. If any ring could be called a marker ring, it was this one. Sometimes finding a micro ring where I knew, from the chronology, that a narrower ring should be, was actually a relief. 1966, a heavy drought year for most of the Northeastern US, quickly (and morbidly) became my favorite year.
I dealt with so many false rings that I felt like I was five and my fingers were all turning green (I’m glad no one ever showed me this; I always felt like a princess). Every time I thought a sample couldn’t have any more missing rings I found more. I started thinking everything was a micro ring.
The black oak took a week and a half. I’ve gotten through three batches of baldcypress, and I’m on my fourth: I started over winter break and it is currently spring break. Of course, I’ve been working on other things as well, including a poster presentation on my black oak samples for the Northeast Natural History Conference, but it feels as if the baldcypress just doesn’t want to leave me alone.
Yes, I do have a type. I like real rings, I like big rings and I like rings that conform. In the end, however, I’ve learned more from the “problem children” than the ones that worked out like I wanted them to. I might even admit that the baldcypress has been much more rewarding to work through.
Shhh, don’t tell the black oak.
Ana Camila Gonzalez is a first-year environmental science and creative writing student at Columbia University at the Tree Ring Laboratory of Lamont-Doherty Earth Observatory. She will be blogging on the process of tree-ring analysis, from field work to scientific presentations.
By Daniel D. Douglas
“Are you using this idea for your thesis research?”
I heard this as I stood in front of a classroom full of old-growth forest ecology students. The question had come from Neil Pederson, who was sitting directly in front of me. He was asking this question because I had just spent the past 12 minutes discussing the intricacies of land snail biology and ecology that would make them great organisms to use for ecological modeling in regards to disturbance. Things such as their lack of mobility, susceptibility to desiccation and sudden change that would occur because of major disturbance make their preferences for habitat similar to the defining characteristics of old-growth. Neil looked at me with the excitement of a small child on Christmas morning because he knew that I could potentially be on to something.
So, you can imagine his dismay when I answered his question with “No, I hadn’t really given it any thought.” I know I winced (at least on the inside, if not physically) after I answered because I had suddenly realized that I could be passing up a golden opportunity. I remember walking back to my apartment that night, thinking about what had just happened. I thought about it another hour or so after I arrived home and then emailed Neil to discuss the potential that my presentation had for being used as a master’s research project. Long story short, we developed a research plan of attack with the help of David Brown, my co-advisor, to study how anthropogenic disturbance* can shape land snail communities.
Not many people study land snail ecology. I had the fortune of working under someone that did, Ron Caldwell, while I was an undergraduate at Lincoln Memorial University. I had become deeply interested in these ignored and overlooked organisms. So, as I entered graduate school in biological sciences at Eastern Kentucky University, I had a fairly strong background in “snailology”, aka malacology. I had been unsuccessful in finding a graduate program where I could continue to work with land snails and was wandering the halls of EKU uncertain about what I was going to do for a graduate research project.
What happened in Neil’s class that semester was really fate telling me this is what I should be doing. A year and a half later, I found myself sitting on my back porch sifting through leaf litter samples, picking out micro-snails, excitedly thinking “I’ve got something here.” It was clear that these organisms could be indicators of past human disturbance.
This research took me to some of the most memorable places that I’ve ever been. Since the availability of old-growth in Kentucky is sparse, my sampling sites were limited. The first place I sampled, Floracliff Nature Sanctuary, was just a few miles north in the Bluegrass Region of Kentucky and, oddly enough, a few miles outside of Lexington. It’s crazy to think that a place with trees hundreds of years old exists right outside a fairly large municipal area, but it does.
Floracliff rests on the Kentucky River Palisades in a very rugged, deeply dissected network of gorges cut by streams over eons of geologic time. It also has some of the most spectacular examples of old-growth trees you’ll find in Kentucky, including the oldest known tree in Kentucky to date: a 400+ year old Chinqaupin Oak.
Though this wasn’t true old-growth, it gave me some of the best results I got for the entire study: there was a clear separation of the land snail communities between old and young forest sites. In fact, abundance, richness, and species diversity, were all greater in the older sites. This is also the site where I found the most new county records (i.e. never documented from that county). These results only whet my appetite for more data from different forests.
The next stop was EKU Natural Areas‘ Lilley Cornett Woods Appalachian Ecological Research Station, a small patch of prime mesophytic old-growth forest in Letcher County. It’s bizarre to think that forests like this exists in the Cumberland Plateau portion of Kentucky, due to the fact that our countries insatiable thirst for natural resources has left the region in one kind of an ecological ruin. I was deeply impressed by this forest as wandered around. The snails at LCW did not disappoint either. I saw the same patterns as in Floracliff: old-growth forest had greater abundance, richness, and diversity. The highest species richness for the entire study came from LCW as well, which is something that I did not expect. The evidence was beginning to stack up.
My final study site was Blanton Forest State Nature Preserve. This preserve is over 1200 hectares and contains the largest tract of old-growth forest in Kentucky. Dominated mostly by oak and hemlock, the forest is very rugged and it had more rhododendron than I care to remember. Nevertheless, it is impressive. Comparing Blanton to a nearby young forest didn’t necessarily give me the same exact results, statistically speaking, but I still saw the same trend of higher abundance, richness, and diversity of microsnails in old-growth forest.
You may be asking, “What does this all mean” or, “Well, he found that there is better habitat for these organisms in undisturbed forests. That’s doesn’t really seem novel.” In reality, this is novel. Better, it is important.
First, I documented that a minimum of several decades, if not more than a century, is needed for land snail populations to recover to a point that resembles what their assemblages looked like before human disturbance. As an important part of forested ecosystems in terms of nutrient cycling, organic material decomposition, calcium sequestration, and food sources for many other animals, it is vital that we know things like this so that we can better manage our forests for everything that lives there, starting from the ground up. Second, all of you must know that everything in an ecosystem is interconnected and, once one thing is removed, it can have cascading effects throughout the ecosystem. Better management practices will help us maintain ecological integrity of forests. Third, my findings also indicate the need for locating and protecting remnants of old-growth forests. As I have shown, old forests, whether true old-growth or lightly logged by humans a century or more ago, are biodiversity hotspots and therefore deserve protection beyond their representation of how complex forests are at great ages. And finally, my findings also indicate that land snails have great potential for being used as indicators of old-growth. This is something that many scientists, especially citizen scientists, have been chasing after for decades.
For myself personally? This means that I have a lot more work to do. Despite the fact that there are people out there that study land snails, they remain poorly understood. I feel as if it is my job to bridge that gap in the knowledge. I also hope that what I have accomplished with this research will open the door for future studies on not just land snails, but other non-charismatic fauna. I also hope that my work enables people to look at more than just the trees in old-growth forests. The trees are wonderful, and we are lucky to still have them, but there is a lot going on underneath those trees that we don’t know much about.
* = the linked article is open access and free for downloading – download away!
Daniel Douglas earned his master’s degree in biological science from Eastern Kentucky University in 2011 studying terrestrial snails, important, but less charismatic creatures.
Prior to the late 1700s, the Brahmaputra River flowed farther east by up to 100 km. It then switched, or avulsed, into a straight north-south route, possibly triggered by an earthquake in 1787. The small river whose course it usurped was called the Jamuna River. Now, below the avulsion point where what is now the Old Brahmaputra deviates from the present course, the Brahmaputra is called the Jamuna. The last two days were upstream of that location. Now we are downstream of it and thus on the Jamuna River. Our first stop was Sirajganj. This town is protected by a stone embankment. The river has been migrating to the west, threatening the town. As a result, the embankment now protrudes into the river. When I was here in 2011 I saw several collapses along the embankment and my class
saw them repairing it in 2012. They now have a lot more riprap at the base to protect it.
We drove along the embankment, a nice promenade, to the ghat and got a fast boat. Chris had picked out an area with a lot of diversity, so we could efficiently do our sampling. We checked our notes and found the char that had joined to the very large stable island was not the one we visited in 2005. That char was now a thin sliver. We stopped at the head of Katanga Char, only 2 years old, where the high ground was stabilized by grasses and people were growing peanuts and rice on the flanks. We then crossed a channel to the tail of the next char to the north. Here, what had been a grass-covered highland had been
ravaged by the river. Tufts of grass that had help on were surrounded by large scours over a meter deep. The little remnants had the same teardrop shape as the larger chars. Here and on another small char, we were able to collect all the samples we needed. We headed for the ghat and our hotel with an outside chance of taking their boat to the char I visited with my students last year. However, before arriving, we finally found green coconuts for sale. We had been searching for days for green coconuts. The seller cuts off the top with a machete, inserts a straw and you drink the refreshing coconut water. Afterwards, he splits it and you can eat the coconut jelly, not yet matured into the coconut meat. To add to our enjoyment,
Chris also found a shop selling the wasabi potato chips he had been searching for. With the extra stop and the slow check-in process, we abandoned visiting the char, but it was still early, so we went into Tangail for some shopping, although we found most shops closed as it was Friday.
For our last stop in the field, we continued south to the confluence, where the Jamuna meets the Ganges to form the Padma River. There are ghats for crossing the Padma and for crossing the Jamuna. We went to the later, which is smaller now that there is a bridge over the Jamuna. As the chars shift, so does the ghat. We had to walk for the last ½ km to the rental boats as Babu’s van could not go. We started at the southern end of Shivayala Char, a large char at least 30-40 years
old. However, the southern end had been eroded and then grew back. Where we were was only few years old. From there we went to the next, newer char for examining and sampling as it showed a lot of variety on the satellite imagery. That done, our next stop was a piece of fluviotourism, the confluence or actual meeting point of the Brahmaputra and Ganges Rivers. We stopped upstream and walked down the long narrow char. There were huge scour pits from the turbulence of the two rivers meeting during the monsoon. The point where the tow rivers met wasn’t as clearly defined as in 2005, but we waded around and found it our final group photo. Our work was done and it was time to return to Dhaka for some final meetings and a last hartal, and then home. As usual here, many things did
not go as planned, but with some adjustments, everything we planned got done.
- The four of us standing a the confluence of the Brahmaputra (left) and Ganges (right) rivers.
We left the pleasant house in Kushtia to resume our nomadic existence. We spent a full day driving to northern Bangladesh. We will now work our way downstream stopping at multiple places along the Brahmaputra River. Finding little traffic, we drove past Rangpur, where we will be staying to the Tista River, a tributary of the Brahmaputra. While it is a large river during the summer monsoon, today it was a shallow stream with exposed sandbanks and people growing crops in the middle of the channel. Chris decided the hour we had before sunset was enough time, so we climbed down the embankment and hired a boat to cross the river. It was shallow enough that we saw children wading across and Chris got out and walked the rest of the way, followed by the chidren. Water diversion projects upstream means
there is little water here in the winter. Some exploration, some sampling, some photos and we were done.
We were up early for the long drive to the Brahmaputra. We hadn’t planned on coming this far north, so we didn’t have maps of this years arrangement of the river. I found two possible places for boat hires and ended up choosing Chilmari as the place easiest to get a boat. When we got the to river agound 11am, we found a cliff. Apparently ~1 mile of the coast had eroded here. An old woman chastised us that we should either prevent the bank erosion or give them money so they could move. We learned the boats were a few hundred meters upstream where you could walk down to the water’s edge. Along the way we
passed a group digging up the topsoil along the cliff to sell before it toppled into the river. We could see the cracks where the next pieces of land would be lost.
We bought some snacks for lunch and hired a boat. The fist char (sandy island) was unnamed, but 5 families from Bazradiarkhata Char had settled the north end and started farming, growing squash, wheat and dal. The char was only 5-6 years old. The families still returned to the larger char in the summer and New Bazradiarkhata Char, as we called it, was chest deep in water during the summer. We continued north to Kachkol Char. This char was 8-10 years old. However, it was now attached to Bazradiarkhata Char. The corn, wheat, dal, etc. growing was being farmed by
people from Bazradiarkhata Char. The village we visited were people who only moved there 6 months ago when their village and land on a char was claimed by the river. They were working a paid laborers and did not have their own land to farm. They were concerned that Meredith be careful of the sun so she wouldn’t get burned. They also suggested that if she moved to the char, she could get dark like them. We then went downstream to Bazradiarkhata Char itself. This char was formed during the major 1988 flood when 2/3 of Bangladesh was submerged. Now, 25 years later it had lots of trees homes, crops, an elementary school and an adult education center. We were surrounded by children, particularly Meredith. She could get the girls to pose for her,
but I could not. On the side of the village, there were great sedimentary features and Meredith and I measured a channel for some flow calculations. At all of there sites Chris sampled and documented the sediments and vegetation cover. By now it was getting late, so we left and circled the downstream end of New Bazradiarkhata Char. Newer and still unpopulated, the cut banks showed amazing patterns of crossbedding from the migration of the sand waves that built the char during high water. We explored this end of the char as the sun set over the right bank of the Brahmaputra.
Today, February 21st, is Language Day commemorating the 1952 martyrdom of students protesting Pakistan’s law making “Urdu and only
Urdu the language of Pakistan” when the Pakistan army opened fire. The ultimately successful language movement in the 1950s marked the beginning of the path toward independence. On our drive to Gaibanda, we saw numerous troups of school children heading to their local Shahid Minar, language day memorial, to pay their respects and drop off flowers. In Dhaka people laid numerous fantastic decorations made of flowers.
Gaibanda was the opposite of Chilamari. Here the coastline has grown outward and we had to walk out to the docks. We later discovered that the new land filled in what was the channel we crossed to reach Rosulpur Char in 2005. It is now attached to the mainland. The embayment by the coast is all that is left of the channel. Humayun again hired
a boat and we went south to an area where Chris could see numerous color variations on the satellite image. We found the land has changed substantially from the image of early January. The channel we wanted was too shallow for the boat, so we had a very long walk. A new Landsat image to be acquired tomorrow should be close to what we saw. Where we stopped was Manikkor Char, only 6 years old. The tree covered area to the north was Kashkhali Char, which is 13 years old. We walked towards it and met a farmer. He told us that there was a town and bazaar here 30-40 years ago, but it was lost to the river. When it returned he received land because his grandfather had owned land here. Such is life on the ephemeral chars. We continued walking towards Kashkhali, but wanted to cross to another area. Only Chris
and I walked through the muddy shallow waters of the embayment. In this area, which we called New Kashkhali Char, we met another farmer, but had no translator. Still, he helped us sample.
After finishing sampling, we went north to Rosulpur char that we visited in 2005. We showed the people photos on my iPad, but found that most of our photos were of people who resided there only temporarily due to their land being lost. They now lived across the channel to the east. Still we were welcomed and follow by lots of children and a few people remembered us from 2005. The teacher remembered Chris, but wasn’t sure about me. Overall, the village seems to be doing well with lots of corn growing on the char. We ended early, but then had a long drive to Bogra for our hotel.
We got to Khulna about 5 pm and met up with Chris Small, who was brought from the boat with all the Vanderbilt University people by Bachchu. This is the last segment of my trip. The next day, we went to an area near the compaction site. Chris had analyzed 10 years of MODIS satellite images and just west of the compaction site was an area that stood out for having increasing vegetation over that time. We drove to the site and then continued on the small dirt road that followed the small creek. We went around a bend and followed the road as far as we could with Chris snapping photos the whole way. We talked to locals at two places and the second one had the answer. Most of the rice fields were still fallow, but one area had a pump watering some fields. We walked over and immediately
became a center of conversation. This area had previously been converted to shrimp farming. About 15 years ago the BWDB built and embankment, which was the road we were on. This stopped the tidal flooding of the land inside the embankment. The shrimp company pulled out and as the land was cleared of its salt by successive monsoons, everyone switched to rice farming. That started about 8 years ago and the land has become more productive with time. This is what caused the long-term trend.
On our way out, we stopped at the compaction site. The Scotts had done everything but download the GPS data. Only the mother and youngest son were home. We were welcomed warmly and served cookies and pakan-pitha, a
pastry filled with a dal paste. Then I downloaded the data and visited the wells. We were invited for lunch and told that Mr. Islam would be upset if he knew we left without lunch, but we were already behind schedule. We had to go on to Kushtia near the Ganges. During the long drive, we found out that there was a hartal called for Monday. We had to rework our plans since we had a lot of driving to do that day. It was dark when we got to Kushtia, Humayun’s hometown. We were surprised to find we were staying in his aunt’s house. Only the caretaker was there and we split the 3 bedrooms. Staying in a home reinforced the plan we had come up with. We would need to stay here three nights. An added plus is we’re close enough to hear the protesters singing every night.
For our new plan, we went to the Ganges downstream of Rajshahi and back so we can go locally at Kushtia during the hartal. During the long drive it started raining. We also had trouble finding a ghat (dock) to rent a boat. We ended up driving to the river and then walking out on a semi-attached char (sandy island). The mud was incredibly slippery in the rain, but I only fell once. Chris sampled along the riverbank and then the two of us waded over to the char to sample some more. Chris will measure the spectra of these samples back home to calibrate his satellite analysis. He will be able to distinguish the percentage of different sediment types for each pixel of the satellite image, which we will then use to better understand the changes in the rivers. The chars move around, appear and disappear
every year during the monsoon. Meanwhile, we were getting soaked and called it quits. Good thing we didn’t go out on a boat for hours.
Today, is another hartal (general strike), however, we were able to walk to the Gorai River here in Kushtia. We went to a park where a lot of boats come to take people on rides, but none were here this early. Still, we managed to flag one down and hire it for the day. We went up the Gorai into the Ganges and headed upstream to Ranakor Char. We spent the day visiting three chars (sandy islands), stopping at multiple sites on each. The cold overcast day brightened as it went on. We did sampling and a lot of walking around examining the bedforms and varied sediment deposits. We could see 5 different scales of bedforms from the
chars themselves to the tiny ripples in the lows of larger waves. This area by Kushtia now has numerous chars and they are much more accessible than the ones we tried and failed to visit yesterday. When we returned in the late afternoon the empty park was filled with people.
After the resistivity, I was supposed to go to Khulna to join Scott and Scott on repairing the compaction meters. We have two places with sets of wells where we installed optical fibers. A local person uses a device to measure the length of the fibers each week by shining a laser through the fiber. Unfortunately several on the fibers have broken since we installed them. The Scotts will be repairing them, as well as the usual yearly measurements and data collecting. They went to the northern site first – we saw them heading north while the conclave group was heading south. I was going to join them for the southern site, but their work went so much faster than expected that they finished while I was doing resistivity. Thus there was no need for me to go to Khulna before meeting Chris Small for the river work. I spent the two extra days in Dhaka. I had plenty of people to look up that I didn’t expect to have time to meet.
On the first day, Humayun and I went to the US Embassy to meet with people who couldn’t make it to the conclave due to the hartal. Even the US Ambassador was going to meet us when he took guests to a resort in Sylhet. As Humayun and I passed through several layers of security, we ran into the Ambassador on his way out. We chatted for a few minutes and then went on to our meeting. After making it back to the university for lunch, we went to the Geological Survey of Bangladesh, where my main contact has been promoted to Director General. I showed him our results and we discussed collaborations, particularly on GPS. All around the university women were dressed on yellow, orange and red
saris for the first day of Bangla spring. Finally back to the Ambala Inn where I met up with the Scotts and Doug and all of us went to dinner with Chowdhury, my collaborator from the Bangladesh Water Development Board (BWDB). He has gotten us a huge dataset on the water levels in the rivers and in groundwater wells. Well over a million individual measurement. Water is so central to life in Bangladesh that there is an excellent monitoring system in place that we use to determine the amount of water impounded in Bangladesh during the monsoon. It is over 100 billion tons of water.
The next day, we went to BITWA to try to obtain more detailed information about the tide gauges for examining sea level changes. Tide gauges measure the height of the water relative to the land, but here the land is sinking. We put 2 GPS
to monitor the land subsidence next to tide gauges. That will let us separate the sea level rise from the subsidence. The combined effect has Bangladesh worried about land loss and water salinification. We went meet with the wrong person twice before we finally found the correct person, a woman whose sister had been a student of Humayun’s. It will now be straightforward to get the detailed data. The afternoon was spent working with one of the students from the resistivity training. Sojon wanted to go through everything in detail so he knows how to run the system. Fayaz would have joined us, but he was out filming archeological sites with Doug. The two of them have taken the initiative to be leaders among the group. The 10-minute ride back to the Ambala Inn took an hour. An area just north of the
university has been blocked off because of the peaceful protests against the razakers, the groups that collaborated with the Pakistani army during the revolution and helped them in their killings. The Islamist party’s hartals for the release of their leader has lead to a larger movement wanting the death sentence for him and others. It is Occupy Dhaka. It was very strange to see women dressing in colorful clothing yesterday with headbands calling for death for the razakers. Finally, I arrived and waited for Meredith, the last of our party to arrive from NY for the river work. The bad traffic meant she arrived very late. Doug and I had a last dinner together at 11 pm in a local packed restaurant.
Today I am finally on my way to Khulna with Meredith and Humayun, with Babu as our driver, of
course. I am stuck waiting to get on the ferry across the Padma River, formed by the merger of the Ganges and Brahmaputra. Once across, we will be in the more leisurely and relaxing south to meet up with Chris in Khulna.
After returning from Sylhet, I left Dhaka the next morning for Comilla for 4 days to train a group of Dhaka University students and graduates on operating our resistivity imaging system. Many of the conclave people headed out to the Padma River, formed by the joining of the Ganges and Brahmaputra to do sampling for a remote sensing study of the rivers. I will be doing this later in the trip, but had other plans now. The transects of wells that we are drilling provide detailed vertical records of the sediments, but how do we connect the dots when the wells are 3-4 km apart? It turns out we can do it with electricity. Clay and mud has much lower electrical resistivity (or higher conductivity) than sands. The basic technique it to pound two pairs of electrodes (stainless steel rods) into the ground. We then use a car battery to
send a current between one pair and measure the voltage at another pair. The voltage depends on the rock type between the 4 electrodes. For our system, we have 84 electrodes that can be spaced up to 9 m apart and a long cable in 12 sections to connect them. A sophisticated resistivity device then sends current to one pair and measures the voltage at up to 8 other pairs at a time. The device is programed to do measurements with thousands of different combinations. The result is similar to doing and electrical catscan of the earth showing the distribution of sand and mud.
I came to Comilla with 6 trainees, Fayaz, Sojon, Jia, Rabi, Fuad and Paval. During the 4 days, they will work with me to learn to use the system
well enough to be able to carry out these surveys on their own. For the training site, we came to Comilla where to work around the Lamai anticline. It is the westernmost hill sticking up out of the floodplain. To help interpret the structure creating the anticlines, we need to know the dip, or slope, of the folded beds. This has been roughly done from topography, but the exposed topography is partly eroded. We want to image the boundary between the older Pleistocene sediments of the anticline and the younger Holocene sediments that cover them. Both sediments are similar, but the surface exposed during the last glacial period when sea level was 120 m lower has been altered to clay. This should show up as a dipping layer of low resistivity. We will do 4 lines, two on each side of the anticline to image the dipping beds.
Our first day was short because of the time it took to get here. We laid out a short line with 56 electrodes a short distance south of one of the wells that was drilled on the east side of the anticline. The car batteries we took along were not fully charged, so we hooked up Babu’s van to provide more power. That worked well and decided to use the car to run the equipmet the rest of the days. However, that meant the lines had to be where a car could go. Humayun did not join us because his wife has been ill. That meant we didn’t have a GPS to record positions or track where we were. We managed to use the GPS in my camera to get the positions of the line. We moved to our home for the next few days, the Bangladesh Academy for Rural Development or BARD.
The next day we shifted to the west side the next day. Google Earth became our tool for finding sites. With a USB modem we had slow, but continuous internet. We found a set of fields close to the one of our drill sites. We navigated to it by recognizing buildings, mostly gas stations from Google Earth. The fields were fallow, so we could cut across them. Everything was going smoothly. We finished early and I was able to spend the late afternoon teaching the students. That evening we processed the data for both lines. The first one showed the boundary we were looking for to be very shallow. A river had eroded part of the anticline. Thus we were on top of it and not on the flank. Good data, but it didn’t provide us with a slope. The other line had noise problems from a power line, but clearly showed the layer we wanted dipping ~3° to the west. The system was providing hard data.
We still needed a line on the east. We tried our first site, but Babu’s van could not drive to the line location. On to plan B, a country road on the west side. We drove our electrodes into the fields at the base of the road being careful not to disturb the growing vegetables. The data was marred by some power lines, but showed our layer for part of the line. It lined up well with the previous day’s results. For our final day, we need a good line on the east. I picked several candidates on Google Earth. The first was inaccessible, but I quickly found another road and we did it there. Because they were planting rice, the side of the elevated road was not useable. The top turned to not be that good a place. The data was much worse quality than any of the other sites. Still, it gave reasonable results. Humayun and Doug came out, so we interspersed working on the resistivity line with filming. That line competed our work here and the training and we all headed back to Dhaka. The students were trained and we learned how to select good sites.
Now that the hartal was over, we were free to travel as we wished. We also switched film crews. Doug and Diane from Earth Images are independent filmmakers that make PBS specials. They arrived in Dhaka on the morning of Feb 6 during the hartal, so could not travel here. Humayun arranged for them to be picked up by an ambulance, exempt from the hartal, and taken to the Ambala Inn to wait out the strike. That meant they were able to spend the day walking around getting footage of Dhaka without cars, a rarity. Colorful bicycle rickshaws ruled the road. They left Dhaka in the afternoon when the hartal was dying down and arrived at the Shuktara around 11 pm.
The geology that we saw over the hartal changed our drilling plans. Steve Goodbred was excited enough by what he saw to change the day’s well from the flat floodplain to the back of the anticline. He and the Vanderbilt team went there early in the morning with the AMNH film team to get their last shots before heading to Dhaka. That meant the rest of us had to stay away. Most of the group went to the Sylhet anticline outcrops near the cricket stadium and airport. I later learned that they found clear evidence of rivers cutting through the anticline while it was growing. It caused mud deposits from the ponding on one side and gravels from the steeper slope on the other. I was recruited by Doug for an interview and to take him up to the Jaflong area by the Shillong Plateau so he could film that. Nafisa and Mosher stayed with us. After they watched my interview from behind a
wall, our group headed north. At the site where Nano gave us an overview, I repeated his story with a 3D camera rolling. Nafisa, Mosher and I held conversations about the geology while Doug filmed us over and over. We then went over to the Rangapani River where border guards stopped us and informed us that foreigners were not allowed to film there. After some explanation from Nafisa, they call their superiors and we were OKed. The pits we had seen a few days before were now deeper and the miners had uncovered a large tree trunk and exposed boulders up to 6 ft across. We continued our conversations for the camera until the border guards told us it was time for us to go. Doug still tried to get more footage, including outcrops out of site of the guards until they followed and saw us still going. We left peaceably.
All the filming and multiple takes meant there was no time for Jaflong itself. We rushed back to the Sylhet Anticline in time to catch the drilling before it got dark. Since we only had a short ride back to the hotel instead of a 1-2 hr drive, a car full headed to Sylht City for shopping. As it was the last night of the conclave, we had a barbeque on the deck on the roof of one of the bungalows. They barbequed fish and tandoori chicken along with a host of other dishes and a procured bottle of vodka. An excellent end to the meeting.
The next day it was time to head back to Dhaka, stopping at a few of the anticlines from southern Sylhet on the way. As usual, getting everyone out and the cars loaded up took longer than expected. Nano and Ellie decided to stay another day in Sylhet and then go straight to the airport rather than have a day in Dhaka. Our group was shrinking. Jenn and Sanzida had already left early
because of ill relatives. A few people had canceled because of illness. We were down to about a dozen people heading to Dhaka. However, the defections and splitting of the groups the last few days made the field stops less unwieldy and more efficient. On the way south, we had a quick stop at Sreemongal, where a group from Singapore we are collaborating with put in a GPS. Then we saw tea gardens, a sure sign of an anticline. Tea needs well-drained soils and cannot be grown on the floodplains. However, the first tea plants were on flat land. The rising anticline had uplifted some of the floodplain on its flank, another useful observation. Then we entered the Rashidpur anticline proper. Several stops revealed that the dips of the beds were not preserved, limiting the value of the outcrops. We stopped for lunch in a tea garden and continued on to our GPS station and seismometer at a school in Chunarughat. In
2007 when we installed the site, we found the building we originally selected was unsuitable. It was brick made to look like reinforced concrete. We found this site by driving down the main street of the town on a Friday night. We found this school and contacted the headmistress, visiting her at her home on the weekend evening. The next morning we installed the site. Now on this visit, Humayun and I were again pressed into service for filming, along with a Nafisa, Mosher and Fayaz. By the time it was finished, we had to head straight back to Dhaka. Some quick stops at the next anticline revealed it too had poor outcrop. We then hit some of the worst traffic I had ever seen. The highway into Dhaka, never very fast, was at a standstill. Babu, our driver, turned around and led
us through back streets to alternative routes until we found one that was moving. It was almost 10 pm by the time we reached our hotel and officially ended the conclave and part one of my trip. Still it was extremely successful, pulling together the different groups and changing the direction of our research.
Our experience in in Bangladesh in nothing will go as planned, but somehow we are able to get everything done. Living in this ever changing land beset by numerous natural disasters has made Bangladeshis incredibly resilient and adaptable. This was tested over the last few days – and may continue to be over the next weeks – by a hartal. A hartal is a strike in which transportation is shut down. The party calling it sets up roadblocks and attacks cars and buses on the streets. Bicycle rickshaws and the green baby taxis are OK. This one was called by Jamaat-e-Islami, the largest Islamic party. The reason was that their leader was sentenced to life imprisonment for war crimes during the 1971 Independence War. The religious
parties supported remaining part of Pakistan and are accused of helping the Pakistani Army in killings. Estimates are that 3 million people were killed in the war for independence with Hindus and intellectuals particularly targeted. The leader on trial was specifically accused of killing 12 and assisting in the killing of 369 others. The problem is that the Jamaat-e-Islami is part of the opposition coalition and many believe the trials are politically motivated to take down part of the opposition before the elections later this year.
On Feb 5, there was a hartal called that ran from 6am-6pm. Driving around in our vans was our of the question. Luckily, it was the day to visit outcrops on the Sylhet anticline, where our hotel is. The sites at the airport and cricket stadium
were out of the question. We found out later that there were bombs thrown in Sylhet, although, thankfully, no one was hurt by them. The third area of outcrops we planned to visit were right by our hotel. We walked to the sites situated by the tea gardens and tea factory to see them. They were not the greatest outcrops, but still provided valuable new data and discussions. We returned to the hotel for a late biryani lunch, a step up from the cold packet lunches we’re been having. For the rest of the afternoon, we held discussions around our large poster-sized maps, or relaxed. The Bangladeshi students took advantage of the early night to go into town after the hartal ended. This was also the day that the AMNH team was doing interviews, so we were able to have people walk back and forth to their makeshift studio in one of their rooms.
More serious was when a second day of hartal was called for Feb. 6. The visit of the U.S. Ambassador to Bangladesh to our group was cancelled. But what were we to do now? We were to visit outcrops to the north and one of our drilling sites. After exploring several options, Humayun rented a very small pickup truck. This type of vehicle should be exempt from the hartal. To play it safe, we started our work by continuing along the same small road over the anticline that we walked on the day before. There are no roadblocks on a small country road. We continued the geologic work over the anticline. These young weathered sediments were hard to interpret confidently. However, we did see the dips of the strata switch from towards the south to towards the north
as we went over the crest of the anticline. We crossed where the floodplain sediments lap up against the folded strata. Our excitement about the interactions we are having in the field continues to grow. After completing this part of the drive, we came to a decision point. Would we continue to the main road and risk facing a possible roadblock? Did we want to travel that far on the back of a pickup? In the end, our group split up. The film crew rented a baby taxi and went off to get footage of the countryside. A second group walked back to the road over the anticline to visit more outcrop and pick potential drilling sites. Steve Goodbred was excited enough by what we saw to change tomorrow’s drilling site from the floodplain to the anticline. The interaction
at the conclave was now altering our project plans. It is working. The last group, including myself, continued as planned with the pickup. Not only was there no roadblock, but it was a pleasure to drive through Bangladesh with so few cars on the road and so little traffic. We got to the well site as they reached the maximum depth they could drill. Gas in the sediments impeded the drillers ability to lift the sediments out of the hole. We could see the gas bubbling up. We continued on to Jaintiapur and took a pleasant hike through a new set of outcrops and beautiful views. I personally found the evidence of a long gap in sedimentation 20-30 million years ago puzzling. As darkness fell, we had to leave the solution for another day. But at least the 2-day hartal was over.
Up to now, each group in our Bangladesh project has worked individually on fieldwork in their subject of expertise. Now that our project is now in it’s third year, we decided it was time to get together in the field to integrate our results. A major focus of the project is the interaction of tectonic forces and sedimentary processes. This week, is our opportunity to have experts on each interpreting the same outcops together. We have gathered a group of 9 Americans and 7 Bangladeshis in Sylhet in NE Bangladesh to what we have termed the “conclave”. I guess we have to send up a puff of white smoke if we all agree. Sylhet is an area where the large basement block of the Shillong Plateau and the Dauki Fault that bounds it meets the fold belt of the Burma Arc with its tea garden covered anticlines. It is also has a rapidly subsiding basin being filled with sediments in which the level of the rivers go up and down with sea level. Lots to see through different prisms. On top of the excitement of the conclave, we have a film crew from the American Museum of Natural History with us for the first 6 days to make a video to be shown in the AMNH and other museums about our project and the science we have been working on. After they finish, will we have another film crew from a company that makes PBS documentaries following us.
Everyone is doing their individual fieldwork before or after the conclave. Several of us arrived in Bangladesh just before the conclave, while others drove over from their fieldwork in western Bangladesh and two crossed the border from studying the Shillong Plateau in India. We all arrived and filled all of the rooms in the Shuktara Nature Retreat. For our first day, we headed to the Patheria Anticline with the Madhabkundu Waterfall. While the waterfall was spectacular, if took most of the day to get there. Pulling out maps after breakfast, we spent time discussing the region, slowed by the filming. Then the drivers took a wrong turn that took us and hour out of our water plus another ½ hour to double back via a faster road. It was 2:30 by the time we got there and almost 3:00 when we finally reached the falls. While there were great outcrops, we only had a hour there before having to start back. It was too late to visit our second stop and quite late before our cranky group got back to the resort for dinner. Overall, a disastrous first day.
Having gotten our bad day out of the way early, we had nowhere to go but up. And it did. We headed north toward the border with India and the Shillong Plateau. At the first stop we got an overview and our first view of the 2000 m high mountain and the geology while standing on one of the folds that mark the frontal area of the Dauki thrust fault. Then we went on to the Rangapani River where the large boulders are washed down from the plateau. There is a huge industry in Bangladesh mining rocks and gravel from the rivers along the border. Bangladesh has a shortage of rock that can be used in construction, particularly making concrete. The Indian border is clearly marked by the presence of rocks. On the Bangladeshi side they have all been stripped away and they are digging
pits to mine the rocks from the older river sediments. This results in beautiful exposure of the sediment layers and we scrabbled around in a pit while the workers mined the rocks around us. After a brief stop at the border crossing where trucks bearing rocks enter Bangladesh, we went to Jaflong, where the mining industry is even larger. The amazing thing about Jaflong is that besides being an industrial site with rock mining and noisy rock crushers, it is also a tourist site where people come to see the mountain. There are tourist kiosks, snack stands and guides mixed in with the industry. For us, there were also outcrops of the older strata from before the uplift of the Plateau. Our final stop was a visit to our GPS and seismometer station at Jalfong. Humayun and I were filmed explaining our work there while the others visited the geology exposed on the side of the hill we were on.
Day 3 was an exciting trip up the Shari River. We rented three wooden country boats and sailed up the river, crossing through exposures of sediments of various ages. The originally horizontal layers of strata have been deformed from the tectonics. The dip of the sediments started at 38° then increased to nearly vertical before decreasing back to ~45°. This folding is due to the sediments riding over structures beneath, possibly a fault. We also saw that the oldest sediments were marine and the seceding layers went to estuarine and then fluvial (rivers) due to the increasing amount of sediments coming from the Himalaya. Our boats traveled together and occasionally leap frogged from outcrop to outcrop. Chris Paola, our river specialist, also noted changes in the shape of the river indicating active tectonics. Our group of specialists is coalescing into a team. Meanwhile, we passed other teams of people dredging the sand and gravel from the river bottom using buckets into their boats.