For our last morning, we did a dawn silent boat ride up a tidal channel. Since the students did one the day before, a few sat out. The ones that remained stayed silent to increase our chance of sighting animals. We saw many birds: kingfishers, kites, egrets and others. There were numerous mud skippers – fish that come out of the water to avoid predators – and a wild boar. The highlight was sets of fresh tiger tracks. The first set came down one bank and up the other. Tanjil, our guide, estimated that they were 5-6 hours old. After returning to the ship, we headed north through the Sundarbans towards Dhaka, a day and a half journey.
Along the way, we had a quick stop at a small village along the Baleshwari River. Chris Small had noticed that the width of the villages in this area had doubled between 1989 and 2010. We wanted to find out why. A small party went ashore to talk to the villagers. Unlike Polder 32, the water here is fresh and it shows. Lots of trees and a more prosperous and happier population. Boys jumping
into the creek from the top of the sluice gate. The trees included betel nut, papaya and other fruit trees and well as trees for wood. The local policy is that for every tree they cut down, they plan 4 new ones. This accounts for the increased size of the villages, a net switch from rice field to trees. After only a ½ hour, we had to return to the boat, drop off Carol and Saddam where a car would take them back to Khulna, and continue on our way.
We decided not to stop for visiting Barisal or swimming and thus were able to get to Dhaka the next afternoon rather than at night. Instead of spending the night on the Kokilmoni on the polluted, smelly, Shitalakshya River, we went into Dhaka and back to the Ambala Inn. More importantly for the students, we arrived with time to
shop. After checking in, we formed groups of 2 US and 1 Bangladeshi and sent them off by foot and rickshaw to New Market for shopping. The lack of shopping opportunities was the main complaint about the trip. They made up for it with clothes for themselves and presents for friends and family. That accomplished, we gathered for a final dinner in Bangladesh at Voot, one of our favorite restaurants. The slow service with cooking for 22 allowed plenty of time for socializing and picture taking. The students showed off their new Bangladeshi togs and a good time was had by all.
The next morning was our chance to see Dhaka. We met our counterparts the university and headed to Old Dhaka. We stopped at the 800-year old Dhaleshwari Temple where a child was getting
her first solid food in a Hindu ceremony. Then on to the Lalbag Fort built by the Mughals in 1676, or so we thought. Sunday is its day to be closed. We decided to go to the Ahsan Manzil, known as the Pink Palace. As we drove through the narrow streets, traffic got slower and slower. Finally, we stopped and decided to walk the last quarter mile. Now we all got a true taste of Old Dhaka, dodging rickshaws, hand trucks, pedestrians, and workers balancing parcels on their head. We managed to get all of us there and toured the grounds overlooking the Buriganga River then the massive palace built by the Nawab of Dhaka in 1872.
After the chaotic walk back to the vehicles, we spent an hour going the few kilometers back to Dhaka University. When we finally got back, we
had to abandon our plans for visiting the National Museum. We went to lunch at a very Bangladesh restaurant, picked up our luggage at our hotel and headed to Aarong. It is an upscale shop that sells all Bangladeshi clothes, crafts and products. The students got their last fill of shopping. Satisfied with their gifts, we headed to the airport. They went home, while I started my next leg in Kolkata and Aizawl, India.
For our spring expedition, NBP1503, to the margin of East Antarctica we will live and work on board the United States icebreaker Nathaniel B. Palmer. Together we are eight scientists, 10 science support staff and 19 crew members of the ship’s crew. As of today, March 22, all cargo and food for the journey has been loaded on the ship and tomorrow we are filling up the gas tank, which will take 10 to12 hours! After that we will start our journey south from Hobart, Tasmania to the coast of East Antarctica.
During the cruise I’ll study the vulnerability of East Antarctic ice streams to warm ocean water incursions and if this action is already responsible for the observed thinning of the ice sheet. Also on board the Palmer for this expedition are researchers from Australia’s University of Tasmania — you’ll find more information about our cruise and their research in this press release.
Follow Frank Nitsche on Twitter for more frequent updates from the Southern Ocean.
We left Hiron Point with the high tide and sailed through small channels of the Sundarbans Mangrove Forest. As a tidal marsh, the Sundarbans is crisscrossed by channels with sizes that range from 10 km across to less than a foot. The tides rise and fall periodically inundating all of the land. Mangroves are trees that are adapted to living in brackish water. Different tree species are found in different parts of the Sundarbans, adapted to different levels of saltiness.
We arrived at Kotka in the afternoon. Most of the group went on a forest walk with Tanzeel, our guide. A smaller group of us split off to visit thee remains of 300-year old salt kilns. We passed Chital deer and a wild boar on the way. A stag was silhouetted at the coast before it ran off. The
people that built the kilns used to allow seawater to flow into evaporation pans at Spring high tide. Before the next Spring tide they would bake the concentrated brine in clay pots to produce salt. The kilns are surrounded by innumerable potsherds, and quite a few intact clay pots. It is thought that the operation was suddenly destroyed, abandoned and buried, perhaps by a 1699 cyclone that killed 50,000 people. Recent erosion, include the destruction by Cyclone Sidr in 2007 have unearthed them.
Since the age of the kilns is known, it is a good site for Liz to use OSL dating to determine the sedimentation rate. We drilled several auger hole to determine the stratigraphy, the deepest one was 5.8 meters. Liz drilled assisted by two crew from
the Kokilmoni while I took notes and photos. The kiln site is now in the intertidal zone – exposed at low tide and covered at high tide. This means that they have subsided since they were last used. The rate is estimated as 4.1 mm/yr by a German group that worked here. We completed 3 holes, but ran out of daylight before we could take the OSL samples. We returned to the ship, walking past buildings destroyed by Sidr with our larger group who ended their forest walk at the kiln site.
We returned at dawn the next morning – with a guard to protect against tigers – while the remainder of the group went on a silent ride up a tidal creek. We collected 3 OSL samples from different depths, the last one completed as the rising tide reached over our knees. Whenever the
sampler was removed from the hole, one of us had to keep our hand in the hole, usually Matt, so we could find it again. Happy with our successful sampling, we returned to the ship for breakfast.
Back with the others, we set out for a forest walk to Kotka Beach. Climbing an observation tower, we got an overview of the region. There are old shoreline deposits here that are above the high water level. These sediments provide evidence of the seaward progradation of delta. As a result there is a meadow and many non-mangrove species as the area doesn’t regularly flood. This attracts a lot of deer and, as a result, tigers. However, we only deer. We also walked through the muddy mangrove forest and finally emerged at Kotka Beach where we went swimming in the Bay
of Bengal. We continued along the beach for a few kilometers passing hordes of scurrying crabs. Finally, we rejoined the Kokilmoni for a late lunch.
In this area, plans always have to be adjusted according to the tides and weather. As a result, we switched our visit to Bird and Egg Islands to later in the afternoon instead of the following morning. These two islands emerged from the sea about 20-25 years ago and have grown and merged. In answer to the age old question, the Egg came first. While a few people skipped the walk after the morning’s trek, most of us went along. It is a great place to see the biological succession that develops on a new island. The coast is bare sand with the high water mark littered with plant debris. Beyond the wind-blown coastal dunes, grasses
have taken hold. Then tall grasses and a scattering of shrubs and then trees in a muddy salt marsh. Finally in the distance is a full-fledged mangrove forest. We saw tracks and spoor of deer and monkeys, but as of yet there are no tigers on the island.
An unsuspected bonus was a tidal channel near the beach. Here at small scale, we could see all the features of river systems that we discussed in class: cut banks and point bars, meanders and avulsions, small deltas and chars. All at a scale that brought the geology to life for the students far better than any lecture or photos. It was a long and very successful day in the Sundarbans.
We sailed downstream to join the M/V Bawali with the Vanderbilt-Dhaka-Khulna group working on Bangladesh late at night and awoke to greet old friend and meet new ones. After breakfast, we all headed to Polder 32. Polder 32 is one of the islands that had embankments constructed around them to prevent flooding and improve agriculture. They use the Dutch term polder for the embankments. Polder 32 was one in which the polders failed during Cyclone Aila in 2009. As it turned out, while the polders improved agriculture as planned, it also led to subsidence of the island. It is now over 4 feet lower than land outside the island. This led to widespread flooding of the island after the cyclone that lasted for almost 2 years. We have been studying the causes and impact for the last few years. The subsidence inside the polders put everyone at risk as an unintended consequence of keeping out the natural flooding and sedimentation to improve agriculture. How to manage this system now is a difficult problem.
We also learned about the water problems at Polder 32. The groundwater is saline and not usable for either drinking or irrigation. They can only grow one crop a year, so the fields are all fallow except for some vegetable gardens by the homes. In other parts of Bangladesh 2 and even 3 crops a year are possible. We saw the abandoned tube wells installed by a wealthy donor after Cyclone Aila. They are all saline. Kazi Matin showed us his MAR site – managed aquifer recharge. They are attempting to create a pool of fresh groundwater over the heavier salt water providing a source of sweet water. Nearby, the Vanderbilt team is
installing equipment to measure water levels and flow at different depths, trying to better understand the groundwater system.
While the students fanned out to discuss agriculture with the farmers and test what few tube wells they could find, a small group of us took a speed boat to a large industrial shrimp farm on Polder 33. We found the site to be surrounded by a barbed wire fence. We found out later that it is to protect the site from tigers as it is on a peninsula surrounded on 3 sides by the Sundarbans. There was a rumor that the shrimp farm had closed and could be used to calibrate remote sensing data, but it was fully running. They grow 2 crops of jumbo shrimp a year over 9 months and spend the
remaining 3 months cleaning the ponds and preparing for the next season’s crop. They were one of the first large-scale shrimp operations in Bangladesh.
We sped back to the ship to find that the others had all returned and were having a swim break. I barely managed to change into my swimsuit and jump in before we all had to return to the ship to sail to Hiron Point. The strong tides in southern Bangladesh set our schedule as we try to catch tides going our way and avoid sailing against the tide. We sailed down channel between Polder 32 and the Sundarbans to the Shibsa River. At the end we passed Kalibogi. It is a peninsula at the end of Polder 32 that has had about a kilometer of erosion. It is now very narrow and the
embankment has been moved north of the peninsula, abandoning it. The shrimp farms that were once here are gone. There are only homes poorly protected from the elements and fishing is their only livelihood.
We sailed down the Shibsa to the Pusur River and overnighted in a narrow channel across from Hiron Point. In the morning we crossed. This stop is manly for me to service our GPS installation. We are using the precise measurements to determine the subsidence rate of this part of the delta. There is a tide gauge here that monitors the relative level between the sea and the land. While intended for navigation, over time it records the combined effect of land subsidence and sea level rise. With the GPS, we will be able to separate the two rates.
We all took the small wooden launch into the channel to the Forest Station. The Kokilmoni stayed outside lest it get trapped behind the mouth bar when the tide goes out. Hasnat and I, with Sabrina filming went to service the GPS while Liz demonstrated how to auger to get stratigraphy and sample for OSL dating. Small groups also took turns going up the observation tower. I discovered that I did not have my internet adapter – Apple have eliminated them from the newest Mac. I was stuck. Hasnat rushed back to the ship with the launch to get his computer. I could only wander around. I was shown the small spring with natural gas bubbling up. It could even be lit on fire. Finally Hasnat returned and we were able to download all the data since my last visit and upgrade the firmware of the receiver. We finished right at high time and rushed back to the ship to sail to our next stop. Thanks to Hasnat, we were able to accomplish our goals here.
The shortest route to where we are headed has silted up and is no longer passable. Farmers have moved in and started shrimp farming there. As a result, we and others have to take a longer route through the Sundarbans Mangrove Forest. Our first tantalizing sight of the forest we will return to later. Will lots of ship traffic on this route, the inevitable happened. Last December a ship collision resulted in an oil spill. With initial inaction by the government not wanting to face it, the local people went in and cleaned up the oil themselves by hand. Without any protective gear from the toxic oil, they saved the situation. Now only a slight oily film is visible at low tide. We started at 2 am to travel through the passage with the rising tide.
By 10 am we had passed through the Sundarbans to the Pusur River and stopped to pick up Carol Wilson and Saddam Hosain. They will join us for a few days from another boat that a Vanderbilt-Dhaka University team is using for research work at Polder 32. We continued up to Khulna ghat (dock). We had lunch and transferred to land by launch. In three vans we drove for and hour to asite where we installed instruments to measure the compaction and subsidence of the sediments. In 2011 we drilled 6 wells with depths from 20 to 300 meters installed optical fiber strainmeters. The fibers are stretched like a rubber band and every week one of the sons from the Islam family uses a device to measure its length, watching to see the change as the sediments compact.
While I service the equipment, my students spread out in several groups. Four of my students, each with a Bangladeshi partner spread out over the area with Chris Small to interview farmers about their farming practices, what crops they grow and changes through time. The information the agriculture team collects will help calibrate remote sensing observations. The other 6 students work with Kazi Matin Ahmed of Dhaka University form 5 teams to measure arsenic levels in the wells that provide drinking water. Finally, Liz Chamberlain and Carol use an augur to drill into the sediments. They will look at the stratigraphy and collect a sample for dating. The river that flows through the area used to me 300 meters (1000 ft) wide, now it is only a few meters. The silting in banks have been occupied by squatters using the new land for shrimp farming. The Islam family moved here in 2002.
When we arrive, it is hard to recognize the site. The government is excavating the river, widening it so boats can use it again. There are large piles of mud everywhere. Finally we find the right place and are relieved to find that they went around our instruments. In the afternoon, I met the engineer doing the work and he reassured us that our instruments will be untouched. Only time will tell if the measurements will be affected.
I was the least successful of the groups. We collected the data from the 6 compaction meters and surveyed between the GPS and wells to look at changes in the surface elevation. However, the cap of the well collecting water level data was rusted shut. When we really tugged on it, the pipe started to bend. We will have to return with WD-40.
Even worse the GPS was dead. Some problem with the solar panel system, but with the tool kit back in the states, I couldn’t diagnose it. I will take the receiver back to Dhaka to download the data, but Humayun will have to come to repair the power system. At least the students had a more successful time talking to farmers and measuring arsenic. It was their first time talking to rural Bangladeshis and spending time in the countryside. They thoroughly enjoyed it.
I’m writing from where L’Atalante is currently parked, 18S 170W, right in the middle of a giant, anomalously high sea surface chlorophyll patch. Such a high concentration of chlorophyll—a pigment that helps photosynthetic organisms harvest energy from sunlight, and the one that’s responsible for the green color of plants—can mean but one thing in the ocean: a phytoplankton bloom.
The satellite images of this bloom are stunning: a screaming red splotch surrounded by blue, the desert color of the ocean, which is used to denote regions with very little chlorophyll. Paths of red snake out from the center of the patch and shed light on the physics that drives this phenomenon. A physical oceanographer aboard L’Atalante described it to me as two adjacent eddies, enormous whirlpools of water that stir up nutrients and drive the productivity of phytoplankton.
The satellite reconstruction of this chlorophyll patch is so popping that I expected a noticeable change in the water when we arrived. I just took a stroll around the deck of the ship, and to be honest, to the naked eye the water looks just as crystalline blue as it did outside the patch. I love this about the ocean: it’s an expert at keeping secrets. It forces us to think outside the box—or rather, outside the boat—on a bigger scale than human perspective in order to figure out what’s going on. Because I’m a microbial oceanographer, at the same time I think about processes at the other extreme of the size spectrum, which genes are differentially turned on or off by the microbes in this patch, and I start to get dizzy.
Dizziness has been a common theme this past week on the South Pacific. As if metaphysical thoughts about the size scales of ocean processes weren’t enough to make me queasy, Tropical Cyclone Pam was there to rattle things up as well. Pam is such a nice, innocuous moniker, but this storm is so vicious authorities have renamed her The Monster. It’s the largest to hit the South Pacific in recorded history, and we’ve sailed on its outskirts for the past week and a half.
The captain skillfully navigated us away from danger; the worst we on L’Atalante faced were long, rolling waves and pounding rain—nothing compared to the devastation endured by Pacific nations like New Caledonia and Vanuatu. Our escape path sent us across the International Date Line a day early, literally sending us back in time to flee The Monster. As a result, I had two Thursdays this week. Had we crossed the Date Line at the originally scheduled time, Friday the 13th would have repeated. I’m not superstitious, but while floating in the middle of the largest ocean on the planet during a tropical cyclone, two 13ths is a chance I’m glad we didn’t take.
Today the physicists have the run of the ship as they deploy sensors that characterize the physical structure of this region. This means us biologists have the day off. It’s a welcome respite, because for 15 hours yesterday we conducted a high frequency biological survey as we cruised from one side of the patch to another. It was a sampling frenzy: 12 people queued up to take seawater from one spigot every 20 minutes. Everyone else needed maybe half a liter. In the Dyhrman Lab, we think big (about the smallest critters, that is). I hobbled up to the spigot each time with three 20 L carboys, explaining in all the French I could muster, “I need this much for the genes! For the genes!”
If you’d like to read more about what’s happening on the OUTPACE 2015 cruise, check out the blog of another oceanographer on board L’Atalante, Marcus Stenegren, a graduate student at Stockholm University in Sweden. Totally worth your click if you want to see action shots of me, with a mustache, hopping between blocks of wood during the “OUTPACE Olympics.”
Finally, if you’re still interested in seeing more—and if you want to brush up on your French—check out the video features of OUTPACE happenings, produced by the co-chief scientist, Sophie Bonnet.
I am once again teaching a Sustainable Development course on hazard in Bangladesh. The highlight of the course is that the 10 students, the teaching assistant and I are all traveling to Bangladesh over Spring Break. However, our plans have been disrupted by the continuing political unrest in Bangladesh. The opposition BNP party is calling for new fair elections by calling for a continuous blockade of travel and periodic hartals – general transportation strikes. They have been trying to enforce it by tossing Molotov cocktails at vehicles that defy it. Over 120 people have been killed so far. The ruling Awami League refuses to give into violence and neither the UN, EU or US
have been able to make a dent in the situation. The two parties and their women leaders hate each other. Neither side will back down on the unrest that started with the Jan 5 anniversary of the election. While more and more people are defying the blockade, after 2 months people have to make a living, the risk is too high to take a bus load of undergraduate students around the country.
Our solution, Plan B, is to stay off the roads and travel the country by boat. Dhaka, the capital is quiet, so we are visiting there at the beginning and end of the trip. The boat we were planning to use to visit the Sundarbans Mangrove Forest came up to Dhaka to meet us after we had a difficult trip. The 14 of us (Chris Small of Lamont and Liz Chamberlain of Tulane University are also joining us) made it to JFK skirting traffic
only to find a 4-hour delay on our flight. The airline nicely rebooted us for the next connection to Dhaka and escorted us through the airport to catch it. However 4 bags missed the connection. By the time we got to our hotel it was midnight and we still hadn’t had dinner. It was two AM by the time we go to bed. My TA, Matt, had to go back to the airport in the morning with Sukhen, but only 3 of the bags arrived. The missing one was Matt’s, but having lived in Dhaka, he had clothes in storage there.
The rest of us went to Dhaka University to meet our Bangladeshi counterparts, 8 students and 2 professors that are traveling with us. After a quick tour of a few spots around Dhaka, we headed to meet the Kokilmoni. I have sailed on her twice before. With Plan B, we will have to skip some areas, like the Brahmaputra River, that we cannot get to by boat in our limited time. However, we will get more time at other spots of interest and see what will be new parts of the country for me from a different vantage point. We started on a the Shitalakhya River east of Dhaka and sailed south in larger rivers finally passing the confluence of the Padma (combined Ganges and Brahmaputra) with the Meghna River before tying up at Chandpur for the night.
A boat is a much more pleasant way to travel than a bus with more places to hang out and rest from jet lag. The food is good and plentiful. The cabins are tiny and hot, while the showers are cold. The main thing the students missed is any opportunity to buy Bangladeshi clothes. Along the way we made two quick stops, one above and one below the confluence, for Liz to take samples for OSL analysis, a dating technique that uses electrons trapping in quartz to determine the last time the sediments were exposed to sunlight. The samples, collected by hammering a tube into the outcrop, must not be exposed to sunlight. Otherwise, these first days are quiet as it will take us until tomorrow afternoon to reach our first extended field stop. Boats are a comfortable, but slow way to travel.
Since the dawn of mankind, I imagine we’ve gazed
In wonder and awe at the sky’s starry crown;
More recently, we have been deeply amazed
By the long-obscured, staggering view looking down
To the depths of the sea, through crust, and below
Where rock moves like taffy, dark forge of the Earth,
Great molten sculptures and stark chasms grow;
A womb steeped in intrigue, the mantle gives birth
To breath-taking mountains, and wide rolling hills,
We humans gaze down from our ships, our sea cruises
We probe this vast landscape with sound waves and drills;
From ridges of awesome proportions, crust oozes
With a rhythm, it seems, that’s tied to the sun!
Our planet’s history, scrawled on ripped pages
Of rock and of sediments, piled by the ton
Rippled and riddled with tales of ice ages;
From ridges revealed, a pattern discovered
Orbital rhythms in a seafloor slice,
The pulse of the planet, a sculpture uncovered,
Does the deep earth exhale in concert with ice?
How climate influences sea floor topography, Conrad 2015 Science
Glacial cycles drive variations in the production of ocean crust, Crowley et al. 2015 Science
Mid-ocean ridge eruptions as a climate valve, Tolstoy 2015 Geophysical Research Letters
This is one in a series of poems written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory and the Department of Marine and Coastal Sciences at Rutgers University.
I’ve never been good at navigating. When I come out of the subway I invariably turn the wrong direction, even though I already have my nose buried in Google Maps, and then walk around the block to save face.
The navigation strategy for this cruise, however, is one that is particularly tailored to my strengths: we’re using DNA to guide our trek through the South Pacific.
Each day, water is sampled from the surface ocean down to around 40 meters, and a team of graduate students from Stockholm University extracts the DNA from the microbes within these samples. Then they use a technique called quantitative polymerase chain reaction, or qPCR, which enables them quantify the number of copies of particular genes within a sample. This technique requires pipetting miniscule volumes of liquid into microscopic tubes with razor sharp precision—a challenging feat on land, and one that makes me seasick just thinking about on a moving ship. This qPCR technique is being used to look for hotspots of a particular, newly discovered group of unicellular nitrogen-fixing bacteria called UCYN.
Unlike Trichodesmium, which I can identify in a water sample just by looking, the UCYN group is mysterious and elusive. First off, they’re tiny and unicellular, so even under the microscope they can’t be distinguished from other bacteria. To make matters more complicated, many are thought to live in symbiotic association with larger eurkaryotic microbes. The physiology of these organisms is interesting as well: they’re cyanobacteria, but some are thought to be missing half of the photosynthetic machinery. In short: these critters are weird, but they have a potentially overlooked but critically important role in the marine nitrogen cycle.
For our next long duration stop, we’re on the hunt for a region with particularly high abundance of these organisms. It seems like each station we visit has more and more UCYN bacteria present. Unfortunately, we’ve yet to stop for another extended period because we’re trying to outrun a tropical cyclone.
The outskirts of this are storm catching up to us, and each day the waves seem to be getting stronger and stronger. I’m thankful that I just have to look at the UCYN qPCR data and not generate it myself. I’ve been thinking more and more about the Dramamine stashed in my desk, but that being said, the temperature is still way above freezing and I don’t think I’d trade it for the end of winter in New York City.
From 20 degrees south, 179 degrees east in the South Pacific, Kyle.
Greetings from the center of that eddy I mentioned in my last post! We’ve been here for five days so far, but tomorrow we are finally moving on. As far as eddies go, this is a tiny one, only 15 kilometers, but larger eddies can be 100 to 200 kilometers in diameter. The eddy we’re in is anticyclonic, which means it has a warm water core and rotates counterclockwise, albeit imperceptibly from my point of view on the deck of L’Atalante. Here in the center, the water seems smooth as a pond.
The physical oceanographers on board were excited about studying the turbulence throughout the water column here in the eddy center. I share in their excitement because studies have shown that Trichodesmium abundance is correlated with anticyclonic eddies.
Cruising toward the eddy, I pictured a swirling stew of Trichodesmium, an ephemeral phenomenon that would dissipate, sweeping away clues about how these transient physical features influence microbial physiology and biogeochemistry. We found a ton of Tricho out here, but it wasn’t necessarily soupy until today. At some point between this morning when Andi and I went out with the net tow and this afternoon, the surface water around us became dense with mats of Trichodesmium.
As the ship maneuvered to maintain position, the bow sliced through the mats, sending tendrils of green curling away in our wake. I watched the green swirl with the blue water and pondered what all that Tricho was doing up at the surface. It’s inhospitable for any organism floating out there in the direct sunlight. I can attest to this: the five minutes I stood on the deck taking pictures of the Trichodesmium were enough to give me a sunburn.
I’ve heard that floating mats of Trichodesmium is the sign of a crashed bloom. So, what changed suddenly changed? Some limiting nutrient could have been depleted to critically low levels, or a virus could have decimated the Trichodesmium population around us. Or the physics of the eddy could have forced the colonies to the surface. Whatever happened, it likely altered the physiology of the Trichodesmium, and consequently the environment.
Retreating back into the shade, I realized that our time in the eddy could encompass a narrative of a Trichodesmium bloom. Each day I’ve taken in situ samples of Trichodesmium, meticulously cleaned the colonies of any stowaway microbes. Back in the Dyhrman Lab at Lamont-Doherty Earth Observatory, I will extract the RNA from these samples and look at how gene expression of Trichodesmium changed over the course of our stay in this eddy. Hopefully this will help get a step me closer towards answering the questions above.
Now, however, with the day’s experiments finished, samples safely stored and bottles washed, I’m looking forward to a mini break from 24/7 science as we steam to the next station. As I was frantically running up to the incubators to harvest the last experiment, I noticed the crew building something on the front deck of the ship. Later, I enquired about this mystery project: it’s a hot tub.
Au revoir from 19 degrees south, 164 degrees east!
We have completed the first two stations of the OUTPACE cruise and we are steaming to Station 3. By noon tomorrow we should be in the center of an eddy that our colleagues back on dry land have used satellite data to identify. Apparently they are detecting very high chlorophyll in the center of the eddy, which should make for good sampling.
Trichodesmium is everywhere out here. I just looked out of the porthole next to the desk in my cabin, and a giant bloom was floating by on the surface of the waves. Filaments of the cyanobacterium Trichodesmium clump together and form little colonies about the size of an eyelash. When we’re on station, Andreas and I fish for colonies using a special net that we tow up and down through the water column to concentrate thousands of liters of water’s worth of biomass. It’s grueling work—I have blisters on my hands and my biceps are sore…but it makes me feel like I’m earning the five-course French meals served on this ship.
Once we’ve fished for colonies, Andi and I individually pluck out Trichodesmium colonies from amidst the other organisms that were concentrated during the tow and rinse them twice in sterile filtered seawater to remove all but the closely associated symbiotic microbes that colonize Trichodesmium. This is grueling work too, but for a very different reason than towing a net. Imagine using a tiny pipette to grab things the size of eyelashes out of water while rocking side to side on a moving ship in 90 degree Fahrenheit weather. Come visit me in the lab at Lamont and I’ll let you try and pick some Tricho—it’s hard even when the ground isn’t moving beneath you.
So far, we’ve set up experiments to look at how nutrient uptake changes when we add different microbial communication molecules to the Trichodesmium colonies we’ve plucked, and of course we’ve taken samples so I can look at the molecular underpinnings of these physiological changes. The first two stations have been pretty successful. The ship is stable enough that I haven’t had to take any Dramamine, and really, the food is incredible. I woke up to sample at 5 a.m. yesterday, buoyed by the smell of freshly baked croissants.
Now that we’ve got our sea legs, I think we’re ready for the big kahuna, so bring on whatever’s happening in that eddy!
The OUTPACE 2015 cruise has set sail on February 20! We left port in Nouméa at 8:30 a.m. last Friday morning. I lost sight of land around 10 a.m. or so, and I won’t see it again until we return to port in Papeete, Tahiti on April 3.
Preparations before departure were so hectic that I didn’t even take a moment to appreciate the last time my feet left dry land as I climbed the gangway onto the ship. I spent the majority of my last two days in New Caledonia in a nickel mine north of Nouméa with a man from Vanuatu named Lulu. One of the byproducts of nickel mining is liquid nitrogen, the ultra-cold substance used to make ice cream, slow down the Terminator, and most importantly, preserve our samples until we can analyze them back at our labs on land. There are around 30 scientists on board, and with the exception of the physical oceanographers, everyone needs liquid nitrogen. I am very thankful for Lulu, he was my escort between ship and mine as I filled dewar flask after dewar flask of liquid nitrogen, he was my translator when I thanked the miners for their time, and he very kindly obliged when I suggested that perhaps he could drive slower because the dewars are fragile and his truck had no seat belts.
Having a stockpile of liquid nitrogen is especially critical for the samples I am planning to take during the OUTPACE cruise. I mentioned before that we are interested in how communication between Trichodesmium and other bacteria influences physiology and biogeochemistry. In the Dyhrman Lab at Lamont-Doherty Earth Observatory, we go about answering these questions in part by looking at what genes these microbes turn on or off under different conditions. To do this, we sequence the RNA, or the messenger molecules that act as the intermediary between the genome and the proteins that do the work in an organism. This data provides us with a snapshot in time of every single thing the cell was doing. The unique challenge is that RNA turns over incredibly rapidly. Shortly after fishing a Trichodesmium colony out of the ocean, their RNA profile could change from representing their in situ physiology to representing the response to sudden changes in temperature, light levels or the other stresses that accompany getting jostled around in a pipette by a graduate student trying to maintain balance on a moving boat. From ocean to liquid nitrogen, I have around five minutes before the samples are ruined.
It’ll be a day and a half until I take the first sample of the cruise, however. We’re currently steaming northwest from the southernmost point of New Caledonia to our first sampling station. For now we are rehashing plans, looking at satellite data to figure out where the eddies are and the patterns in sea surface chlorophyll, and finally ensuring every single thing in the lab is secured now that there is the pitch and roll of a cruising ship.
The most astonishing thing about the universe, in my eyes,
Is not merely its gargantuan, unfathomable size,
But the way its vastness ferries gorgeous, primordial light,
So that as we look up into the night,
The farther afield our gaze penetrates, the higher we climb,
The farther we can see back in time.
Like ancient missives carefully tucked into a bottle,
Flashes of history race towards us full-throttle,
At the speed of light traversing a fabric expanding,
These waves touch our shores, and fuel our understanding
Of quasars and black holes, the light and the dark,
The Very Beginning, the bright cosmic spark
From which all this sprang – upon us, the story rains:
Of how we arose with star stuff in our veins.
Gigantic Black Hole Discovered from the Dawn of Time, National Geographic
An ultraluminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30, Wu et al. (2015) Nature
This is one in a series of poems written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory and the Department of Marine and Coastal Sciences at Rutgers University.
Scientists from research institutions around the world are participating in a research expedition aboard the R/V L ‘Atalante to study how microorganisms in the South Pacific Ocean influence the carbon cycle. Lamont-Doherty Earth Observatory graduate student Kyle Frischkorn is among them; his goal is to assess how the microorganism Trichodesmium, and other microbes, interact and the resulting physiological and biogeochemical impacts these processes have on marine ecosystems. This is the first in a series of posts in which Kyle shares what it’s like to do research at sea.
I am reporting from the shores of New Caledonia. I am just about as far away from my home in New York City as one can get—literally and metaphorically: New Caledonia is an island in the southern hemisphere, in the subtropical South Pacific, east of Australia. I am in the capital city, Nouméa, where palm trees lines streets that move at a leisurely, island pace. It’s also about 80 degrees Fahrenheit warmer than New York City right now, which is perhaps the most jarring difference of all.
Few have heard of New Caledonia, a French “special collectivity”. I hadn’t either, until I had to get a plane ticket here. During World War II this island served as the South Pacific headquarters of the US military. This was strategically important for the Allied forces during WWII, it had good infrastructure and developed roads. Additionally, the hospitality of the New Caledonians and the tropical amenities offered much needed respite for the soldiers. This is a snippet of what I learned at the Musée de la Seconde Guerre Mondiale, just one stop on my two-day exploration of the city before embarking on 45 days of non-stop science.
As luck would have it, on my way to the museum I rode the bus one stop too far—an easy mistake to make, the street signs are miniscule and in French, also the buses blast catchy, island-y remixes of American Top 40 songs so I was reluctant to disembark. After I stepped off the bus, I got my bearings and by chance found myself face to face with the research vessel L’Atalante, my home for the next 2 months.
Scientists from research institutions around the world are partaking in this expedition, the broad, overarching goal of which is to study how microorganisms in the South Pacific Ocean influence the carbon cycle. My specific project focuses on one particular microorganisms, a cyanobacterium called Trichodesmium. This microbe is important in the low nutrient, oligotrophic ocean because of their ability to take in and fix carbon dioxide through photosynthesis, and because they have the relatively rare ability to transform atmospheric nitrogen into a form that is a utilizable nutrient for other organisms in the ocean. These abilities make Trichodesmium colonies oases of biological activity in a desert-like ocean. My colleague Andreas Krupke, a post-doctoral researcher in the Van Mooy Lab at Woods Hole Oceanographic Institution, and I will be conducting a series of experiments on this transect from Nouméa, New Caledonia to Papeete, Tahiti to assess how other microbes and Trichodesmium interact and the resulting physiological and biogeochemical impacts these processes have.
Before we can get started on the science, however, the first mission is to unpack all of the gear I shipped from Lamont and re-assemble the Dyhrman Lab on L’Atalante. It’ll function just like our lab back on dry land, but all the equipment is literally tied, drilled or bungee corded to the benchtop… stay tuned!
Early winter in the Northern Hemisphere marks the start of austral summer in the Southern Hemisphere, and the beginning of the Antarctic field season. Each year, several thousand scientists head to the icy continent to take advantage of the relatively mild, though still very harsh, weather and the 24-hour daylight; the next time the sun will fall below the horizon at Antarctica’s McMurdo Station is February 20, 2015.
Lamont-Doherty Earth Observatory scientists are among the many researchers currently doing fieldwork in Antarctica. They’re leading and participating in expeditions near, above and on the continent, doing critical studies that will advance understanding of Antarctica’s land and sea processes.
Lamont biogeochemist Sonya Dyhrman is aboard an icebreaking ship, the R/V Nathaniel B. Palmer, for one month. In that time she’ll slowly travel south from Punta Arenas, Chile to research sites located off the Western Antarctic Peninsula. Dhyrman, graduate student Harriet Alexander and the other cruise scientists are investigating polar food web dynamics, with a focus on the feeding and swimming behavior of krill, a small shrimp-like crustacean. During the research cruise, Dyhrman and Alexander will collect samples of water and phytoplankton from a number of different sites. Their goal is to understand the physiological ecology of phytoplankton, which form the base of the marine food web in the Southern Ocean, and are a major source of food for krill.
More than two thousand miles south, six scientists from Lamont’s Polar Geophysics Group are at McMurdo Station, a U.S. Antarctic research center located on Ross Island. They’re deploying an ice imaging system, known as IcePod, which consists of ice-penetrating radar, infrared and visible cameras, a laser altimeter and other data-collection instruments. IcePod attaches to a New York Air National Guard LC-130 aircraft and measures, in detail, the ice surface and the ice bed; important data that enables the scientists to track changes in ice sheets and glaciers.
The scientists are testing the instrumentation and training the New York Air National Guard in the deployment and operation of the instrument; this is the first time IcePod is being used in Antarctica. After the testing and training, IcePod will be operated in up to 15 other flights for routine data collection.
Also at McMurdo Station are Lamont geologists Sidney Hemming and Trevor Williams. The two scientists and their colleagues Kathy Licht and Peter Braddock will soon fly to a field site in the remote Thomas Hills, near the Weddell Sea in the Atlantic sector of Antarctica. There they’ll spend four weeks making observations and collecting rock samples from the exposed tills on the edge of the massive Foundation Ice Stream, as well as from the Stephenson Bastion and Whichaway Nunataks.
The group is examining how ice sheets in the Weddell Sea embayment will respond to changing climate, specifically how Antarctic ice retreats and which parts of the ice sheet are most prone to retreat. Understanding the behavior of the Antarctic ice sheets and ice streams provides critical information about climate change and future sea level rise.
Thanks to the Internet and the scientists’ dedication to outreach, it’s possible to join their Antarctic expeditions without donning extreme cold weather gear. Follow the Dyhrman’s cruise activities on Twitter via @DyhrmanLab and #TeamDyhrman, and learn more about their research on the cruise website.
The first dedicated Antarctic Icepod mission was flown out across the center of the Ross Ice Shelf. Ice shelves are thick floating extensions of the ice sheet that form as the ice flows off the continent and into the surrounding ocean. These are critical ice features in Antarctica, bounding a full 44 percent of her coastline, where they serve as a buttress to slow the ice movement off the continent into the ocean.
The Ross Ice Shelf is the largest of the Antarctic ice shelves, measuring just under the size of the state of Texas. It is several hundred meters thick, although most of this is below the water surface. Along the ~ 600 kilometer front edge of the shelf, the ice towers up to 50 meters in height; a sheer vertical wall of white and the iridescent blue of compressed ice.
The goal of the six-and-a-half-hour mission was to test how the Icepod could image the varying processes at the base of the ice shelf and how well the gravimeter would work flying 90m/sec.
The gravimeter is a new addition to the Icepod suite of instruments. Housed separately inside the plane, the gravimeter requires a very stable platform. The instrument will be critical for determining the water depth beneath the Ross Ice Shelf, the least explored piece of ocean floor on our planet. The plan was to cross the front of the ice shelf towards Roosevelt Island, then fly inland until the plane crossed the J9 site where the first hole through the ice shelf was drilled in the early 1970s as part of the Ross Ice Shelf Project (RISP). Icepod would then fly back toward McMurdo along a line where there are plans for another science project to drill next year.
The collected radar data showed remarkable variability over the ice. Crossing over Roosevelt Island, the change from floating shelf ice to marginal crevasses (deep cuts or openings in the ice) to ice sitting directly on the bedrock was imaged. The variation in the reflection from the bottom of the ice probably represented the different processes occurring at the ice sheet base. In some places there was evidence of ice being added to the bottom of the shelf.
When the RISP team, which included Lamont’s Stan Jacobs, drilled through J9 in the 1970s, they found refrozen ice with a structure that resembled waffles. That team also captured pictures of fish beneath the ice shelf, demonstrating that the area below was not the wasteland that it was originally believed to be. Icepod overflew the best fishing hole on the Ross Ice Shelf while the team looked at the pictures of the bright-eyed fish in the Science paper, and smiled. It is almost 50 years later, and while we have a much better understanding of Antarctica, there remains so much that is unexplored.
Icepod and the LC-130 returned to Willie Field and began immediately to plan for the next flight.
For more on the IcePod project: http://www.ldeo.columbia.edu/res/pi/icepod/
Scientists at Columbia University’s Earth Institute will present important talks at the Dec. 15-19 meeting of the American Geophysical Union, the world’s largest gathering of earth and space scientists. Here is a journalists’ guide in rough chronological order. Unless otherwise noted, presenters are at our Lamont-Doherty Earth Observatory. Formal abstracts of all presentations are on the AGU meeting program. Reporters may contact scientists directly, or call press officers: Kevin Krajick, firstname.lastname@example.org 917-361-7766 or Kim Martineau, email@example.com 646-717-0134.
Will Rapid Global Warming Resume Soon?
Braddock Linsley firstname.lastname@example.org
Global temperatures rose quickly until about 15 years ago, and have since largely plateaued. Now, coral records from the south Pacific Ocean suggest the so-called “hiatus” may soon end. Researchers hypothesize that water in the Pacific has slowed atmospheric warming by storing excess heat generated by CO2 emissions. But when the most recent phase of the 20-some-year Pacific Decadal Oscillation comes to an end, some of this stored heat may end up back in the air. Geochemical analysis of more than 220 years of coral growth rings from the islands of Fiji, Tonga and Rarotonga adds new support to projections that the PDO will switch states within 5-10 years, triggering a new phase of rapid warming.
Monday, Dec. 15, 8 a.m.-12:20 p.m. Moscone South Posters. A11B-3017
Related: Global Heat Hiding Out in the Oceans
Frontiers of Geophysics Lecture: Jeffrey D. Sachs
Jeffrey Sachs, director of The Earth Institute, is an economist, senior United Nations advisor and best-selling author. In this headliner talk, he will speak on “The Earth Sciences in the Age of Sustainable Development.” Among other initiatives, he will discuss the Deep Decarbonization Pathways Project, a new interdisciplinary effort by scientists from the top 15 carbon-emitting nations to map specific ways each country can reorganize energy systems to limit future warming to 2 degrees C. Journalists wishing to meet with Sachs may contact press officers.
Mon. Dec. 15, 12:30-1:30 p.m., Gateway Ballroom, Moscone South
Sachs’s Earth Institute home page
Deep Decarbonization Pathways Project
Battling Epidemics With Remote Sensing
Andrew Kruczkiewicz email@example.com, Pietro Ceccato firstname.lastname@example.org (Intl. Research Institute for Climate and Society)
Remote sensing is playing a key role in showing how shifts in weather drive outbreaks of deadly diseases, and how to counteract them. Kruczkiewicz will discuss how remote sensing has linked outbreaks of leishmaniasis in Sudan and South Sudan to dryer than normal conditions during the transmission months of April-July. Imagery suggests that cracks in dried-up soil—the breeding habitat of leishmaniasis-carrying sandflies—proliferate during these months, leading to outbreaks later. Ceccato will discuss programs of The Earth Institute, City University of New York and NASA to develop practical remote-sensing tools aimed at helping African nations predict and prepare for outbreaks of leishmaniasis, as well as malaria, trypanosomiasis and schistosomiasis.
Mon. Dec. 15, 5:15-5:30 p.m., 3020 Moscone West. H14A-05
Fri. Dec. 19, 11:20-11:35 a.m., 3001 Moscone West. GC52A-05
IRI’s work on climate and health
All IRI talks at AGU
Arsenic: A Mass Poisoning In Progress
Alexander van Geen email@example.com
It could be the largest mass poisoning in history: the 1990s discovery that newly drilled wells meant to provide clean water across southeast Asia were instead poisoning 130 million people with natural arsenic. International efforts have since gone into studying the geology and hydrology of the problem, drilling wells into safer aquifers, and getting people to use them. But as van Geen reveals, many people are still exposed, for reasons that have as much to do with politics and public education as geologic conditions. Van Geen and colleagues are leaders in studying and remediating all aspects of the problem. They are now working in the United States as well, where new health studies are showing that wells laced with arsenic are affecting people in the eastern U.S. and Canada.
Tues. Dec. 16, 9:30-9:45 a.m., 2005 Moscone West. U21A-06 (Invited)
Related: Do Arsenic Concentrations in Groundwater Change Over Time? Therese Chan, Tues. Dec. 16, 1:40-6 p.m., Moscone West Posters. H23E-0921.
Columbia’s arsenic research program
Van Geen’s work in southeast Asia
Low Ground, High Risk Seismic and Flooding Threats in Bangladesh
Christopher Small firstname.lastname@example.org, Leonardo Seeber email@example.com
A five-year program has brought into focus the potential for Bangladesh, the world’s most densely populated nation, to suffer catastrophic earthquakes, tsunamis and river-course changes—possibly all at once. Seeber and Small will discuss definitive signs of previous big quakes and at least one great tsunami; hidden features under the Ganges-Brahmaputra delta that may drive these disasters; and rapidly moving urbanization that is making the risks ever greater. The evidence rests on satellite imagery, GPS measurements, seismology and sedimentology. Posters on Thursday will delve into the details of apparent past events that could now be repeated with much greater loss of life and property.
Chris Small: Tues. Dec. 16, 8:15-8:30 a.m. U21A-02 (Invited). Leonardo Seeber: Tues. Dec. 16, 9:15-9:30 a.m. U21A-05 (Invited). 2005 Moscone West. Posters: Paleoseismic Records of Earthquakes Along the Southeastern Coast of Bangladesh., T43B-4712; Evidence for Tsunami Generated by the 1762 Great Arkan Earthquake,T43B-4732. Thurs. Dec. 18, 1:40-6 p.m., Moscone South.
Short film on the project
Warmer Climate Threatens Airplane Takeoffs
Ethan Coffel firstname.lastname@example.org Radley Horton email@example.com (Center for Climate Systems Research)
Climate plays an important, underappreciated role in how much weight aircraft can safely carry at takeoff. Hot weather can reduce lift, forcing airlines to offload cargo and passengers, eating into their bottom line. In what may be the first study to look at the changing economics of flying in a warmer climate, researchers estimate that airlines flying out of four airports—Phoenix, Denver, New York’s LaGuardia and Washington D.C.’s Reagan—will see 50 percent to 200 percent more weight-restricted days in spring and summer by 2050-2070. Worldwide, airports at higher elevations and with short runways and limited room to expand will feel the impacts most. Future airplanes may have to be designed to compensate for reduced lift in the weather of the future.
Tuesday, Dec. 16, 5:30 p.m.-5:45 p.m. Marriott Marquis Salon 13-15 PA24A-07
Lamont-Doherty Earth Observatory/Environmental Sciences Party
More info: Kevin Krajick firstname.lastname@example.org
Traditionally on Tuesday night at AGU, Lamont-Doherty Earth Observatory and Columbia’s Department of Earth and Environmental Sciences gather staff scientists and the many alumni who have since gone on to other institutions worldwide. It is a great opportunity to make acquaintances, hear informally about the latest ideas and work, and have fun. All journalists covering AGU are welcome.
Tues. Dec. 16, 6:30 p.m.-8:30 p.m. (or beyond), San Francisco Marriott Union Square, 480 Sutter Street, Union Square Ballroom
Mapping Defenses Against Urban Heat Waves
Alex de Sherbinin email@example.com (Center for International Earth Science Information Network)
Already vulnerable to heat waves, city dwellers face greater risks as the planet warms. In Philadelphia, where this is already evident, geographers have combined multiple data sets to pinpoint where higher temperatures, less vegetation and a concentration of poor or elderly puts people most at risk. The map is aimed at helping the city plant trees and vegetation where needed (including on rooftops), help social workers respond, and provide other defenses. In 1980-2013, the average number of heat-wave days per year here grew from 4 to 12, largely because streets and buildings trap heat, and there are fewer trees.
Friday, Dec. 19, 8 a.m.-12:20 p.m., Moscone West Posters. GC51B-0417
Using Submarines to Chart Arctic Ocean Conditions
Raymond Sambrotto firstname.lastname@example.org
Since the 1990s, U.S. Navy subs cruising under Arctic Ocean ice have produced seminal data not available by other means, including measurements of thinning sea ice. The program, dubbed SCICEX, was recently expanded to sample water temperature, chemistry and biology. Sambrotto presents the latest data from the remote western Arctic, gathered in spring 2014. Among other things, it establishes the levels of nutrients under the ice available for biological productivity the following summer, when melting takes place—critical to understanding how ongoing dramatic changes in ice cover may affect Arctic ecology.
Fri. Dec. 19, 8 a.m.-12:20 p.m., Moscone West Poster Hall. OS51C-0989
Water Systems of the Future
Upmanu Lall email@example.com (Columbia Water Center)
Lall, director of the Columbia Water Center, examines currently overlooked opportunities to redesign water systems to meet rising demand and declining supply. He envisions a new world in which water is treated exquisitely, like a crop of expensive vegetables, for consumption. This would include sophisticated systems to harvest rainwater; new technologies to recycle wastewater; and sensors and smart grids to monitor and manage usage in communities and buildings. He will discuss the technological, financial and social barriers that need to be overcome, and ways to accomplish that. Other talks from the Water Center during the week will cover studies of flooding in rivers from the Hudson to the Danube; newly launched satellite tools to survey global surface moisture; and the operation of China’s Three Gorges Dam.
Fri. Dec. 19, 10:35-10:50 a.m., 2009 Moscone West.
All Columbia Water Center talks
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The Earth Institute, Columbia University, mobilizes the sciences, education and public policy to achieve a sustainable earth. Researchers at our following centers are presenting at AGU:
Lamont-Doherty Earth Observatory is one of the world’s leading research centers. It seeks fundamental knowledge about the origin, evolution and future of the natural world. More than 300 research scientists study the planet from its deepest interior to the outer reaches of its atmosphere, on every continent and in every ocean.
The International Research Institute for Climate and Society aims to enhance society’s ability to manage the impact of seasonal climate fluctuations. From environmental monitoring and forecasting to risk management tools in water resources, public health, agriculture and food security, IRI and its partners focus on opportunities to build capacity for bringing climate information into regional planning and decision-making.
Goddard Institute for Space Studies, an affiliate of The Earth Institute, is a NASA-based climate research center that models and monitors earth systems, to predict atmospheric and climate changes. It also plays an important teaching role, conducting science education programs at universities, schools and other organizations.
The Center for International Earth Science Information Network (CIESIN) works at the intersection of social, natural and information sciences. It specializes in spatial data integration, and interdisciplinary research related to human interactions in the environment, providing data that informs decision-makers worldwide. .
The Columbia Water Center tackles the issue of freshwater scarcity through innovations in technology, public policy and private action. Combining scientific research with policy, it aims to design reliable, sustainable models of water management on local, regional and global levels.
This blog is an outgrowth of my own research examining the past temperature of Earth’s surface and the relationship of temperature to the Earth’s carbon system. I became interested in the scientific aspects of this work as a geology undergraduate, staring at regular layers of rocks in the countryside of central Italy, back and forth, dark and light. These layers were related to past oscillations of the climate, warmer and cooler, related to long-term changes in the incoming solar radiation entering our planet from the sun. Such changes are small, but positive and negative feedbacks in the Earth system interact to translate the small changes into the radically layered rocks we see in outcrops. This was the start of a journey of discovery that continues to this day and is the foundation of my research at the Lamont-Doherty Earth Observatory.
How does the carbon dioxide (CO2) content of the atmosphere influence climate? This question was first seriously considered in the mid- to late-1800s, amid an accelerating, newfound interest in the natural sciences on the European continent. Specifically, the Victorians were fascinated by looking backward in time, at periodic extreme cold spells, also known as ice ages, when glaciers as tall as skyscrapers covered vast areas of land that today are free from ice.
The discourse about past climates began with this approach, through a discussion about how the driving forces in the Earth system might have caused our globe to periodically enter and exit the ice ages. Many factors, including emissions from volcanoes, the rearrangement of continents, the evolution of plants and vegetation, solar sun-spot cycles, and even asteroid impacts can and do impact the average surface temperature of the planet.
Yet time and again scientists returned to the role that greenhouse gases, and specifically carbon dioxide (CO2), play in the climate system. CO2 molecules in the atmosphere absorb heat (infrared radiation) coming from the Earth’s surface and then re-radiate some of that heat back to the surface to generate a warming effect. How is this related to the glacial ice age cycles of the past?
One way to think about this problem is to imagine the Earth system as a huge, naturally occurring experiment (though the sample size by most experimental standards is low). Sometimes the Earth has been warmer than today, even ice-free at the poles. When the ice melts, sea level rises, continents spring back after being depressed by the weight of the ice, and plants that need warmer weather expand their habitat pole-ward. The Earth has also been cooler than today, most recently at the last glacial maximum (~20 thousand years ago) when more ice was locked up in the polar ice sheets rather than in the ocean, making for lower sea level, which exposed more of what is today the ocean floor.
Today the framework of thought has turned around, so that instead of looking back through time to understand the climate of the past, we also try to learn lessons from the past to further our understanding of the climate of the future. By burning fossil fuels for heating, electricity, transportation and other purposes, humans add CO2 to the atmosphere. Yet, by comparing ways in which the Earth’s temperature, CO2 concentration, sea level and ice sheets have changed in the past, we are able to learn valuable lessons about the climate system of today and tomorrow. You can share in this adventure here.
One last word of caution: At the turn of the last century, people also began to wonder if land-use and manufacturing—human-induced variability—could play a role in climate. Because this issue has become highly politicized, I won’t get into all the back-and-forth arguments here. That forum has other locations online. However, for a modern history of this fascinating topic, check out the American Institute of Physics (which can be found at http://www.aip.org/history/climate/co2.htm); and for more on the science, check out what the EPA has to say (http://www.epa.gov/climatechange/ghgemissions/gases/co2.html). Both purport an objective analysis of both the history and basic science involved.
Migrating south in the winter is a behavior that Antarctic scientists share with many species of birds, although the scientists fly just a bit further south. For the IcePod team, it was time to join the migration so they could test their equipment in the most challenging environment the Earth has to offer. After three “equipment shake down” trips to Greenland over the last two years, 20 hours of flight time have been set aside for flights in Antarctica, part of the final hurdle in the commissioning of the pod.
The team arrived early this month at McMurdo Base on a large C-17 to –14°F weather and beautiful clear blue sky as the plane touched down on the Pegasus Blue Ice Runway. The first few days were spent in training for everything from driving trucks in the cold to being environmentally sensitive to the Antarctic microbes to a crash course on interpreting the complex way trash is handled in Antarctica — an impressive 60 percent of everything is recycled.
The gear arrived soon after the team… first the gravity meter, borrowed from New Zealand, wrapped in a warm, manly pinkish quilt. With many boxes being stacked in the aircraft, the color was selected for its high visibility to assist with quick location and unloading. The IcePod and the equipment rack had paused on their trip down in Pago Pago, arriving a few days after the rest of the gear, but it was all quickly set up and humming in a bright yellow and blue rack tent next to the Willy Airfield on the Ross Ice Shelf. While waiting to fly, a GPS was installed on top of the tent, and equipment was set up to test performance. Both the GPS and the gravity meter measured the movement of the ice shelf as it shifted up and down on the tide ~ 1 meter a day. In addition to the rhythmic up/down movement, the tent, the airfield and the ice shelf are all moving northwards at 30 cm or 1 foot a day.
Finally, IcePod was cleared to fly and complete her first Antarctic survey mission installed on a Pole Tanker mission flying on Skier 95. The flight was delayed as the C-17 practiced airdrops over the South Pole runway, but as soon as the C-17 was out of the way, icePod took off and headed south.
Low elevation data was collected on the way out to make sure the C-17 was clear. All the instruments worked in the flight across the very flat Ross Ice Shelf, then over the Transantarctic Mountains and across the spectacular East Antarctic Ice Sheet.
The low angle of the sun made the mountains, crevasses and wind scour areas stand out beautifully in the imagery. The deep radar imaged the structure of the Ross Ice Shelf even from 21,000 feet. The infra-red camera showed the variable temperature of the different types of ice in the Beardmore Glacier and the high plateau. The gravity meter that had rolled in on the speed pallet was extremely stable. At the South Pole, Skier 95 offloaded fuel while the IcePod team made a quick trip to the actual pole.
The flight was a success – data collected on an opportune flight and fuel delivered.
For more on the IcePod project: http://www.ldeo.columbia.edu/res/pi/icepod/