From left to right: Sampath Rathnavaka, Sumant Jha, Gillean Arnoux, Colton Lynner and Terry Cheiffetz.
We had a smooth trip to Kolkata with our two taxis amazingly staying together through the traffic. After checking in and freshing up, we went out for dinner and found a great Bengali Restaurant filled mostly with Bangladeshis around the corner. Our hotel turned out to be next to an area where Bangladeshis frequently stay, including Humayun previously. In the morning, he and I went for an early morning walk through the park and saw the Queen Victoria Memorial. Circling back past all the cricket players, we passed Fort William, the original British fort here, and joined Doug and Diane for breakfast. Our car arrived and before heading to the Sundarbans, we drove around to get shots of the Hooghly River. Before the 1600s, this was the main course of the Ganges, but since
then it shifted to it present course into Bangladesh. We got some shots from the new bridge before being chased off. Then we headed to the Strand to get close to the river. While we were filming, a funeral procession arrived to scatter ashes of the deceased into the river. Once the Holy Ganges, always the Holy Ganges. We couldn’t have planned it better.
Then, off to the Sundarbans. Where we were going was a lot farther than implied. This is because of a difference in naming. In Bangladesh, the Sundarbans is the National Mangrove Forest. The cultivated areas that previously were forest are not considered the Sundarbans. In India, they are. Thus we entered the Sundarbans after 2.5 hrs, but still had that long to go to meet our boat.
Admittedly, some of the cultivated areas in India still maintain mangroves outside of the embankments, which is not the case in Bangladesh. Continuing on, we reached literally the end of the road and carried our luggage (including a 50 lb. bag of rock samples) down to a ferry that took us to Gosaba. There, we first got a hand rickshaw to get the luggage across the town, then got two motorized rickshaw trucks to cross to the other side of the island. Finally, we were met by a boat that took us across the river to the eco-lodge where we would stay. After a late (4 pm) lunch we went on a sunset boat ride through some tidal channels. The saw and heard lots of bird and at times the channel became so narrow that we had to push branches away to fit through. The
trees here overhang the channels more than in Bangladesh. We would see further differences tomorrow. After finally showering off, we met other people staying at the eco-lodge, started by 4 cousins including Ajoy, who is leading our trip. The lodge is solar powered, so electricity is limited,but the water was refreshingly cool, not cold. We all heard a performance of Bengali Baul music, recognizing some songs from similar experiences across the border. After dinner, we all went for some local rice wine and then a boat ride to see bioluminescent plankton in a small channel. If you wave your hand in the water dots of light flash.
In the morning, we started at 6 am to have enough time before I had to head for the airport. We picked
up food and a cook and permits and a guide and finally were ready to enter the forest. In India, no one is allowed off the boat to step on the forest, nor to stay overnight in the forest, even on a boat. Thus many hotels and lodges have sprung up outside the forest for tourists. Many come simply to party and drink. We are very glad to be using an eco-lodge that is more respectful of the land and the local population.
At 8, we finally entered the national forest. Among the differences from the Bangladesh side we noted were the shorter height of the trees in the more saline water, the lack of sediment in the water, and the extent of bank erosion. Where the eastern Sundarbans is fresher with ample sediment carried by the tides due to its proximity to the Ganges-
Brahmaputra-Meghna River mouth, the western, Indian Sundarbans is more saline and lacks new sediment. Between subsidence and sea level, it is loosing ground. More land is being lost than gained. With the higher salinity, there is also less wildlife. However, there was a tiger sighting this morning. We sailed to the spot, but it was too late, we missed it. Still, we spent 4 hours sailing through tidal channels of different size, eating, and filming. Doug captured the beauty of the Sundarbans and I was interviewed with a great backdrop.
After completing our work, we briefly visited an observation post, we took a short cut through an interior channel in Gosaba Island, dropped off our guide, and crossed the channel to our car. Three hours later, I arrived here at the airport to start my journey home. It was an intense, yet calm 48 hours in West Bengal, the third leg of three very different pieces of this trip.
We are now aboard the R/V Palmer and on our way to East Antarctica. Due to two storms in our direct way we are heading west first to go around the storms and we’ll then head south on their backside. After passing the 200 mile zone off of Australia we turned some of the instruments on that collect data constantly while ship is under way. These instruments measure properties including surface water temperature, water depth, gravity, and weather data. In addition to their specific scientific missions research ships like the Palmer are also floating observatories that collect important data from remote areas of the world.
Follow @FrankatSea for additional updates and images from the Southern Ocean.
Humayun Akhter, my main collaborator in Bangladesh, joined me at the airport and we flew together to Kolkata. We spent the night at a nondescript hotel near the airport. The next morning, we met up with film makers Doug Prose and Diane LaMacchia in the airport and all flew together to Aizawl, the capital of Mizoram state in NE India. Doug and Diane have funding from NSF to expand the 5-min YouTube video they made about our project two years ago (https://www.youtube.com/watch?v=WTETuqJPygs) to a ½ hour TV special. Their previous films have been shown on PBS.
The Sumatra subduction zone, source of the 2004 earthquake and tsunami, continues to the north where it encounters the Ganges-Brahmaputra Delta. The 15-20 kilometer thick delta sediments are folded and faulted as they enter the subduction zone. Because of the huge amounts of sediments, this is the only subduction zone whose front is subaerial – entirely exposed on land. In Bangladesh we can see the beginning of this process. Here in Mizoram, farther east, the former delta sediments are folded up into a very hilly terrain. The steep slopes are subject to frequent landslides. One that started last October has moved again and blocks the main road from the airport to the city of Aizawl. As a result, we had to take a longer, slower, bumpier and dustier road to get to the city.
We met up with Nano Seeber and Paul Betka from Lamont at breakfast. They have been doing geologic mapping the region and returned to Aizawl late the night before. We spent the day circling the city and visiting outcrops, many ones I had seen my last time here. We had several interesting discussions on differences of interpretation of the strata. I had visited most of these outcrops before, but it was the first time for Humayun. At the end of the day we were joined by
Vineet Gahalaut from the mainland, as the rest of India is considered here. The people here look Asian and the Mizo language is a tonal language in the Tibeto-Burmese family. Plus, almost all Mizo are Christian. Mizoram is part of India, but also distinct, like many of the other states in NE India. Part of the sense of separation is that the 7 NE states are only connected to the rest of India by the narrow 23 km (14 mi.) Siliguri Corridor between Bangladesh and Nepal – the chicken neck. We spent the evening talking with Vineet about future joint projects in this region.
The next day we were joined by Victor Ralte, our partner from Mizoram University, who became a proud father of a fourth daughter last week. We all headed north, visiting geological sites and filming
beautiful vistas, dropping Vineet off at the airport and continuing on to Kolasib, a small town about 70 km north as the crow flies, but probably twice that on the windy roads of Mizoram. We stayed in Hotel Cloud 9. I had been told since I was a child that I was always off on Cloud 9 and now I was actually here. However, the electricity wasn’t for the first few hours, so showers were cold, but the dinner was hot.
The next day we headed still farther north to see some complex faulting associated with the growth of the anticlines – the hills of folded strata. As we examined each outcrop, it was also clear that we were passing through several kilometers of rocks in which the environment that were deposited in shallowed from the inner continental shelf (10s of
meters water depth) to the tidal zone to estuaries like the present Sundarbans to fully fluvial (river). This represents the ancient Brahmaputra Delta passing across this area as it grew southwards. That several kilometers of sediments were deposited while the environment only shallowed by 10s of meters indicates that there was a lot of subsidence to make space for the sediments. I will have to model this when I return.
Stopping for a beautiful sunset over the hills, we finished heading back to Aizawl for a last dinner together. In my room as it turned out since the restaurant closed for some repairs. The six of us ate a mixture of American, Indian, Chinese and Mizo food with plates dishes and ourselves filling all available surfaces. Today, a quick stop at Mizoram University and then back to Kolkata for my last leg before home.
The lakes along the Great African Rift Valley are among the largest fresh water lakes in the world. They lie in depressions created by slow stretching and thinning of the east African continent over millions of years. Many of the essential geological structures that enable the continent to tear and produce earthquakes are hidden within the Earth below these lakes. Lake Malawi (Nyasa) is the southernmost of these Great Rift Valley lakes and represents one of the youngest segments of the East African Rift System today. The lake is a whopping 550 km long and up to 70 km wide and surrounded by three countries : Mozambique to the southeast, Tanzania to the northeast, and Malawi to the west.
To image geologic structures and record earthquakes beneath northern Lake Malawi, our science team is undertaking a major “marine” seismic study as a part of the NSF-funded SEGMeNT (Study of Extension and maGmatism in Malawi aNd Tanzania) project. This part of the project involves generating sound waves using a towed array of “air guns” and recording the sound waves on a 1500-m-long cable filled with pressure sensors and an array of seismic stations deployed both onshore and on the lake bottom. The scientific and technical staff for this part of the project come from Lamont-Doherty Earth Observatory of Columbia University, Syracuse University, the Malawi Geological Survey Department, the Geological Survey of Tanzania, Aarhus University and Scripps Institution of Oceanography.
Marine seismic studies like ours are routinely done in the oceans using scientific equipment and research vessels outfitted specially for these purposes. Collecting comparable data in a great lake in Africa requires creative repurposing of available vessels and adaption of scientific equipment. To deploy and recover seismometers on the lake floor, Jim Gaherty and team used a small research vessel (R/V Ndunduma) operated by Malawi Fisheries Department. Deck space is limited, requiring efficient packing and multiple trips to deploy 34 seismometers in the lake with a boom normally used for dragging fishing nets. For the seismic imaging component, we transformed a large container ship (M/V Katundu) into a seismic research vessel. Containers were placed on the deck that house our scientific “lab,” a workshop for repairing science equipment, a storage space for extra gear and miscellaneous items, and an accommodation container with 8 bunks to sleep some of the science party. We have also added large spool for the seismic streamer, generators and compressors to drive the seismic sound source, and a large metal arm (termed “the ironing board”) for towing the seismic source. Using non-standard ships, equipment and data collection procedures requires a team with technical expertise and ingenuity, and happily we have that in spades.
We are now slowing steaming across beautiful Lake Malawi in the M/V Katundu acquiring fantastic data as we go …
Donna Shillington and Natalie Accardo, M/V Katundu, 22 March 2015
I grew up outside of Chicago and I wasn’t a Boy Scout, so sometimes I feel like I missed out on learning the type of practical—albeit rarely used—skills that would have garnered merit badges. As I mentioned before, I’m hopeless with navigation. I could probably build a fire, but it would take a lot of matches. I don’t know how to whittle. Upon reflection, fire and navigation aside, now that I’m nearing the conclusion of my fourth research expedition at sea, I think I have amassed a few badge-worthy tricks.
I can plumb a filter rig like I was born holding Tygon tubing. For example, in my lab space on this ship I had to snake the tube to the vacuum pump through the ceiling, across the floor and up a table leg. And last week I devised a spill-proof method for siphoning 20 liters of radioactive waste into a storage container, no heavy lifting required. You’d be hard pressed to find any Boy Scouts with merit badges for hazardous materials handling. Finally, I can tie a bowline knot with my eyes closed. Of all these obscure, oceanographer skills I’ve acquired, I’m perhaps most proud of this one.
The bowline knot is considered the king of the basic maritime knots; simple but strong, and no matter how hard you pull it’s always a cinch to untie. I use a bowline to secure the rope of our plankton net to the ship each time Andi and I fish for Trichodesmium. If we lose the net to the ocean, that means no more Tricho, and no more Tricho means no more experiments. No more experiments and I might as well walk the plank. I’d bet all of my samples on the security of that knot, but no matter prune-y my hands are, it’s easy to untie when I’m exhausted during clean up at the end of the day.
The bowline knot is a practical trick to ensure the safety of an essential piece of equipment, but I also think it serves as a symbol of life as a scientist on the high seas: strength and mutability. On this cruise in particular, I’ve come to appreciate that when you’re at sea for two months, mutability is key.
For example, when I sailed away from New Caledonia in February I wrote that I wouldn’t see solid ground again until I returned to port in Papeete, Tahiti on April 3. Yet, when I woke up on Saturday morning I smelled land. It was like rain on soil—specific and unmistakable. Sure enough, when I climbed out of my bunk and made my way to my porthole, I was greeted by the sight of one of the smallest countries on the planet: the coral atoll of Niue, population 1,611. Niue is barely three times the size of Manhattan, and it’s completely isolated in the Pacific. However, a crew member of the Atalante injured his knee, and an eight hour detour to the island brought us to the nearest hospital.
Even though we were within swimming distance from the shores of the island and hours away from our planned cruise trajectory, the labs on the Atalante were still a flurry of activity as scientists sampled water and set up experiments, creating a makeshift station out of what would have otherwise been a floating hospital waiting room.
We’re back on track now, steaming full throttle towards our final long duration station of the voyage. If the volcanoes, tropical cyclones and surprise visits to land of the previous month and a half are any indication, we should still be ready to adapt to the unexpected. I still haven’t had to whittle at sea, but I’ve got two weeks left on the South Pacific, and you never know what might happen.
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.
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!