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Salt Kilns and Landscape Change in the Sundarbans

Geohazards in Bangladesh - Sat, 03/21/2015 - 05:58
Rabi, Diana, Khris, Joelle, Dan and Alamgir watching the landscape as we sail through the Sundarbans

Rabi, Diana, Khris, Joelle, Dan and Alamgir watching the landscape as we sail through the Sundarbans

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

A boat harvests leaves for thatching roofs in the Sundarbans.

A boat harvests leaves for thatching roofs in the Sundarbans.

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

Remains of trees destroyed by Cyclone Sidr along the coast at Kotka

Remains of trees destroyed by Cyclone Sidr along the coast at Kotka

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

Liz standing by the remains of 300-year old kilns used for salt making surrounded by shards of the pots used for holding the salt

Liz standing by the remains of 300-year old kilns used for salt making surrounded by shards of the pots used for holding the salt

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

We finish collecting our last sample as the tide came in and water covered the site.  We had to pound the last bit of the sampler through the water.

We finish collecting our last sample as the tide came in and water covered the site. We had to pound the last bit of the sampler through the water.

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

View from the observation tower at Kotka.  The sandy paleo-shoreline separates the meadow on the left from the mangroves on the right

View from the observation tower at Kotka. The sandy paleo-shoreline separates the meadow on the left from the mangroves on the right

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.

Group photo on Egg Island.  We stand at the transition from sand to grass while behind us the entire succession to mangroves is visible

Group photo on Egg Island. We stand at the transition from sand to grass while behind us the entire succession to mangroves is visible

As the sun sets, we climb into the launch to leave the island and return to the Kokilmoni

As the sun sets, we climb into the launch to leave the island and return to the Kokilmoni

Polder 32 and Hiron Point

Geohazards in Bangladesh - Fri, 03/20/2015 - 11:48
Mimi, Matt and Yassamin sitting in the bridge of the Kokilmoni

Mimi, Matt and Yassamin sitting in the bridge of the Kokilmoni

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.

Kazi Matin explains his MAR site on Polder 32

Kazi Matin explains his MAR site on Polder 32

 

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

Shrimp farm we visited at Polder 33

Shrimp farm we visited at Polder 33

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

With limited tube wells to test, the group returned to the ship early and had a swim break.

With limited tube wells to test, the group returned to the ship early and had a swim break.

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

Homes on the edge of the eroding peninsula at Kalibogi

Homes on the edge of the eroding peninsula at Kalibogi

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.

On the wooden launch sailing to Hiron Point forest station

On the wooden launch sailing to Hiron Point forest station

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.

Group photo at Hiron Point in the Sundarbans Mangrove Forest - a world heritage site.

Group photo at Hiron Point in the Sundarbans Mangrove Forest – a world heritage site.

Working in the Bangladeshi Countryside

Geohazards in Bangladesh - Fri, 03/20/2015 - 05:08
Sailing through the Sundarban Mangrove Forest

Sailing through the Sundarban Mangrove Forest

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.

The team studying agriculture changes in Bangladesh meet with Chris Small to plan for interviewing farmers

The team studying agriculture changes in Bangladesh meet with Chris Small to plan for interviewing farmers

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.

Tanner and Yassamin in a discussion at sunset.

Tanzir and Yassamin in a discussion at sunset.

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.

Fisherman on the Pusur River using the incoming tide to sweep fish into their nets

Fisherman on the Pusur River using the incoming tide to sweep fish into their nets

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.

We arrived to find that 2 weeks earlier excavations had started to widen the river. It has shrunk from 300 to 3 meters wide.  Gratefully, they left our instruments intact.

We arrived to find that 2 weeks earlier excavations had started to widen the river. It has shrunk from 300 to 3 meters wide. Gratefully, they left our instruments intact.

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.

Collecting a water sample for testing arsenic levels at the well of the Islam family, host of the compaction meter.  It came out clean.

Collecting a water sample for testing arsenic levels at the well of the Islam family, host of the compaction meter. It came out clean.

Liz augurs through the sediments on the riverbank  to get a sample for OSL dating, attracting a crowd

Liz augers through the sediments on the riverbank to get a sample for OSL dating, attracting a crowd

Best Views Yet of Mercury's Ice-Filled Craters - BBC News

Featured News - Tue, 03/17/2015 - 16:15
Scientists obtain the most detailed views yet of ice deposits inside the permanently shadowed craters at Mercury's north pole. Quotes Lamont-Doherty Director Sean Solomon.

Mercury As Never Seen Before - Nature

Featured News - Tue, 03/17/2015 - 16:13
In its final weeks, the MESSENGER mission reveals fresh details about the planet's scorched surface. Quotes Lamont-Doherty Director Sean Solomon.

Best Images Ever of Mercury's Scorched Surface - Scientific American

Featured News - Tue, 03/17/2015 - 16:11
Quotes Lamont-Doherty Director Sean Solomon.

Sampling up a Storm

Wide Ocean, Tiny Creatures - Mon, 03/16/2015 - 12:00
 A printout of the targeted chlorophyll patch in the South Pacific and the trajectory of the ship’s path as physical and biological oceanographers characterize this region.

A printout of the targeted chlorophyll patch in the South Pacific and the trajectory of the R/V L’Atalante’s path as physical and biological oceanographers characterize this region.

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.

 NASA)

NASA satellite imagery shows the eye of Cyclone Pam just northwest of Aneityum, the southernmost island of Vanuatu. Image: NASA

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.

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

MegaDrought Study Authors Break It Down - Raw Science

Featured News - Mon, 03/16/2015 - 11:00
Interview with Jason Smerdon, Ben Cook of Lamont.

Sailing Around Political Unrest in Bangladesh

Geohazards in Bangladesh - Sun, 03/15/2015 - 06:24
Opposition leader Khaled Zia (left) and Prime Minister Sheikh Hasina (right)have been alternating as Prime Minister since 1996.

Opposition leader Khaled Zia (left) and Prime Minister Sheikh Hasina (right) have been alternating as prime minister since 1996.

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

Visiting the Shahid Minar, the memorial to students killed in 1952 protesting against Urdu as the sole language of Pakistan. Now February 21 is a major celebration of the Bangla language.

Visiting the Shahid Minar, the memorial to students killed in 1952 protesting against Urdu as the sole language of Pakistan. Now Feb. 21 is a major celebration of the Bangla language.

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

One of the sculptures we saw at the Art Institute in Bangladesh near the National Museum and Shahbag Square.

One of the sculptures we saw at the Art Institute in Bangladesh near the National Museum and Shahbag Square.

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.

The students catch up on texts and e-mails at Dhaka University after 2 days without a connection

The students catch up on texts and e-mails at Dhaka University after two days without a connection.

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.

 

Sitting on deck between Liz Chamberlain and Miriam Kaplan and we sail across Bangladesh.

Sitting on deck between Liz Chamberlain and Miriam Kaplan as we sail across Bangladesh.

Liz Chamberlain of Tulane University takes samples for OSL analysis from the bank of the Meghna River.

Liz Chamberlain of Tulane University takes samples for OSL analysis from the bank of the Meghna River.

Students board the launch that will ferry us to the Kokilmoni.

Students board the launch that will ferry us to the Kokilmoni.

The M/V Kokilmoni, our home for the next 8 days. This tourist boat for the Sundarbans Mangrove Forest came all the way to Dhaka to pick us up.

The M/V Kokilmoni, our home for the next 8 days. This tourist boat for the Sundarbans Mangrove Forest came all the way to Dhaka to pick us up.

Abyssal Rhythm

Geopoetry - Fri, 03/13/2015 - 10:00
 ADAPTED BY P. HUEY/SCIENCE

When sea level drops, pressure at mid-ocean ridges decreases, which may influence the production of ocean crust. A new study suggests that the pattern of hills on the sea floor reflects the timing of sea-level change during ice age cycles. Illustration: adapted by P. Huey/Science

 

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?

 

_________________________________________________________

Further reading:

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.

 

Navigating the South Pacific Using DNA

Wide Ocean, Tiny Creatures - Tue, 03/10/2015 - 13:14

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.

 avoid the impending tropical cyclone.

Chief Scientist Dr. Thierry Moutin explains our cruise trajectory for
the next week. New mission: avoid the impending tropical cyclone.

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.

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

 

Bjarke Ingels on the New York Dryline: 'We think of it as the love-child of Robert Moses and Jane Jacobs' - The Guardian

Featured News - Mon, 03/09/2015 - 11:00
"The city should be proud of the project," says Klaus Jacob,... "Except it has a fixed height. As the sea level rises, you need ever smaller storms to overcome it. It's exactly New Orleans' problem during Katrina."

Science Nabs Illegal Ivory Sellers - Phys.org

Featured News - Mon, 03/09/2015 - 11:00
A Toronto-based company has been convicted of selling illegal ivory in the first case to use a technique for dating ivory developed by a scientist at the Lamont-Doherty Earth Observatory in collaboration with other colleagues.

A Swirling Stew of Trichodesmium

Wide Ocean, Tiny Creatures - Mon, 03/09/2015 - 09:43
A large population of Trichodesmium, known as a bloom, seen from the side of the R/V L'Atalante.

A large population of Trichodesmium, known as a bloom, seen from the side of the R/V L’Atalante.

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.

Colonies of Trichodesmium (also known as"puffs") collected from the South Pacific

Colonies of Trichodesmium (also known as “puffs”) collected from the South Pacific.

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!

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

Trichodesmium is Everywhere!

Wide Ocean, Tiny Creatures - Thu, 03/05/2015 - 20:26

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.

Sunset over the South Pacific ocean at the end of Station One.

Sunset over the South Pacific ocean at the end of Station 1.

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!

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

Trichodesmium is Everywhere!

Wide Ocean, Tiny Creatures - Thu, 03/05/2015 - 18:00

So far, 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.

Sunset over the South Pacific ocean at the end of Station One.

Sunset over the South Pacific ocean at the end of Station One.

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!

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise.

Jawbone of Early Human Puts Evolution in a Whole New Light - LA Times

Featured News - Thu, 03/05/2015 - 12:00
"It's as if we were putting together this gigantic, multidimensional puzzle," DeMenocal said. "There was a big missing piece we couldn't find anywhere in the box. Now, we've magically found it."

OUTPACE Cruise: Setting Sail

Wide Ocean, Tiny Creatures - Tue, 03/03/2015 - 11:28

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.

Filling dewar flasks with liquid nitrogen at a nickel mine in Noumea in preparation for the OUTPACE research cruise.

Filling dewar flasks with liquid nitrogen at a nickel mine in Noumea in preparation for the OUTPACE research cruise.

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.

Follow @kylefrischkorn and the @DyhrmanLab on Twitter for more frequent updates from the OUTPACE cruise

Climate Change Helped Fuel The Syrian Conflict, New Paper Finds - Huffington Post

Featured News - Mon, 03/02/2015 - 12:00
Quotes Lamont scientist Richard Seager.
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