Land ho!

We are about to be back on land! We have finished packing up the lab, and are ready to go through customs. After that we will go back to WHOI with all of our gear and finish some final measurements before we head back to Wellesley.

The science party for the Irminger 6 cruise
We’re excited to get back to land, but sad to be leaving the ship and everyone we’ve met along the way. This has been an amazing trip and we are so happy and appreciative of our time spend on this cruise. The Irminger 6 cruise has been an experience unlike any other we have been on. Once we arrive back on shore, we will be going our separate ways to start off the upcoming semester. Hilary is starting at Boston College, Claire is going back to Wellesley, and Thanda is about to start her semester abroad in Tanzania. We’d like to thank Hilary, fellow science party members, and the crew of the RV Neil Armstrong for a fantastic time at sea. Thank YOU for following us on our journey and reading our blog.

Another picture of us in Greenland

Signing off for the final time,
Claire and Thanda

Behind the scenes

Now that we are almost back to the States, I thought I would take some time to look back on some moments from this cruise that did not make it into other blog posts. We don’t do science 24/7 and down time opens up the chance for some fun moments.
Sheri with the day's crossword

In between mooring deployments, water samplings, and rosette management, there were things that became routine to the members of the science party. Everyday has started off with a new crossword puzzle from The New York Times, and despite the various degrees of difficulty our chief scientist Sheri White has never failed to finish a puzzle (Claire and I have only finished two this whole trip). With a record time of 8:00 she is truly a crossword wiz.

Another staple in the Armstrong schedule, and a crowd favorite, is cheese-thirty (or cheese o’clock depending on who you ask) which starts at around 2:30 and extends until dinner time. They put out fancy meats and cheeses and some fruit along with different types of bread and crackers. Some people plan their dessert eating schedules around cheese-thirty and others see it as a “pre-dinner dinner.” No matter what it is a high point of people’s days and great for ship morale.


One of the best spots on the ship is the bridge, and if you are out there at the right time, the captain just might let you drive the ship. There was a day where we had to do glider maintenance after we had deployed them, so we set out to find them and as we were searching our captain Derek Bergeron let Claire, Shawnee and me each have a turn driving the ship. While it was terrifying at first, we were assured that nothing bad would happen and it all worked out smoothly.

Shawnee, Claire, and me each taking a turn steering

On our transit back, once all the science was done there was a lot of down time, and during in that down time we filled it with a bunch of different activities. We’ve had a scavenger hunt, a photo contest, a very intense game of Pictionary, a planking contest, and a game night, amongst other activities. One day I realized the ship stopped moving and when I went outside people were fishing off the side of the ship we were out there for a while trying to catch fish and we did catch some. It took me a couple tries but eventually I also caught one!

Me with the pollock I caught
Hilary posing with a cod 

From movie marathons to dance parties, dull moments on the Armstrong are few and far between, and there are only a couple more of them to go.

Signing off,



Last week we followed through with the oceanographic tradition of sending Styrofoam cups down to the bottom of the ocean with the CTD rosette. After decorating our cups, we sent our art work down to 2,600m below sea level to shrink them. The pressure at depth pushes all of the air out of the Styrofoam, dramatically changing both their texture and size. It was our first time sending down cups, and so Thanda and I had taken some back home to decorate with family, as well as decorating some on the ship. Thanda drew memes and moorings, Shawnee drew the Irminger sea, and I decorated my cup with moorings, fish, and gliders. Right before we sent them down with the CTD rosette we carefully wrote the latitude, longitude, and the depth the CTD was going down to. We even used Styrofoam cups from Truly Yogurt, an ice cream store in Wellesley. Hilary said that different types of Styrofoam shrunk different amounts, so we were interested to see how the cups compared.
Hilary attached our laundry bag full of cups to the CTD rosette, making sure to securely attach the bag to the CTD, and even use zip ties to create columns of cups so that they would shrink evenly, and not fall into each other. We had learned that cups had shrunk together last year, and that it was hard to pry them apart, so we did our best to prevent it. We sent down the CTD and waited for our cups to return.
All of our carefully decorated cups before they went onto the CTD
After working and waiting, the CTD rosette returned with our cups! I was surprised by how much they had shrunk.
The CTD rosette being lowered into the water with our cups in a mesh laundry bag zip tied to the CTD frame
While none of the cups had shrunk together like they did last year, some of our cups had bubbles in them! In the cups with bubble the top part of the cup had shrunk, but then at the bottom some cups the lower rim simply remained unchanged, while with others you could clearly see bubbles. It was fun to think about how that air went to 2600m below sea level and back up, all the while keeping the shape of the cup the same. However other than the couple of cups that had bubbles, the other cups turned out really well!
Post ocean cups! The white cup in the background is the original cup size, and shows how much the cups have shrunk
It was really fun decorate cups and take part in this oceanographic tradition, and especially thinking about bringing home a very original, priceless souvenirs for friends and family.
Shawnee (left), Thanda (middle), and me (right) with our cups on the CTD

Are we allowed to to take samples in Greenland?*

Me and Claire at the bow of the Armstrong 

Hello all! This is Thanda and on day 12 of our cruise I am reporting to you from Greenland! After many days of speculation about the weather, our quest for a spare part for the rosette is finally complete at the Prince Christian Sound.

Ellen handing us the rosette piece

Ever since we realized that the CTD rosette was not functioning properly early on in the cruise, it has been up in the air about whether or not we were going to get it fully operational again. There were talks between our Chief Scientist Sheri White, our Master Derek Bregeron, the SSSG techs Chris Seaton and Amy Simoneau, and people back at WHOI about the part we needed and how to get it out here. With the weather forecast changing everyday and people at WHOI being four hours behind us, it was never clear on if we were going to be going to Greenland or not, but here we are. We got into Greenland’s waters two nights ago and spent yesterday riding up the sound trying to find a good rendezvous point to meet up with Ellen, the person who works at WHOI who volunteered to travel to Greenland to bring us the rosette piece. Today, bright and early in the morning, Ellen arrived alongside the Armstrong in a small boat that she had chartered to bring her to us from Nanortalik, we got the part that we needed, we gave Ellen a thank you gift bag, and we were on our way out. Now we are off back to the mooring sites for a day full of CTD casts to get enough data to calibrate our mooring and glider sensors before we make the transit home!                                                                                                                                                                                                                                          

Me chilln with a berg
Despite the heavy winds and rain, Greenland is hands down the most gorgeous place I have ever been to. While this post is to give an update about the CTD rosette, I mostly just wanted to post beautiful pictures of Greenland.

Signing off,

*No, we did not take any samples in Greenland because to take samples within 12 nautical miles of another county, you need to have prior clearance, and since we did not have that clearance, we did not take any samples
More Greenland!

Problems with the CTD

Hello everyone!

Like I mentioned in my last post, CTDs are one of the most important instruments in studying oceanography. Different sensors on the CTD measure conductivity, temperature, and depth, as it is sent down through the water column in a CTD cast, giving us profiles of the water they move through. This helps give oceanographers get a sense of how water changes down the water column. On the Armstrong, we have a rosette attached to the CTD. This rosette has 24 niskin bottles, which are essentially big tubes with lids on the top and bottom that close on command as the CTD rosette moves back up to the ship from the bottom of the ocean. This allows us to sample water from the bottles, and can test for dissolved oxygen, nitrate, chlorophyll, dissolved inorganic carbon, dissolved gases, and particulate organic carbon, so that we can understand what is happening in the biological carbon pump at different depths. The CTD rosette also has a variety of different sensors which measure things like oxygen, chlorophyll, and salinity. One of our favorite sensors is the dissolved oxygen sensor, because it is one of the main variables we are looking at in our research.
Chris and Amy (wonderful SSSGs) working on fixing our CTD. The instruments are located in the core of the CTD rosette, and the niskin bottles are the the grey cylinders. Photo Credit to Shawnee Traylor. 
However, in a classic example of how things don’t necessarily go to plan at sea, we have been having problems with our CTD rosette. When we sent down the CTD cast for a test run on the second day we were at sea, we received data from the CTD instrument itself and the rest of the sensors attached with it (so we could see depth, temperature, salinity, and chlorophyll), however we couldn’t close the bottles that we needed to practice taking samples with. After a few days the SSSGs (incredible people who help with technical support on the ship) opened the chamber that held all of the hardware for the bottle closing mechanism to find 3 inches of water! The components were would not be able to work because of the salt water, which meant that we will not be able to close the bottles, or take samples from them. This shifted the focus of what we could do for our research. OOI provides incredible infrastructure to oceanographers by providing an array of sensors at different depths in the Irminger Sea. However, our data for studying the biological carbon pump needs extremely precise measurements, so without sampling from the rosette, we would not be able to calibrate the sensors to the extent that we would need to.
Pieces of CTD rosette hardware that have salt crystals on them after getting wet

Closer up picture of salt crystals on CTD rosette hardware 
So far, we have three solutions. The first is to add an oxygen optode (or a sensor that measures dissolved oxygen) like the one we have on our gliders and on the surface mooring to the CTD sensor package so that we can better understand the calibration between multiple instruments. The SSSGs did this the day after we found out we wouldn’t be able to take water samples. However, because one of the main goals of our project was to provide more specific calibration points for our biological carbon pump measurements, we wondered if we could do more.
CTD rosette set up with acoustic releases (yellow cylinders)
Acoustic release mechanism that will close the niskin bottles. This piece is found at the bottom of the acoustic releases
This led us to our second option, which is to try to figure out a way to get a couple of bottles to close with an anchor release. On the night that we found out that the CTD wouldn’t work and people started suggesting all kinds of different solutions, and James, a science crew member, suggested this ingenious solution. On all of the moorings, there is a system that releases the cables and instruments on it from the anchor that held it down for a year. The idea is that we would use the same mechanism that releases the cable from the anchor to close the bottles at specific depths. Last night we put this idea to the test. Using acoustics, Stephanie and James fired the acoustic release, and closed a bottle. We were able to close three bottles, and take samples!
Everyone happily sampling from the niskin bottles last night 
However, the CTD still needs the part that was broken on its test run. Our chief scientist has decided that now that we have finished deploying and retrieving all of the moorings that we need to, we will go up to Greenland to pick up the part that was broken. The current plan is to meet a ship off the coast with someone from WHOI who will be in a smaller boat with the part we need, after having taken an epic journey traveling from Woods Hole to bring it to us. After we pick up the part and fix the CTD, we will then try to sample as many of the sites in the OOI array as we can. Weather could be a lot rougher than it has been so far, so hopefully we will be able to get back out to the array before we start our transit home so that we will be able to collect as many samples as we can.

That’s all for now, wishing us a quick transit to Greenland!

It's a bird! It's a plane! No it's a glider!!

It has been a lively couple of days on the R/V Armstrong. Yesterday was the surface mooring deployment which was super exciting, and the excitement continued today with the glider deployment! There were a total of three gliders that got put in the water today along with the hybrid profiling mooring (HYPM), but that’s something to be explained in another blog post. Today, the focus is on gliders.

Two days ago, I got to speak with Collin Dobson who is in charge of all the gliders (I nicknamed him the “glider G.O.A.T”) about how gliders function and collect data. Contrary to what you may think, gliders don’t actually fly.  They manipulate buoyancy to navigate the water column. To do this, each glider has an oil reservoir and a pitch battery that move throughout the glider to change its volume which changes its density to either sink or float. To sink, the oil reservoir retracts, and the pitch battery moves forward an inch to become negatively buoyant and sink, and to float back up, the oil expands out of the reservoir and the pitch battery moves back. The wings are attached to the glider to prevent the glider from sinking straight down to the sea floor and there is also a rudder on the tail to help the glider sink at an angle. While it has a crush depth of 1200m, the glider only dives down to 980m and it does so at an angle of 26 degrees. When the gliders come back up, they don’t always surface, each time they go down to depth and come up to reach 50m is called a “yo” and they have two yos per dive segment before they resurface.  There is an air bladder in the tail that helps the glider reach the surface and only that tail comes out of the water, and once that tail is out of the water the glider can “call home.” During these calls home, the gliders send OOI back information on their condition and every tenth point of data it collects.
Collin posing with  gliders

There are two types of gliders that we have on the cruise with us: the profiling glider and the open ocean glider. The profiling glider functions near the surface mooring and the hybrid profiling mooring (HYPM) collecting data from the surface to 200m and has most of the sensors for data collection with a CTD instrument which measures salinity temperature and depth, PAR (Photosynthetically active radiation) sensor, an oxygen optode, and a SUNA nitrate sensor. Open ocean gliders basically act as data mules for subsurface moorings that cannot transmit data on their own. They operate on triangular routes collecting data throughout the range of 50-980m. These gliders also have the sensors that most oceanographic instruments have including an oxygen optode, a ctd, and bb3 which samples chlorophyll and backscatter amongst other things.
For our project, we've modified the open ocean gliders to have oxygen optodes in a special place at the top of the glider so that it can measure oxygen in the air when the glider surfaces, which allows us to better calibrate the oxygen sensors throughout the year

Before going in the water all gliders get named pictured is 515 named "Aurora" and our project glider 525 which is named "Homefry" by the BCP team
 With all the gliders in the water in the water, including the one funded by out project, the day comes to a close, only with more deployments tomorrow!

Signing off for today,


Team BCP with our project glider Homefry


Surface Mooring Deployment

We are underway, and made it out of Icelandic waters a couple of days ago. Neither of us have been too seasick, and we are starting to get our sea legs.

Today is an exciting day aboard the Armstrong because we deployed the surface mooring this morning! The surface mooring is essentially a giant buoy with a variety of instruments on it that can make measurements in the water and air. It is powered by a combination of solar and wind power, which allows OOI to collect measurements year-round to better understand this remote area.
In this photo the crew lowers the top buoy of the surface mooring into the ocean

There is a wide array of instruments on the mooring. The top of the surface mooring has different instruments that measure different properties of the atmosphere, which we can later use to compare with these properties in the water. Seven sensors make meteorological measurements, such as wind speed, which help give a better sense of the weather in the area, but could also help inform scientific observations, for example relating a specific phenomenon to a storm. There are also satellites, a GPS unit, and a SBD (a device that receives email message commands) all of which help OOI communicate with the surface mooring and know where it is. It also has a camera on it, which can help engineers understand how their equipment is fairing and the current conditions in the Irminger sea.
Stephanie Petillo, OOI SGSN software lead, explaining different instruments on the top part of the mooring. Most of the instruments are attached to the two 'halos' on the tower of the mooring.
Moving down to the lower part of the buoy there are a lot of different instruments to measure different properties of the water. Most of the instruments that are on this part of the surface mooring measure the exact same things we have been looking at in our lab. The surface mooring has a fluorometer, which measures chlorophyll and backscatter, a SUNA, which measures the amount of the nutrient nitrate in the water, and an oxygen optode, which measures the amount of dissolved oxygen. Additionally, there is a spectrophotometer, which shines a beam of light across a small area of water, and uses the absorption and scattering of different wavelengths to see what is in the water. There is also a pCO2 sensor, which also has a tube going to the air, so we can measure the difference in CO2 between the air and the sea.
Stephanie explaining different instruments on the bottom part of the mooring. She also showed us ingenious engineering designs to help secure the mooring, but still allow it to move with the ocean.

From the buoy there is a long cable that goes all the way to the sea floor! Along this cable there are a couple of key instruments attached. Between 130 m and the surface, the cable has a fluorometers, oxygen optodes and a pCO2 sensors attached onto it in cages. Additionally, CTDs are attached intermittently between the surface mooring and 1,500 m. CTDs are one of the most important oceanographic instruments, they measure conductivity, temperature, and depth of the water they are in. Later on in the cruise, we will send a CTD down to the bottom of the ocean so that we can compare the profile from the surface mooring to that data. At the very bottom of the cable are 72 glass balls which will be released from the anchor at the very bottom to retrieve all of the instruments along the line next year.
Here we are helping hold CTDs to attach to cable.
The surface mooring is an incredibly important instrument in this array because it is the only mooring that has instrumentation that measures the air, and the only mooring that has power. This allows it to measure many more aspects of the region that other moorings cannot, giving us a more precise understanding of what could be changing different variables in the region.
A picture of us with the surface mooring!
Until next time!