Category Archives: Cruises

Cruise Report AR69-03

By Fiamma Straneo

Cruise Track: AR69-03 Reykjavik to Nuuk, August 18 to September 24, 2022
An awakening of gusty winds and capricious waves
Replace images of Reykjavik
Hesitant movement on the ship as we abruptly begin
Steam, Stop, Sample
Rollercoaster at the surface mirrors the spires of the mid-Atlantic ridge beneath us
As we head across the Irminger Sea
Steam, Stop, Sample
A rhythm slowly unfolds
Steam, Stop, Sample
Waves become longer and movements less hesitant
Sensors pierce through young and old waters on their way down
Warm waters, suggestive of tropical climes 
Give way to cold, newly formed mid-depth waters and 
Look! The deep waters from the Iceland-Scotland Ridge
Crawling at the bottom, invisible to the surface
The essence of the overturning circulation
Text book learning turns into experience
Steam, Stop, Sample
Until the end of the line
Marked by Greenland’s jagged mountains
Here icebergs with mesmerizing shapes drift in cold, clear waters
Every now and then a glacier comes into view

Turn back to pick up buoys left behind last time we were here
Steam, Stop, Release
Hoping they will cede to our call and drop their anchor
Hoping to be the first to spot them as they pierce through the surface 
Waiting turns into excitement. 
Steam, Grapple, Hoist
Help the heroic instruments back onboard 
Scrub them clean of temporary dwellers
Before greedily listening to the stories they tell.
Two years inside the overturning.
Steam, Stop, Release
Steam, Grapple, Hoist
A rhythm slowly unfolds 
As the instruments pile up on deck
Flurry of laptops, cables, instruments
Young scientists turned overnight into crusty, able oceanographers 
Until, one of many low-pressure systems scurrying across the Atlantic,
Stalls Over Us
Roll, Tie-down, Roll
Toes wedged between wall and mattress anchor us during sleep
Water floods across the deck 
Pilot whales surf in the waves by the ship beckoning
Then just as it came the storm leaves
Leaving sunshine, icebergs, glaciers and northern lights 
Steam, Stop, Sample
Deep canyons guide tropical waters towards the ice
Steam, Stop, Sample
Time to head back to the buoys
Steam, Stop, Release
Steam, Grapple, Hoist
Every buoy replaced by a twin
For more stories in two years.

We cross to the Labrador Sea through a steep-walled shortcut
Here it all repeats
Steam, Stop, Sample
Steam, Stop, Release
Steam, Grapple, Hoist
A rhythm slowly unfolds
Backdrop of southwest Greenland’s gentler peaks 
Crane stops working. 
Intermission filled by acrobatic flights of dark-eyed fulmars
Crane fixed. 
Steam, Stop, Sample
Sensors piercing waters cold and warm, fresh and salty
And deep down the dense waters again.
Crawling at the bottom, invisible to the surface
Steam, Stop, Sample
Vials of precious salty waters packed in endless boxes with little numbers
Some emptied into alchemic alembics 
The vials too tell stories.
This time of origin and happenings along the way
Steam, Stop, Release
Steam, Grapple, Hoist
Every buoy replaced by a twin
To measure for two more years
At night different canyons drive same swirling currents

Steam, Stop, Sample
In the day 
Steam, Grapple, Hoist
At night
Crane breaks. No fix this time
Pause nonetheless to watch great shearwaters wing-dipping in cold water
Without a crane weights are dragged on deck 
Until all the twins are deployed.
Take a break in the icy, flat waters of a fjord before heading out into another storm

Cape Desolation beckons us with its submerged rocks and mountains
Whale spouts in the distance and stiff wind ahead
Forty knots gusting fifty
Fifty knots gusting sixty
This is the North Atlantic after all
Roll, Tie-down, Roll
Steam, Stop, Sample
White waves bounce us in the dark.
Until time’s up 
And the lights of Nuuk’s bustling harbor appear
Hesitant movement on land after 37 days at sea
Ocean data, recently declared world heritage, 
Tucked deep in our pockets in a small hard-drive 
A giant effort by a ship, 17 scientists and 22 crew 
A small step forward for overturning science
To be continued to provide answers
twin buoy after twin buoy
vial after vial
one crusty oceanographer after another. 

The OSNAP zoo

By Donald Slater

The walk-in fridge/OSNAP zoo. Photo: Donald Slater.

The walk-in fridge in the main lab of the RV Neil Armstrong has for the past 5 weeks functioned as anything but a fridge. With storage space at a premium, it has hosted much of the moored instrumentation, including the microcats that measure ocean temperature and salinity, and the aquadopps that measure ocean velocity. The door has further become a pinboard for the birds, whales and mystery gelatinous objects encountered on our travels, collectively known as the OSNAP zoo. Before diving into the individuals that inhabit the OSNAP zoo, I’ll note that Aurora Roth has found Greenlandic names for many of the species and locations, which are noted in parentheses.

Starting with the birds, we do not count among us any ornithologists of great repute, so all identifications should be taken with a pinch of salt. Speaking personally, it is at the relatively tender age of 32 that I find myself at the top of the slippery slope that leads to spotting scopes, but I have been ably assisted by enthusiastic colleagues. We steamed out of Reykjavik on 19 August accompanied by bold gannets (timmik) and shy puffins (qilanngaq), the latter clumsily shooting under the water at the first sign of the boat. We picked up some great shearwater (qaqullunnaq) during our transit of the Irminger Sea, before proximity to southeast Greenland brought sightings of little auk (appaliarsuk) and common murre. While sheltering in the mouth of Tasermiut Fjord in southwest Greenland we were graced by a magnificent white-tailed eagle, and once further offshore, kittiwake.

What started out as an OSNAP aviary rather quickly became a zoo with the sighting of pilot whales (niisarnaq) on 22 August in the central Irminger Sea, where a huge pod appeared to be playing together in the waves for a number of hours. Pilot whales have been perhaps our most frequent sighting, but we’ve also glimpsed seals, orca, humpback and fin whales, most commonly on the east rather than west coast. The crew on the bridge of the boat are always the first to spot a whale, and often kindly radio down to the science lab where there is then a scrambling for jackets and binoculars.

Pilot whales in the Irminger Sea. Photo: Jamie Holte.

Some creatures have been brought out of the ocean against their will. While in Ikerasassuaq (Prince Christian Sound) one of the crew caught some Atlantic cod that constituted dinner that evening. A great variety of life has emerged from the ocean on our recovered moorings, including basket stars and many hard to identify gelatinous creatures, some apparently found to be clavelina lepadiformis. We’ve also had some smaller birds temporarily increase the number of boat inhabitants beyond 39 humans. In late August, during a storm with winds of 50 mph and waves over 4 m, a small group of Greenland wheatear found refuge on the bow of the Armstrong, but sadly perished a few days later. In early September, while over 70 miles offshore in the Labrador Sea, we were visited by a sanderling (siorarsiooq), who surveyed the boat for a few hours before deciding it preferred its own company.

Greenland wheatear (left) and Sanderling (right) on the RV Neil Armstrong. Photos: Donald Slater.

Our most constant companions, however, have been fulmars. Since leaving Reykjavik harbour to the time of writing near Cape Desolation, there has not been a moment without fulmars in view, so that it would be easy to believe the same fulmars have followed us every step of the way. Fulmars constitute the first chapter of The Seabird’s Cry by Adam Nicolson, a book that Fiamma will recommend to anyone who will listen, and which describes fulmars as “wind-runners, wind-dancers, the wind-spirits, alive with an evolved ability to live with the wind, in it and on it.” This has certainly been our impression from the boat – the fulmars coming into their own on particularly windy days, when they like to glide from the stern to the bow within touching distance of the boat, then wheel away with dramatic acceleration out into the ocean before looping around behind us to repeat the acrobatics.

Fulmars. Photo: Hiroki Nagao.

Within a few days we’ll arrive in Nuuk and touch our first land for 36 days. This brings mixed feelings from relief at the freedom of leaving the boat to the sadness of the end of a unique experience. The walk-in fridge in the main lab of the RV Neil Armstrong, having temporarily hosted a thriving ecosystem, will go back to being a walk-in fridge.

[Greenlandic animal names may be found at]

When the science stops

By M. Yoder, Boston College

We boarded the R/V Neil Armstrong as scientists on a mission to collect data and redeploy moorings, and while someone is on shift and working 24/7, it’s not all of us at the exact same time. So, what goes on when we’re not deep in the action? Many of the questions we’ve fielded from friends and family are ones we ourselves wondered prior to getting underway. For future oceanographers and the generally interested, read on to find some of the answers to sea-going’s most mysterious questions!

What’s the food like?

In a word, delicious! It would take literary skill far above that of my own to do justice to the myriad of foods we enjoy. Galley crew Eric, Bryan, and Tommy keep us well fed with a rotating menu of yummy and nutritious meals. Somehow nearly four weeks in there is still fresh lettuce, although more canned and frozen foods are making their way into our diets. Anyone whose shift doesn’t align with all mealtimes can have food set aside with their name on it in a special fridge. In between meals, the mess has an assortment of snacks and beverages you can snag if feeling peckish, plus there is a formal mid-afternoon snack time known as cheese-thirty. There’s a banana bread recipe, that if I’m successful in convincing Eric to give me, might be the most valuable piece of data I collect on this trip. (If my advisor is reading this, I am ~partially~ kidding!)

Here, Croy makes some tea at the beverage station. Everyone has their scientist number or crew member title on a corresponding mug, which is your only drinking vessel provided. This allows everyone to take mugs outside of the galley and not mix them up, but also ensures the mugs make their way back, otherwise you won’t have anything to drink out of!

Can you exercise?

If you’re feeling coordinated! We have access to a well-equipped gym, though you’ll need to descend two levels below the main deck, passing through a watertight door and take a ladder through a trap door. A spin bike, rowing machine, free weights, and two treadmills keep us fit, although it takes substantially more finesse when the ship is rolling. The treadmill in particular is not for the faint of heart, with much discussion about where to hang on in order to get the most land-like workout. Some opt to be vertical pole holders, while others channel their inner parent pushing a child in a jogger, and the boldest go tentatively hands-free.

Do you have internet?

Yes! Which you may have guessed considering we posted this from the ship. We each get 2GB of data through the ship’s WIFI every day, a big upgrade from the 1GB on prior 2022 cruises and from the 200 MB a day from 2018. The speed is even fast enough for video calls to loved ones back home.

Can you do laundry?

Yes again! The ship has two washers and dryers in a laundry room. College laundry room rules apply, set a timer or you run the risk of annoying your shipmates and having your clothes moved to the next machine or the counter.

Do you get seasick?

We’ve been extremely lucky with the weather this trip and have had relatively calm seas, although we are currently hiding in a fjord to avoid large swells. Most people come aboard with various seasickness medications and take them depending on the sea state (how rough the seas are) and their sensitivity to motion sickness. Something I personally underestimated was not the seasickness itself, but the challenge of normal life while everything is moving. Walking down the hallway or just standing upright can be more entertaining, or more difficult, depending on your outlook. In my opinion, sleeping is greatly enhanced or hindering depending on the sea state; sometimes the roll is gentle and rocks you to sleep, other times you’re bouncing along the waves and feeling your mattress rise and fall beneath you.

Speaking of sleeping, what are the arrangements like?

Most people share a room with one other person, which has a set of closets, bunk beds with privacy curtains, and a sink. Bedding and towels are supplied. A bathroom with a toilet and shower adjoins with a room next door. For particularly rough weather, there is even a wooden board you can insert between the mattress and frame to prevent the top bunker from taking an unfortunate trip over the edge. Depending on what shift your bunkmate is on, you likely do some getting ready in the dark, either for the day or for bed, and have to adapt accordingly. One technique I’ve employed is pouring the toothpaste directly into my mouth rather than trying to put it on the brush.

Can you go outside? Can you go on land? Can you swim? Do you feel trapped?

Yes, we can go outside and do it quite frequently, with decks on all sides of the shift and a good deal of the science taking place outside. While we’ve been in sight of land many times, we’re not able to set foot on it as we haven’t gone through customs to enter Greenland, plus there is work to be done on the water! Absolutely no swimming, not that you’d really want to in these 5-10°C (40-50°F) waters. I think whether or not you feel trapped on the ship varies day to day and person to person. Some level of claustrophobia and homesickness is inevitable to varying degrees, but luckily there are plenty of wonderful people on board to spend time with, which leads me to….

What do you do for fun?

Lots! First and foremost, I think I can speak generally in saying that we find it very exciting to make preliminary plots of the data we’re collecting and discuss it with one another.

We play games, consisting primarily of group crosswording, some cards, and a complicated game I’ve yet to attempt called Wingspan.

There are plenty of sights to be seen as we’ve been near the coast, admiring icebergs, glaciers, Greenland’s rugged mountains and fjords, sunsets, and the northern lights.

We’ve been seeing a variety of fauna, like pilot whales, puffins, fulmars, and auks. These are logged on the main lab wall with their English and Greenlandic names. We’ve also been learning the Greenlandic names of many places we’ve passed, thanks to Aurora!

I’d be remiss to not mention being greeted by Neil himself each morning on the way down to breakfast. Hopefully, this has given you some insight into the non-science aspects of life at sea!

Mooring Operations along the CF Array

By Hiroki Nagao

On 19 August 2022, the R/V Neil Armstrong set sail from Reykjavík to the cold, stormy waters of the Subpolar North Atlantic. This region consists of a complex network of surface and deep ocean currents, which together play a critical role in the Earth’s climate system via the transport of heat, freshwater, and dissolved gases. Among the objectives of this cruise was to service the Cape Farewell (CF) mooring array, located off the coast of Southeast Greenland.

Each mooring in the CF array consists of a set of instruments that are fixed to a cable, supported by an anchor and a set of floats. These instruments include microCAT sensors, oxygen optodes, and Acoustic Doppler Current Profilers (ADCPs), which measure temperature/salinity/pressure, dissolved oxygen, and current velocity, respectively. These instruments stay at a fixed depth in the water column for two years and are then serviced and replaced. Mooring data are critical for obtaining continual records of oceanographic variables and thereby inferring the temporal variability in ocean circulation and associated fluxes of heat, freshwater, and dissolved gases.

Servicing a mooring first involves its recovery. The technicians from the Woods Hole Oceanographic Institution (WHOI) disconnect the mooring line from the anchor by sending an acoustic ping from the vessel to the release system. Once the mooring line reaches the surface, the whole crew jumps into action to bring all the floats and instruments, one by one, to the deck. The ship carefully maneuvers to the floats and then, the crew works tirelessly to catch the float with a hook attached to a rope. We watch with much anticipation as the float is carefully placed on a stand. Next comes the instruments, from the shallowest to the deepest. We record the serial number of each instrument and clean the grime and the growth that has covered the instruments over the past two years. Finally, the acoustic releases are brought back to the surface.

WHOI technicians working as a team to bring a mooring float to the deck. Photo by Hiroki Nagao.

After the recovery, all the instrument data are downloaded into the computer. We also perform calibration dips of the microCAT sensors and the oxygen optodes. This involves attaching the sensors to the CTD rosette, so that the sensor data can be compared with the measurements collected by Niskin bottles and CTD instruments on the rosette. For example, I found the oxygen optode measurements to be greater than the oxygen concentration determined from titrations of water samples from the Niskin bottles.

Margaret, Bobby, and Nicole preparing for a calibration dip of the mooring instruments. Photo by Hiroki Nagao.

Once the data processing is finished, the re-deployment of the mooring takes place. The WHOI technicians carefully attach all the mooring components to the cable one by one, ensuring that none of them gets damaged. The re-deployment lasts for 1-3 hours, depending on the length of the mooring line. Once all the floats and instruments are sent off the deck, the technicians attach the release system and the anchor to the line, before dropping the anchor to the seafloor.

WHOI technicians preparing to drop the anchor of the mooring. Photo by Hiroki Nagao.

The whole mooring operation along the CF array was challenging. Our plans were contingent on the time of day and weather, since mooring operations are not safe at night or rough waves. Thus, we interspersed the mooring operations with CTD casts off the coast of Southeast Greenland. Moreover, we had to contend with unexpected circumstances in the mooring. For example, several ADCPs from the CF7 mooring suffered extensive damage, possibly because a portion of the mooring line broke off under rough weather conditions. Despite these obstacles, we finished all the CF mooring operations by the end of the second week of the cruise. All our efforts had been paid, as we were treated with picturesque views of the Prince Christian Sound the following day.

Daybreak on the Prince Christian Sound. Photo by Hiroki Nagao.

Learning the Water Sampling Routine

Foggy weather as the rosette sits just below the surface. Photo by Monica Nelson.

By Monica Nelson

Many of us on the CTD watches are physical oceanographers but we were charged with collecting biogeochemical data to complement the OSNAP mission. In addition to the usual water sampling to calibrate the salinity sensors on the rosette, we’ve been collecting water samples to calibrate oxygen sensors and samples to measure ocean carbon, nutrients, and oxygen isotopes (which indicate glacial melt) in the lab once we’re back on land.

For several of our CTD watch brigade, it’s their first time on a research vessel, and for most of us, we’ve never collected samples like these before – let alone been in charge of coordinating it. Trying to figure out how it’s all going to work was daunting and definitely a little nerve wracking. We’re the only science party doing an Irminger Sea section this year, so there’s pressure to do it right.

I was nervous for our test cast, the dress rehearsal before we started the real science, but the mechanical arm that lifts the rosette didn’t work properly. The anxiety of doing the rosette dance well is replaced by the anxiety that we won’t be able to use the rosette at all. Modifications made by the crew while we were in Reykjavik to make it safer restricted its motion. Science at sea is always a matter of overcoming the unexpected. After a few hours delay, now well past bedtime for the midnight-to-noon shift, we all scurried back out on deck for a second attempt. This time the rosette deployment went smoothly, our precious package of sensors and water sampling bottles was swallowed by the sea and dove towards the sea floor. The cable lowering the rosette transmits data back to the boat, allowing us to see the measurements real-time. We sat in the cozy lab, eyes fixed on the squiggly lines worming their way down the computer screen – a different coloured line for each variable we’re measuring. Together, based on the data we were getting back, we chose the water depths we want to sample and sent messages down the wire to close the water sampling “Niskin” bottles.  With five different types of water samples needed, it took some figuring to make sure everyone got the water they want. With each person voicing their sampling needs, Bobby, at the helm of the CTD, was getting inundated with requests.

Computer screen with colorful squiggly lines – aka CTD downcast data. Photo by Monica Nelson.

With all the bottles fired we got the rosette back on deck and a flurry of activity ensued: start downloading the lowered ADCP data, turn the secondary CTD off, and start collecting water samples!

Both watches were doing the test cast together so there was twice as many people out on deck as there normally would be. Meg was overseeing me (Monica) and Hiroki taking water samples for oxygen and carbon. I was overseeing Arthur and Matt taking water samples for nutrients and oxygen isotopes. And Aaron was overseeing Arthur and Matt taking water samples for salinity. Aurora and Nicole were learning how to run the lowered ADCP while also trying to shepherd the rest of us around the rosette in the right order. Too many people needing to be in too many places at once without getting in each other’s way. We’d talked through the sampling strategy and practiced at the sink, but that was our first time doing the dance around the rosette. With heightened stress levels, and so much to try and keep straight, we stumbled through the motions in a state of mild chaos.

Our dress rehearsal on the test cast did not leave me resting assured that we were ready for the real show. I went to bed uneasy about how the first few Irminger Sea stations would go the next day. But when the sampling starts in earnest, there was only four people to communicate between and only one person responsible for any given type of sample – a much better recipe for avoiding tripping each other up. All went well and the vials of sea water start stacking up.

Chaos on the test cast cleared the way for calm on the casts that mattered.

Sunny skies and calm seas for rosette deployment. Photo by Monica Nelson.

By night and by day we repeated this dance while watching the waves, the clouds, and the growing number of sea birds following the boat. By the time we got to the tightly-spaced casts on the Greenland coast we were dancing elegantly and efficiently around the rosette. We’d found our rhythm as a team and our muscle memory guided us through the routine as one.

After 51 CTD casts we’d sampled our way across the entire Irminger Sea from south of Iceland to Greenland and completed our first pass of the Kangerlussuatsiaq/Lindenow trough on the southeast Greenland shelf. We’ve learned to bring a speaker out to the rosette and we’re sampling and shaking bottles to tunes under the ship’s spotlight.

Matt and Nicole of team “Nicebergs”, midnight to noon watch. Hiroki and Aaron not featured. Photo by Aaron Mau.
Bobby, Aurora, Arthur and Monica of team Niisa, noon to midnight watch. Photo by Margaret Lindeman.

Straneo OSNAP: Cruise AR69-03 intro

Some of AR69-03 science party and crew. Photo by Crow Carlin.

By Monica Nelson

Out in the Irminger Sea, our world is at once both very small and very expansive. Confined to R/V Neil Armstrong our world consists of the instrument-laden lab, the sea-spray-soaked deck, and the endless grey-blue ocean stretching for as far as the eye can see – or as far as the fog permits.

We’re here to monitor the beating heart of the ocean: Is it healthy? Is it behaving like it was two years ago, during its last check-up? We transited from Iceland to the east coast of Greenland and are now examining the coastal ocean, taking all sorts of measurements along the way. We take the ocean’s temperature to see how the ocean is regulating the Earth’s climate. We monitor the ocean’s breathing to see how the ocean is pumping oxygen into its depths. We fill vials of water samples to run in the lab back home to see what nutrients and carbon the ocean’s veins are transporting.

Over our five and a half weeks at sea we’ll be recovering and redeploying 20 moorings on the southeast and southwest tip of Greenland, holding over 100 instruments, that measure the ocean’s vitals in between our biannual visits.

We are the fifth and final OSNAP (Overturning in the Subpolar North Atlantic Project) cruise going out this summer, having left port a week after the German Karstensen cruise. This multinational effort monitors the variability of mass, heat and freshwater transport by the ocean. It’s a resource-intensive endeavor: we’re a science team of 17, plus two resident science technicians, and all the crew; we’ve got a boat load of specialized equipment and the whole procedure takes lot of time and money. The busy summer of OSNAP fieldwork continues!

Labrador Sea Weather Forecasts – Meet our Meteorologist and Weather Technician aboard the RV Meteor

Julia (left) and Andreas (right) in their office.

By Anne-Sophie Fortin

Every day aboard starts with looking up the weather forecast from our favourite meteorologist aboard: Julia Wenzel. Her forecasts are central to the planning of our day-to-day operations on the ship. While on land we may be more interested in whether a day will be sunny or rainy, here at sea we are more interested in the wind direction, speed, and wave height. Storms such as the current hurricane “Danielle” and the low-pressure system over Western Europe are also of interest even if they are far away as the swell propagates hundreds of kilometres away from these weather systems.

Forecast of significant wave height (colours, in meters) and the wind strength and direction (arrows). The approximate position of the vessel is indicated by the boat icon. The hurricane “Danielle” (lower left) and low-pressure system (lower right) produce high waves locally.

Our weather technician Andreas Raeke, on the other hand, takes care of all the meteorological instruments (e.g., wind, temperature, humidity) and the weather observations (clouds, visibility, precipitation, waves) aboard the research vessel. The data collected on board is transmitted to a global database by satellites and assimilated into weather models which increases the accuracy of the forecast. Additionally, Andreas launches every morning a weather balloon, which measures the atmospheric pressure, temperature, humidity, and wind speed as it takes in altitude.

Weather balloon launch. Video: Andreas Raeke.

Gliders Recovery with a Rescue Parachute

One of our gliders in the rescue parachute. Photo: Julia Wenzel.

We returned where we investigated an eddy last week to recover our two gliders that have been collecting data since then. Because of the strong winds, low visibility, and high waves, we could not use the Zodiac to recover the gliders this time. Thus, a “rescue parachute”, originally designed to rescue a person that would have fallen off the vessel, has been used for the gliders’ recovery.

Mooring Deployment at Station K1

Everyone is helping with the deployment of the mooring K1.

This week, we recovered, serviced, and redeployed the last mooring of our cruise, the K1 mooring. This mooring measured continuously temperature and salinity in the central Labrador Sea since the early 1990s. More recently, oxygen sensors have been added to the uppermost part of the mooring. Measuring oxygen in the central Labrador Sea is quite interesting as the deep convection there results in intense oxygen uptake.

The K1 mooring was also the most complex mooring that we had to deploy as it has a large surface buoy with an instrument to transmit its datasets in near real-time to a global database by satellites. Near real-time datasets greatly improve the accuracy of weather forecasts and ocean analysis as they are assimilated into weather models.


Left: Bottles of seawater sampled at different depths during CTD casts. Right: Some gas is added to the bottle to push the water into the syringe.

By Elizabeth Wallace

Here aboard Meteor, there are many interrelated projects happening which will all add to our understanding of this complex region of the ocean, the Subpolar North Atlantic. One such project is the measurement of nitrous oxide (N2O) gas. You may be familiar with N2O as the “laughing gas” used during surgical procedures, but it is also very important in the Earth’s climate system – N2O is a greenhouse gas, and the amount that is present in the ocean is controlled in part by marine microbes.

Past measurements have not yet been able to determine whether this region of the ocean is a “source” or a “sink” of N2O, whether N2O moves from the atmosphere to the ocean water or the other way around. This is particularly important in the Labrador Sea because some of the water here moves to the bottom of the ocean and does not touch the atmosphere again for a long time.

On board, water samples are collected from the Niskin bottles on CTD casts in order to measure the N2O concentration at different locations and depths. The N2O cannot be measured on the ship, so the samples need to have a little bit of poison added so that the microbes inside die (sorry, microbes) and cannot change the amount of N2O before the measurements are made back on land. Samples are also being collected to measure other nitrogen-containing molecules, like ammonium, nitrite, and nitrate, since they are important nutrients for biological activity and are often influential in the formation of N2O. The goal for the whole cruise is about 2000 samples!

Combining measurements of N2O with the other measurements of ocean dynamics happening on board will begin to provide insight into the full story of N2O – where is there a lot and where is there only a little? Where does it come from and where will it go? If conditions change in the future (warming temperatures, changes in currents and deep water formation) what might happen to N2O?