Category Archives: Cruises

By Anne-Sophie Fortin

Departure from St John’s Harbour

August 11-12, 2022

The water is still in the harbour by night. Shrouded in what seems like a perpetual mist, the Meteor is waiting patiently. People step aboard the ship in small waves and wash up in their beds, exhausted from their long flights. As the sun rise, the crew finalizes the preparation for the departure. A few hours later, we are all on the deck to say goodbye to St John’s. As the ship leaves the harbour, we have a stunning view of St John’s rocky coast. As the land fades away, the swell appears and activities on board begin!

You may find this blog post also at https://www.oceanblogs.org/meteor184. In addition, you can follow Meteor’s position and path at https://beluga.geomar.de/m184.

Meet the Scientific Crew Abord the M184 Cruise

First, let me introduce to you the scientific crew aboard the M184 Cruise. The chief scientist of this expedition is Johannes who takes care of the general smooth running of scientific activities on board. He can rely on Sunke (also a co-chief scientist), Félix, and Fehmi, the CTD watch leaders, and on the technicians Wiebke, Philipp, Christian, Andreas, and Paul, which are a great help in all kind of situations.

Paula, Augustin, Hendrik, Mario, Pia, Sam, Jörg, Anne-Sophie, and Hannah are split into three groups that are under the supervision of the CTD watch leaders. These teams are doing rotating shifts so that real-time data is taken around the clock, even at night.

Some people on board take the lead responsibility of specific experiments, such as the analysis of nutrients and oxygen in the water performed by Elizabeth and Lea. Sam oversees the deployment of a highly sensitive bottom pressure instrument from the Scottish Association of Marine Science (SAMS) that has a 10-year lasting battery. This instrument is one of a set of two designed to measure the sea surface height across the North Atlantic. Jochen and Paula handle the deployment of Hereon drifters, which follow surface currents. Paul manages the MicroCATs, i.e., the instruments measuring the temperature and conductivity, on the moorings deployed as part of the OSNAP program.

Throwing Scientific Instruments Overboard

August 13, 2022

Today we (purposely) throw some scientific instruments overboard, the firsts of many. In the picture, you may see Paula lowering a Hereon Drifter with a rope. A Hereon Drifter is a Lagrangian surface drifter, which means that it follows the water mass where it has been deployed, under the condition that the water mass in question stays in the upper part of the ocean as the Hereon Drifter float at the surface. It is quite useful to estimate upper water currents as the instrument report its position every 5 minutes.

Upper Ocean Survey with the Moving Vessel Profiler

August 14, 2022

As we transit toward the next station with a speed of about 10 knots, we are taking continuous profiles of the upper 100 meters of the ocean. To do so we use a Moving Vessel Profiler (MVP), an instrument measuring temperature and conductivity (from which salinity can be derived) is free-falling in the ocean and then automatically pulled back to the surface.

The goal here is to survey the Labrador Current fronts, which are sharp changes in the temperature and salinity vertical structure over short distances, and the mixing of Labrador Current water with other water masses over the Labrador continental shelf. The Labrador Current is a water mass particularly cold, fresh, and high in dissolved oxygen.

Testing Instruments in the Deck Pool

August 14, 2022

Today was entertaining as Paul, Félix, and Christian calibrated the buoyancy of two Gliders. Gliders are autonomous underwater vehicles using buoyancy to move around. As they can change their pitch, i.e., angle, they can glide horizontally while moving up and down the water column. Calibration of the Glider’s buoyancy consists of setting the Glider density close to that of the water mass it is deployed. To do so, a small pool has been assembled on the deck and filled with seawater. Then Paul and Félix put on an aquaphobic combination to not get cold as they had to stand still in the water which temperature is around 10^oC. After successful tests, the Gliders are now ready for deployment in the ocean, but that will be for another day.

Station K8 – Recovery of a Mooring Array in the Fog

August 15, 2022

To measure the ocean circulation, mooring arrays have been deployed since 2014 in the Labrador Sea as part of the OSNAP program (o-snap.org) and are serviced every two years by scientific expeditions like ours. Today we successfully recovered the K8 moorings and the measurements that it took over the past two years. But it was not so easy!

The weather was quite nice in the morning. As we were approaching station K8, we sent an acoustic signal to the K8 mooring array so that it detaches itself from its anchor and starts floating at the surface. However, a few moments later, we entered a thick fog, which complicated the recovery. Despite the fog, we could guide ourselves to the array using the acoustic deck unit, which shows at which distance we are from the array. After a few hours of hunting in the fog, we finally got visual contact with the array. The crew then recovered the mooring array with their winch, and we could start cleaning it, extracting the datasets, and the preparation to put it back to sea for another two years.

Glider Deployment

August 16, 2022

After the successful calibrations performed yesterday, one of the two Gliders has been deployed today. It will be autonomous and take measurements of water properties, such as temperature, salinity, oxygen, and chlorophyll until its recovery a few days from now.

By Daan Reijnders

“Well, I’m somewhat of a stowaway here…” This is how I’ve been introducing myself to some crew members in the messroom during dinner or when fetching some late-night cereal. I had never been to the open sea before this cruise. I usually study the ocean from my desk, using models. Some are idealized, capturing just the essence of a particular process, while others aim to represent the ocean as well as possible. Still, we will never be able to simulate the entire ocean, with all its diverse structures, in the finest details. This is why sea-going oceanographers embark on research cruises – to try to observe how the ocean truly behaves.

Although ocean observations are not directly part of my Ph.D. research at Utrecht University, I consider myself a physical oceanographer-in-training. Of course, part of that training is to get out there and see the thing I’ve been studying from my desk for the past years. With some asking around, I was lucky to get a spot in Femke de Jong’s science party from the Royal Netherlands Institute for Sea Research (NIOZ) on this cruise aboard the R/V Neil Armstrong. Our goal is to recover and deploy moorings that are part of OSNAP (Overturning in the Subpolar North Atlantic Program), together with scientists from the University of Miami. Last week, we steamed off from Reykjavik, and we will return there again in two weeks.

While we’re working on the mooring array, we’re ‘doing CTDs’ along the way, measuring conductivity, temperature and depth at specific locations. This helps us understand the water’s profile and properties at the locations between the moorings. CTDs are the “bread and butter of observational oceanography”, as Bill Johns, chief scientist of this cruise, phrased it during the science briefing. So, what better way to immerse myself in observational oceanography than to immerse the CTD into the water every day? By the way, CTD refers to the measurements, the activity of taking those measurements and the instrument set we use for it. As a ‘CTD watch’, I take care of the measurements by dropping a set of instruments into the water, or rather, communicating with the bridge and the winch operator to carefully lower the CTD to specific depths. The CTD’s casing is lined with a ‘rosette’ of so-called Niskin bottles, that can be closed at specific depths to sample water, which is used for calibration of the instruments. Every time the CTD gets back on deck after we sent it off to 20 meters from the ocean floor (making sure not to hit it!), we take the samples from the Niskin bottles. We literally get in touch with the water’s profile as the sampled water that streams over our hands get colder with the depth at which the bottles were closed. If I’d ask for more immersion, I’d have to jump off the ship and swim away with the pilot whales.

I’ve now grown accustomed to my bread and butter and hopefully, it’s smooth steam from here on out. With approximately one week done and two ahead, I’m looking forward to helping out with the recovery of the NIOZ moorings, but also to continued fun with everyone on board. The major takeaway from my participation on this cruise is an obvious one: it takes a tremendous amount of effort in terms of time, planning, resources and most of all people power to deploy a mooring or to go out on a CTD transit, from the scientists and engineers to the mates, oilers or cooks that form the ship’s crew. It’s something I knew, but also something I will forever appreciate, whether I’ll be looking at observations or models. What is the latter without the former anyway? In any case, after this experience (and earning my sea legs) I’ll never again have to introduce myself as a mere stowaway modeler.

By Phoebe Hudson

It’s 11 pm – time to wake up! I re-open my porthole and it’s now dark outside, with only the whitewash as a contrast against the dark sea background. I stumble around my cabin – getting dressed, brushing my teeth and hair – struggling to tell if I keep bumping into things because of my lack of balance in the morning or the ship’s swell!

I pop into the main lab on my way up to breakfast to check everything is going ok for the previous shift (and to work out how many CTDs we’ll be doing tonight)! It’s then time for a quick breakfast before my shift starts. My typical breakfast of porridge is almost as accurate as the radar measurement of significant wave height – with the milk sloshing back and forth as I put my porridge in the microwave. Then it’s back to the main lab to start the shift (and convince those on the previous shift that it’s time for them to go to sleep)!

As mooring recovery and deployment need to be done during the day, we as the night shift typically do back-to-back CTDs. Over the first few days of night shifts, when we were over the relatively shallow shelf, this reached up to 4 CTDs in one night! But it calmed down considerably over the next week to 1 or 2 CTDs a night, when we entered deeper water and each CTD deployment took considerably longer (~2-3 hours)! This was particularly true of the “caldip” moorings, used to calibrate sensors pre and post-mooring recovery/deployment, which have 5-minute stops at various depths.

It’s then time to prepare the CTD logsheet ready for the first CTD. If the CTD’s recovery is imminent or we’re lucky (and those on the last shift were bored) this will already be ready for the first CTD of the shift. It details the Niskin bottles fired and what depth they were fired at, as well as what Niskin bottles/depths we need to take water samples from such that we can analyse them for dissolved oxygen, and dissolved inorganic carbon (DIC), nutrients and measure their salinity. This logsheet also details the Niskins / depths from which duplicate or triplicate samples will be taken. We also write out a separate logsheet just for the dissolved oxygen samples that contains the bottle numbers of each sample (along with the associated Niskin bottle it will come from and the depth of that bottle) and another logsheet if we are also taking DIC samples.

Once the CTD is almost up, we pop on our waterproofs, steel toecap boots and hard hats and bring out everything we need to collect our samples. This includes 2 clipboards with all the logsheets, lots of numbered bottles with stoppers (for dissolved oxygen, DIC and nutrients), plastic tubes for collecting dissolved oxygen and dissolved inorganic carbon samples, a thermometer and spare beaker for measuring Niskin bottle water temperature, and Stanley (the carry crate that holds the pipettes with and in them, used for the dissolved oxygen samples).

We watch the CTD being recovered – on day 1, we all watch with avid interest and by day 10, it’s all just part of the routine. Once, we’re informed the CTD is securely back on board, it’s time to begin sampling! We start with dissolved oxygen – to limit the gas exchange of water in Niskin bottles and the surface air – making sure to close each bottle securely after sampling. First, we take each Niskin bottle’s temperature before rinsing the first sample bottle and filling it – hopefully without any bubbles!!! We then work our way around the CTD, starting with the first Niskin fired (at the greatest depth) and finishing with the shallowest Niskin.

If taking DIC samples, we then have someone (in our case me) follow that first person, making their way around the CTD rosette, collecting each sample. By the last day, we’d perfected the art of knowing when the DIC sampler should start, such that a Niskin bottle would never be open for 10 minutes but such that the DIC sampler never caught up with the dissolved oxygen sampler! The DIC samples then go back to the chemistry lab to be poisoned (and stop any phytoplankton still living in the sample from removing all the DIC!).

Next up is nutrients. Niskin bottle water goes through a filter to remove any large particles before entering the plastic nutrient tubes. These samples are then frozen, ready to be transported back to SAMS to be analysed.  

Finally is salinity – we obtain a sample from each bottle in order to be able to calibrate the conductivity reading from the CTD rosette. Each sample is collected and then the neck of the bottle must be dried (inside and out) to make sure no salt crystals can form on the top of the bottle and fall into the sample – artificially raising the conductivity (and salinity) measurement. The sample is then stoppered and capped, before going back into the crate of samples. Once a crate is full, it gets rinsed and carried to the salinometer room, where samples will later be analysed by the autosal salinometer. As conductivity measurements are very temperature dependent, the entire room is kept at a constant temperature (of 21C), such that all the salinity samples can equilibrate to this temperature before analysis.

Once we’ve successfully managed to collect all the water samples we need, we return to the main lab. We then need to scan all the logsheets to make sure we have a copy just in case anything happens to them. We also run a series of scripts to process CTD data, removing all the times when sensors were recording before and after the CTD was in the water and removing any spurious data spikes (particularly in salinity).

This cycle repeats until the waft of freshly cooked pastries informs me it’s almost breakfast time! I’m then faced with 20-30 minutes of temptation to run and grab a croissant/pain au chocolat whilst they are still fresh! It’s then time for breakfast and time to say good morning (/ good night / good day?) and to hand over to those on the day shift.

By Marilena Oltmanns

Tirelessly, full of determination, and with a hint of stubbornness, the ship cleaved its way through the sea. It hadn’t seen land for days and now, in the middle of nowhere, it was hard to believe that anything but ocean existed. As the ship diligently fulfilled its duties, station by station, day and night, it had almost forgotten where it came from and where it was heading. And why shouldn’t it? In the vastness of space, it was easy to lose perspective.

Its overarching mission, however big and important it may have been, faded away, like land disappearing behind the fog. The world’s problems and crises, uncertainties, and all the questions without answers, became tiny compared to the everyday struggles with the elements, making it easy to create a new meaning, safe, and far away from a world that was about to capsize and in which fossil fuel consuming ships had no future.

Thus, the ship moved on, faithfully, from station to station, clinging to a reality on the narrow line between the water and the sky. If the world went down in this very moment, the ship would not notice. For a split second, it would startle. Like a sleeping cat surprised by a sudden noise would it wake up, before drifting into another dream on another sea, in another world, as a new time had begun.

By Rita Markina

By Rita Markina

The UK OSNAP team left Southampton on 12 July and is heading into the sub-polar North Atlantic. We will be working on the very eastern part of the OSNAP line from the Hebrides shelf via the Rockall basin to the Iceland Basin. This is the region where two major branches of warm and salty Atlantic waters flow into the Arctic, and we have various different oceanographic equipment on board to measure these ocean currents.

Picture 1: Map in the main lab showing the expedition region with the current location of the ship, mooring stations, and Argo deployments sites (ship’s position is updated daily). Photo from Rita Markina.

We will recover and redeploy several moorings that have been recording ocean properties continuously since Oct 2020. We will do a bunch of CTD stations where we will measure vertical profiles of ocean temperature, salinity, oxygen, fluorescence, pH and current velocity, and sample water at different depths for sensor calibration and chemical analysis of carbon, oxygen and nutrients. Apart from this, we will deploy three biogeochemical Argo floats which will measure CTD profiles and at least three (pH, nitrate, chlorophyll) out of the six biogeochemical Argo parameters (oxygen, chlorophyll, BBP, nitrate, pH and irradiance). These parameters are important to assess ecosystem health. There is also a brand-new bottom pressure recorder on board that we will deploy. A second recorder will be installed at the western basin during M148 led by our German colleagues from GEOMAR in August. The bottom pressure data on either side of the Atlantic will allow us to estimate the amount of water transported between the two instruments. More on this measurement system and how it works here: https://www.sonardyne.com/ocean-bottom-pressure-data-unlocks-amoc/

While our ship is moving north, the crew, technicians and science team prepare all the equipment, and those of us who are here for the first time are familiarising ourselves with the ship – which looks gorgeous. Check it out with this virtual tour: https://noc.ac.uk/facilities/ships/rrs-james-cook/rrs-james-cook-virtual-tour.

This morning we saw the dolphins! They came really close to the ship – curious about what we are up to (or just enjoying the waves).

Picture 2. Dolphins following RSS James Cook in the Irish Sea. Video from Rita Markina.

More details about our work and life on board are soon to come!

By Ellen Park

Life at sea is organized chaos.

Each day is incredibly valuable because sea time is so expensive.

As a result, prior to stepping foot on the boat, we had a detailed schedule outlining what operations, like mooring recovery/deployment or a CTD cast, would be completed on each day and their duration in a set order. But this order wasn’t really “set.” It was more realistically the ideal order of operations, assuming no major setbacks. Ultimately, forecasted weather and instrument malfunctions required us to be flexible, forcing us to prioritize certain operations over others due to factors like local conditions, limits on deck space, or transit time to stations.

To keep track of all these moving pieces, everyday a plan of the day (POD) was outlined by the chief scientist, Sheri White, for the upcoming workday. Conversations both amongst the science party and between the science party and the ship’s crew were essential for ensuring that all operations were conducted safely and smoothly and that both scientific agendas for OSNAP and OOI were met.

While the POD often changes multiple times (five times within one day once because of weather!), there are some aspects of life at sea that are constant.

Typically, most days start bright and early at 6am to prep the deck for a mooring deployment/recovery operation or preparation of the rosette for a CTD cast. After breakfast, mooring deployment/recovery or CTD casts begin. Mooring operations last anywhere from 2-6+ hours, depending on the height of the mooring and number of instruments attached. CTD casts on this cruise typically were 2-3 hours and went to 2,000-3,000 meters depth. Depending on the duration of the morning operation, we would break for lunch and afterwards continue or start a new operation. Occasionally, we conduct a few late night CTD casts after dinner, but for the most part all operations are complete by 18:00.

To help stay sane and entertained, people participate in a variety of evening activities after operations are completed. Some people workout in the onboard gym. Others read, play card games, or watch TV/movies in the lounge.

With the end of the cruise approaching, it is exciting to celebrate the accomplishment of achieving all the OSNAP and OOI objectives, despite the weather-related setbacks we encountered. This could not have been possible without the hard work from everyone on the ship’s crew and members of the science party. As we begin our transit to Reykjavik in the upcoming days, I know that I am looking forward to returning to land, but, at the same time, I will be a bit sad to leave the R/V Armstrong.

by Ellen Park

On our eight-day transit to the Irminger Sea, we completed a few calibration casts for instruments that will be deployed on the OSNAP moorings and saw some pretty incredible sunsets (see Figure 1).

Once we reached our target region, we got to work right away. First, we deployed all of the new components of the OOI Global Irminger Sea Array, which consists of a surface mooring, three subsurface moorings, and gliders. Then we moved on to recover the OSNAP Greenland Deep Western Boundary Current (GDWBC) moorings, which are all subsurface moorings. One of the key differences between the OOI and OSNAP moorings is how collected data are stored and recovered. OOI data are stored locally and also telemetered so that data can be accessed by the public in near real time. OSNAP data, on the other hand, are stored locally and cannot be accessed until the sensor is recovered and the data are downloaded.

Before recovering each mooring, we do a CTD cast roughly 0.5 nautical miles away from the mooring to provide an endpoint for each timeseries (see Figure 2). Not only can sensors drift overtime, but they also can become biofouled, which will affect the measured value (see Figure 3). Having an endpoint value is important because it allows us to correct the sensor data for these phenomena and provide more accurate results.

Many of the casts that we have done so far went below 2,000 m depth because we are interested in the GDWBC. Sensors deployed at these depths must be able to withstand harsh conditions and extremely high pressures. 10 m of water is roughly equivalent to 10 decibar of pressure (~1 atm). Therefore, at 2,000m depth, sensors experience 200 times the pressure that they experience at the surface. We could see the pressure effects on Styrofoam cups that we sent down with one of the deep CTD casts (see Figure 4).

We have roughly another week to finish up all of our operations before heading to Reykjavik, where we will leave the ship and fly home. During this time, we will finish recovering and deploying moorings and taking a preliminary look at the recovered two years’ worth of data!

by Heather Furey

It’s been a minute.  The sun is shining, it is a perfect July day on the Irminger Sea.  After an eight-day transit, some amount of CTD casts, some amount of CTD sensor diagnostics, some amount of moored instrument calibrations, and a few glider deployments, we are finally getting to the guts of the work: the mooring deployments and recoveries. 

It’s day 12 of 28. We are interweaving the OOI and OSNAP mooring operations.  It’s a workload that is in flux; we are up to ‘Plan C’ right now. Plans have changed due to weather days, both the good kind and the bad kind, and a glider recovery. The general plan is to deploy OOI moorings first, as we need to get the deck cleared of equipment before we will have space to recover a similar amount of gear.  After OOI moorings are deployed, we recover and then deploy OSNAP moorings, and once done, we recover OOI moorings.  That’s the idea, though Plan C has some deviations on that generalized plan. We have 2 out of 16 mooring operations complete so far.

Meanwhile, the galley staff keep cranking out great food, the crew are awesome as always, and we steam along from work task to work task, checking things off the list.

More later, Heather