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I don’t think one can actually describe what it feels like to be on board and what you think before the expedition even starts. I would say I didn’t have any expectations beforehand, trying to go with an open mind and just enjoy this whole experience, which I most definitely did. Nonetheless, I remember that when I first saw the SONNE ship out of the window of our bus – I thought it looked smaller than what I would have thought or possibly even hoped. Once I was actually on board and looked up to the windows of the bridge my impression definitely changed into one of awe, and just this overwhelming feeling that I could never possibly know my way around such a large vessel. I would say that the second impression is more accurate: even after 4 weeks on board I am still finding new ways around the ship and I only really know my way within the areas of my everyday use.
Speaking of everyday… life on board is also different than what you normally experience on land, although nowadays shiptime might be more normal than the new normal of social distancing. Once on board, after the at-home self-isolation, hotel quarantine with 2 negative tests, and additional 10 days on board of being cautious and wearing masks in larger crowds, we were finally able to just sit next to one another, chat without a care in the world or even share the same water bottle, which seems unthinkable on land. It was surprising how easy it was to go back to not always thinking if you are currently transmitting a disease, since you knew everyone around you didn’t, and couldn’t, have it.
Besides that, there are two different everyday cycles on board, depending if you are currently on station or on transit. Once on station there is a strict schedule of when and which gear is being deployed by which winch. Everything is planned down to half an hour, so that everyone knows when they need to be with their equipment or otherwise try and catch some sleep. Once a station is completed, we move on to the next. Over that time the samples need to be looked at in more detail, sorted, or other first results processed. For most people this is the time to try and get back to a normal sleep schedule and refresh a bit. For the hydroacustics team it is almost flipped around. They are gathering data during transit times and map the next research area once the ship arrives, but being on station is often not as busy for them as it is for the rest of the team, although they also help out wherever it is needed, e.g. sieving the samples of the box corer. Every day provides new exciting tasks and projects. Even though the gear and schedule between stations might be the same, you never know what kind of samples you will get this time. Is the wind too strong for the plankton gear? Or did one of the nets rip? With the benthic gear one is always praying that the equipment had good contact with the ocean floor and that everything worked. Even if that is the case, the sample might still get disrupted while being heaved to the surface. It is never boring.
Now the big question is always: What did I learn on the cruise? What experiences am I taking home that I will never forget?
One thing I learned early on was that I am not as immune to the waves and the ship-movement as I thought I would be. The body always needs time to adjust to a change in ship movement. For me that meant, while being on station we had lesser and increasingly even movements, meaning I felt fine. Once we started moving again, the movement changed, and my body needed to adjust all over again. Another thing I learned is to rely on your team. If you are exhausted or sea-sick and need an hour or two of sleep, go lay down. Your team will call you when you are absolutely needed. In general, I learned a lot about the workflow with the different gears, and between scientists and ship crew, which is just hard to summarise in short.
Now things I am taking home with me, in a figurative way, might also be summarised as a list of firsts. For the first time ever, I touched sediment from the seafloor. I still can barely wrap my mind around the fact that the clay in my hands came from a depth of more than 5000 m. To continue along that line, I was also able to see and touch animals that live in that depth. In those depths they have no light, less oxygen, and less nutrition, than in closer surface proximity, but still some animals manage to live and thrive down there. Even more fascinating is that there are still so many species that are yet to be discovered. One other larger species that we encountered during our expedition were dolphins. Early on in the English Channel, between Britain and mainland Europe, lots of dolphins were riding the waves produced by our vessel and it just warmed my heart to be able to see these animals in their natural habitat and, just living life to the fullest.
To end this list of firsts for me, it was the first time that I went weeks on end without seeing any land at all. I thought about this beforehand a lot and always imagined it to be an amazing feeling, but to experience it in real life was more than I could have imagined. Standing on the ‘Achterdeck’ (Poop deck), feeling the wind in your hair, and seeing the waves surrounding the ship, knowing that below you, there is about 5000 m of just water, it gave me the feeling of serenity and just calmness, realising how small, and possibly insignificant, you as a human actually are. Always being cooped up in cities between tall buildings provides a very narrow view of the world, while being out here is almost like freedom, even though you are confined to a ship. Feeling these forces of nature is something I always wanted to experience and will forever keep as a memory in my mind.
Sometimes escaping from bad weather conditions has very nice side effects. While the entire Atlantic goes wild around us, there is a tiny little passage with calm and sunny weather. But it’s getting even better: below the ocean surface is an underwater wonderland! On our last deep station, we are sitting on a flat -4200m sea basin, surrounded by an impressive seamount chain. From the satellite images we can derive plateaus at -200m, as well as active debris flow structures along the mountains’ slopes. So far, the multibeam bathymetry confirms those estimations and so do the sludgy multi- and box corer samples which we retrieved from the deep-sea floor at this very moment. The area was discovered in 1869, during one of the earliest oceanographic expeditions and is known as Horseshoe seamount chain.
One of the most astonishing structures around is Josephine Seamount, an almost flat-topped, oval-shaped elevation, with a very steep slope on its southern flank. It originally arose as an island volcano in the Middle Tertiary but became extinct around 9 million years ago. As with all submerged volcanoes, active or not, Josephine Seamount is home to a broad array of marine species. In fact, Josephine is so unique that it has been declared a Marine Protected Area (MPA) by the OSPAR Commission – an international convention signed and ratified by fifteen member governances for the protection of the marine environment of the North-East Atlantic. MPAs, as announced by OSPAR, are especially designed to cover areas of high biodiversity and aim to protect those ecosystems, maintain and improve their current health status, prevent further devastation and exploitation, and to provide a liveable habitat for all marine wildlife. Those areas of protection can be designated within but also outside the sovereign territory of a governance (exclusive economic zone, usually 200 nm off a State’s coastline). Areas beyond national jurisdiction are called the High Seas and there are only a few regulations prevalent here. Ships operating in the High Seas are principally under the jurisdiction of their Flag State, but port States may intervene if, for example, international environmental rules are being violated.
The legal framework concerning the use of marine resources and its resources is provided by the United Nations Committee of the Law of the Sea (UNCLOS), an international agreement on the rights and responsibilities of nations towards the world’s oceans, which has been ratified by 168 parties. However, this legal structure provides basic directives rather than distinct laws, and regulations for specific human activities on the High Seas are far less defined. Against this background, establishing MPAs here in areas beyond national jurisdiction (ABNJ) is a delicate matter and, as all nations have equal rights in international waters, raises a number of difficult questions: Who has the competence and knowledge to designate MPAs in ABNJ? What are appropriate considerations and on which basis can decisions be made? Who will be in charge of MPA ‘management’ and how can it be achieved so that any activity is in compliance with the regulations? Answering these questions is difficult, not least because there is no uniform definition of what an MPA is. As a common denominator, MPAs essentially have a special status in terms of regulations on human activities in relation to habitat conservation. Yet this does not mean that any activity, for example fishing, is prohibited – it may only mean that certain types of fishing practice are not allowed. Not surprisingly, there is a conflict of interest between legislative committees who designate MPAs and the fishing industry, with the latter presenting significant threats to biodiversity in the High Seas. Cooperation between all involved parties is essential to achieve marine conservation (Molenaar and Oude Elferink, 2009). OSPAR has committed itself to pose and answer those questions and to set up a coherent network of MPAs in waters beyond national sovereignties in the NE Atlantic.
Scientific research in MPAs has to undergo a risk assessment prior to any measurement activity. On the one hand, the designation of MPAs is solely based on scientific knowledge without which there wouldn’t be a profound decision basis. Additionally, research activities can also pose a threat to the ecosystems if falsely deployed. Sampling ground-truth data with benthic gear always carries the risk of harming delicate structures like corals or sponges. Depending on the sounding frequency, hydroacoustics can severely disturb the communication of local inhabitants such as fish shoals as well as of those animals travelling far distances, e.g., the endangered Leatherback turtle, who use seamounts as a stopover to rest and feed. Thus it has to be decided carefully what sort of research is sensible in order to obtain the necessary knowledge needed to support the case for establishing an MPA.
In our case of Josephine Seamount, we found out that there isn’t a coherent high resolution bathymetry, which is crucial as seabed topography has direct effects on floral and faunal assemblages. So we decided to spend the last day of our station work mapping this beauty, and this certainly has not been disappointing! Although there is a lot of fishing activity in this area and nearly the entire plateau has been devastated by former trawling, a complex-looking structure at the slope of our Josephine indicates a potential abundance of coral reefs. However this is a hypothesis and needs further evaluation to be confirmed.
Meanwhile, we are on our transit back home. The weather conditions have been absolutely fantastic throughout the entire journey so far, but in the next couple of days, we expect storms and high waves. Let’s hope for the best!
On a final note, I would like to express my enthusiasm about this cruise. It has been a full success regarding the scientific achievements, driven by the efforts of every single person on board of R/V Sonne to keep the daily (and nightly) business up and running. For the last four weeks, we have been blessed with working and living on a floating corona-free island, and we can consider ourselves very lucky about the circumstances which make this possible. In that sense, I would very much like to say thank you to everybody, crew members and scientists, and especially to the Captain Lutz Mellon, for whom this is his last cruise before he leaves for retirement. It has been a special honour to meet him and in the name of everyone on board, I wish him all the best for his future on the solid ground land life!
Erik J. Molenaar & Alex G. Oude Elferink (2009): Marine protected areas in areas beyond national jurisdiction: The pioneering efforts under the OSPAR Convention. URL: http://www.utrechtlawreview.org/, Volume 5, Issue 1 (June) 2009
OSPAR Commission: Protecting and conserving the North-East Atlantic and its resources. URL: https://www.ospar.org/work-areas/bdc/marine-protected-areas/mpas-in-areas-beyond-national-jurisdiction
OSPAR Commission (2011): Background Document on the Josephine Seamount Marine Protected Area
The naked eye cannot see them, the trained eye has difficulty spotting them and when enlarged under a microscope they are ‘aliens’ – or should I better say the bumble bees, beetles and butterflies of the deep sea? What would the world be without insects? Well, did you know that marine crustaceans are siblings to insects – or – so to say – systematically, insects are a sister taxon to crustaceans!
This topic is connected to the term “biodiversity loss” on land and an urgent issue in terrestrial and marine biodiversity research. Who is talking/caring about these little, alien butterflies living down in 5500m depth, in a different cold, dark, wet world at high pressures in one of the most extreme environments on our blue planet? Here they are, the unseen sediment secrets: the little crustaceans, worms, snails and bivalves! Their beauty is revealed by sieving bucket-loads of mud collected by our gear after diving down attached to kilometre-long cables to the seafloor. Just think about the proportions: RV Sonne is 118m long compared to the water depth: the seafloor is reached by over 5 km length of a heavy, 18mm thick wire cable attached to the 0.18km long vessel!
Well, at first view, the seafloor looks like a pristine sandy beach, nothing is seen. Boring? Or boring?!? Caused by bioturbation below the sediment’s surface, you can spot Lebensspuren- and poo! Poo is everywhere and this means somebody lives there, consuming the seafloor for its nutrient content…
During the OFOS deployments, we spotted larger marine animals, the native deep-sea inhabitants, but also plastic litter of human origin on the seafloor. Even a pair of trousers made it down here. And from the ocean’s surface – some 500 miles from the nearest beach – we fished out a single flip-flop, being used as a raft by all different kind of crustaceans and snails.
Let the pictures speak and have a look:
1 ) Just imagine yourself swimming through honey! How must it feel for this little isopod fellow paddling actively across the deep-sea sediment? Munnopsid isopods swim using their posterior paddle legs while the four pairs of front legs are used for walking. 2) Tiny bivalves of 2 or 3 mm size connect with their byssos to anything they can get hold on in the sediment plains – even holothurhians are used as a taxi! 3) This little 1 mm size comma shrimp or cumacean can only be found under the microscope between the single sand grains. 4) Fossil and recent, old and young – sharks were swimming around and loosing their teeth…. The story behind stays a riddle or comes alive in your own phantasy. 5) A salp colony glows in the dark. Never alone in the vast environment hanging around in the water column…
Animals seen from the OFOS: A) Caridean shrimp; B) Brittle star; C) Liparid fish; D) Holothurian
Lebensspuren seen from OFOS: A) Animal track; B) Burrowing single animal; C) Starfish imprint; D) Burrowing animal colony
Litter seen from OFOS: A) Plastic sheet; B) Brown glass bottle; C) Trousers; D) Plastic sheet
Early May 1996 I stood on the wooden pier of Puerto Williams, the southernmost city of South America, waiting for the rigid inflatable boat of RV Polarstern to pick us up. We were joining the ship to sample the seafloor animals living on the South American shelf and deep-sea slope of the Drake Passage to compare them with those living in Antarctica. I was an undergrad student, send to deploy a newly designed epibenthic sledge (EBS) with an epi-benthic and a supra-benthic sampler collecting animals living on the seafloor as well as swimming about one meter above it. My aim was to collect samples for my upcoming PhD project.
And now, almost 25 years to the day, I am standing on RV Sonne, 500 km north of Madeira and am waiting to send our double-sampler EBS BERTA to the Abyss (Figure 1). The aim is to collect the small-sized invertebrate animals (e.g. shrimps, worms, clams, brittle stars and their friends) from 4170 m depth so we, the marine biologists and taxonomic experts on board and back on land, can study their biodiversity and distribution patterns. You could call us the modern day Linneaus’ or Darwins, as our research starts with studying the animals we collect in detail; identifying their scientific names or if newly discovered, describing them and giving them scientific names, before we use their morphological and molecular characteristics to analyse their evolutionary relationships. The taxonomic group I am most familiar with are the bivalves, the two-valves seashells that include clams, cockles, and mussels, and especially those from the Antarctic and the deep sea. Over the last 25 years colleagues of mine and I have collected marine seafloor animals by epibenthic sledges throughout Atlantic Ocean, the from Iceland via the tropic to the southernmost Weddell Sea in Antarctica. This enables me now to evaluate taxa, like the pictured Cuspidariidae (Figure 2), a group of carnivorous bivalves, for their distribution ranges, phylogenetic relationships, and postulate what resilience they might have for climate change.
So far I have deployed our EBSs six times to ocean depth of 4900 m to 5500 m depth and I am hoping for another four deployments before we have to end our biological field science and steam back to Emden. And while each mudding sample coming up might only have a few litres of volume, these can include hundreds to thousands of the small animals my colleagues and I want to study. The first expressions of joy you can hear when we sift the samples over 300µm sieves and see a faint movement of an isopod, this is a marine woodlouse, or worm, or the shimmering shell of a bivalve.
This IceDivA expedition or SO280, following RV Sonne’s numerical expedition order, is very special to me, not only because it marks 25 years for me of joining ship-borne expeditions, but also being allowed to enrol during the current pandemic. As national and international travel is heavily restricted and many nations are in lockdown, we on board, after quarantine and multiple tests prior to and social distancing at the start of the expedition, are now allowed to work together like in the past. And working in temperate and non-polar waters is still exceptional for me. Being employed at the British Antarctic Survey, I am more familiar with an ocean covered in sea ice (Figure 3) than with water and air temperatures above 15°C. And I thought travelling to the North Atlantic in January would be mean cold days of working on a windy deck. Therefore, I packed my Antarctic, padded, extra warm, waterproof overall, to stay warm and dry. How did I fail. Luckily, RV Sonne’s store sells branded T-shirts to stop me over heating while at work.
My only other warm-water expedition has been the scientific Maiden voyage of RV Sonne in December 2014 to January 2015. Coming back on board six years later and seeing familiar faces from the ship’s crew again is another pleasant point of this expedition. Knowing you are in great hands that will enable you to collect your research samples 24/7 but also telling you when your scientist’s ideas/plans are technically or weather-dependent unachievable.
It’s 2:30 in the morning, everyone on board is sleeping…everyone? No! A small group of extremely diligent people are already up and running their daily business: the cooks and the stewards! They are the very fundamental part of all the work on a research vessel because without food, no-one would ever lift a finger. But it’s not only about eating to satisfy a hungry stomach. What the kitchen staff conjure up on our plates every single day is far more than that. Everyone on the ship can have a warm dish three times a day, one for each breakfast, lunch and dinner. If someone happens to feel hungry in between, the door to the pantry is always open where the well-stocked fridge can be found. The dishes never repeat during the whole cruise and almost everything is made by hand – even the bread rolls and buns in the morning! Even after five weeks of being at sea, there is still fresh fruit, vegetables, and even salad.
To supply 54 hungry mouths for such a long time involves good planning and preparation. Andrew Garnitz, the first cook, starts to set up an order request three weeks in advance of each cruise and it takes him about one entire week to finish this order. At the end, he has a shopping list which contains something similar to:
The order is submitted to SVR, a huge international company with depots in every port worldwide, who supply ships with everything that’s needed. This also includes spare machine parts like screws, nuts, antennas, filters – anything that could possibly fail and needs to be exchanged. But let’s stick to the roots – once the food order arrives at the vessel, it goes to one of the four cool storage cabins, depending on whether it needs to remain frozen or just has to be kept in a dry place. When setting sail, the stores are spilling over with supply but – surprisingly – everything is gone after the cruise! The more highly perishable food (and the ice cream!) is stored at -22° C and there it can be kept for a very long time. Veggies and fruit live in the 4° C room, along with cheese and other non-frozen food. Everything is under strict quality control but the cooks also take care to minimise unnecessary waste, using up anything with a short best-before date.
A normal day for the cook and the kitchen staff starts in the middle of the night at around 2 – 4am (depending on what is on the agenda) and ends at 6pm. It is one of the hardest jobs on the ship as there is no such as Sundays off, enjoying a nice evening after work and a lie-in the next morning, or a public holiday. On the contrary: a day like Christmas, New Year’s Eve, or someone’s birthday (and it’s always someone’s birthday at least once per cruise) – the kitchen staff has even extra work. They do it with super enthusiasm which translates to the taste and the love the meals are prepared with, which they deserve first-class praise and appreciation for. In that sense, and on behalf of all cruise participants, I would like to express my most sincere gratitude to the kitchen staff for their tireless effort to provide us all with the finest meals and treats!
We have almost completed our work at the station at 42°N 19°W! It has been a tight schedule, with mapping the area first to make sure that the stage is ready for seafloor gear deployment, followed by ‘the plankton block’ and sediment sampling with the benthic part.
On this trip, the Senckenberg plankton group brought three different nets to sample the water column: A large hose net, an array with multiple nets of differently sized apertures, and the Bongo net. The latter consists of two pairs of nets and, due to its shape, is named after the bongo drums. All of them are dragged or lowered over the side of the ship to collect creatures from the water column, and are rinsed afterwards to fix the samples. Amongst other objectives, the focus of investigation is microplastics in zooplankton stomachs (yes, zooplankton does have a have little stomach!) to estimate how far the synthetic material has entered the food chain already. We also have the Neuston catamaran – an instrument to collect and analyse larger parts of floating plastics.
To discover the seafloor, its composition and inhabitants, we have the OFOS, a towed camera system along with a variety of bottom sampling instruments. Ground truthing along a deep-sea transect is done with the epibenthic sledge (EBS) which sweeps over the floor and collects the uppermost layer of seafloor material. Point location sampling is carried out with a boxcorer and a multicorer.
Usually, at least in the deep sea or abyssal plains, the seafloor composition is clay, silt, and sometimes sand. At those latitudes, the mean sedimentation rate – i.e. the rate at which particles accumulate on the seafloor – is around 2.5cm per hundred years. Hence digging half a metre into the seafloor means looking back twenty centuries!
On a sad note, a young blue shark who got tangled in a long fishing line came up on deck along with the EBS. Longline fishing is a method for targeting meso- and bathypelagic sea inhabitants, and it has a long and controversial history. One line can be up to 62 miles long carrying about 10,000 baited hooks at intervals of several metres. Some techniques demand dragging the line behind a fishing vessel, others drift in the water column until they are retrieved. The non-selective nature of longlining is a major issue as the amount of incidental bycatch of untargeted species such as dolphins, penguins, sea turtles, sharks, or sea birds. In particular it is estimated that per year, more than 300,000 birds drown being hooked on longlines (https://doi.org/10.1053/j.tcam.2013.09.006). Mitigation attempts are made to reduce preventable bycatch involved in industrial open ocean fishing, but such findings are a reminder that consumer education and ethical practices still have a way to go in the modern world.
There are various good reasons why mapping the seafloor is important – and today, we can prove at least one of them! Many years ago, people thought that the deep sea was a vast and boring place, primarily flat and full of mud – an inhospitable world where nothing lives or survives. Well, this has been shown to be untrue by numerous scientists and seafarers when they started ‘sounding’ the oceans using lead lines as a first depth measurement around 1850. A couple of years and a lot of lead-line cruises later, those data charted on early seafloor maps showed the outlines of mid-ocean ridges. In 1912, this led Alfred Wegener to assume that we live on drifting continental plates. What a daring statement! It took no fewer than 50 years, until 1960, that people started to consider his hypothesis as true. Today, the tectonic movement of continental and oceanic plates is a widely accepted theory and a very hot research topic that is constantly underpinned by new discoveries. Many of those findings involve ocean floor features, nearly all of which are somehow related to continental drift. Even if being far away from the fresh spreading centres on the mid-ocean ridges, the ultra-slow tectonic driving forces which literally keep the world going round have effects on the most remote seabed formations.
Today, we made such a discovery – whether this can be connected to continental drift still has to be discussed, but one thing is for sure: What we found is an amazing underwater world in the middle of the abyssal plain – the deep-sea nowhere. On the satellite image it looked like a small but very deep hole situated just off a craggy terrain. Looking at the new bathymetry revealed an enormous mountain chain, nearly as high as the Alps, arising from 6000m deep ocean flat basin. The surrounding environment is very flat and two-dimensional, as if someone had taken an iron to flatten the seafloor. The discrepancy between the satellite-derived bathymetry and the ‘real’ one is related to the acquisition method. Satellite ocean depths are modelled from the earth’s gravity field – the denser (‘heavier’) the subsurface, the larger is its gravitation value. This however means that denser material, for example rocks with a high iron content, also have an increased gravity field. Those areas form bulbs on the water surface which can then be linked to the actual water depth. This is how the shape of the sea bottom is obtained from space. Ship-based bathymetry, on the other hand, is a direct measurement of water depth and thus much more accurate.
Mapping this area wasn’t part of the original planned cruise route, but it came into our view located in the route from the ARGO float area to our next planned working area. In accordance with our slogan, which has been created since the weather conditions demand frequent and spontaneous re-scheduling, we took a little side step to visit this place. And it has been absolutely worth it!
When you encounter such alpine relief in the underwater landscape, it brings the question of which animals live in the 6000m plains, and which on the mountains next to it? Maybe we’ll have some time to discover this at the end of the expedition when we’re on our way back north. Now, we are heading south, right in front of the next storm approaching to catch the time window for our station work. Our motto: Watch out for the good weather periods and be spontaneous, creative and multi-flexible!
After a long transit we reached our first station! The weather gods haven’t been too gracious with us, but at least we are able to deploy our first CTDs and launch the ARGO floats over board. ARGO floats are gliders that take measurement profiles along a depth transect in the water column. They go with the current until their battery dies, and every now and then they pop up at the surface to send their data via satellite. Among other parameters, they sense salinity, temperature, and pressure during their lifetime. There is already a fleet of 3500 active ARGOS circulating the world’s oceans, and after this cruise, it’ll be 12 more!
This time, they have new types of sensors ‘on board’ and the idea is to compare their measurement results and performance. Hence, those sensors should measure an equal value range of parameters to have comparable data. Thus ideally, they should stick together in a bunch while travelling and not drift too far from each other. This is why the German BSH (Bundesanstalt für Seeschifffahrt und Hydrographie) ARGO team has chosen a small eddy as launch position, whose current will capture the floats within its centre.
Sailing and working rough seas is not only a challenge for everyone’s physical condition, but also for those involved in the deck work. Especially when deploying or recovering instruments via cable over a crane, heavy weight hovers over people’s heads and sudden big waves hitting the ship from the side can be an unexpected danger. Hence trained and experienced crew members are an absolute must and without them, a cruise like this wouldn’t be possible! Also, daily habits such as climbing stairs, walking straight, doing yoga poses, or simply placing a mug on a table is not as what we are normally used to! Depending on whether riding up or down a wave, a normal staircase can turn into an unbeatable enemy or make you feel light as a feather, as G-forces are in- and decreased, respectively, in orders of magnitudes by the acceleration of the ship when moving up or downhill. Following a straight line becomes impossible and so are most of the yoga positions, at least those which involve less than two hands and both feet on the floor. Any item sitting on a table can fly through the room at some point, if not secured properly. These are challenging conditions for sure, but it is also a most exciting experience and eventually, everybody will be used to the rocking sea!
Welcome (back) to the blog site of our current cruise on R/V Sonne: SO280, a.k.a IceDivA!
This morning around nine o’clock we left the harbour of Emden again to research the Atlantic. Connecting to our last cruise in summer 2020, the IceAGE3 expedition, where we explored the northern part of the Atlantic around Iceland, we now head for the southernmost point of our IceAGE measurement transect to continue the scientific journey towards the equator.
After two weeks in self isolation over Christmas at home and three days in the quarantine hotel and fortunately two negative Covid-19 tests for everyone, we were allowed to board R/V Sonne on 6 January 2021. It then took us the rest of time before leaving to unpack the containers with the gears, instruments and lab equipment and getting started.
As we are on transit towards out first working area for the first 4 days of our expedition and we have to wait for our science actions until we arrive on station, this might be a good chance to introduce the ship that will be our home for the next month.
The new R/V Sonne was launched in 2014, to take over from the old Sonne, who has been in service over 40 years. Overall, it’s 116m long, 20m wide and 42.4m high (so standing on the bridge facing waves on eye-level means that there is quite heavy weather outside). It can stay at sea for up to 52 days, being driven by four main engines and two propellers which convert fuel to motion energy up to a speed of 15kn. When operating at full capacity, there are 33 crew members and 40 scientists onboard – and enough food, fuel and water for 52 days! Most of the scientific life takes places on deck 3 of the Sonne’s eight decks, and this is also where all the large gear is stationed.
We are 53 people in total on this cruise with 32 people in the ship’s crew and 21 scientists. Most of the scientists are from Senckenberg Institute in Wilhelmshaven and Hamburg, accompanied by researchers from GEOMAR, the BSH (Bundesamts für Seeschifffahrt und Hydrographie) and the University of Oldenburg. Our science gear on board are the two Epi-benthos sledges “Ursula” and “Berta”, one Multicorer, one box corer, a CTD, various plankton nets and – as add on – an Ocean Floor Observation System, OFOS in short. It is a camera system which is towed over the side of the ship to take video footage of the sea floor. But more about our instruments when they are in action!
Now we are steaming towards the English channel and, depending on the weather conditions, will probably reach our first station on 12 January – at about 45°N and 21° W.
Our wonderful cruise is now definitely coming to an end. We are nearly on our way back home, heading for one last station where we will cast a final CTD and send an ARGO float on its journey. These floats are part of a giant international project and basically drift with the water currents, all the while consistently measuring the salinity, temperature and pressure of different water layers. While writing these lines, there are about 4000 floats deployed in the world’s oceans. Tonight, it’ll be 4001. The floats are able to adjust themselves to maintain a certain depth and take measurement profiles along vertical transects. Every now and then (approximately every 10 days) they dive up to the surface and send the acquired data to a central data base. Being equipped with a SIM card, the communication between the ARGO on the sea surface and the data centre happens via satellite – this is the only stable and reliable way to transmit data, especially when being so far from land and away from any network reception. Once transferred, the raw data are processed and quality flagged automatically. This data freely and publicly available – if you are interested in the project and its data, you can visit the German hydrographic office website, who provide a platform for the ARGO program as well as regular updates on the whereabouts of active floats.
All of those measurements, data handover, and their publication happen within minutes to very few hours – hence anyone can observe the ocean parameters in near real-time. Scientists all over the world use these data to compute and predict currents, temperature variations, and weather and climate forecasts – they can even be used as tsunami early warning systems.
The life span of an ARGO float is about 4-5 years which is, compared to their small size (~ 2 x 0.3 m), a very long time – considering constant data recording, as well as large temperature and pressure variations, is battery intensive. When their expiry date has almost arrived, they travel to the surface one last time to send an EOL (end-of-life) message saying goodbye to the operators and then dive down to 1000 m to die. Unfortunately, there is no effective procedure yet for retrieval and re-use which is why all the ex-ARGOS gather in the water column at -1000m. However, efforts are being made to design a recovery method and involve recyclable material for the ARGO construction process. Once in a while, dead ARGO floats are being caught by accident. Last week, one was retrieved by a Portuguese fishing vessel – it is now on land and back in the hands of the operator. Its final words are not yet spoken and maybe it gets a chance to live a second life!
From my side, unfortunately these are the final words on this blog. It has been a true pleasure writing it and I would like to say thank you to you, dear readers. I hope you keep an eye on our iAtlantic homepage and on the Senckenberg website – our mission goes on and so does ocean research! At the end of an expedition, we scientists always have the ideas for the next one. The story will be continued…