…. or my 25th Anniversary cruise!
29 January 2021
Blog by Katrin Linse
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.
22 January 2021
Blog entry by Mia Schumacher
A Day in the Galley (aka: The Other Engine Room)
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:
- 150kg butter
- 170kg flour
- 3500 eggs
- 500l juice
- 100kg onions
- 150kg potatoes
- … and so much more!
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!
17 January 2021
Blog entry by Mia Schumacher, GEOMAR
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.
14 January 2021
Blog entry by Mia Schumacher, GEOMAR
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!
12 January 2021
Blog entry by Mia Schumacher, GEOMAR
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!
Expedition blog by Mia Schumacher, GEOMAR
8 January 2021
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.
Day 32: 22 July 2020
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…
Day 27: 17 July 2020
The cruise is slowly coming to an end and we get a sense of home as we cross 54° N latitude. However, sniffing familiar air again doesn’t mean that there is no more work – on the contrary: we have reached the deep abyssal plains of the North Atlantic and start our measurements from 3500m down to 4500m water depth to get an idea about species distribution along a depth transect. Abyssal plains are the remote result of a spreading sea floor that is constantly being pulled sideways and stretched, meanwhile being covered in a fine grained sediment layer of silt and clay. Those plains make up almost 50% of the Earth’s surface – and they play a major role in the ecosystem.
To the untrained eye, there is not much to see: basically ‘only’ mud, wormholes, a fish every now and then, and countless numbers of sea cucumbers in all forms and sizes. For an expert however, the vast sediment desert and its residents are crucial to the fundamental carbon circle and, therefore, to the entire nutrition cycle. Anything that is washed into the oceans by rain, rivers, and organic matter from dead biomass eventually settles on the seafloor. Abyssal plains therefore act as carbon sinks, with carbon being held in the sediment until it is reworked by crucial fauna. The time taken for material to reach the seafloor can be incredibly slow, with sedimentation rates in the order of mm/1000 years.
This is also what life is like down in the deep: Unhurried and relaxed. Predators are opportunist feeders – waiting for prey to swim by rather than actively hunting it. Less so are the sea cucumbers or holothurians, who constantly devour the sediments and filter it for nutrients. Through their transparent bodies, this process is clearly visible and basically what goes in, comes out again, once particular organic matter has been digested. They leave (sea-cue-)cumbersome traces on the sediment as they gradually sweep over the seafloor– and sometimes, these trails end all of a sudden in the middle of nowhere, with no one in sight anywhere. This is when sea cucumbers decide to travel for a longer distance – they flood their body with water until they float and then go with the flow, wherever it may take them. Some specimens also have a sail that enables them to aim in a certain direction.
Day 25: July 15 2020
We leave the beautiful vent site behind us and head further south, riding on the storm and through heavy waves again. Time to take a look at what is going on in our onboard laboratories!
When samples are taken – geology or fauna from the ROV dives, EBS, plankton net, MUC, and box corer – they have to be observed and documented. Depending on the sample type, there are various methods to investigate the ‘prey’: sediment is being washed and sieved, water is being filtered to remove ‘pollution’ – larger bits that may misrepresent the actual sample – whereas bigger samples from the ROV or plankton net go directly into the labs to be examined under the microscope. Then comes the sorting. If you have ever wondered why biologists (maybe humans in general) have the tendency to create never-ending lists of various categories: groups, families, sub-families, genus, species and sub species … (to be continued) – here is why: things have to be put somewhere! Following ‘if you have a problem, give it a name’, taxonomy and generating categories are key to communicating about biodiversity and our understanding of how species distribute, behave and function together. This is why biologists sort all samples (in laborious, time-consuming fashion) under the binocular microscopes into groups: to find common features, similarities and differences across the collected species. The most frequent animals they find in the micro- to megafauna are: corals (anthrozoa), sponges (porifera), crustaceans (including decapods, amphipods and isopods), shells, molluscs (bivalvia and gastropoda), and the vast array of worms – the polychaetes. Each of them tells their own story about its habitat and the ecosystem it has been living in, as well as tales about its eating habits and travel patterns. For example, worms prefer soft sediment where they can dig a hole and either filter the water to feed or, in some cases, catch passing smaller animals. A rocky mid-ocean ridge is not a suitable environment for a soft sediment worm – hence it acts like a natural barrier and keeps the worm in place. All of those elements – fauna or ‘dead’ material like sand and stones – are interwoven in highly complex patterns, all interacting and forming unique and vulnerable habitats that react to even the smallest changes. We still have a long way to go and are far away from understanding this multifarious structure, but in very small steps we are getting there.
Depending on the field of interest, the next steps in the sample processing journal are fixing (preserving) the animal in either formol or ethanol, to allow us to investigate its morphology or genetics, respectively. The removal of animals from the seafloor is a very sensitive subject, and we strive to not take more specimens than we need to understand and describe the ecosystem efficiently.
But now for something completely different. It’s …. dark again at night time! After three weeks of 24h sun, which is stunning and beautiful but completely messes up the daily rhythm, a few dark hours are a gratefully-received gift for a much-needed sound sleep!
Day 22: 12 July 2020
We found it! Our wish came true after about two hours of ROV diving in the dark on the legendary Reykjanes Ridge structure: The long desired hydrothermal vent field suddenly appeared in front of the cameras! Spewing out hot water up to 300°C, these little vents enable unique biodiversity in a peculiar looking environment. If I didn’t know we were about 700m under water, I’d probably think we had landed on the moon: standing on bizarrely-formed rocks and watching a chimney 1.5m high that pours hot fluid into the near-freezing cold water column is an extraordinary experience. Huge red fish, a giant halibut and numerous squids joined our dive through this dreamlike world. Unlike our former dive areas, where sediment and coral reefs prevailed, this one looks like as if giants had played cosmic marbles: the seafloor is covered in rocks (pillow lavas) that are almost perfect spheres, each about 0.5 – 1m in diameter. And what seems to be inhospitably rough environment is in fact full of life. A fundamental part is played by the large bacteria mats that spread in a smooth white layer over the rocks. They feed on the hydrothermal fluids and announce themselves by dispersing what look like big snowflakes in the water column. Hence each time we felt like flying through a cold winter night’s landscape, those bacteria mats couldn’t be far! And where they are, hydrothermal activity must be, thus they act as perfect signpost for our vent hunt. Many species rely on these mats, amongst them are a variety of anemones, crustaceans, corals and fish. They also enjoy the warmth of the vents and they vanish once the hydrothermal activity stops – that is why we passed over vast coral graveyards: similar to volcanoes on land, hydrothermal vents have an expiration date and cease to be when their time is up. The surrounding water that used to be lovely 20°C cools down to about 5°C which makes it uninhabitable for these corals. They die and leave behind fields of brittle bony pieces.
© 2024 iAtlantic. All rights reserved.
This project received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 818123 (iAtlantic). This output reflects only the author’s view and the European Union cannot be held responsible for any use that may be made of the information contained therein.