Expedition IceArc: Sea ice - ocean - seaflor interactions in the changing Arctic
54 international researchers including chief scientist Antje Boetius of the Alfred Wegener Institute for Polar and Marine Research study the central Arctic ocean on board the research ice breaker Polarstern. They will investigate the rapid sea ice decline, what lives in and under the ice, down to the deep sea floor. The biology, chemistry and physics of the Arctic Ocean appear to change drastically as a consequence of climate change, but how exactly the different factors and processes interact is unknown. This is why the researchers on board Polarstern plan to carry out comparative analyses of degraded and full sea ice cover in different areas of the the Arctic ocean, and the entire ocean system from the surface ice to the seafloor of the deep Arctic basins.
The expedition participants publish their impressions from the expedition in this blog. A German blog on the website of our media partner GEO shows additional informations including photos and videos. There is also the possiblity to post your comments there!
20 September 2012 - Thousands of metres below the ice
My name is Raquel Somavilla and I’m an oceanographer. I work at the Alfred Wegener Institute (AWI) since one year ago, and I live in Bremerhaven although I’m Spanish. I’m studying at AWI the deep water masses of the Arctic Ocean and the Greenland Sea. Maybe it doesn’t sound very exciting, but don’t trust in the appearances.
Why should we care about the deep water masses of the Arctic? Well, most of you probably know about the high vulnerability of the Arctic to climate change due to among other reasons the big changes in sea surface temperature or ice cover that are taking place here. However, the importance of the Arctic not only resides in the surface. Few things are known about the changes that could be taking place in the deep waters (until 5000 m. depth), because for a long time the deep Arctic Ocean has been considered imperturbable to the remaining changes observed in the surface.
Besides, in the Arctic Ocean and Greenland Sea, deep water formation takes place. This is a very important process for our climate, because these waters that sink to the bottom are substituted by warner waters coming from southern latitudes at the surface. Without these movements of warm waters at the surface from the Equator to the Polar Regions, and cold waters at the bottom from the Poles to the Equatorial regions, the low latitudes would become warmer and warmer, and the high latitudes colder and colder. This is one of the ways in which the deep Arctic Ocean and Greenland Sea contribute to the regulation of our climate, and for this reason the changes in their deep water masses are very important.
What are the causes of these changes? Well, the changes in the deep water masses of the Arctic and the Greenland Sea have the origin in processes thousands of meters above and thousands of kilometres away. How is it possible? Well, it will take me a little while to explain it, but if you read until the end you will understand.
In Fig. 2, I show you a map of the Arctic Ocean and the Greenland Sea including temperature and salinity data measured in these ocean basins. I know that at the beginning of our cruise my colleague, Ben Rabe, explained you how we measure temperature and salinity in the ocean. Returning to our figure, I have included for you some typical plots used for the study of different oceanographic processes, as the Temperature-Salinity diagram in Fig. 2b used to identify different water masses (waters formed in different ocean basins as the Arctic Ocean or the Greenland Sea), or the vertical profiles of temperature and salinity in Fig. 2c and d, very useful to see how is the vertical structure of the water column which inform us, for example, about mixing processes. In the map you also see a white arrow. It represents an important current entering the Greenland Sea from further south in the Atlantic; then, in the Arctic Ocean through Fram Strait; and flowing all around the Arctic until its exit again through Fram Strait towards the North Atlantic. The maximum representation of this current is the flow of Atlantic water that you can identify all along the Arctic through a subsurface temperature and salinity maximum (they are the shadow areas that I mark you in the temperature and salinity vertical profiles in Fig. 2 c and d).
What does this picture tell us about the Greenland Sea and the Arctic Ocean? The main feature of the Greenland Sea that we can infer from Fig. 2c and d is that temperature and salinity are quite homogenous from the surface to the bottom (4000 m.) in comparison with the Arctic Ocean. It is the result of a process known as open ocean convection which is a very effective mechanism of winter mixing due to the strong cooling during the winter months. Why is the water column in the Arctic Ocean different? Because in the Arctic the presence of the ice and fresh water in the surface enhances the stability of the upper layer and deep convection, as occurs in the Greenland Sea, cannot take place.
What more things do you notice in Fig. 2? I suppose that the presence of warmer and saltier waters in the deep Arctic Ocean, further north than the Greenland Sea, could result an odd feature. What are the reasons for that? In the vertical of profiles of temperature and salinity (Fig. 2c and d), we also observe how as we move into the Arctic Ocean following the white arrow (dots pass from pink to dark red in the map and also in the vertical profiles) the deeper waters become warmer and saltier while the waters above, including the Atlantic flow, become colder and fresher. How??? One moment, I continue, but first I leave you another figure that will help us to understand this better. Look at it while you read the next paragraph.
During the winter, very, very low air temperatures occur in the Arctic. The sea surface temperature decreases until the freezing point and ice formation takes place. I’m sure that my colleagues of the ice-physics group have explained you that the ice cannot incorporate the salt present in the sea water, and so when the ice is formed the salt leaves the ice increasing the sea surface salinity. Depending on the temperature and salinity that these waters get because of ice formation, the density difference with the surrounding waters will be higher or lower. The ice formation mainly takes place on the Arctic shelves on small areas named polynyas. From there, because of their higher density these waters created on the shelves (plumes) will deepen in the water column, ‘falling’ along the slope until its density equals that of the waters at the same depth. Similar to a snowball, the volume of the plumes increases as they ‘fall’ down the slope. Their volume increases because they incorporate ambient water in their descent and it makes their properties to change, as the scheme in Fig. 3 shows. To understand how this works, we can imagine a black snowball falling down a white mountain. As it descends, its volume increases getting lighter, and lighter grey, because it takes white snow from the mountain, while the mountain also results darker. The water that our ‘snow ball’ takes from the mountain (slope) belongs to the flow of Atlantic water that we already know. We also have seen that the Atlantic flow transports warm and salty water. Thus, our ‘snow balls’ falling along the slope in the Arctic take part of the heat and salt in the Atlantic layer and transport it to deeper levels in the Arctic. It explains the decrease of temperature and salinity in this layer and the corresponding increase in the deeper levels as we move into the Arctic Ocean following the white arrow.
So, I hope now you understand why the origin of the deep waters in the Arctic and Greenland Sea is in surface processes; in water that comes from southern latitudes in the Atlantic where it acquires its properties (temperature and salinity); and that any change that they provoke in the deep waters of the Arctic and Greenland Sea will have the potential to affect our climate. I find the understanding of the physical mechanisms linking all these processes at different compartments in the ocean climate really interesting, and I feel lucky that my research may contribute to it.
However, we are not only taking measurements of the deep water masses of the Arctic during our cruise. We have also deployed four ITP (Ice-tethered Profiler) on the ice. An ITP is an instrument that makes profiles of the water column below the ice automatically, measuring temperature, salinity and depth, although other sensors can also be installed (Fig. 4). We have recovered several moorings which have been recording properties as temperature, salinity or currents during one year at both sides of the Gakkel Ridge. We have done temperature and salinity measurements above this ridge that help us to investigate the presence of hydrothermal activity in that area. Similar to this blog, I also have a blog about ocean and climate sciences where I have been writing about all these things during our cruise. Thus, if you want you can read more about them there (http://fromtheblueside.blogspot.de/).
14 September 2012: SUIT HISTORY, 2012 ARK XXVII/3 - First Dutch content on AWI website (in Italics)
By Michiel van Dorssen (self-employed technician on board FS Polarstern at this moment), Workgroup/ Werkgroep : Iceflux (Hauke Flores, Carmen David, Benjamin Lange, Michiel van Dorssen)
In the year 2002 I was asked to think about the technical realization of an idea of Jan Andries van Franeker, a biologist working at Wageningen IMARES in The Netherlands. When I met him for the first time at his home address, there was a little wooden model on the dining table. The first SUIT (Surface and under ice trawl) in the world. The only thing was, it had to be constructed out of steel, it had to be simple and strong, and it was supposed to function. Functioning meant: it had to become a frame with a fishing net attached. A fishing net with an approximate size of 2.5 m by 4.0 m by 14.0 m. It had to be put into the water behind the ship and it should shear out on the starboard side. It should be capable of diving under the ice on its own and drive against the underside of the ice. Hereby it could fish the 2 m upper layer of the water column, in which we could find the food for the higher level predators. The question was: Can you realize such a system?
In 2002 werd ik gevraagd mee te denken over de technische uitvoering van een idee van Jan Andries van Franeker, een bioloog verbonden aan Wageningen Imares in Nederland. Bij mijn eerste ontmoeting met hem, stond er een schaalmodel van hout op tafel. De eerste SUIT (Surface and Under-Ice Trawl) ter wereld. Nu moest het alleen nog in ijzer uitgevoerd worden, simpel en sterk zijn en het moest nog functioneren ook.Dat functioneren hield in: Het moest een frame worden met een visnet er aan van ongeveer 2.5m bij 4.0m bij 14.0m. Het te water laten moest achter het schip gebeuren en na het geven van genoeg sleepdraad moest het uit zichzelf uitscheren naar stuurboord en onder het ijs kruipen naast het schip. Eenmaal onder het ijs moest het dan tegen het plafond van het ijs rijden en zodoende de bovenste 2.0m water bevissen waarin het voedsel voor de grotere predatoren zich zou moeten bevinden. Of ik dat kon realiseren.
A nice challenge but first I had to write down on paper that I would do the utmost to realize it but I couldn’t guarantee the success of the construction. During the building process I had to imagine and visualize the system without the possibility to try it out under the ice in the waters around the Netherlands.
In the meanwhile van Franeker searched for a driven and passionate PhD student to do most of the work that was required in order to realize the scientific success of fishing with the SUIT. In 2004 Hauke Flores was hired on as a PhD student. Within a short time after he started his new job at Wageningen IMARES we went for an expedition on the FS Polarstern on an autum cruise, March-April 2004, to the Antarctic. And by 'we' I am referring to: Jan Andries van Franeker, André Meijboom, Hauke Flores and myself. The expedition was successful. After this expedition we were allowed to make two more expeditions to the Antarctic. A winter- and a summer expedition. In the meanwhile, of course, we didn’t rest. We improved a lot of things and solved a lot of problems we experienced during fishing. The further we get into the process of developing the SUIT, the more the SUIT becomes a carrier of complex sensor equipment to measure the under-ice environment which makes the dataset around the fishing more and more complete.
Een leuke uitdaging waarbij ik wel even zwart op wit heb gezet dat ik bereid was om mee te denken maar dat ik niet garant kon staan voor succes. Het bouwen was `natte vinger werk` en ik had in Nederland niet de mogelijkheid om het onder het ijs uit te proberen.
Ondertussen ging van Franeker op zoek naar een geschikte PHD om al het werk te doen wat wetenschappelijk nodig was rondom het vissen met de SUIT. In 2004 werd Hauke Flores voor deze klus aangenomen . Vrij snel daarna, in maart / april 2004, zijn we voor het eerst met haar op reis gegaan op een herfstexpeditie in Antarctica op de fs `Polarstern`. En met we bedoel ik Jan Andries van Franeker, Andre Meijboom, Hauke Flores en ik zelf. En niet zonder succes. Na deze reis hebben we nog een winterreis en een zomerreis mee mogen maken in het gebied rondom Antarctica. In de tussen tijd hebben we natuurlijk niet stilgezeten. We hebben allerlei verbeteringen aangebracht en diverse problemen opgelost die zich in de praktijk voordeden. En hoe verder we in dit proces komen, hoe meer de SUIT ook nog een vervoermiddel wordt van allerlei meetapparatuur die de dataset rondom het vissen meer en meer compleet maakt.
Ten years after starting the development of the SUIT, suddenly the time was here, the SUIT’s sampling area became bi-polar. In the meantime Flores completed his PhD and shortly after he received a research position at the Alfred Wegener Institute and expands his area of research in cooperation with van Franeker. He gets the possibility to join the IceArk Expedition ARK XXVII/3. He hired 2 new PhD’s, Carmen David and Benjamin Lange. He also asked me to come with them to help out with the technical aspects of the work. In August 2012 we left with the FS Polarstern for a 9 week cruise to the Arctic Ocean and the North Pole. We became wise by shame and damage in the Antarctic, and because of our collective experience I thought it wouldn’t be necessary to join them again to keep the SUIT in shape. However, behind such a big and heavy ship and in the heavier Arctic ice conditions, something can easily go wrong.
Tien jaar na de eerste practische ontwikkelingen van de SUIT is het dan opeens zover dat haar werkterrein vergroot is. Flores, inmiddels gepromoveerd, heeft een baan aangenomen op het AWI, zet het onderzoek voort , in samenwerking met van Franeker, en krijgt de mogelijkheid om deel te nemen aan de IceArc Expeditie ARK XXVII/3. Hij heeft 2 nieuwe PHD’s aangenomen, Carmen David en Ben Lange. Tevens heeft hij mij gevraagd mee te gaan voor ondersteunende werkzaamheden. In augustus 2012 zijn we met FS Polarstern vertrokken voor een cruise van 9 weken naar Arctica. We zijn in het Antarctisch gebied door schade en schande wijs geworden en ik heb wel eens gedacht dat we een punt bereikt hadden dat het niet meer nodig zou zijn dat ik mee zou gaan om de SUIT in “de race” te houden. Achter een schip dat zo groot en zwaar is en in ijs wat absoluut niet onder de indruk is van zo’n apparaatje kan natuurlijk gauw iets fout gaan.
IceArc is a different voyage compared to the other three we previously experienced. We started off with a partly new group, a partially changed fishing system and fishing in a new area. After a short period of getting to know each other and the materials, the group is functioning as it should, everyone knows what to do. The SUIT has got three new floaters especially made by OceanWide Safety at Sea, and she does exactly what we want her to do. The new area means that we are fishing in heavy ice most of the time. This was obvious during one of the SUIT deployments, it was the third time we fished and it went totally wrong, the frame came out of the water with quite some damage. Lucky for us it looked worse then it was. After two days of grinding, bending and welding, we have a frame again, something that will work properly. Since the accident things have operated smoothly and we have not experienced any further serious damages. For me as the builder of the frame it is very nice to be here, working with materials that I am very familiar with and working on the net and frame that has been 10 years in the making. Here I directly see not only the weak points of the construction but also the practical part. From here plans for future modifications are steadily rising which means many more hours in my workshop back in the Netherlands.
For effective and efficient SUIT deployments we need a lot of cooperation and I really want to mention this. Relatively we need many crewmembers on the deck to put the net in and out of the water. This demands discipline and effort. It is great that the crew on deck and on the bridge has a lot of experience nowadays. Captain Uwe Pahl, Chiefmate Steffen Spielke and Bootsman Burkhardt Clasen with his crew, they all give 110%. Not to forget our Chief Scientist Antje Boetius, who shows us everyday that she can be flexible, has a good understanding of all scientific projects and is prepared to do the work that is required to realize the objectives of each scientific team. Everybody thinks and works together and that is the recipe for a successful Polar expedition.
IceArc is in vele opzichten een andere reis dan de andere drie reizen. Een grotendeels nieuwe groep met een deels aangepast vistuig in een nieuw gebied. Na een korte inwerkperiode functioneert de groep zoals hij hoort te functioneren, de taken zijn goed verdeeld en een ieder doet zijn/haar deel. Het vistuig, deze reis voorzien van nieuwe op maat gemaakte drijvers,door OceanWide Safety at Sea, doet precies wat we willen. Het nieuwe gebied houdt in dat we meestal onder zwaarder ijs vissen dan voorheen. Ja, en dat hebben we geweten. Tijdens de derde trek ging het behoorlijk mis en kwam het frame behoorlijk beschadigd boven water. Het zag er erger uit dan het was gelukkig. Na 2 dagen slijpen, buigen en lassen hebben we weer een vistuig waar we goed mee kunnen werken. Na die tijd hebben we geen schade meer gehad. Voor mij als bouwer is het geweldig om er zo met m’n neus bovenop te zitten. Zo zie ik niet alleen van dichtbij de zwakke punten in het constructieve gedeelte, maar ook van het practische gedeelte . Hier groeien de plannen die in de werkplaats in Nederland uitgevoerd kunnen gaan worden.
Om de exploitatie van dit geheel rond te krijgen is veel samenwerking nodig en ik vind het leuk om dat ook nog even te benoemen. Relatief hebben we veel leden van de bemanning aan dek nodig om het net uit te zetten en binnen te halen. Dit vergt inzet en gelukkig kunnen we tegenwoordig bogen op een jarenlange ervaring van dekpersoneel en van de brug. Kapitein Uwe Pahl, Chiefmate Steffen Spielke en Bootsman Burkhardt Clasen met zijn ploeg, zetten zich allemaal met enthousiasme in. En niet te vergeten de Fahrtleiterin Antje Boetius, die elke dag laat zien dat ze flexibel is , overzicht heeft, en bereid is moeite te doen om iedere onderzoeksgroep aan zijn/haar trekken te laten komen. Een ieder denkt en werkt mee: “Het recept voor een geslaagde Poolexpeditie”.
29. August 2012 - The hidden garden
By Hauke Flores (Polar ecologist at the Alfred-Wegener-Institute, presently on board of RV Polarstern). Working group: Iceflux (Hauke Flores, Carmen David, Benjamin Lange, Michiel van Dorssen)
The greyish pale of the endless pack-ice plain ceases away in the foggy distance.
The magic of Arctic ice gardens is only revealed, when the sun illuminates the melt ponds like Caribbean lagoons, the fog above the ice glowing in all colours of the rainbow.
In their blog of August 19th, Christiane Uhlig and Mar Fernandez introduced us to the world of sea ice gardening. The algae growing in and under sea ice fascinate in contrast with their barren surroundings. And the cyan-coloured melt ponds resemble the art of Japanese garden architecture.
On land, however, nobody would build a garden that is doomed to vanish after a few weeks. Except on gardening fairs, of course. Nature does not care about the long-term endurance of her artwork. And as usual in the wild, flourishing plants attract a variety of visitors.
In my blog of August 9th, one of them was already introduced. It’s the polar cod, which we catch with our under-ice net. It should not be confused with the well-known Atlantic cod. Because of its small size, polar cod is rather unsuitable for consumption.
Just like fishes living in reefs and at rocky shores, polar cod use the labyrinth-like structures and caves of older ice floes. They feed on small crustaceans, particularly amphipods. These animals resemble a mixture of scorpions and shrimp, and are well-adapted to the sea ice environment.
Back home, amphipods can be found in small rivers, ponds or on the beach. To those who notice them, they appear small, grey and hyperactive. Arctic sea ice amphipods, however, can grow to several centimeters in size. Many of them have beautiful colours: some are orange, others are pink. One species is white, but has deep-red legs and antennae. Ice amphipods dwell at the ice underside, where they feed on ice algae and small animals. And serve as the food of polar cod and other predators.
Only centimetres below the ice, the floating world of the water column begins, known as the pelagic zone. It contains life forms that appear to stem from another age. The pelagic zone of the deep-sea constitutes the largest, and least known, habitat on earth. Who has ever heard of flying slugs? Or gelatinous predators?
The wings of the thumb-sized sea angel Clione limacina move gently under the sea ice. Their faint of pink contrasts with the deep-blue background of the Arctic deep-sea. Its cone-shaped body has no shell. It is almost transparent, except for its purple-red tip. The organs inside the animal are clearly visible. Its stomach is empty. Clione limacina is waiting. She is picky. There is only one dish on her menu: L’escargot of Limacina helicina.
Thousands of the up to one centimeter large Limacina float under the sea ice. They unfold giant nets made of slime, with which they filter micro algae out of the water. These vegetarians are the ideal meal for Clione; salad included. To protect them from predators, they carry black shells.
Which does not protect them from their worst enemy. The pinkish predator stops the harmonic flapping of her wings, assaults one of the black snails, and captures it between her wings. The shell cannot resist the chitinous jaws of the angel-like predator. Within minutes, the intestines of Clione limacina appear black from the meat of its preferred delicacy. Feeding and being fed on at -1.9°C.
The scenery turns surrealistic, as the next predator appears. First a barely visible shadow in the distance, a gelatinous mass of a nearly cylindrical shape moves closer. It is a large comb jellyfish. It measures 15 cm in length, and 5 cm in diameter. Lacking tentacles or fins, it controls its movements by means of small comb-shaped plates. These are arranged in eight rows from the front to the back of the animal. Breaking the dim under-ice light by their delicate structure, the comb plates rhythmically flash in rainbow colours.
Similar to medusa, comb jellyfish consist of not much more than an intestinal tube embedded in a gelatinous body. The two types of jellyfish are, however not related with each other. Comb jellyfishes without tentacles ingest small crustaceans and young fish by sucking them into their mouth. Other comb jellyfishes are equipped with two meter-long tentacles, bearing numerous extensions. With these, they unfold giant networks to catch their prey. The tentacles of comb jellyfish feature unique super-glue, from which there is no escape for their prey.
Just like everywhere in the wild, elegance and beauty of the under-ice world come along with the hardness of the struggle for survival. The ever-changing sea ice and the bottomless water underneath it constitute their own world beyond our everyday imagination.
At both Poles, this is a world undergoing rapid change. Just a few days ago, a new negative record of the Arctic summer sea ice extent was made public. The environment of ice amphipods and polar cod, as well as of the fish, seals and polar bears depending on them, is melting away at increasing pace.
When my 4 year-old daughter will be grown-up, the Arctic will be completely different from the one described in her children’s books. The new Arctic will not only bring new shipping routes and access to resources. Its biological richness will change, too. How these changes will affect human societies and the earth system, is barely understood. Much is at stake for the people of the Arctic, and their environment.
21 August - What do you miss from home?
by John Paul Balmonte, University of North Carolina at Chapel Hill, Department of Marine Sciences
We are fifty-four scientists from twelve different countries, but one thing binds us all: the mutual feeling of missing certain things from home. In an effort to better get to know my colleagues, I conducted an interview with several of them asking the question: What do you miss from home?
Me: So, what do you miss from home?
Christiane Uhlig: My plants.
Me: Your plants? That’s interesting. Maybe you can culture some of the algae aggregates that you find and make them your temporary plants?
Both of us laugh
Christiane U: Yes, of course! And I miss my bed also.
I can understand what Christiane means when she says she misses her bed. It is not that the beds here are uncomfortable, but there is a certain comfort that comes from sleeping in your own bed, with your own sheets, and with more than one pillow. Here on the Polarstern, we are quite fortunate, actually. The stewardess provides us with fresh new sheets every week, and the duvet comforters feel very comfortable. The small size of the bed, of course, is a compromise that one must accept.
Heidi Sørensen: Rye bread.
Me: They don’t have that in the Messe? (Messe is the dining area, and the Polarstern is equipped with two)
Heidi S: No. I’ve already told my family to have it ready for when I come back.
Me: Please spell “rye”.
Heidi S: I can give you the Danish word.
Heidi S: Rugbrød.
Me: Can you pronounce that again for me?
Listening to her pronounce that word allowed me to realize two things.
First, I have come to appreciate the beauty of the different languages spoken amongst the scientists on the ship. From German, to Danish, to Russian, to Catalan – the diversity of the spoken language here is phenomenal, and I am constantly immersed in it. Every day I learn new words, syllables, and sounds. And on most days, some of my colleagues learn new English phrases from me. We all have a highly mutualistic relationship, in terms of culture and language.
My second realization from Heidi’s response is that we tend to miss the things we usually take for granted. At home, we live in abundance of certain foods that we eat, or we take for granted the local sushi restaurant or the nearby Thai restaurant. We are accustomed to our own habits, much like how Heidi eats rye bread at least once a day. And when we are on a research vessel away from what is familiar, we long for these everyday, common things.
Luisa Galgani: I miss the weather!
Me: The German weather or the Italian weather?
Luisa G: Italian weather. And Italian wine! Oh, and I also miss really good, strong coffee. And Italian olive oil. And my boyfriend. And I miss the night!
Me: I do, too!
Luisa G: But I love the fresh air that we get here in the Arctic.
Luisa, who is originally from Italy but currently studying in Germany, seemed to miss many things from her home country. Maybe this is not about being on the ship for two months – maybe she just needs to fly back to Italy for a visit, and she will feel renewed. However, I do think that most of the scientists will agree with her on several things: missing a significant other, warmer weather, and a clear distinction between night and day. While having sunlight 24 hours a day, 7 days a week, allows one to work throughout the night, getting sleepy when there’s constant sun can be an issue. How do we deal with the sunlight at night? By pulling down our blinds.
Karl Attard: My mommy.
Me: Alright, noted.
Karl A: And Skype. And the internet.
Karl brings up a good point – missing our parents. While all of us on board are adults, most (if not all) of us maintain a healthy relationship with our parents. Karl communicates with his parents in Malta at least twice a week. I am slightly more frequent with my communication with my parents in California – almost every day. So, to have almost no way of contacting the outside world (except for e-mailing) is a little difficult, but manageable. And this brings me to my next point: not having internet certainly has its disadvantages, but can be quite refreshing.
During our interview, Karl mentioned that having the internet would probably take away from the experience. Not having been on the Polarstern before, I had very little expectations of communicating with anyone back home. I did not know the phone or internet situation. I was told we had e-mail, and that provided some relief. I prepared myself mentally to not verbally communicate with my friends, family, and significant other for two months. But the Polarstern is actually equipped with a satellite phone; hence, we can purchase a phone card for 27.50 €, which allows us to talk for 45 minutes. As for the internet, there isn’t any due to the very high latitude. Only the chief scientist can dial in when urgent, but it is complicated. And this lack of internet is something that some of us can appreciate. We have less distraction, and we are able to focus on our research. And equally important is that we are able to live in the moment and get to know our fellow scientists personally.
Antje Boetius: My rose garden in my terrace.
Me: You are the second person that mentioned plants!
I couldn’t quite joke around with Antje and tell her to culture her own algae, because she probably would have done it! She usually works with bacteria, so maybe she would have cultured some cyanobacteria.
Perhaps the biggest surprise of all of my interviews comes from my roommate, Daniel.
Me: Daniel, can I interview you?
Daniel Scholz: No.
Me: What do you miss from home?
Daniel S: Silence.
At first I wondered about his response, but, after speaking with the other scientists, I realized how Daniel’s answer went beyond any of our material longings.
He was referring to personal space and the escape from certain noises. In this vast research vessel where mechanical tasks are in queue almost 24 hours, 7 days a week for over two months, it is difficult to find quiet solitude. There is the constant sound of the Polarstern breaking through ice, or the autoclave beeping that it is ready, or the crane lowering equipment into the water column. However, sometimes we find solace and isolation in the weirdest places – the cold room, the lavatory, or in the sauna.
But despite all of these things that we miss from home, I believe I speak for everyone when I say that this cruise is a special opportunity for which we would be more than willing to sacrifice many things that are comfortable and familiar to us. We are fifty-four scientists from twelve different countries, and although we are far from home, each of us are blessed with fifty-three friends conducting research and forty-five friends that are part of the Polarstern crew.
15 August 2012 - Playing with mud, water… and bacteria
by John Paul Balmonte, University of North Carolina at Chapel Hill, Department of Marine Sciences
While most of my friends from my undergraduate years are now finding ways to cure various diseases, I am currently traversing the Arctic, edging towards the North Pole, collecting mud, water, and bacteria. Was I absent in class when they taught us the benefits of medical research? No. I have simply found an appreciation and love for understanding bacteria and their role in our ecosystem! Have no fear – most of the bacteria in the environment are harmless! By education, I am a molecular biologist and environmental scientist. By training, I consider myself more of a microbial ecologist, or even a marine microbiologist. To be very specific, I study the extracellular enzymatic activity of bacteria. Don’t be intimidated! It’s a very easy concept to understand!
Let’s break this down word for word. Extracellular can be broken down into two parts: extra and cellular. Extra, in this context, means outside, and cellular means exactly what it says: the cell. Enzymatic refers to enzymes. Enzymes are proteins secreted by bacteria to do different things – some enzymes are meant to degrade or breakdown other proteins, carbohydrates, while other enzymes are meant to build things within the organism. So let’s now put this together: extracellular enzymatic activity refers to the bacterial breakdown of proteins and carbohydrates by enzymes that are released outside of the bacterial cell. Now you might be wondering why all of this is interesting and what is it used for? Let’s start with “What is it used for?”
When you and I eat, we put food in our mouth and we chew it. From our mouth, the food that we swallow travels all the way to our stomach. During this process, acidic juices, combined with mechanical action breaks down, and digests our food. So we eat food, and then digest it. For bacteria, the process of “eating” is quite different – they do not eat WHAT we eat, nor do they eat HOW we eat. Heterotrophic bacteria (heterotrophic refers to the dependence on carbon sources, such as proteins and carbohydrates, for energy) do not eat and then digest like we do, but rather they digest and then eat. The process is backwards! Why can’t they put food in their mouths like we do? Well, first of all, they don’t have mouths to put food in. They have what are called bacterial porins. Bacteria take in food through porins all over the surface of their cell, and in order for them to take in their food, they first have to digest it outside of their cell. Hence, they release extracellular enzymes or digestive enzymes. These enzymes break down proteins and carbohydrates into pieces that are small enough to enter the bacterial porin. Without these enzymes, their food would be too large to consume! Therefore, bacterial extracellular digestive enzymes are comparable to the acidic juices in our stomach – they break down food.
Now let’s try to understand why all of this is important. The foods that bacteria consume are from particles that are present in the environment – in this case, it is the ocean. The particles that bacteria utilize as food come usually from decaying organisms – phytoplankton, zooplankton, or maybe even large mammals! Bacteria are very special organisms in that they can degrade a wide variety of substrates – or, to put it simply, they can find food in different things! What bacteria eat, and how efficiently they can eat it are dependent on several factors: 1) bacterial community structure (what types of bacteria are present), 2) how active the bacteria are, 3) what types of digestive enzymes the bacteria release to break down food, 4) what types of food are present, 5) and how much of this food is present. All of this can change with global climate change – less ice on the water surface could mean higher productivity (more phytoplankton, zooplankton, etc) in the water column. When these organisms die and sink down the water column, more food becomes available for the bacteria.
I am here to study how efficiently bacteria from the water column of the ocean and the underlying surface sediment can degrade different types of foods, and how this can change depending on where they live – whether they live in open water, in water that is sometimes covered with ice, or in water that is always covered in ice (refer to Photo 1). I take bacteria from different depths in the water, and bacteria from the sediment (or mud as I like to call it) and I give them different types of food to see whether they are capable of breaking them down. No, I did not bring decaying organisms – I brought peptide and polysaccharide substrates. These substrates contain carbon in different structural forms, and if the bacteria from the Arctic waters and sediment have the proper extracellular digestive enzymes, then they will be able to digest the substrates and use them for food and energy. If temperatures change here in the Arctic as it is currently predicted, then the types of bacteria that live here may change. This means that the efficiency with which bacteria can digest their food may also change! By comparing the bacterial extracellular enzymatic activity and community composition in the water and sediment under different ice conditions, we may have insight as to how climate change could change bacterial activity and the types of bacteria that can thrive with less ice.
And that is the reason for my visit in the Arctic!
13 August 2012 - Trace Metals Biogeochemistry
by C-E. Thuróczy (Postdoc, NIOZ-NL) & M. Le Guitton (PhD student, NIOZ-NL)
Who are we and what are we doing on the ARK-XXVII/3?
Charles-Edouard Thuróczy and I, Marie Le Guitton are the so-called “Super super Clean Team”. What does it mean, will you asked. We are working on trace metals, i.e. elements found at very low concentration in seawater, which have essential roles in living organisms. We mostly focus on iron (Fe), which is the 4th most abundant element on Earth. Iron was found at very high concentration in oceans in the past. However, during the early life evolution when the photosynthetic microalgae appeared, producing oxygen, iron has been oxidized and precipitated. Nowadays, it is a scarce element in seawater. Despite its very low concentrations, iron is essential for phytoplankton in the surface ocean. Iron is used in enzymes and in vital processes in the cells like photosynthesis. The Fe fraction that is accessible for phytoplankton uptake (bioavailability) controls the plankton community and consequently the biological carbon pump. Our general objective is to assess the role of sea ice as a source of bioavailable Fe and other bio-essential trace metals (Mn, Zn, Cu), their impact on primary productivity and on the biological pump. This project is part of the GEOTRACES framework.
How does it look on the field?
Well, try to find Ilka Peeken (AWI, Germany) and us on this picture! We don’t wear white suits to hide from polar bears – even if it might work well, but trust us, you don’t want to try: polar bears are nice and cute only from far away. More seriously, studying trace metals is very sensitive and so, requires lots of precautions to avoid contamination. You can’t sample trace metals with metallic equipment. Unfortunately in science, most of the equipment is made out of metallic alloy (iron, aluminium, etc). Recently, Hein de Baar, Véronique Schoemann and Jeroen de Jong from the Royal Netherlands Institute for Marine Research (NIOZ, The Netherlands) jointly with the workshop, have developed a titanium corer to sample ice cores. Why titanium? The main reason is because it not sensitive to corrosion. “But titanium is a metal, isn’t it? ” might ask some of you. Yes, it is. However, we are not interested in measuring it (yet!).
To investigate the sources of iron and other bio-essential trace metals, we sample sea-ice (by taking cores), but also snow (when there is), under ice seawater, sack holes and melt-ponds. Our first ice station was a success and went pretty smoothly thanks to the help of Ilka Peeken. We are now getting ready for the next ones.
9 August - Ice fishing
By Hauke Flores (Polar ecologist of the Alfred-Wegener-Institute, presently on board of RV Polarstern)
Working group: Iceflux (Hauke Flores, Carmen David, Benjamin Lange, Michiel van Dorssen)
Rumpling, screaming, and sometimes banging, Polarstern pushes its way through the sea ice of the Arctic Ocean. For 30 years, she has been doing nothing else: From October to May in the Antarctic; from June to October in the Arctic. Year after year. With regard to her age, it may be well appropriate to speak of sovereignty in her way of dividing the ice.
Our team of four impatiently awaited the ship’s arrival into the sea ice as we were about to enact a premiere. For the first time ever, our heavy under-ice net was going to be towed under Arctic sea ice.
The crew named our sampling gear simply ‘the carriage’, after the death-bringing carriages of antique warriors: A steel sledge of more than 1,000 kg, to which two 15 meter-long fishing nets are attached. This Surface and Under-Ice Trawl (SUIT) was designed by the Dutch research institute IMARES. Large floaters keep it at the surface during fishing, while it glides along the underside of sea ice. A sophisticated design enables it to shear to the side of Polarstern, ensuring that it does not sample in the brash ice left behind by the ice breaker. So far, the ‘carriage’ has only been used in the Antarctic Ocean. Would it withstand the thicker, rougher and heavier multi-year ice of the Arctic? (see Picture: SUIT after deployment behind Polarstern. Photo: Benjamin Lange)
And now, finally. Sea ice. On the morning of August 7th, tension increases on the working deck of Polarstern, as the ‘carriage’ is being prepared for deployment. Pressure ridges several meters high make us nervous. A 3-meter ridge above the surface can easily mean 4 to 5 times more ice resides at its underside. The SUIT is deployed using Polarstern’s large A-frame on the aft deck. Everybody takes maximum care, as the heavy frame, lifted by a single steel wire, may become dangerous for crew and scientists. But the crew is experienced with the ‘carriage’, and the SUIT finally floats in the water. As the ship accelerates, the SUIT shears to the starboard side of Polarstern. At a speed of 2.5 knots, it meets the first ice floe, and…
the ‘carriage’ smoothly dives under the ice.
A big surprise awaits us, when the catch is retrieved about half an hour later: We caught polar cod. Unlike its well-known sibling species, the Atlantic cod, polar cod are well adapted to living at the underside of sea ice. In its barely accessible habitat, the up to 20 cm long fish are difficult to sample for scientific purposes.
Micro algae living in sea ice constitute an important carbon source in Polar ecosystems. Through the food chains, their carbon sustains the populations of Arctic fishes, wales, seals, and polar bears to a significant extent. As a prey of seals and sea birds, polar cod are an important part of these food chains. Investigations on polar cod may contribute significantly to unravel the importance of sea ice in Arctic ecosystems. Such research helps to find out which changes may be expected in the future, as sea ice diminishes further. Such knowledge contributes to better predictions on the future fate of Arctic fish stocks and biodiversity. (Pictures on the right side: A polar cod Boreogadus saida in our small aquarium. Almost all fish were still alive after being caught by the SUIT. Photos: Hauke Flores, Alfred Wegener Institute)
While we are proudly taking our catch into the ship’s inner laboratories, the bridge announces the first polar bears of the expedition. Polarstern passes a polar bear mother and her cub. Their fur shines in the light of the polar sun. A greeting from the undisputed top predator of the Arctic, as if to acknowledge our efforts. (Picture on the right side: Polar bears ahead. Photos: Bridge camera of RV Polarstern)