Category Archives: ForBio

Phylogenetics course

Phylogenetics course 2014

Phylogenetics course 2014

This week was dedicated to phylogenetics. In five intensive sessions on the computer lab, students were practising exercises using a range of different software packages. The main purpose with the course is to get some hands-on experience with the work-flow from phylogenetic data to phylogenetic trees and their interpretation. Course instructors were teachers and PhD-students associated with the Invertebrate Collections.
The course is also open for students in the internordic Research School in Bioinformatics run by four university museums in Norway: ForBio. In addition to students from UiB, this year we also had visitors from the Universities of Iceland, University of Copenhagen, Gothenburg University, University of Oulu, and the University of Salford, UK.

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Good-bye Greenland!

The last days before leaving the Arctic Station were busy: last boat trip, last samples, last possibility for filming work with the underwater-camera. Personal projects to finish, lab to clean, things to pack, and on top of all that: a football match against the Qeqertarsuaq “Old Boys”!

Photo: A Mucharin   Photo: A AltenburgerLast days in the lab: full house!                         The underwater film team: Mette and Jenny

Photo: I Meyer-Wachsmuth

Bathing between icebergs – who can resist?

Photo: A Mucharin

Football match against the Qeqertarsuaq “Old boys”, who turned out to be not that old… and pretty fit!

We left the Arctic station on a beautiful sunny day and headed towards Ilulissat, where we spent two days in wait for our flights back to first Kangerlussuaq and then Copenhagen. And beautiful days that was: Ilulissat is known for its icebergs and some of us took an icefjord tour on a handsome, oldish, boat with red paint and wooden deck. And – to our surprise – it turned to be out the old Porsild – the Arctic Station’s former research vessel!

Photo: D de Abreu

On the way to the ice fjord in Ilulissat – on board of the boat that turned out to be the Arctic Station’s former research vessel (the “old” Porsild!).

Now we are back to our respective homes – wrapping up coursework and getting on with our lives, PhD projects, master theses, scientific work and teaching. But we all agree: this was a very special course bringing us close to Arctic nature and providing us with outstanding possibilities to collect and study Arctic marine organisms.  We could both widen our taxonomic knowledge and – in different degrees – even get data that are of direct use for our ongoing research projects.

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At the end of this blog, we want to thank all those who helped us during this trip: Ole Stecher and Akaaraq Mølgaard at the Arctic Station, the crew of RV Porsild: skipper Frederik Grønvold and boatmen Søren and Johannes. Also, we are thankful to Reinhard Møberg Kristensen (Univ. Copenhagen) for suggestions concerning sampling sites and use of equipment!

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The Research School in Biosystematics (ForBio) is funded by the Research Council of Norway and by the Norwegian Taxonomy Initiative – thanks for making a course like this possible!

And thanks to all of you who have been following us via this blog!

Written by: Christiane Todt (coordinator ForBio, University Museum of Bergen);                   Featured image: (Jenny) under the rainbow. Photo: Anne-Helene Tandberg

 

Photo: P Funch

Team blue mussel on the track of the expanding blue mussel in a changing Arctic climate

The blue mussel (Mytilus edulis) is on the run, a historical run. Blue mussels are currently expanding towards the North with an unprecedented pace, taking over new areas along the way.  

Photo: J Thyrring

Rich and healthy mussel beds in the Arctic

Blue mussel is an ecologically well-studied species that often dominates the coastal zone, where these characteristic bivalves form a specific habitat with a distinct associated fauna. Such habitat formers, which influence ecosystem structure, have a potential for wide impact if they are able to migrate into new areas due to changing climate. With the record increase in ocean temperatures, the blue mussel has already expanded its northern distribution well into the High-Arctic region.

My PhD project at Aarhus University aims to investigate the distribution, abundance and physiological adaptation of the blue mussel along the West Greenland coast. Thus, my participation in the “ForBio marine field course, Greenland” was of central importance for my project. During my “individual project” in the course, more than 4500 blue mussels were collected at several prime locations! All mussels were measured, weighted, and aged by counting growth rings – a work accomplished by the energetic ‘Team Mussel’, mainly consisting of Josefin and me – Jakob. In spirit though, everybody on the course was a part of this amazing team, and I thank them all for helping out by collecting Blue Mussels in Disco Fjord, while I stayed behind at the station for physiological measurements in the quiet laboratory.

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Happy collecting of blue mussels at Disko Bay

In the final days we expanded our project, collecting material for comparing population dynamics of mussel beds in the low and high tidal zone. To catch the low tide, Josefin and I went on a rainy, cold and dark morning to collect mussels. Despite the early hour, lack of coffee, and no breakfast, we returned to the lab in the rising sun with a whole bunch of mussels. Mette and Jenny had finally seen the light and joined ‘Team Mussel’ full time to help getting everything done in time.

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‘Team mussel’ consisting of Mette, Jenny, Josefin and Jakob hard at work

All blue mussel data collected during this course will be used to increase our understanding of the ecological consequences of the expanding blue mussel in the Arctic. By comparing population dynamics and macrophysiology among populations found at Nuuk, Disko Island, Upernavik and Qaanaaq, our studies will allow us to better understand the direct (and indirect) impacts of the changing Arctic climate. Eventually, we hope to expand our knowledge of how species susceptible to expand their current distribution range will influence current ecosystem structure and function in a warmer future.

 

By Jakob Thyrring (Aarhus Universitet)

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The “Greenland Big Five”

Obviously there are no lions, rhinos and zebras in Greenland – and polar bears are seen on Disko Island extremely rarely. Thus we had to create our own categories for a “best of” photocompetition:

1. Best iceberg

Our September stay has exposed us to never ending varieties of iceberg beauties, and catching the right angle and the right light has occupied our master photographers on boat rides and on trips to the beach near to the Arctic Station, which is where many an iceberg ends their existence.

Photo: A Altenberger

Icebergs, icebergs, icebergs – the vote for best iceberg photo fell on this one! Photo: Andreas Altenberger

2. Best whale

On our trip to the Arctic Station we had a stopover in Aasiaat, where a whale watching trip was one of the highlights. We followed a group of four humpback whales, icluding a “youngster”, for some time and they were really cooperative by coming close and showing different aspects of flippers, backs, and flukes.

Photo: J Egardt

One of the Aasiaat four – Jenny caught the moment just before the whale was diving down close to our boat. Photo: Jenny Egardt

3. Best polar light

Seeing polar lights was a “first time” for a number of us – thus Andreas and his “polar light app” were checked as regularly as the night skies. And then – at last – polar lights! But not all cameras showed to be equally useful…

Photo: A Mucharin

After a few nights in Greenland the conditions were perfect: Northern lights over the Arctic Station! Photo: Arom Mucharin

4. Best sledge dog (puppy)

Sledge dogs are ever-present in Greenlandic towns and villages. The adult dogs have to be chained to prevent them from roaming around and harm each other or even people. The young ones, however, can enjoy their lives and even though they usually are very cautious towards strangers, they are also curious. And incredibly cute!

Photo: A Mucharin

In Aasiaat, before even arriving at the Arctic Station, Arom met this cutie and managed to catch his interest. Photo: Arom Mucharin

5. Best Greenlandic fisherman/hunter

We found out that Greenlanders are not necessarily happy about being photographed by tourists –  like us. But getting to know them changes this considerably – especially if boats, fishing, or hunted-down seals are involved. Therefore our last category: Greenlandic fisherman/hunter.

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Johannes and Søren – our two boatmen on the trip to Disko Fjord – in action on Arctic Station’s “jolle”. Johannes impressed our guys with unseen-before fishing and hunting abilities, and the ownership of a most striking mustache. Photo: Peter Kohnert

Finding the best

For this photo competition, everybody could hand in their best photo for each category and everybody could vote. In total there were 35 submissions. Arom (2 “best photos”), with her relatively simple compact camera, showed that often it is the choice of motive and not the advanced equipment that makes a good photo! Congratulations!

Photo: A Altenberger

Arom, Mari, Jeroen, Josefin, Sandra, Henning, and the puppies in Kangerluk.

But of course there were lots and lots of great photos also outside the categories and finally combining all photo material added up to more than 50 GB (!!) of photo material!

Written by: Christiane Todt (University Museum of Bergen)

Featured image: Iceberg hunters with their prey, by Henning.

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Sculpin fishing in Greenland

As a PhD student from the University of Gothenburg researching gastrointestinal motility and blood flow in fish, you may wonder how did this man arrived in Greenland on a Forbio marine field course!! Well, let me explain……..

Gastrointestinal motility and blood flow in fish can be affected by a range of abiotic (e.g. temperature) and biotic (e.g. diet) factors.  As part of my doctoral research I video record the movements of the gut and produce spatio-temporal maps allowing me to qualitatively and quantitatively characterize gut motility patterns in vivo in fish. Using this method I want to investigate the effects of diet and temperature on gut motility patterns in a fish species called shorthorn sculpin (Myoxocephalus scorpius). However, before I can experimentally test the effects of different compositions of fats, proteins and carbohydrates in food on motility patterns I need to know the natural diet of these animals…….and thus, much to my joy and excitement, we arrive at Disko Island, one of the more northern areas in the geographical distribution of shorthorn sculpin!!!

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Fishing for sculpin…..arctic style

Due to strict luggage regulations I was unable to bring my ultimate sculpin-catching device (fishing rod) and instead had to arm myself with a 50 DKK handline from the local supermarket, which made things increasingly difficult (that was my excuse anyway!!).  After numerous failed attempts at a range of beautiful locations, my total catch included a piece of seaweed, 4GB of wicked photos, no hooks and sinkers left, and my pride was taking a severe dent as people were now sarcastically referring to me as the ‘master fisherman’.  Eventually through a combination of the stars aligning and the purchase of a ‘lucky hook’, the fish started biting….hallelujah!!!! After the slightly messy business of extracting the stomach contents from the individual fish back at the lab, it was time to identify what these animals feed upon.

Photo: J Brijs

Removing the food contents from the stomach…

Luckily for me there was an abundance of excellent taxonomists on the course to help me identify the semi-digested prey items.  Thus without further ado……. they feed upon pretty much everything they could get their ‘hands’ on!!!!! This included gastropods (Littorina saxatilis, Littorina obtusata, Margarites groenlandicus), polychaetes (family Glyceridae), amphipods (fam. Caprellidae and Gammaridae), chitons (fam. Leptochitonidae), molluscs (Mytilus edulis), shrimp (Pandalus borealis) and big blocks of nicely cut up seal blubber (which was the bait of choice!!).

Thus in conclusion……shorthorn sculpin are opportunistic feeders and will utilize a range of different prey items to satisfy their metabolic demands.  Now that I have arrived back in Sweden, armed with new skills and knowledge on invertebrates, I would like to do a similar study on the shorthorn sculpin residing on the west coast of Sweden to compare differences in diet of the two different populations, which will make up an integral part of my PhD thesis.

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Not a sculpin…but a halibut!!!…..a predator of the sculpin as we found a whole sculpin inside the stomach!!!!

All in all it was an amazing adventure which I will not forget and I strongly advise any students to take part in future courses!!!!!!!

Signing out……..Jeroen Brijs (Gothenburg University)

Photo: AH Tandberg

Our Favourite Things

The participants of “ForBio Marine Course Greenland” represent a highly diverse group. This is our presentations of ourselves through our favourite organisms (“things”):

Near the end of the Greenland Adventure, full of unforgettable experiences and close to collapse of exhaustion after long days of sampling and sorting, our Arctic explorers took a few minutes of their precious time to write about themselves and which organism made them head North, up till latitude 69 degrees.

Photo: A AltenburgerAndreas Altenburger (University of Copenhagen): 

The aim of my project is to investigate the embryonic development of animals in the phylum Kinorhyncha. During the course I use the possibility to collect several kinorhynch species and try to make them reproduce.

 

Anne Helene Tandberg (Institute of Marine Research, Tromsø):

Photo: AH Tandberg

Amphipods from the genus Metopa are my favourite animals. This is a photo of Metopa alderi, who, just like its “cousin” Metopa groenlandica has been found here; they both live inside mussels. I love the way the tiny details help us determine which species we look at, and that they have found such clever ways of living – nice and cozy inside another animal…

 

Christiane Todt (University Museum of Bergen):

Photo: A AltenburgerMy special interest are molluscs, and especially the shell-less and worm-shaped aplacophoran groups. The small solenogaster (or neomeniomorph) on this picture has already gained some fame in 2011 by being featured as “Greenland neomeniomorph” in a publication in  the journal Nature (480: 364–367) – but it has no valid name yet! We found 10 more specimens – enough to analyze its anatomy and spicule morphology to come up with a proper species description and a scientific name!

Photo: AH Tandberg

 

Daniela de Abreu (University of Gothenburg): 

Yes! Slow moving amphipod. My favorite animal, so far, is Socarnes vahlii, the cutest, most colorful, and slowest amphipod I spotted on the Lithothamnion aggregation samples of Disko Fjord. This guy has the most amazing chromatophore patterns and colors of the crustaceans collected in this trip.

 

Photo: H Flørenes

Henning Flørenes (University of Bergen): 

Here on Greenland we’ve had a great variety of fauna that are absolutely fascinating. I’m currently working with calcareous sponges that are as amazing as anything you can imagine. My personal favorite is the fabulous Brattegardia nanensi. With its elegant form and lovely network of asconoid tubes, it ranks as the top sponge on my favorite list. It’s known to be around the Disko Island area so I’ve had the great opportunity to get a specimen and take a closer look at it.

 

Inga Meyer-Wachsmuth (Stockholm University): 

Photo: I Meyer-WachsmuthMy favorite animal didn’t show up, but there were a few close relatives that were unexpectedly colorful. This is a possibly undescribed species of Acoela of less than a mm length, with a beautiful red coloring. It was found with the Lithothamnion aggregations.

 

Photo: J Thyrring

                                                                    Jakob Thyrring (Aarhus University): 

I am working with blue mussels as they are ecological important species. I will investigate how this species that are susceptible to expand their current distribution range will influence the Arctic ecosystem structure and function.

 

Photo: J Egardt

Jenny Egardt (Gothenburg University): 

I am a PhD student working with biodiversity and habitat change as a measurement of human impact in shallow marine coastal areas. In Disko, I am interested in learning more about arctic species and their abundance, and compare video footage taken during this course with footage from two years ago to see if the habitats are still the same.

 

Jeroen Brijs (Gothenburg University): 

Photo: Jeroen BrijsI’m doing a PhD on gastrointestinal motility and blood flow in fish, specifically shorthorn sculpin (Myoxocephalus scorpius). I have captured a few here in Greenland to examine their stomach contents to determine what prey species they feed on so that I have a better understanding of their feeding ecology as this will assist me in understanding the digestive processes which occur within this fish species.

Photo: J Sefbom

 

Josefin Sefbom (Gothenburg University): 

I am investigating population genetic patterns of the diatom Skeletonema marinoi – a common and important bloom-forming primary producer found in many coastal waters.

 

 

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Mari Heggernes Eilertsen (University of Bergen): 

For my PhD I will be working on several different animals, but at the moment my favorite animal is a small calcareous sponge called Sycon abyssale, which is found in the deep North Atlantic and Norwegian Sea. Interestingly it is also found in shallow waters (<100 m) in Norwegian fjords, and I will use genetic analyses to establish if these populations are the same species and investigate the geneflow between populations, especially across the Greenland-Iceland-Faroes ridge, which is believed to be a major barrier to dispersal for deep-sea organisms.

 

Mette Møller Nielsen (Aarhus University): 

Photo: J Egardt                                                                  I am a PhD student from Aarhus University, Denmark working with kelps. Kelps are widely distributed and highly productive and they are important organisms in coastal zones where they form key habitats. They act as substrate for sessile organisms as well as shelter and nursery area for fauna in general, thereby stimulating biodiversity.

Photo: A Altenburger

 

Arom Mucharin (Aarhus University): 

This small (ca. 3mm long) juvenile of Cucumaria frondosa (Gunners, 1767) we found in the Lithothamnion samples is really cool! I have been working with sea cucumbers in Thailand and in Denmark for some time now, but usually the specimens I deal with are much larger!!!

 

 

Photo: Peter Funch

 

Peter Funch (Aarhus University): 

The penis worm Priapulus caudatus from the mud outside the habour of Qeqertarsuaq (Godhavn), Greenland, was one of the best finds of this course for me. Together with my students in Aarhus I investigate symbiotic bacteria that live in the gut of these creatures.

 

Peter Kohnert (Ludwig Maximilian University, Munich):

Photo: P Kohnert I do my PhD on the evolution and phylogeny of pteropods, my main interest is the sampling of specimens of Limacina helicina and its predator Clione limacina (see picture), generally known as “sea angel”. Besides that I enjoy exploring the diversity of arctic gastropods in general.

Photo: A Altenburger

 

Maria Perpétua Scarlet (Gothenburg University): 

The small (10-13 length), fragile bivalve shells of the species Ennucula tenuis, are beautiful, olive-yellowish or brown in color outside and nacreous inside; tho specimen was dredged at 50 m depth on mud of Eqalunguit, Disko Fjord.

 

 

Sandra Lage (Stockholm University):  

Photo: S Lage

Ceratium fusus found in the surroundings of Disko Island, is my favorite organism of the day. You can find them everywhere, from Tropics to the Arctic, the marine and fresh waters teem with life; a so tiny…microscopic life that ultimately all trophic chains depends on. While most of these species of phytoplankton and cyanobacteria are harmless, there are a few that create potent toxins given the right conditions, and this are the ones that I have been always fascinated about.

 

Edited by: Sandra Lage (Stockholm University) and Christiane Todt (University Museum of Bergen)

Photo: AH Tandberg

Let’s go to the beach! (Or: Sieve this and sort that!)

What are the most unpopular activities for marine biologists working with fauna from the sediments? Yes, SIEVING! And then SORTING all the samples! What a “painful” moment you can experience, although not as “painful” when you have running sea water to sieve the samples. But, if you don’t, you´re going to have a sore back for the next day or two.

Photo: AH TandbergHere is the tip if you for any reason find yourself at the Arctic Station with a 50 liters tub of soft mud sediment from Disko Island, and you don´t have any running seawater on the laboratory to use. On the most beautiful sunny day go in your best mood ever and with your cheerful colleges to the beach just in front of the station and bring a set of sieves, buckets, plastic cups and tweezers. Oh, and of course, remember to carry the tub of mud with you! This is what we did and it worked! In less than some hours the work was done.

By pouring a portion of mud on the set of sieves and adding sea water with the buckets we started our great sieving and sorting on this great sunny day. To better wash the different fractions of the samples collected on the set of sieves, we separated them and washed each sieve directly into the sea with the waves giving a hand. We repeated the process until all the mud was sieved.

Photo: AH Tandberg

Daniela, Anne-Helene, Henning, and Perpétua enjoying sieving and sorting of samples

Then… the sorting. We started to sort the faction collected on the 4mm mesh size sieve directly at the beach looking carefully at each shell, kelp remains and stones for anything that moved, placing the different animal groups on the plastic cups full of seawater. Completing this process and with our fingers numbed by the cold water and feeling something resembling a sore back, we packed all our stuff, not forgetting the sieves with the smaller fractions of the sample.

Photo: AH Tandberg

Henning chilling out

 

Before leaving to the lab to take care the rest of the samples, we enjoyed some minutes at the beach chilling out, stretching our backs and warming up.

Photo: AH Tandberg

What a great morning!

Written by: Daniela and Perpétua (Gothenburg University) and Henning (University of Bergen)

Featured image: Perpétua, Daniela and Henning on the beach

Photo: MHEilertsen & H Flørenes

Calcareous sponges of Disko Bay

Fifteen species of calcareous sponges (phylym Porifera, class Calcarea) are known from the Disko Bay area, and nine of these have their type locality here, which means that this was the area they were fist described from. During this fieldtrip we wanted to collect calcareous sponges from Disko to get material that can be used for genetic studies to investigate the relationships between the populations in Disko Bay and populations of what is believed to be the same species in other localities.

Photo: MHEilertsen & H Flørenes

Photo: MHEilertsen & H Flørenes

Spicules from Brattegardia nanseni.

Photo: MHEilertsen & H Flørenes

Largest calcareous sponge found during this fieldtrip.

Identifying calcareous sponges is not a straightforward business; first of all they are very small (most < 1 cm), and secondly they do not have any obvious external characters like bright colours, legs or even a head. In stead they have spicules. Spicules are small needle-like structures that function as the skeleton of the sponges, and in calcareous sponges they are made out of calcium carbonate. The shape of the spicules is an important character to identify sponges, in addition to the morphology of the sponge body and the arrangement of different types of cells. To look at the spicules of the sponges we need to clean the spicules from tissue and mount them on microscope slides. We cut out a piece of the sponge and add household bleach, which is left to work for 30 minutes, followed by three rounds of cleaning with distilled water, each taking 30 minutes. To make a permanent slide that we can look at again and again we use an imbedding medium that takes about 24 hours to dry sufficiently, so the time between we find a sponge specimen until we can identify it can be quite long.

Photo: MHEilertsen & H Flørenes

Collection of sponges fixated on ethanol.

We have had quite good sampling success so far, with over 50 specimens of calcareous sponges, and a few sponges of other classes. Most of the specimens were found sitting inside globular aggregations of Lithothamnion, a red algae (described in an earlier blogpost). Getting the sponges out from the Lithothamnion was tricky, both because they are very small and hard to spot, and because they were sitting quite far inside the globules, probably to get shelter. We also got many specimens from a triangular dredge sample that was sieved through a 1mm sieve. This is also where we found our largest specimen so far on this course! A beautiful Leucandra penicillata with a length of a whopping 5 cm! The calcareous sponges we have identified belong to at least eight different species, but the material has to be examined by experts to be certain of the identification.

Not all the samples we collect are equally interesting, but ones in a blue moon something special comes along. Yesterday, while sorting through the material from the dredge, we realized that we had just found the remnants of our good friend Spongebob Squarepants! It was a sad day indeed as we sieved out our global mascot from the murky waters. A memorial was thrown in his honour with the Greenlandic flag on half a pole. But life goes on and so does the search for new exciting sponges in different parts of the world!

Photo: Daniela de Abreu

Oh no – Sponge Bob is dead!!

By Henning and Mari (University of Bergen).

Featured image: Variety of calcareous sponges from Disko

 

Photo:Arom Mucharin

First experiences with Arctic sea cucumbers.

During the first day of our stay (13 Sep. 2013) at Qeqertarsuaq bay, Disko Island, we sampled using the triangular dredge at depth 37 meters. We got many specimens of animals and plants. Anne Helene picked a sea cucumber from the sample container and called me to see it. It was stained with mud, but after quick cleaning it looks better.

Photo: A Mucharin

Peter, Anne Helene, and skipper Fari were busy with triangular dredge sampling

Photo: A. Mucharin

Pentamera calciger (Stimpson, 1851)

In the evening, I checked its outer characters and ossicles (small spicules in the skin) and identified it as a Pentamera calciger (Stimpson, 1851). It lives buried in the mud while its dendritic (branched) tentacles reach out above the mud surface for feeding.

Photo: A. Mucharin

 

 

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Above: Ossicles from Pentamera calciger skin: tables, elongated plates and end plate

I got the second species of sea cucumber from the Amphipod Team as well (Anne Helene, Daniela and Henning). They found four specimens while looking for amphipods in algae. I was excited about those because they were Apodida (sea cucumbers without tube feet), the same group as I am working with in my PhD thesis. After examination, I found out that they are Chiridota laevis (Fabricius, 1780).

Photo:Arom Mucharin

Chiridota laevis (Fabricius, 1780)

Photo:  A Mucharin

Chiridota laevis ossicles: wheel development (above) and irregular wheels (below)

Photo: A. Mucharin       Photo: A. Mucharin

One week later, Christiane and Inga gave me 6 sea cucumber juveniles from the large Lithothamnion aggregations, Kangerdluk, Disko Fjord. Of course! I never seen them before, they are so small (2-4 mm long) and have a nice orange colour. Under the microscope, they are a bit transparent and the ossicles are easy to see. I find that so amazing. I also asked Andreas to take these beautiful photos for our blog.

Photo: A. Altenburger               Photo: A. Altenburger

Both belong to the dendrochirotid order. The species are Cucumaria frondosa (Gunnerus, 1767) and Psolus sp., respectively.  Cucumaria can become close to 30 cm long when they grow up!

Photo: A Altenburger

My lab work corner – sea view with icebergs (photo by Andreas)

Although I found only four species of sea cucumbers, for me, a student coming from a tropical country, this is a great experience and a good start to learn more about Arctic sea cucumbers. It is so cool!

 

Written by Arom Mucharin (Thai Ph.D. student from Aarhus University, Denmark)

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Rodoliths !!!

During our field-trip to Disko-fjord we took samples from an area densely covered with so-called  Lithothamnion-aggregations (rodoliths) – a very special habitat (see also Mette and Jenny’s entry on our “Trip to Disko Fjord”) !

Photo: AH Tandberg Photo: AH Tandberg

Mette taking a sample at the site. Christiane holding a gigantic  Lithothamnion rodolith.

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Screenshot of a movie taken by Anne Helene at the site

Lithothamnion species are calcareous red algae, that is, they have hard thalli due to calcium carbonate deposits. Most commonly they form a coating over hard substrates, but in Disko Fjord there is a species (Lithothamnion glaciale) that rather looks like a coral and forms so-called rodoliths. These aggregations grow to about fist sized “balls” that under stormy conditions may tumble on the muddy seafloor, much like tumble weed through old western movies, but usually they just lie there peacefully.

Photo: I Meyer-Wachsmuth

Broken up Lithothamnion aggregate with sipunculid worms (the muddy, sticky-out thing on the right is actually an animal!)

As they are the only hard substrate in an otherwise very “soft” environment, they act as oases attracting a wide range of animals otherwise not found on mud. Also, the rodoliths appear to act as a nursery habitat for diverse species (we found baby chitons, baby sea cucumbers and various baby snails).

Photo: I Meyer-Wachsmuth

Teenage chiton (Tonicella rubra)

Some of the animals are big enough to be seen by naked eye and are sitting on the algae. Other organisms are very small and need to be persuaded to let go and come out of their holes. So after picking all animals that we could see by eye, like some tiny sponges of not more than a centimetre, beautiful pink chitons, brittlestars, small sea urchins and sipunculid worms, we smashed all the algae and submerged them in magnesium chloride.

That is a rather sneaky method to get to the tiny hiding creatures that still hold on and/or escaped our attention. Magnesium chloride acts as an anaesthetic and the animals let go of the substrate and can be washed off into a fine-meshed sieve and then be transferred into our petri dishes for further examination. And this method revealed an even more stunning variety of animal life under 1 cm length: several possibly undescribed species of Acoela, microscopic worms that by some are thought to resemble the first bilaterian animals, but also different snails, flatworms, mites, polychaetes and crustaceans. Photo: I Meyer-Wachsmuth

Meiofauna extracted from the rodoliths (with several acoel flatworms)
Photo: A Altenburger

Some of the “Greenland neomeniomorphs”

Also, Christiane found several individuals of a certain species of solenogasters (worm-shaped, shell-less, spiny mollusks) hitherto only known as the “Greenland neomeniomorph”. She desperately had been looking for some additional specimens to get an official taxonomic description completed. – Juhuuu!

 

 

Rodoliths! – These beautiful algae turned out to hold an astounding variety of animal groups.

Written by Inga (Stockholm University) and Christiane (University of Bergen)