On the Hunt for Tiny Polyps

Two weeks ago I had the chance to go field-sampling on the research vessel Hans Brattström. The sampling this time was focused on a broad range of marine invertebrates ranging from Hydrozoans, Bryozoans, Polychaetes, Phoronids and Brachiopods. I was especially on the hunt for polyps of the family Hydractiniidae (Cnidaria: Hydrozoa) that grow preferably on shells of molluscs or hermit-crabs. I was happy to look for new specimens for NorHydro and my master’s project, especially since opportunities to go field-sampling have been rare due to the covid-19 restrictions. The area of Bergen has been sampled quite well for the NorHydro project, but I was especially looking for rare species or species that haven’t been sampled before.

The first sampling for NorHydro this season – and with great conditions! Picture Credit: Lara Beckmann

To collect hydractiniids, we took bottom samples using a triangular dredge and a grab sampler. When the dredge gets back on board, the sample gets sorted on a large table on deck. Then the detailed search begins, and every stone and cranny gets inspected. The polyps I was looking for can be tiny, ranging from less than 1 mm up to 8 mm. The substrates that they grow on vary in size and shape, it can be crabs, molluscs but also algae or stones, often not larger than a few centimeters. So it isn’t an easy task to find the polyps in a freshly collected sample. Luckily I found several conspicuous hermit crabs and also one snail that I took back to the museum. At first, I didn’t see the polyps – only under the microscope in the museum laboratory I was able to see that hydractiniid colonies were growing on the shells.

Video: A polyp colony of the species Podocoryna areolata (Family Hydractiniidae). The polyps were growing on the shell of a living mollusc, probably of the species Steromphala cineraria. Video Credit: Lara Beckmann

One colony of the species Podocoryna areolata was growing on the shell of a living mollusk. The mollusk provides a nice substrate because the movements of the snail provide the polyps with more opportunities to encounter food. Also, the colony is protected by the small wrinkles of the shells surface where the polyps can hide. The polyps of this species are super difficult to measure, but most are smaller than 0.5 mm. When disturbed, the polyps shrink to small blobs even smaller than this. When relaxed, they can extend a bit longer in size. Especially the tentacles reach out to get hold of any potential food that swims by, such as small crustaceans. This species releases medusae, which can frequently be found in the plankton in this area.

A single polyp of the same colony of Podocoryna areolata. Picture Credit: Lara Beckmann

On shells inhabited by hermit crabs of the species Pagurus bernhardus, I found several colonies of a yet unidentified species of the genus Podocoryna. This species is very commonly found as polyp almost along the entire Norwegian coast. I’m still studying the specimen to figure out the correct identification. Since there is a lot of confusion in the hydractiniid taxonomy, I need to combine genetic information and morphology to overcome the existing problems in their identification and naming. The colony was reproductive and medusa buds were growing on it. Interestingly the medusa of this species is rarely found in the plankton.

Polyps of the genus Podocoryna. On the right are parts of the grasping claws visible belonging to the hermit crab Pagurus bernhardus. Picture Credit: Lara Beckmann

All over the colony were medusa buds. These are growing medusae, which will be released in the water when they are mature. The medusae can do what the colony itself can’t: releasing eggs and sperm and thus reproduce sexually. Picture Credit: Lara Beckmann

Besides the polyps, I found several other organisms living with the colonies on the shells including Crustaceans, Nudibranchia, Foraminiferans and other hydroids. The shells provide a home for a diverse range of marine life and it resembles a tiny forest. But it is not all peace and harmony in there, the smallest amphipods were quickly munched by the Podocoryna polyps. Those, in turn, get eaten by nudibranchs, that crawl on the colonies and some species feed specifically on hydroid polyps.

Video: An amphipod that lives on top of the hermit crab shell, walking through the colony of Podocoryna polyps. Video Credit: Lara Beckmann

 

I didn’t find any more hydrozoan species that were interesting for NorHydro during the sampling trip (at least not while scanning with the bare eye). But, I want to show one more very common species around Bergen –Ectopleura larynx– just because it is such a nice-looking hydrozoan. It even was reproductive and released its larvae right into my petri-dish. The small bulbs that grow between the polyp tentacles contain the larvae, which are called actinula. They break free and swim around, swinging their tiny tentacles until they will settle on a piece of algae for example, and grow to a large colony again.

The species Ectopleura larynx is a common species at the Norwegian coast. On the left the released larvae, called actinula. On the right a polyp that usually grows in a large colonies with up to a hundred polyps. Picture Credit: Lara Beckmann

-Lara

You want to learn more about hydrozoans and why it is important to study them? Read more about it in my blog article for Ecology for the Masses: link.

Also, keep up with the activities of NorHydro here in the blog, on the project’s facebook page  and in Twitter with the hashtag #NorHydro.

Sun is out, scientists are out!

 

Staff engineer Lina Ljungfeldt with the Bladderwrack algae Fucus vesiculoses in Glesvær, Norway. Photo Bjarte Kileng

With few good weather windows here in the West coast we need to take the opportunity for collecting when it arises. Tuesday afternoon (27.04)  we took our chance to sample in Glesvær for some fresh copepods and Bladderwrack (Fucus vesiculoses) for researchers from the University of Trier.

The team consisted of staff engineer Lina Ljungfeldt, PhD student Justine Siegwald, Citizen scientists Bjarte Kileng and head engineer Cessa Rauch.

The Tuesday afternoon sampling team from ltr Lina Ljungfeldt, Cessa Rauch and Justine Siegwald. Photo BK

Picture of the photographer himself, citizen scientist Bjarte Kileng joining the expedition team. Photo Justine Siegwald

We chose Glesvær because we needed easy access to the shore with rockpools and lots of algae. Researchers from the University of Trier (Germany) are collecting Fucus vesiculoses from different parts in the world to study the community of animals and bacteria that are associated with the algae. We were happy to help out while also collecting fresh copepods for HYPCOP (@planetcopepod).

We needed 20 individual algae pieces that needed to be cut from the substrate and any epifauna big enough to the naked eye had to be removed.

Justine Siegwald picking out individual Fucus vesiculoses algae from the rocky shore. Photo BK

After collecting the algae in the green baskets we needed to rinse the algae and put them in bags afterwards. The algae were transported back to the museum on ice and stored in the freezer waiting for their final journey to Germany.

Cessa Rauch rinsing the algae, dry suit came in good use! Photo JS

HYPCOP member Cessa Rauch went along and collected some copepods from the beautiful rockpools.

Cessa collecting copepods from the rockpools in Glesvær. Photo BK

Rockpools are great source for easy benthic copepod collecting. When low tide leaves the rockpools exposed, many small marine organisms stay ‘trapped’ in the cracks of the rocky shores. Just sampling some small algae and the water itself contains many benthic organisms like our copepods. The copepods, along with the algae, were taken back to the museum and sorted based on their morphotype. These fresh specimens will later be used for DNA extraction and barcoding.

If you wish to see how beautiful benthic copepods are than don’t forget to follow @planetcopepod on Twitter https://twitter.com/planetcopepod and Instagram https://www.instagram.com/planetcopepod/ or become a member of or Facebook group, for the latest updates! https://www.facebook.com/groups/planetcopepod

-Cessa

 

 

Copepod girls!

Copepod girls; Cessa Rauch (left) and Francisca Carvalho (right) working on copepods, photo Katrine Kongshavn).

International Woman’s Day was on 8th of March and this coincided this year with the start of a great fieldwork trip with an (almost) girl only expedition team!

Multiple research projects headed towards Espegrend Marine Biological field station in Bergen, to spend the week collecting and sorting specimens. The group consisted of representatives of Hardbunnsfauna (rocky shore invertebrates @hardbunnsfauna), Norchitons (Norwegian chitons @norchitons) and HYPCOP (copepods @planetcopepod).

From ltr; HYPCOP (Cessa Rauch), Norchitons (Nina Mikkelsen), HYPCOP (Francisca Carvalho), Hardbunnsfauna (Katrine Kongshavn). Photo: Jon Kongsrud

The plan for the week was to have access to the research vessel Hans Brattström while also working from the field station on the mainland. This would give us very good opportunities for reaching different sampling habitats. But as always with fieldwork expect the unexpected; unfortunately, after day 1, our R/V Hans Brattström got motor problems, so the planned dredge sampling did not happen. It is good to be creative in those situations because we still managed to get a lot of sampling done by collecting at the piers where the research vessel was docked and in front of the research station itself.

View from the research station in Espegrend, photo Cessa Rauch.

Sampling from the pier in front of the research station, photo Francisca Carvalho

On one of the days (when the sun was out!) we took the small research boat from the field station to explore the habitats of the nearby islands and do some shallow sampling there.

Out sampling with the small boat, photo Cessa Rauch

Once we arrived at the island of Søre Egdholmen we needed to dock the small boat without a pier; rest assure this gave interesting scenarios with being half in the water while the rest of the team and the equipment was in the boat.

Docking the small boat without a pier, photo by F. Carvalho

Once on the island we started to collect lots of material; for copepods, especially shallow benthic ones, that is quite a simple task. The best way is to use a fine meshed net, like a plankton net, and grab a lot of substrate like algae, some sand and small gravel. A lot of species basically stick to the substrate and with the plankton net have no way to escape. By keeping the plankton net with substrate in a bucket with seawater the samples stay fresh the longest.  Back to the marine biological station we kept the freshly collected samples in tanks with good saltwater circulation (which the station has access to in the laboratories).

Well let me tell you, we had such nice samples off copepods, not only just the quantity (because with copepods that is never a real issue), but very diverse too.

A drop of copepods, rich diversity from Espegrend. Photo: Cessa Rauch

Every single morphotype was being documented while they were still alive to keep the colors intact.

Overview of the different morphotypes we collected

And then numbered, labeled and fixated in ethanol for the collection.

Copepod collection

The goal for HYPCOP this week was to collect and register fresh copepod samples for DNA barcoding.

Back in Bergen we brought our copepods to the laboratory for DNA barcoding.

Their DNA is, as we speak, on their way to the sequencing center in Canada to become part of the Barcode of Life Data System that eventually everyone will have access to. Curious to see what this platform is all about, check out http://www.barcodinglife.org.

Until next time! Don’t forget to follow @planetcopepod on Twitter https://twitter.com/planetcopepod and Instagram https://www.instagram.com/planetcopepod/ or become a member of or Facebook group, see you there! https://www.facebook.com/groups/planetcopepod

-Cessa & Francisca

 

 

 

Sled test for copepods

R.P. sled onboard R/V. H. Brattström

Happy new year to everyone! We managed to start 2021 with a day at sea, testing the R.P. sled for collecting benthic copepods from greater depths . January 27 we went out with research vessel Hans Brattström, crew and research scientist Anne Helene Tandberg who also turns out to be a true sled expert! She would join HYPCOP to teach how to process the samples from the R.P. sled on the boat.

 

 

 

 

Anne Helene Tandberg (left) joining HYPCOP (Cessa Rauch right) for teaching how to use the sled.

But first, what is an R.P. sled and why is it such an important key in the collection of copepods? The R.P. sled is an epibenthic sampler. That means that it samples the epibenthic animals – the animals that live just at the top of the (soft) seafloor – and a majority of these are often small crustaceans. The “R.P.” in the name stands for Rothlisherg and Pearcy who invented the sled. They needed to collect the juveniles of species of pandalid shrimp that live on the sea bottom floor. These animals are very small so a plankton net was necessary to collect them; a ‘normal’ dredge would not quite cut the job. They needed a plankton net that could be dragged over the bottom without damaging the net or the samples and also would not accidently sample the water column (pelagic); and so, the R.P. sled was born. This sled was able to go deeper than 150m, sample more than 500m3 at the time and open and close on command which was a novelty in comparison to the other sleds that where used in those days (1977). The sled consists of a steel sled like frame that contains a box that has attached to it a plankton net with an opening and closing device. The sled is heavy, ca. 150kg, and therefore limits the vessel sizes that can operate it; the trawl needs to be appropriately equipped including knowledgeable crew. It is pulled behind the vessel at slow speed to make sure the animals are not damaged and to make sure it does not become too full of sediment that is whirled up.

 

 

Sieved animals from the decanting process

So off we went with r/v Hans Brattström pulling the heavy gear at ca. 700m depth with 1 knot and a bottom time of 10 minutes sampling the Krossfjorden close to Bergen. It was a beautiful day for it with plenty of sun and calm seas. The crew handled most of the sled, leaving sorting the samples up to HYPCOP under the guidance of Anne Helene. Which is not as straight forward as it may sound! The process of filtering the samples after collecting them from the sled is done by decanting, which you can see in this movie from an this blog (in Norwegian) from earlier.

Decanting set-up for R.P. sled samples

Decanting means separating the mixture of the animal soup from the liquid by washing them in a big bucket, throw the liquid through a filter and collect the animals.

Sieved animals from the decanting process

This all needs to be done with care as the animals are often very small and fragile. After collecting, the most time-efficient and best preservation for the samples is to fixate them immediately with ethanol, so they don’t go bad while traveling back to the museum.

Fixating collected animals with technical ethanol

For collecting copepods we use a variety of methods; from snorkeling, to scoping up water and plankton nets, but for greater depths and great quality benthic samples the R.P. sled will be the most important method. We thank Anne Helene for her wisdom and enthusiasm that day for showing HYPCOP how to work with such interesting sampling method

 

We got some nice samples that will be sequenced very soon so we can label them appropriately. Although this first fieldwork trip off the year was mainly a teaching opportunity, we still managed to sample two stations with plenty of copepods and lots of other nice epibenthic crustacea, and Anne Helene is especially happy with all the amphipods she collected during the day. So for both of the scientists aboard this was a wonderful day – sunshine and lovely samples to bring back to the lab!

Some fresh copepods caught with the R.P. sled

– Cessa & Anne Helene

Follow HYPCOP @planetcopepod Instagram, for pretty copepod pictures https://www.instagram.com/planetcopepod/

Twitter, for copepod science news https://twitter.com/planetcopepod

Facebook, for copepod discussions https://www.facebook.com/groups/planetcopepod

See you there!

What’s growing on the shell? – Insights into the Diversity of Hydractiniidae in Norway

This summer I started my master degree project at the University Museum of Bergen and joined the research of Luis Martell and Aino Hosia. I’m a student in the program ‘Biodiversity & Systematics’ at the University of Stockholm and for my 1-year thesis project I wanted to learn more about hydrozoans. Looking for hydrozoan biologists, which there are not so many, I came across the project NorHydro led by Luis and Aino and I decided to go to Bergen to study and learn more about this fascinating group.

My thesis project especially focuses on the diversity of the hydrozoan family Hydractiniidae. Most commonly hydractiniids are encountered on snail- or hermit crab shells where they can build a mat of polyps. Those shells are often inhabited by other animals and the polyps feed on the left-over meals of those and in return defend their host against predators. With their small tentacles, which are equipped with hundreds of cells containing venomous stingers (the nematocysts) they are great predators and catch tiny animals from the plankton.

Schuchertinia allmanii growing on Pagurus pubescens hermit crab. Picture credit: Bernard Picton

Each individual polyp is connected to each other and build a colony of polyps with different functions. Some act as food suppliers, some as reproductive polyps. From those polyps some hydractiniid species grow tiny medusae (jellyfish) which will be released in the water column. The medusa is morphologically comparable to the polyps, equipped with tentacles, a stomach, gonads and nematocysts – but living upside down and not attached to the sea floor. With their ability to swim around they contribute to disperse themselves in the water and can produce a lot of offspring.

Video of a Pagurus bernhardus hermit crab. A hydractiniid polyp colony is growing on the underside of the shell. Video credit: Lara Beckmann

Several species in this family are often used in development biology or immunology research. For example the species Hydractinia echinata led among other organisms to the discovery of stem cells and is still widely used as a so-called model-organism nowadays. This is because this animal group shows a high ability to regenerate and if you cut a hydroid polyp in two pieces, it will just re-grow again to its initial state.

The life-cycle in hydractiniids can include a polyp and medusa stage. Species of the genus Podocoryna release medusae from their colony. Other genera in this family develop only reduced medusae and lack a free-swimming jelly. Illustration credit: Lara Beckmann

The hydromedusa Podocoryna borealis is released from a polyp colony that can grow on various substrates such as snails or worm tubes. Picture credit: Lara Beckmann.

But despite this spotlight to some species, the diversity of this family is still poorly known and there is little attention to hydractiniid species because of their inconspicuousness and difficult identification. To highlight the problem I did some research: how many and what species are commonly recorded in Norway? Which species could potentially occur in this region according to species descriptions? In private observations and ecological surveys only three species were commonly recorded. However, our preliminary results suggest at least 6 species in Norwegian waters with some surprisingly frequent species that are rarely recorded in surveys. This indicates, that there happens a lot of misidentification in the field and we need to get a better estimate of the true diversity of Hydractiniidae in this region in order to improve awareness and to prevent misidentification in the future.

Two polyps of a colony of the species Clava multicornis. You can see reproductive units (so-called sporosacs) growing on the polyp body, which will release eggs or sperm when fully grown. Picture credit: Luis Martell

In order to do that I study this group in much detail. A great advantage of being a taxonomists in these days is that we can use a variety of different sources of information to develop and test for species hypothesis. This so-called integrative approach includes morphological, ecological and genetical information in order to define taxa diversity from several perspectives.

The first step in this process is to gather polyps and medusae of Hydractiniidae from various spots in Norway ranging from Olso, via Bergen and up north to Bodø. I will use already collected samples from previous years and hopefully will also be able to add some more samples from field-trips in the next months.

Getting the plankton-net back on board – and Maryam and me trying to open the jar carefully without spilling the fragile plankton inside. After removing the jar from the net, we directly pick the hydrozoans and put them in a cold environment, so that we can look at them alive when we are back in the lab. Picture credit: Maryam Rezapoor

With fresh material the first step is to take pictures of the living animal. Since hydrozoans tend to shrink and lose a lot of it characteristic traits in the ethanol preservative it is important to take pictures right away when the animal is still alive. Furthermore the samples are identified using a microscope, identification keys and additional literature. With additional collected data such as habitat, location, sample depth and so forth we create a large database for our samples and develop so-called e-vouchers: an electronic data storage for each individual to ensure to gather and store as much information as possible. That makes it possible to go back to the database and look at the specimen data e.g. where did it live? On what substrate was it growing on? How deep was the sampling site? This way I don’t only rely on the preserved material but can easily use the e-voucher material and the additional collected data that can be useful for further analyses.

Besides the morphological and ecological data I also include molecular information: what does the DNA tell us about the specimen? For that I use three different genetic markers (short DNA fragments, or genes) to see how those differ in their sequence of bases between the sampled hydractiniid specimen. In the course of evolution, DNA sequences change due to selection, genetic drift, gene flow and random mutations. That is why we are able to infer evolutionary relationships between biological entities – in this case we are interested in species – and with mathematical models and some simplified assumptions we can delimit species based on their molecular attributes.

Me in the DNA lab waiting for the first results of lab work for this project! Picture credit: Maryam Rezapoor

In order to do so, I will process the sampled material in the lab. First, I extract the DNA from a tiny piece of polyp or medusa tissue and then amplify the specific target region using PCR (Polymerase-Chain-Reaction). This short DNA fragment will further be sequenced which outcome I will check, process and analyze using different computer programs and algorithms. The final results will be summarized and visible in so-called gene trees, revealing the evolutionary history of those three different DNA markers. I will use the gene genealogies to delimit the species and observe how much diversity of hydractiniids we have in Norway.

Using specific genes also facilitate us with species barcodes which are used to create a reference library. This in return enables researchers to identify a specimen without the need to identify the sample using its morphology. This can be the case e.g. for metabarcoding projects (sequencing a mass of DNA from unknown origin) or if samples are unidentifiable. The scientist will then sequence the barcode gene and compare it to the reference library and will eventually be able to tell the species. Those barcodes can be informative in biodiversity studies but by no means substitute taxonomists, which are still needed to describe and identify species when no DNA is available.

A monograph of the Gymnoblastic or Tubularian hydroids by George James Allman, published in 1870. I found this book in the library of the Tjärnö laboratories in Sweden. Allman was a pioneer in hydrozoan research and described many species. Nowadays it is much easier to access original descriptions since many book are available online. You can find a PDF* of this book in the Biodiversity Library. Picture credits: Lara Beckmann

Also, the DNA does not help us when we have no reference we can map the specimen to in order to determine the species. That is why this master project also aims to create a barcode-library for the species in the family Hydractiniidae.

What I really like about this project is that it contributes to our basic understanding of the diversity in our oceans – in this case even in two completely different environments: the water column as well as the seafloor.

Even if hydractiniids are just a little part of the ecosystem, they play their role and influence the ocean in their own way. Also, my work is super diverse and I need to be an allrounder in many respects: trying to find species descriptions I search and read taxonomic literature from the 19th century (coming in Latin, German, English, Swedish or French). Then I work in the laboratory where I combine traditional working methods like drawing, microscopy or photography with modern techniques from DNA sequencing to computational science and bioinformatics.

I love this kind of work, and it is great to contribute just a little bit to reveal the mysteries of our oceans.


– Lara

You want to learn more about hydrozoans and why it is important to study them? Read more about it in my blog article for Ecology for the Masses (link).

Also, keep up with the activities of NorHydro (link to project home page) here in the blog, on the project’s facebook page (link) and in Twitter with the hashtag #NorHydro.

*Link to pdf of A monograph of the Gymnoblastic or Tubularian hydroids by George James Allman

Brattström baby, HYPCOP goes offshore!

Last days of November HYPCOP spend two days (26th & 27th) offshore. We had the possibility to join some sampling efforts of NorHydro and others on the research vessel Hans Brattström.

Research Vessel Hans Brattström ready early in the morning, photo Cessa Rauch

This vessel is owned by the University of Bergen and operated by the institute of Marine Research (IMR, Havforskningsinstituttet).

H. Brattström is used 200 – 230 days a year along the West coast of Norway. It has the capability of operating different sampling gear, which makes it useful for multiple projects, studying a variety of marine organisms, from fish, to worms, jellyfish, and yes, also copepods!

On the first day HYPCOP joined NorHydro consisting of Luis Martell (UiB) and Joan Soto Angel (Sars):

NorHydro team and HYPCOP; from ltr Cessa Rauch, Luis Martell and Joan Soto Angel, photo Cessa Rauch

Plankton net being lowered in the ocean with some early morning sun, photo Cessa Rauch

 

 

The main sampling gear consisted of a large plankton net that was slowly dropped to 660m, 245m and 128m depth.  We sampled close to Bergen in Raunefjord, Krossfjord and Fanafjord.

Sampling for jellyfish needs to be done with caution, with the net going up to fast, the animals will just fall apart because of the pressure. So, a depth of 660m can take up to an hour and more before we could see the results.

 

 

Joan Angel Soto scanning the shore for birds, photo Cessa Rauch

During the waiting times we didn’t let our time go to waist, with binoculars we scanned the air and shore for birds.

After waiting for some time, the plankton net was brought back on board and contained, besides jellyfish and other pelagic planktonic dwellers, many million copepods. Mostly consisting of a few species. One of the species had a distinguishable blue egg sack, this is Paraeuchaeta norvegica (Boeck, 1872). This species is an active predator that feeds on other (smaller) copepods by rapidly jumping on them and catching their prey with their large maxillipeds (mouthparts).

 

 

The second day HYPCOP joined head engineer Bjørn Reidar Olsson (UiB) and PhD student Miguel Meca (UiB)

HYPCOP (Cessa Rauch left) joining Miguel Meca (middle) and Bjørn Olsson (right), photo Cessa Rauch

They were looking for shark teeth and polychaetes (marine worms) respectively and used the grab, which is perfect for benthic copepod sampling. The grab is basically a big metal clamshell that collects sediment from the seafloor. Working with grab samples gets dirty very quickly, you have to wash through the sediment to find your animals.

The grab with Cessa Rauch (HYPCOP left), Miguel Meca (middle) plus operator Bjørn Frode Grønevik (right), photo Bjørn R. Olsson

Most of the sediment was filtered out in order to find our copepod friends. Although less plentiful in comparison to the plankton net sampling the previous day, we still found some copepods hiding in the dirt. At moment of this writing, the the copepod species we collected have not be named yet, however, the last months we have been experimenting with barcoding the first batch of 60 different specimens. We had a 43% success rate. Usually, marine invertebrates have a success rate between 40 – 70%, so it was still within the margin, but not with a lot of enthusiasm. HYPCOP will spend the remainder of 2020 and the beginning of 2021 in the laboratory figuring out what the culprit of this low success rate could be.

For HYPCOP this will be the last blog before the Christmas holidays and the New Year. Therefore, we want to take the opportunity to wish you happy holidays and hope to see you around in 2021 with from us more copepod news to share!

-Cessa

Follow HYPCOP @planetcopepod

Instagram, for pretty copepod pictures https://www.instagram.com/planetcopepod/

Twitter, for copepod science news https://twitter.com/planetcopepod

Facebook, for copepod discussions https://www.facebook.com/groups/planetcopepod

See you there!

Fieldwork at Sletvik Fieldstation!

From Monday 12th of October till Monday the 19th a bunch of different projects funded by the Norwegian taxonomy initiative travelled up North together to meet up with researchers from NTNU in the NTNU Sletvik field station.

Front of Sletvik fieldstation main building, photo credits Nina T. Mikkelsen

Sletvik fieldstation is NTNU owned and is a short drive from Trondheim. The Germans built the station during the Second World War. Ever since it has been used as a town hall, a school and a shop. In 1976 the NTNU University took over the building and transformed it into a field station, which it remains ever since. The entire station contains of two buildings that has room for a total of 75 people (Before Corona). The main building has a kitchen, dining and living room plus a large teaching laboratory, a multilab and two seawater laboratories. Besides it has bedrooms, sauna, laundry rooms, and showers, fully equipped! The barracks have additional bedrooms and showers, all in all, plenty of space.

 

From the Natural History Museum of Bergen, 5 current running projects would use the NTNU fieldstation facilities for a week in order to work on both fixed as well as fresh material. Besides HYPCOP (follow @planetcopepod), we had Hardbunnsfauna (Norwegian rocky shore invertebrates @hardbunnsfauna), Norhydro (Norwegian Hydrozoa), Norchitons (Norwegian chitons @norchitons) and NorAmph2 (Norwegian amphipods) joining the fieldwork up North!

Lot of material needed to be sorted, photo credit @hardbunnsfauna / Katrine Kongshavn

 

At the Sletvik fieldstation, a lot of material from previous fieldwork was waiting for us to be sorted.

For HYPCOP we wanted to focus mostly on fresh material, as this was a new location for the project. And not just new, it was also interesting as we have never been able to sample this far north before.  Almost every day we tried to sample fresh material from different locations around the fieldstation

Cessa and Francisca on the hunt for copepods, photo credits Katrine Kongshavn)

On top of that we aimed to sample from different habitats. From very shallow heavy current tidal flows, rocky shores, steep walls, almost closed marine lakes (pollen called in Norwegian) and last but not least, sea grass meadows

Different habitats give different flora and invertebrate fauna, photo credits Nina T. Mikkelsen

Sampling we did by either dragging a small plankton net trough the benthic fauna or the most efficient way, going snorkeling with a net bag

Ready for some snorkeling with Cessa and August, photo credits Torkild Bakken

Benthic copepod species tend to cling on algae and other debris from the bottom, so it is a matter of collecting and see in the laboratory whether we caught some copepods, which, hardly ever fails, because copepods are everywhere!

Copepods are difficult to identify due to their small nature, differences between males, females and juveniles’ and the high abundance of different species. Therefore, we rely heavily on genetic barcoding in order to speed up the process of species identification. So, after collecting fresh material, we would make pictures of live specimens to document their unique colors, and then proceed to fixate them for DNA analyses.

Yet unidentified copepod species with beautiful red color, photo credits Cessa Rauch

Winter Wonderland! Photo credits Cessa Rauch

The other projects had a similar workflow so you can imagine, with the little time we got, the Sletvik fieldstation turned into a busy beehive! One week later we already had to say goodbye to the amazing fieldstation, and after a long travel back (even with some snow in the mountains), we finally arrived back in Bergen where unmistakably our work of sorting, documentation and barcoding samples continued!

If you are interested to follow the projects activity, we have social media presence on Twitter (@planetcopepod, @hardbunnsfauna, @norchitons), Instagram (@planetcopepod, @hardbunnsfauna, @norchitons) and Facebook (/planetcopepod /HydrozoanScience).

 

-Cessa

Sea slug day 2020; Jorunna in the spotlight

Today we celebrate Sea Slug Day! ✨

The day coincides with the birthday of Terry Gosliner, who has discovered one-third of all known sea slug species (more than a 1000!). Here’s a link to how October 29th became #SeaSlugDay.

And what better way to celebrate it than introducing a new species to the world. Today it will all be about the Jorunna tomentosa species complex that our master student Jenny Neuhaus studied for the last two years.

Jorunna tomentosa, picture Cessa Rauch

Jorunna tomentosa is known to occur in a wide variety of colour patterns, which tossed up the question whether we are actually looking at a single species at all, or maybe dealing with cryptic lineages.

The colour diversity of Jorunna tomentosa, picture by Anders Schouw, Nils Aukan, Cessa Rauch, Manuel A. E. Malaquias

Jenny compared specimens from Norway, Ireland, Spain, Azores and South Africa, both genetically as well as anatomically. She used different gene markers like COI, 16S & H3 to check how these morphotypes compare with each other and evaluate the meaning of genetic distances. But she also did an elaborate morpho-anatomical study to look for differences between these colour patterns. Together with Dr. Marta Pola in Madrid, they dissected the different J. tomentosa specimens and looked at parts of the digestive (radula & labial cuticles) and the reproductive systems. These are all key to help unraveling putative different species and characterize them.

About Jorunna tomentosa

Jorunna tomentosa has an oval-elongate body shape with different colours varying from grey-white to cream-yellow and pale orange. They can reach a size up to 55 mm and occur at depths from a few meters down to more than 400m. they feed on sponges of the species Halichondria panicea, Haliclona oculata and Haliclona cinerea. J. tomentosa can be found from Finnmark in northern Norway, southwards along the European Atlantic coastline, the British Isles, the French coast, Iberian Peninsula, Mediterranean Sea up to Turkey, and the Azores and Canary Islands,. Besides the species has even been recorded from South Africa.

Before Jenny studied J. tomentosa, the various colour morphs were regarded as part of the natural variation of the species. By combining molecular phylogenetics with morpho-anatomical characters Jenny investigated the taxonomic status of the different colour morphs of J. tomentosa.

Jorunna sp. nov.?

Jenny sequenced 78 specimens of which 60 where successful for using in the final phylogenetic analyses. Her results supported a new Jorunna species, and a possible case of incipient speciation in J. tomentosa with two genetic lineages morphologically undistinguishable.

From left to right Jorunna spec. nov. Jorunna tomentosa lineage A and down Jorunna tomentosa lineage B

The new Jorunna species was based on material collected from Norway (Kristiansund, Frøya & the North Sea). Jorunna spec. nov. has a distinct colour pattern of cream-yellow with dark small dots (plus, as important; major differences in the radula and reproductive system).

Jorunna spec. nov.

It has been our pleasure to have Jenny here as a student, and she has done excellent work. Last year she won best student poster award last year with her work on Jorunna tomentosa at the World Congress of Malacology in California, USA. Most recently, Jenny defended her thesis on October 26 and passed with an A for her great work – congratulations from all of us at the Museum!

-Cessa Rauch

Sea slugs of Norway Instagram: @seaslugsofnorway

Sea slugs of Norway Facebook: www.facebook.com/seaslugsofnorway

HYPCOP workshop at the IMR fieldstation in Flødevigen

HYPCOP (Hyperbenthic Copepoda) is a young project starting date May 2020 with joined efforts between researchers from the Institute of Marine Research (IMR; Tone Falkenhaug), Natural history museum of Bergen (UiB; Cessa Rauch, Francisca Correia de Carvalho, Jon Anders Kongsrud) and Norwegian Institute for water research (NIVA; Anders Høbæk). If you want to read more about what HYPCOP entails, read it all in our previous blog here: link to HYPCOP kickoff blog.

We were already off with a good start with having quite some fieldwork and sampling done this Summer in and around Bergen, Killstraumen, Lillesand, Drøbak and now with our most recent trip to Flødevigen.  During week 35 (24 – 28 August), all the different researchers from HYPCOP traveled to the IMR fieldstation in Flødevigen to participate in a sampling excursion. It was a special event because it was the very first time since the project started that all the collaborators would meet, in real life! We had many meetings via the digital platforms but working together face to face is quite a different and more pleasant experience (Picture 1).

Team members at the field station; from ltr: Anders Hobæk (NIVA Bergen, Jon Kongsrud (UoB, Tone Falkenhaug (IMR), Cessa Rauch and Francisca de Carvahlo (UoB)

The HYPCOP project is special in many ways; besides the involvement of many different institutes, the team deals with quite a steep learning curve. As off now there are very few hyperbenthic copepoda taxonomists in the world and none in Norway. Anders Hobæk has experience with freshwater copepoda, however his skills are transferrable to the marine species, which helps us a lot. Tone Falkenhaug has experience with copepods from previous projects (COPCLAD; Inventory of marine Copepoda and Cladocera (Crustacea) in Norway). However, the difference between COPCLAD and HYPCOP is the habitat: COPCLAD invented the pelagic realm, while HYPCOP focuses on the Hyperbenthos.

The copepod light trap from Tone Falkenhaug

We decided to use the few days we had together to start from scratch, which meant, first getting some samples from the water.

We all used different techniques to make sure we got copepods from different habitats;

Jon went for snorkeling;

Anders brought his miniature plankton net,

and Tone set her light traps out.

 

This ensured that we had a higher chance of getting different species to look at. Next we would look at our freshly caught samples under the microscope and tried to sort them based on morphotypes (as much as that is possible, as they move fast!).

Copepods can actually have very nice colors! Therefore, we prefer to take live images of the animals as well as when they are fixed on absolute ethanol. So, after sorting them, we continued to make pictures before fixing the animals ready for the next steps.

A colourful specimen, as of yet unidentified

After fixing we experimented with different staining methods in order to make the exoskeleton of the copepods more visible for detecting important morphological features. An important part for species identification is studying the individual body parts of the animals, like the antennae, the individual pair of legs, the claws (maxillipeds).

The animals also have differences between males and females, so it is key to make sure that you identify it as the same species! With morphological identification it is important to also keep some specimens aside for genetic studies. Only when the DNA barcode and the morphological identification agrees we can be certain about the right species identification! As you can read there’s a lengthy process involved before we have the right identification of a copepod specimen and there are hundreds of species described for Norway alone! It is truly very extensive research! Follow us on Twitter and Instagram @planetcopepod to follow our story, or become a member of our planetcopepod Facebook group for the latest news and finding!

See you there!

-Cessa

Scavengers in the ocean

Lysianassoid amphipods from a trap in Raudfjorden, Svalbard. Photo: AHS Tandberg

Most animals are sloppy eaters. They have their favourite piece of food that they go for, and then they leave the rest. This allows for others to pick up where others leave. One of the laws of ecology is that “there is no such thing as an empty ecological niche”. That can be translated to “where there is a food-source (or a place to live) someone or something will use that food-source (or place to live). And that gets us to the sloppy eaters out there, and not least the animals picking up after all the sloppy eaters.

From the pigeons crowding under your cafe-table for your panini-crumbs to the rats in our sewers, our “local scavengers” tend to be animals we feel slightly uncomfortable around. Is it different with the scavengers we dont see so often? It does not seem that way. Vultures  are not the most popular birds, even the word “vulture” has a negative connotation – and we mainly use it in its non-bird meaning.

How about the scavengers of the sea? As on land, we have many different animal-groups that can be classified as scavengers. Many of the marine scavengers are invertebrates (even if some fishes also scavenge). Let us look at the scavenging Lysianassoid amphipods. Are these as little loved in our world as the rats and vultures seem to be?

A typical lysianassoid amphipod. Photo: AHS Tandberg

Lysianassoid amphipods can mostly be distinguished from other amphipods by their “telescope-like” antennae: a very fat inner article with the two next looking like a collapsed old fashioned radio-antenna; two short rings. We know that the antennae of crustaceans are often used to “smell” things in the water – food or mates or possibly even enemies. It is not thought that the radio-antenna-shape of the Lysianassoid antenna specifically has to do with being a scavenger, as other amphipods and indeed several other crustaceans not having such an antenna are also scavengers. But most Lysianassoids have that antennae, and it makes for an easy first-sorting for the scientist. (Getting further – towards a genus, or even species name on the other hand, is not so easy).

Other general traits in most Lysianassoids, are the smooth exterior, and their high swimming abilities. Both are good if you need to get to some leftover food-source fast, and to “dive” into the food-source while not getting stuck through the entry.

Leftovers of bait (polarcod) after 24 hrs in the trap. Not much left for dinner… Photo: AHS Tandberg

And this is where many Lysianassoids loose out when it comes to human appreciation. They seem to love to scavenge on fish caught in fishnets and traps, and both professional and hobby fishers don’t like to share their catch. We dont think it is very appetising to find our fish-dinner “infested” by non-fish. I am quite sure the scavengers being pulled up with their lovely find of dead or dying fish also are not pleased with having to share their dinner with us.

Lysianassoid scavenging amphipods are the focus of our NBIC-financed project NorAmph2. Here, we will collect and register what different species are present in Norway, and we will try to barcode them. These are quite tricky animals to identify properly, but luckily we have teamed up with the best lysianassoid-expert we know – Tammy Horton from the National Oceanography Centre in Southampton, UK.

We use baited traps to collect: put some lovely, smelly fish out there and see who comes to dine. So far, we have collected from Svalbard in the north to Kong Haakon VIIs Hav in the south, and from the intertidal to the deep. They are often many, and the size-variation is great. We look forward to continuing finding out what species we have, and to see if what morphologically seems one species really is (only) one species genetically. (This previous blog-post (in Norwegian) tells the story about one scavenging amphipod that turned out to be 15 (or maybe even more!) separate species)

Anne Helene