Project ParaZoo: there is a critter inside my jellyfish!

ParaZoo (complete name ‘Metazoan parasites of non-crustacean zooplankton’) is one of the most interaction-focused projects currently running at the Invertebrate Collections of our Museum. This project, funded by the Norwegian Biodiversity Information Centre (Artsdatabanken), aims at studying the different animals that live together inside and on the surface of Norwegian jellyfish. This means that for the next two years we will be looking for tapeworms, flukes, roundworms, and amphipods as ParaZoo tries to answer the question of which of these organisms are associated with gelatinous hosts in Norwegian waters.

ParaZoo is focused on animal parasites and symbionts associated with jellyfish. Thse parasites include roundworms like Hysterothylacium aduncum (left, in Euphysa aurata), amphipods like Hyperia medusarum (middle, on Aequorera forskalea), and flukes like the members of family Didymozooidae (right, in Beroe gracilis). IC: Aino Hosia (left), Katrine Kongshavn (middle), Joan J. Soto-Àngel (right).

Besides jellyfish, arrow worms (Chaetognatha) are also members of non-crustacean zooplankton that host different types of parasites, like this H. aduncum roundworm (Nematoda). IC: Joan J. Soto-Àngel, Luis Martell.

Parasitism and symbiosis are extremely common life styles in the animal kingdom. In fact, some researchers believe that there may be more species of parasites than of free-living animals, given that each free-living species hosts many species of parasites (most of them unique) and those parasites also host their own parasitic tenants. Marine zooplankton is no exception to this trend, and many parasites and symbionts are expected to occur in copepods, krill, and gelatinous zooplankton. Jellyfish and arrow worms, for example, may be important hosts for flatworms and other helminths, yet our knowledge of these animals in Norway is very scarce.

ParaZoo’s logo includes two of the target taxa of the project: roundworms (Nematoda) and hyperiids (Amphipoda). The third main parasitic group covered is flatworms (Platyhelminthes), illustrated by the larvae of Derogenes varicus parasitizing Halopsis ocellata shown in the right side of this figure. IC: Joan J. Soto-Àngel, Luis Martell.

Understanding zooplankton parasites is important because many of them are going to be transmitted to fish, where they may cause serious diseases. To get a better overview of which critters live in non-crustacean zooplankton, ParaZoo will sample, record, and DNA-barcode specimens from all over the country. The collected animals will be included in our museum collections after being identified, documented photographically, and fixed in ethanol. We will then generate an open-access database of information including pictures and DNA sequences that will help with the identification of the parasites. Aquaculture facilities, fishermen, and managers of marine areas will benefit from this database to better plan and counter potential negative impacts caused by the parasites.

Flukes, such as Opechona spp, parasitize gelatinous zooplankton (in this case a sea-gooseberry Pleurobrachia pileus) as larvae called metacercariae. IC: Joan J. Soto-Àngel, Luis Martell.

The larvae of tapeworms (Cestoda) sometimes use jellyfish to reach their definitive hosts: fish. IC: Joan J. Soto-Àngel, Luis Martell.

ParaZoo is committed to present the diversity of jellyfish parasites to all those not familiar with them. In order to do that, we will regularly write entries here on the blog, as well as participate in several academic and not-academic meetings. The official info webpage for the project is available here, so don’t forget to check it out!

–Luis

A new online resource for identifying ‘fur snail’ hydroids, and a farewell to project NorHydro

Finding the correct name of the hydroids growing on shells of snails and hermit crabs can be notoriously difficult… but fear not! A new online resource is now available and we hope it will help everybody who is interested in these little critters.

Fig1. Have you seen these pink/orange ‘blobs’ growing on washed-up algae along the coast? They are hydroids of the species Clava multicornis. Read more about this and other Norwegian hydractiniids in the new arter på nett webpages. IC: Luis Martell (left), Katrine Kongshavn (right).

We (the UMB research team of NorHydro: Luis, Aino, Joan, and Lara) have created a series of species identification sheets for all the hydroids and jellyfish belonging to family Hydractiniidae. This family includes some hydroids that can be easily encountered during a walk along the coast or when snorkeling and scuba diving in Norway, and therefore we wanted to provide beach-goers and divers with a tool to find the correct name of these animals.

Fig2. The new identification sheets for Hydractiniidae are available inside the section I havet of the Arter på nett platform in Artsdatabanken’s website. IC: Artsdatabanken.

Many hydractiniids are known as ‘snail fur’ because they give a furry appearance to the shells they are growing on, while others grow on rocks or on algae. Identifying the species still requires a little effort, but altogether they are one of the best groups to start with for anyone interested in hydrozoan diversity in Norway. This is what motivated Lara, a MSc student at the time, to created the first version of these sheets (together with some beautiful illustrations) which were then developed further with text from everybody in the team.
The editors and consultants at Artsdatabanken helped us throughout the process, and we are happy to present the final version of this online resource available here:
Arter på nett: Hydractiniidae

Fig3. The anatomy of a polyp colony of Hydractiniidae is best explained with a combination of images at high-magnification and detailed diagrams. IC: Luis Martell (left), Lara Beckmann (right).

Fig4. Hydractiniid hydromedusae are smaller than 1 cm, but they still have several characters that we use for identification. IC: Joan J. Soto-Angel (left), Lara Beckmann (right).

Fig5. Both the hydromedusa and the hydroid stages of the three species of Podocoryna occurring in Norway are included in the new Hydractiniidae arter på nett. IC: Joan J. Soto-Angel, Bernard Picton, Lara Beckmann

The publication of the Hydractiniidae identification sheets marks the end of our project NorHydro. The project’s main objective was to map the diversity of hydrozoans in Norway, but we also tried to present marine hydroids to all those not familiar with these amazing creatures. During its 3 year’s run, NorHydro produced a detailed inventory of Norwegian hydrozoans through an integrative (morphology + DNA) approach: we collected samples in >90 sites around the country and analyzed existing museum specimens to produce >1200 new records and high-quality, open access DNA barcodes for 160 species. NorHydro’s scientific team identified 12 cases of species complexes, supervised 5 MSc thesis, and participated in >20 outreach activities and presentations in academic events. All in all, NorHydro was an extremely enriching experience and I’m confident its results will help us understand a little better the diversity of marine invertebrates in Norway.

Fig6. Farewell NorHydro!

-Luis

Hydrozoan team at ForBio 2022 annual Meeting

Do you remember that feeling of dread before you must present in class about a topic you didn’t really study for? Your mind racing, trying to scramble a coherent story to tell the sea of eyes fixed expressionless on you and your powerpoint? We believe we all have at least one memory of this from our days in college.

That was a similar feeling to what we felt on November 28th, 2022, when we had just landed in Trondheim and were on our way to the Norwegian University of Science and Technology (NTNU) for this year’s ForBio Meeting, a 3-day gauntlet where we will present the Master’s projects we’re currently working on. Except this time, we weren’t presenting in a small classroom full of uninterested teenagers thinking about tik tok dances, but in an auditorium full of fellow researchers who work on your same field, and who will probably have extremely difficult questions at the end of your talk. Being the first time we present in an environment like this, one can’t help but imagine all the worst outcomes

And so we’re sitting there, watching the hours and the talks go by, thinking to ourselves “I should/shouldn’t try that for my talk!”. At lunch, all we think about is our talks. When we’re doing some light sightseeing in Trondheim, all we think about is our talks. We’re laying in our beds the night before, and all we think about is our talks. “How will I make my topic sound as professional and knowledgeable as I want to?”, we think to ourselves.

The day arrives, and again the dread starts setting in, right until the moment they call each of our names. At our every turn, we walk down the steps, grab the microphone, and start talking. Except for some reason, this time it feels like we’re in control. The words flow effortlessly; we even crack a joke or two, and the audience laughs. There’s no stumbling around the words like those college days.

Because this time, we’re not the average seat-warming student. This time, we’re the ones that have spent cold and raining hours on a research vessel or diving to get our samples; we’re the ones who have spent hours working together with our supervisors, reading and learning about our topics; we’re the ones who have spent hours looking down a microscope trying to identify our organisms. This time, we’re the ones who know what we’re talking about, and the audience is there to learn from us.

After each of our talks, we give our acknowledgements, and everyone claps. The questions thrown at you are answered effortlessly, and the moment is finished with a thumbs up to our supervisors, returning to our seats smiling.

The most exciting part for us was showing to experts what we do with our favorite invertebrates: Hydrozoans. These organisms are an inconspicuous class in the phylum Cnidaria that most people ignore. Our job was not only to present what we do with them, but to show what they are, what they do, how fascinating they can be and why they are important. And we think that we did a good job.

Now we’re finally free to enjoy the world famous Trondheim bike lift (and the Nidaros Cathedral too), closing the night with burgers, beer and friends.

Everything has been great on this trip and we will always remember the advice from other professionals; how different or similar the work of each one is; and the feeling that you are part of a group of specialists who are excited to share their knowledge with others. But, above all, we have learned why these conferences are important: Knowing what other researchers are doing gives us the chance to collaborate together and help each other, because working as a team is how science moves forward.

The hydrozoa group (and friends) from UiB participating at the ForBio meeting

Pedro, Ana & Håvard

Student visit – Ana González

MSc student Ana González visited the collections last month as part of project NorHydro, where she spent some weeks in the lab working with her samples. Here is an account of her experience:

The challenge of identifying benthic hydrozoans
Hydrozoa is a fascinating but poorly understood group of invertebrates, in part because their identification is not always an easy task. I have been studying benthic hydrozoan communities for over a year now, in particular those living in the shallow waters of Mallorca (Spain), and I have realized that the diversity of forms and structures in the group is higher than I had imagined at the beginning of my studies, and their identification is more difficult than I expected. The assemblages of hydrozoans in the Mediterranean are of course very different from the ones that occur in Norway, but something that both communities have in common is that morphological identification of the animals (i.e. telling which species is present based only on the characteristics we can observe) is challenging, which is why one of the aims of my visit to the University Museum of Bergen last December was to learn a different technique (DNA barcoding) that can help me improve the identification of my samples in cases when the morphology of the specimens is not good enough.

Some of the morphological characters that are used to identify benthic hydrozoans. On the left side a member of Campanulariidae, with a stolonal colony, and on the right side Monotheca obliqua with an erect colony.

DNA barcoding consists in finding a short DNA sequence (the barcode) that is similar for all members of one species but different from all other species. It is a relatively recent tool that –among other things– has helped the scientific community identify specimens that for one reason or the other cannot be identified based on how they look. In some groups, such as many colonial invertebrates, this technique has become a key asset because the colonies are often too young or not reproductive, or the important characters for identifications may be found only in one stage of the life cycle and not in others. For this visit I had the chance to bring all my samples from Mallorca to Bergen and I set to extracting the DNA of selected specimens, amplifying two different barcode genes (COI and 16S), and obtaining clean sequences for them. I discovered that, when it comes to DNA barcoding, every step of the process is important, and being patient and careful is essential.

Me at the DNA lab, running the electrophoresis for my samples.

Getting good results in the DNA lab depends on several factors like not forgetting any step and avoiding contamination as far as possible, but the work does not end there: once you have your sequences they have to be cleaned, quality-checked, and finally compared with others. This means that having a complete and trustworthy database of DNA barcodes is necessary, especially if you want to use the sequence to help you corroborate the identification of a specimen. When done right and with a good database, the DNA barcodes can be useful to detect differences between hydrozoan assemblages growing in different parts of the world or between different substrates and levels of anthropogenic impact, which is what I am doing in my MSc project.

Left: Clytia sp growing on the marine plant Posidonia oceanica. Center: A polyp of Halecium sp, one of the most difficult genera of Hydrozoa to identify based only in morphology, especially when the colony is not reproductive. Right: Eudendrium sp., found in harbours in Mallorca in high abundances.

The analysis of DNA sequences is a powerful tool to compare specimens of distinct populations and in some cases animals that apparently belong to the same species turn out to be completely different (e.g. cryptic species). This is not uncommon for benthic hydrozoans, which have high morphological diversity but also high levels of plasticity, resulting in colonies from different species sometimes being very similar to each other when they grow in similar substrates. As useful as DNA analyses are, however, it is also important to consider their limitations. For example, while the abundance of each species in a given community is important to describe the ecological status of a habitat, estimating abundance is still not always possible from sequence reads in DNA analyses.

Many cryptic species have been discovered in Aglaopheniidae thanks to the combination of DNA barcoding and morphological analysis

The use of DNA barcodes in my work is not limited to my current project, as I hope my identifications and sequences will help a little bit to improve the databases for future studies of hydrozoan communities in the Mediterranean Sea, and maybe even allow other researchers to compare their samples with the species found on other parts of the world. I think that looking closely at each specimen is the best way to truly know variation, so both morphology observations and DNA analyses should be combined to obtain good estimates of the diversity of a taxon in any locality. For example, whenever the DNA analyses reveal differences in two clades that were thought to be the same species, it is time to search for new taxonomic characters that we might have missed before, and for that reason it is also important to have a good knowledge of the morphology of each species. Both morphological and DNA-based identifications have limitations and advantages so, if you have the opportunity to use both, why choose only one?

Ana

First visit to Bergen for the Cirratulidae project

We had guest researcher Maël Grosse visiting the lab earlier this winter. Here’s a blog post from his stay:

As part of my recently started Artsdatabanken project, I have just completed a month long visit here at the invertebrates collections. It was a lot of work, but also a lot fun. Everyone was very helpful, providing me with worms to identify (a literally never ending supply!), helping me with the scanning electron microscope and spending hours discussing worms and taxonomy. 

My project aims to study and map the diversity of a large family of polychaetes: Cirratulidae. Cirratulids are notoriously difficult to identify, having few characters to work with hidden between the mass of tentacles and branchiae they drag around (Fig. 1). They are quite common and diverse, but poorly known, which is what I am aiming to fix.

Fig. 1. A SEM (Scanning Electron Microscopy) image of a Cirratulid made at the ELMI lab in Bergen.  Photo: Katrine Kongshavn

Bergen Museum has the largest collection of polychaetes in Norway, with samples ranging from the North Sea to the Arctic waters of Svalbard, and from the intertidal coastal waters to the abyssal depths of the North-East Atlantic. And indeed, thousands of cirratulid polychaetes were waiting on the shelves to be identified. As it is the environment I had been working the most with in the past couple of years, for this visit I decided to focus on deep sea species. This led me to check samples from all over the Norwegian Sea, including some unique and exciting environments such as the depths of Sognefjord or hydrothermal vents.

At the end of the month, over 5500 specimens, belonging to about 23 species have been examined (Fig. 2). While the majority could be given an name or a species number (in the case of as of yet unnamed species), many could not be identified with confidence, because they were  incomplete specimens or from an area where a particular species had not been recorded before. There were even two species I think I had never seen before, which is a very good result for the project! In that case, I selected specimens for DNA barcoding, which will help confirming their identity. I have picked out about 300 specimens for barcoding, so now there is quite a bit of work to do back in my home lab to sequence them all.

Fig. 2. Cirratulidae samples at UMB. Photo: Maël Grosse

So in the end, I would say it was very productive visit, and I will certainly be back for more worms!

-Maël Grosse

Final workshop for hyperbenthic copepods (HYPCOP)

Our first international workshop with from ltr; Anders Hobæk (NIVA), Cessa Rauch & Jon Kongsrud (UMB), Tone Falkenhaug (project leader, IMR), Alexandra Savchenko & Rony Huys (NHM), photo by Alexandra Savchenko

During the last week of September, HYPCOP organized its last and crucial workshop for finishing the project. We invited international collaborators Prof. Dr. Rony Huys and Dr. Alexandra Savchenko from the Natural History Museum in London. Prof. Dr. Huys is a well-known copepod taxonomist and crustacean researcher and published a multitude of species descriptions and books including key identification guides. We were very happy to hear he had time to come and travel to Bergen, paying us a visit while also helping us with species identifications of the many, many copepods we had collected during the two years of our project.

 

During the two years of the HYPCOP project we collected around 600 specimens from different localities all over Norway, including shallow coastal waters and the deeper parts of the mid-Atlantic Ridge (Loki’s Castle field of active hydrothermal vents). From all those specimens we extracted DNA from the soft tissue of the animal. Therefore, keeping the hard exoskeletons, for morphological identification downstream. This is the most time consuming and challenging part. The species can sometimes only be identified based on minuscule differences in the appearance of its legs. Besides, one needs good taxonomic competence to assign these differences to the thousands of marine benthic copepods species. And this is where the HYPCOP team needed help.

HYPCOP started in May 2020, when a lot of countries, including Norway, were in a lockdown and international travel was difficult or even impossible. Therefore, it was problematic for HYPCOP to invite international researchers for most of the time. Thus, we focused mostly on extracting DNA from our collected specimens and building up a barcode library. But what was missing was the nomenclature of the bulk of the specimens. When finally, our first international researchers could come and have a look at our specimens, it turned out to be an enormous task. With the help of Prof. Dr. Huys and Dr. Savchenko we managed now to have almost 300 assigned names to our DNA library of 500 specimens. Quite a few of those are new species and even new genera.

Kickoff of the workshop, which would take place at Marine Biological Station Espegrend for the duration of a week, photo by Alexandra Savchenko

Rony and Alexandra arrived Sunday evening in Bergen together with project leader Tone Falkenhaug and project technician Cessa. We were stationed at the Espegrend marine biological station in Bergen for the entirety of the week. It was for Tone and Cessa the first time they would finally meet Rony and Alexandra in person, after many months of digital communication. It was a nice relaxing first evening. The next day Anders Hobæk from NIVA and Jon Kongsrud from the UiB joined and we started off the week with a presentation overview of the project.

The overview informed everyone about the program of the week and the state of the art of the project. With the DNA barcode library, we managed to construct a COI phylogenetic tree. Some of the larger clades were already identified down to species level, but many more species names were missing from the smaller clades. It was up to us that week together with Rony and Alexandra to identify these last cases.

Alexandra onboard research vessel Emiliana, photo by Tone Falkenhaug

We also had one day of fieldwork planned, to have us work also with some fresh material. This we did with help of research vessel Emiliana and the Beyer’s sled. Both stationed at Espegrend Marine Biological station. We tried to pick out a nice and dry day for going out with the boat and that happened to be in the mid of the week. We went a little bit outside of the Biological Station, with a depth of around 90 – 120m. The Beyer’s sled is an epibenthic sampler, it is called a sled for its form. We got many fresh samples, but due the net being a little large in its mesh size, we did not get as many small species as we liked.

 

Therefore, we also tried another sampling method with help of Anders; he had brought with him a light trap. Light traps are very easy to DIY with a bottle and inverted bottle opening, like a funnel, and a small led light on the bottom. You install the trap in the water overnight; the little led light attracts a lot of small hyperbenthic and planktonic (and some bigger) species.

Everyone working hard at the Marine Biological Station Espegrend, assigning species names to specimens, photo by Cessa Rauch

The entirety of the week consisted of many hours working at the microscope, going through literature, dissecting specimens, and assigning species names to the specimens. Eventually with help of Rony and Alexandra, we managed to assign 298 scientific names to 702 specimens in our collection. From those specimens, we extracted DNA from 593 specimens and produced a DNA library, which we uploaded to the BOLDSYSTEMS (Barcode of Life Data System). This library also has all the metadata of our specimens, such as location, depth, size, and pictures of the specimens (either life, fixed and in some cases parts). And it will be publicly available at the end of the HYPCOP project.

The week was demanding but very rewarding and we got many specimens identified, with even a few new species and genera to Norway and possibly new to science; all thanks to the hard work and help of Rony and Alexandra. We therefore also would like to take this opportunity to thank them again for their time and efforts in helping the HYPCOP project move forward! Until next time.

Rony Huys and Alexandra Savchenko helping the HYPCOP project move forward, photo by Tone Falkenhaug

– Cessa

Unraveling copepod secrets one leg at a time

A blog by HYPCOP

Hyperbenthic copepods (HYPCOP) are a very difficult and diverse group to work with, and identification goes painstakingly slow, because some species can only be distinguished from one another based on small details in some of their tiny legs. As of now, we have no specialists in marine benthic copepods in Norway and our greatest resource is our collaborator Anders Hobæk and the detailed drawings of G.O. Sars from the early 1900s .

Working together under guidance of G.O. Sars and Anders Hobæk

Anders is a senior researcher scientist at the Norwegian Institute for Water Research (NIVA) here in Bergen. He is specialized in copepod taxonomy, but his focus was mostly on freshwater copepods, or marine pelagic copepods. Which makes the marine benthic copepods just a little bit more challenging to work with, however, his skills are transferable and so we get together multiple times a year to work on our collection of benthic copepods to dissect them and identify them.

Beginning of June, we had again one of those get togethers in Flødevigen at the Institute of Marine Research (IMR), where Tone Falkenhaug, the project leader of HYPCOP, is situated. For a week we went through the main clades and groups of species that we had DNA barcodes of but not yet a confirmed species name. A lot of the identification was done with help of the rich and detailed illustrations of G.O. Sars1 published work in 1901 – 03 and 1919 – 21, “An account of Crustacea of Norway”

Detailed copepod drawings from G.O. Sars

Sars dedicated a lifetime of identifying and describing a variety of species and he did not neglect the rich and wonderful group of bottom dwelling copepods. Every species he encountered in those early days he described and drew in detail; he did not leave out the smallest details, that as of now, turn out to be of uttermost importance in determining the species. With small copepods you need a good microscope and fine tools. The first thing to look at is the general shape, is it very dorsally flat, like Peltidium purpureum, or more dimensional like Harpacticus flexus?

Sex is also an important feature; females are often characterized by carrying eggs; one egg sack or two egg sacks can already lead you in the right group. Males have often larger antennule made for holding on to females when mating, and other specialized tools that can be species specific. The little claws, called maxilliped, are they large, small, almost invisible? What about the first pair of legs? The second, third and fourth? The fifth pair of legs is often very characteristic for the species and in certain females, like Thalestris longimana, can be a huge in comparison of the rest of its body.

Thalestris longimana, females of this species has relatively large fifth pair of legs

Our work has a continues workflow consisting of, collecting the copepods, extracting their tissue for DNA barcoding, and keeping the exoskeleton. Once the DNA is successfully sequenced, we can take the exoskeleton and dissect the animal leg by leg to finalize the identification. That way the copepod is identified based on its DNA and morphological features, as this is not always mutually exclusive. DNA can be tricky as you need a good reference library to find the correct species, which is as of now, not complete, or even lacking for many species. Besides, there is such things as DNA contamination, cross contamination between species, therefore you always must look at the morphology to exclude that the DNA gives you the wrong species. Together with images of the animals we are building up a valuable reference library of DNA sequences and a museum collection of dissected animals on fixed slides. This way copepod diversity will continue to be valuable for future generations top study.

Working under the eyes of G.O. Sars

-Cessa

1Sars, G. O. 1901-03. An Account of the Crustacea of Norway. Vol. IV. Copepoda Calanoida.- Bergen Museum, Bergen & Christiana. 171 pp. + 109 plates Sars, G. O. 1919-21. An Account of the Crustacea of Norway. Vol. VII. Copepoda. Supplement. – Bergen Museum, Bergen & Christiana. 121 pp. + 74 plates

Fieldwork for two projects

The projects HypCop (bottom-associated copepods) and Hardbunnsfauna (Invertebrate fauna of marine rocky shallow-water habitats) went on a day-trip to three localities last week.

We made the most of the sunny and calm weather to visit a very exposed site on Sotra, where we collected in the tide pools and on the barnacle-encrusted intertidal.

Afterwards, we went to two marinas, Glesvær and Hjellestad, on a quest for some specific species the projects were in need of.

Back in the lab we set to work documenting the colours of the animals by photographing them alive, as the colours tend to face in fixatives.

It was nice day in the field, and it looks like we found the species we were after!

Follow us on Twitter and Instagram as @PlanetCopepod and @Hardbunnsfauna

– Jon, Cessa & Katrine

 

HYPCOP workshop in Flødevigen

From the 7th to the 11th of March the HYPCOP team once more sat together to work on the identification of the species we have in the collection. The strategy was similar as we had in Bergen last year, but this time we looked focus into specific clades. Besides, we met in Flødevigen this time, instead of Bergen, and visited Tone Falkenhaug at her jobsite with the Norwegian Institute of Marine Research (IMR, Havforskningsinstituttet).

The HYPCOP team in Flødevigen, from ltr; Cessa Rauch (UiB), Jon Kongsrud (UiB), Anders Hobæk (NIWA) & project leader Tone Falkenhaug (IMR).

One way for identifying species of hyperbenthic copepods is by looking at their colors. Unfortunately, these get lost as soon as you fixate the samples in technical ethanol. Therefore, we started the workshop with a short sampling trip just out of the bay in front of the research station. We took a small boat from the research station that had a manual operated hinge on the back of the boat, so we could use that for pulling up the grab.

Preparing the small IMR boat with use of the manual hinge and the grab.

Anders Hobæk operating the grab

One of the advantages of working with tiny animals is that you sometimes only need small gear to collect them. The grab we used is hand size grab, not much bigger than a 10L basket.

However, as it is made entirely out of metal it is still heavy, which ensures it will be able to “grab” the mud from the bottom when it hits the sea floor.

Once we arrived at a nice location with the boat, we placed the grab over the edge of the boat and let it sink to the bottom which was about 40m deep.

Once the grab would touchdown it would close and engulf softbottom material including the animals that are associated with it. The closed grab would be town back with the manual hinge from the boat. Once onboard, we would empty the grabs content in a bucket and sieve some of the material. This material would go back to the lab for examination.

We carefully examined the sediment, and it was not yet very rich with benthos. We caught a few interesting copepods species, that we documented and fixated for identification.

One of the species we caught with the grab

March is not the best season for benthic copepod sampling, the water is still very cold from the winter and most of the small algae needs to grow back. Benthic copepods are much more abundant with rising temperatures and lots of algae growth. Back in the laboratory we started working on our museum collection copepods and assigned clades in our family tree that we would examine first.

Tone Folkenhaug (left) and Anders Hobæk (right) concentrated with dissecting copepods.

Bigger clades had more priority, and so we took those samples and checked the individual specimens. All the specimens we had in our collection are exoskeleton remnants from the DNA extraction (hence we could have a phylogenetic tree). The exoskeletons are still good for morphology identification but hard to see (due to there translucent nature). Therefore, to help with the identification we would often stain the exoskeletons either with lactophyl blue or lignin pink, which resulted in a visually pleasing collection of prepared slides of different colors.

Slides of Lactophyl and lignin pink stained copepods

Thanks to the workshop we now have manage to identify 145 out the 580 specimens; our efforts for identifying will continue and a new workshop is already planned, we meet again in June and in September, with also this time, help of international researchers!

Stay tuned with @planetcopepod!

-Cessa

Hydrozoa course 2022 edition – as told by our MSc student Ana González

Last month, our project NorHydro (together with ForBio Research School of Biosystematics and project MEDUSA) organized a course on diversity, systematics and biology of Hydrozoa at the Marine Biological Station in Espegrend. Fifteen participants from 9 different countries came all the way to Bergen to learn more about these intriguing animals, share their ideas and projects, and start new collaborations. We asked one of the youngest members of the group –our highly motivated student Ana González– to share with us her thoughts about the course and her experiences with her MSc project. This is what she had to say:

When I started my Master’s Degree of Marine Ecology at the University of the Balearic IslandsI already knew about the existence of hydrozoans, but I had no idea how interesting these animals actually were. After some discussions, a lot of reading, and a fair amount of looking at pictures of hydroids and hydromedusae, I decided to work with these inconspicuous invertebrates for my MSc project under the supervision of Dr Luis Martell (University Museum of Bergen) and Dr. Maria Capa (University of the Balearic Islands). My project aims to evaluate whether we can use the benthic communities of hydrozoans as bioindicators of anthropogenic impact on the easternmost coasts of Mallorca Island, in the Mediterranean Sea.

Me on a sampling day looking for benthic hydrozoans at the marine reserve of Cala Gat (top). A closer view of the hard substrates I sample in the marine reserve (bottom left). The common hydroid Monotheca obliqua growing on Posidonia oceanica (bottom right). Picture credits: Maria Capa and Ana González.

Coastal areas are an attractive place to live, and these habitats provide ecosystem services that contribute greatly to the economy of the world, but a bad management of them can generate important damages and drastic changes in the ecosystem. One way to monitor environmental impacts in these habitats is by observing the response of their biological communities, so for this project I decided to study the assemblages of benthic hydrozoans in two opposite sites with different levels of anthropogenic impact: a harbor and a marine reserve. Moreover, I am comparing the communities in different seasons of the year, and I will analyze the assemblages growing on hard substrates (like rocks) and also those growing on a very important Mediterranean soft substrate: the endemic seagrass Posidonia oceanica.

Some hydroids common in my study area are those belonging to genera Clytia (family Campanulariidae, left), Sertularella (family Sertularellidae, middle), and Aglaophenia (family Aglaopheniidae, right). Picture credits: Ana González.

At the beginning, working with benthic hydrozoans was very challenging for me since the specimens I find are easily overlooked if one is not searching carefully for them. But the more time I dedicate to observe these organisms, the more curious I became about their identity and dynamics, and the easier it was to recognize them in the samples. However, identifying hydrozoans is a difficult task and I realized early that I needed some help, so I was very happy when the opportunity arose to apply for the course “Diversity, Systematics and Biology of Hydrozoa” in Bergen. There, I had the chance to meet some of the leading scientific experts in the field that helped me understand better the taxonomy and ecology of these animals. I couldn’t have imagined how much I was going to learn during the different activities of the course, but at the end these organisms were able to catch my attention and time flew between lectures, sampling trips, and laboratory work. One aspect of the course that I particularly enjoyed is the fact that it brought together participants with different trajectories in science, and everybody was happy to share their experiences in the world of hydrozoan science.

We had all kinds of weather during the course: rain, sun, wind, and even snow! Picture credits: Lara Beckmann and Joan J Soto Àngel.

We had the chance to sample on board the UiB research vessel Hans Brattström and we collected several planktonic and benthic hydrozoans in the fjords around the Marine Station. After each sampling event, we went back to the lab to sort the samples, find the hydrozoans and identify them to species. The plankton samples were usually the first ones to be processed, since hydromedusae are quite fragile and they tend to suffer morphological damages after being sampled with a net. We tried to identify all specimens to species level, with the aid of the stereomicroscopes and scientific literature with identification keys that the curse provided. The benthic samples were placed in aquariums to keep the organisms alive and then each of us had the opportunity to observe the specimens in our own stereomicroscope.

A sampling day on board of RV Hans Brattström. Top left: deploying the plankton net. Top right: a full cod-end with plankton sample. Middle right: students and teachers ready to leave the pier. Bottom: benthos sampling with the triangular dredge. Picture credits: Lara Beckmann, Sabine Holst, Luis Martell

Top right and left: students and teachers at the laboratory, identifying hydrozoans. Bottom left: searching for hydromedusae and siphonophores in the plankton sample. Picture credits: Sabine Holst and Lara Beckmann.

All together, we were able to find and identify more than 40 species from all the main groups of hydrozoans, including siphonophores, trachylines, leptothecathes, and anthoathecates. Working with hydromedusae was new for me and I discovered that observing them was more challenging than identifying the polyps, but it was also interesting in its own way. The hydrozoans that caught my attention the most were the polyps from the suborder Capitata, because their morphology is very different from the hydroids that I have observed in my MSc project so far. Capitate hydroids don’t have a protective theca, they possess tentacles that end up in a ball of nematocysts (so-called capitate tentacles), and they are absent from almost all my samples from Mallorca, which are instead dominated by hydroids belonging to the Order Lepthothecata.

Top: Colony of Sarsia lovenii (Anthoathecata: Corynidae) with gonophores (i.e. reproductive buds on the polyp body). You can also see the capitate tentacles, which end in a ball of nematocysts and are typical for suborder Capitata. Bottom: Colony of Clava multicornis showing also gonophores on the polyp body, but with filiform (non-capitate) tentacles. Picture credits: Lara Beckmann (top), Joan J. Soto Àngel (bottom).

My interest for hydrozoans, the great set of experts we had as teachers, and the charismatic animals that we collected were the perfect combination for me to have an incredible experience in this course. I think that courses like these are an excellent opportunity for beginners to learn with experts from different parts of the world. Interacting with all of these amazing people was very rewarding at both cultural and scientific levels, and this whole experience motivated me to keep on studying these interesting animals that are a part of the complex functioning of our oceans.

-Ana