Author Archives: pans

About pans

Zoological taxonomist with a focus on the crustacean order Amphipoda.

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

Why study boring amphipoda and other strange taxa?

Bircenna thieli seen from the front and the side. SEM photo, Fig 6 in Hughes and Lörz, 2019.

This question (or a version of it) is something a lot of us taxonomists are faced with quite often when we try to explain what we do for a living. And I do understand the need to ask – couldn´t our talents be used better doing something it might be easier to understand the use of? We think the study of taxonomy is higly important, and does bring about useful knowledge for the world. Therefore, we have several taxonomic projects in our group, and we write about them here in the blog. (If you read norwegian, you can read about our projects here)

 

March 19th was the world Taxonomist Appreciation Day – a day we have “celebrated” since 2013. Why do we need this day? Taxonomy is the science of naming, defining, describing, cataloguing, identifying and classifying groups of biological organisms. We do this in labs and on fieldwork, and the natural history museums (these days represented from our home offices) have a special responsibility for this work, since one part of the formal description of a taxon is to designate a type and store that in a museum collection. We will come back to the importance of types in a later blog here.

Terry McGlynn, the professor and blogger who initiated the Taxonomist Appreciation Day wrote: ” I want to declare a new holiday! If you’re a biologist, no matter what kind of work you do, there are people in your lives that have made your work possible. Even if you’re working on a single-species system, or are a theoretician, the discoveries and methods of systematists are the basis of your work. Long before mass sequencing or the emergence of proteomics, and other stuff like that, the foundations of bioinformatics were laid by systematists. We need active work on taxonomy and systematics if our work is going to progress, and if we are to apply our findings. Without taxonomists, entire fields wouldn’t exist. We’d be working in darkness.”

Every year a large number of new taxa are described – last year almost 2000 of the new species described were marine. March 19th every year, the World Register of Marine Species (WoRMS) and LifeWatch publish their favourite 10 marine species described in the previous year, and this year – corona-shutdown and all – was no exception.

All ten new species are fun, beautiful and remarkable – but Polyplacotoma mediterranea Osigus & Schierwater, 2019 deserves special mentioning. P. mediterranea is the third species described ever in the phylum Placozoa – who are viewed as one of the key-taxa to understand early animal evolution. They were first described in 1883 (by Schulze), and the name Placozoa indicated what they looked like: small (around 1 mm for the largest of the specimens) platelike animals. 2018 saw the second species of placozoans described – genetically, as it was impossible to separate morphologically – but then our new placozoan came – and it is 10mm large, is branched, and has its natural habitat in the mediterranean intertidal! Phylum Placozoa will never be the same again, and our understanding of the early evolution of animals has become even more interesting.

 

What then about the boring amphipods? Or course they are not boring as in saying they are dull! The “boring amphipod” Bircenna thieli Hughes & Lörz, 2019 bores in the sense that they excavate tunnels into the stem of the common bull kelp Durvillaea potatorum (Labillardière) Areschoug, 1854 in the intertidal and shallow waters by Tasmania.

Bircenna thieli has a head almost like an ant, and a quite unusual shape of its back-body. Fig 8 from Hughes and Lörz, 2019

Their head has an ant-like ball-shape unlike many other amphipods where the head is more ornate or has a visible rostrum, but the exciting morphology comes at the other end of the animal – where the telson and last segment have structures never seen before in amphipods, and structures that only other vegetation-boring amphipods show.

So why do we think describing tiny animals, plants, fungi, bacteria and other organisms is so important? Let us ask you back: how can you appreciate what you have and care about what might be lost if you dont know who they are?

Anne Helene

(this post was written March 19th, but posted later..)


Literature:
Eitel M, Osigus H-J, DeSalle R, Schierwater B (2013) Global Diversity of the Placozoa. PLoS ONE 8(4): e57131. doi:10.1371/journal.pone.0057131

Hughes, L.E.; Lörz, A.-N. (2019). Boring Amphipods from Tasmania, Australia (Eophliantidae: Amphipoda: Crustacea). Evolutionary Systematics 3(1): 41-52. https://doi.org/10.3897/evolsyst.3.35340

Osigus, H.-J.; Rolfes, S.; Herzog, R.; Kamm, K.; Schierwater, B. (2019). Polyplacotoma mediterranea is a new ramified placozoan species. Current Biology 29(5): R148-R149. https://doi.org/10.1016/j.cub.2019.01.068


Do you want to find out more about Taxonomist Appreciation Day or about all the 10 exciting species?

Ten remarkable new marine species from 2019

Today is Taxonomist Appreciation Day!

A compendium of taxonomists on ORCID

and not least –  you can still follow the #TaxonomistAppreciationDay on Twitter (and be prepared for 2021!)

Door #20 The Hitchhikers Guide to the Ocean

The sea is for most of its inhabitants a vast place where danger can get to you anywhere. This might be especially true when you are one of those small and mostly harmless species spending your life slowly swimming around, minding your own business (eating and reproducing), somewhere in the upper 200m or so of water. Because there are many big-mouthed and possibly big eyed animals out there that think you might be one of the best things there is to eat.

Hyperiella antarctica with Spongiobranchaea australis. Photo: C Havermans, AWI.

For the small pelagic (living in the open ocean and not close to the sea floor) amphipods in the suborder Hyperiidea this is one of the dangers of everyday life. The genus Hyperiella can be found in the Southern Ocean, and one of their main predators are the icefishes (Nototheniidae). So what do you do when you are a small and quite tasty animal that is not a very fast swimmer and there are a lot of fishes out there to eat you?

Don´t panic!

Hyperiella antarctica with Spongiobranchaea australis (a and b) and Hyperiella dilatata with Clione limacina antarctica (c). Figure 2 Havermans et al 2018.

Two of the three Hyperiella-species have found a quite ingenious solution. They hitchhike with a group of other small slow-swimming pelagic animals – pteropods. Pteropods (from the greek “wing-foot”) are sea snails (gastropods). Hyperiella australis pics up a life with Spongiobranchaea australis, and Hyperiella dilatata hangs out with Clione limacina antarctica. Both pteropods are from the group we call Sea Angels (Gymnosomata), and in a way they are saving angels for the amphipods: the ice fish don´t eat these strange couples. Why?

It seems the pteropods have developed a chemical protection against predation. They obviously taste extremely bad, for observations of icefish trying to eat the hitchhiking amphipods together with the pteropods result in them both being spit out again. Most times, the fish would see what it thought was good food, and then swim away when they discovered what they were almost eating. Not so very strange, then, that Hyperiella are holding on to their colleagues for their life!

 

 

Clione limacina antarctica. Photo C Havermans, AWI.

It might not be hitchhiking after all, but rather kidnapping – or brute force. The amphipods hold on to the pteropods with their to-three hindmost pairs of legs, and keep the sea angel on their back – much like a backpack. Observations are that they are repositioning them there all the time – almost like kids running with bumpy backpacks on the way to school. They don´t even let go when the researchers preserve them!

Hyperiella antarctica with Spongiobranchaea australis backpack. Photo: C Havermans, AWI

What this treatment do to the pteropods we still don´t know. But it does not seem they are able to eat very much when being held hostage as chemical defence-backpacks. That may not be the biggest problem in a short time-scale – their Arctic relatives have been shown to survive almost a year without food. What happens when they really get hungry we do not know. The amphipods are still able to feed, even though the pteropods can be up to 50% of the amphipod size. Maybe the pteropods do some of the swimming for the amphipods?

This behaviour is much more common close to the coast than in the open sea: close to the McMurdo area, 75% of the Hyperiella were seen hitching with a pteropod. Now we know that this pairing can be found in the open sea, and maybe is it more common that we think. It is not the first thing we have looked for so far when examining samples. When the University Museum of Bergen joins the Norwegian Polar Institute and the Institute of Marine Research to the Southern Ocean in the austral autumn this coming March, we will make a special effort to search for such collaborators.

Anne Helene


Literature

Havermans C, Hagen W, Zeidler W, Held C, Auel H 2018. A survival pack for escaping predation in the open ocean: amphipod-pteropod associations in the Southern Ocean. Marine Biodiversity https://doi.org/10.1007/s12526-018-0916-3

McClintock JB, Janssen J 1990. Pteropod abduction as a chemical defence in a pelagic Antarctic amphipod. Nature 346:424-426.

 

 

The amphipods around Iceland – fresh special issue

IceAGE stations with amphipods. Red stations are analysed in the special issue. Fig 1 from Brix et al 2018

As the IceAGE-project presents their amphipod results in a special issue of ZooKeys, the invertebrate collections are represented with co-authors in 4 of the 6 papers. All papers in the special issue are of course Open Access.

Endre, Anne Helene and IceAGE-collaborators Anne-Nina and Amy have examined the Rhachotropis species (family Eusiroidea) from Norwegian and Icelandic waters, using material both from NorAmph and IceAGE. We see possible cryptic species, and we described to separate populations (and Arctic and one North Atlantic) of Rhachotropis aculeata.

Rhachotropis aff. palporum from IceAGE material. Fig 4G in Lörz et al, photographer: AHS Tandberg

Anne Helene has worked with Wim Vader from Tromsø Museum on Amphilochidae. The new species Amphilochus anoculus is formally described, and amphipod identifiers working with North-Atlantic material will be happy fo find a key to all Amphilochidae in the area. These minute and fragile animals are often lumped as family only, but the times for that are now over…

Key to the Amphilochidae from North Atlantic waters. Fig 14 from Tandberg & Vader 2018

Neighbour Joining tree of COI-sequences from IceAGE. The coloured lines on the side show possible interesting regions for further studies. Fig. 2 from Jazdzewska et al 2018

A paper on DNA fingerprinting of Icelandic amphipods is presented by Ania (who visited us two years ago to work on Phoxocephalid amphipods) and 10 coauthors. This study gives a very nice material to compare with the NorAmph barcodes, and some of the interesting results are discussed in the two first papers.

A summary-paper on the amphipod-families around Iceland (Brix et al) gives an overview of both biogeography and ecology of the amphipods in this area. This paper also presents faunistic data on Amphilochidae from the earlier BioIce project, where researchers from Bergen, Trondheim and Reykjavik sampled Icelandic waters.

Anne Helene

 

 

Literature:

Brix S, Lörz A-N, Jazdzweska AM, Hughes LE, Tandberg AHS, Pabis K, Stransky B, Krapp-Schickel T, Sorbe JC, Hendrycks E, Vader W, Frutos I, Horton T, Jazdzewski K, Peart R, Beermann J, Coleman CO, Buhl-Mortensen L, Corbari L, Havermans C, Tato R, Campean AJ (2018) Amphipod family distributions around Iceland. ZooKeys 731: 1-53 doi:10.3897/zookeys.731.19854

Jazszewska AM, Corbari L, Driskell A, Frutos I, Havermans C, Hendrycks E, Hughes L, Lörz A-N, Stransky B, Tandberg AHS, Vader W, Brix S (2018) A genetic fingerprint of Amphipoda from Icelandic waters – the baseline for further biodiversity and biogeography studies. ZooKeys 731: 55-73 doi:10.3897/zookeys.731.19913

Lörz A-N, Tandberg AHS, Willassen E, Driskell A (2018) Rhachotropis (Eusiroidea, Amphipoda) from the North East Atlantic. ZooKeys 731: 75-101 doi:10.3897/zookeys.731.19814

Tandberg AHS, Vader W (2018) On a new species of Amphilochus from deep and cold Atlantic waters, with a note on the genus Amphilochopsis (Amphipoda, Gammaridea, Amphilochidae). ZooKeys 731: 103-134 doi:10.3897/zookeys.731.19899

When amphipodologists meet.

It generally happens every two years. The event may be seen as a natural phenomenon – or maybe rather  a cultural phenomenon. I am sure it looks strange if observed from outside the community. A lot of people of all ages and affiliations meet up in places most of us usually did not even know existed, and we have the best week of our work-year.

Happy friends meeting in Trapani. (all photos: AH Tandberg)

Happy friends meeting in Trapani. (all photos: AH Tandberg)

The bi-annual International Colloquium on Amphipoda (ICA) is without doubt the scientific meeting I look most forward to.  Every time. The fun, the science, the amphipods, the friendships, the coffee, the familiar banter, the late nights and early mornings, the discussions – all in an atmosphere of friendship.

The Polish Amphipod-t-shirt edition 2017. (photo: AH Tandberg)

The Polish Amphipod-t-shirt edition 2017. (photo: AH Tandberg)

The first day of any ICA could be mistaken for a family-gathering – or the opening credits of any film about best friends. The room resounds of “oh – finally – there you are!”, “how are the kids/grandkids?”, “I missed you this last hour! Thought maybe you got lost since you weren’t here immediately” and not least “Come, let me give you that hug I promised!” Ten minutes later everybody will be organised by the large Polish group for some gathering or fun – and the rest of us are trying to find out how we can get one of the cool group-t-shirts the Łodz-group have concocted this year. Or maybe we should rather go for one of the other cool t-shirts picturing amphipods?

We do talk amphipods, of course. The incredible variety of the group (of animals – as well as people) opens up for a wide spectre of research-questions and approaches, and meetings allow time to learn from each other, get inspired, start new collaborations and share samples and ideas.

Most important: the science of amphipods. Loads of interesting talks and posters! (all photos: AH Tandberg)

Most important: the science of amphipods. Loads of interesting talks and posters! (all photos: AH Tandberg)

 

Those getting to the poster-session fast enough win the crochet amphipods... (photo: AH Tandberg)

Those getting to the poster-session fast enough win the crochet amphipods… (photo: AH Tandberg)

This years ICA was held in Trapani, Sicily – where prof Sabrina LoBrutto on a short one year notice had organised the meeting. The three days we met were packed with more than 60 talks, more than 60 posters and loads and loads of happy amphidologists. With the University situated right across the road from the beach, and a lunch hour long enough for both a coffee and a swim/sample search the friendly atmosphere stretched to drying towels on the railings of the university-hall and sea-salted hairstyles for many after lunch.

Keeping the atmosphere friendly: Beach, coffee and icecreams (all photos: AH Tandberg)

Keeping the atmosphere friendly: Beach, coffee and icecreams (all photos: AH Tandberg)

 

The scientifically helpful Japanese amphipod t-shirt. (now the rest of you should notice the morphological differences between the families). (photo: AH Tandberg)

The scientifically helpful Japanese amphipod t-shirt. (now the rest of you should notice the morphological differences between the families). (photo: AH Tandberg)

We always try to publish the Amphipod Newsletter to coincide with the ICA. You can download the newsletter both from the World Amphipoda Database and the Biodiversity Heritage Library (both places also have back-issues available for downloads). One of the features of the newsletter is a bibliography of amphipod-related literature, and a list of new taxa. Since last AN we have 79 new species, 14 new genera and 12 new families! Every AN includes an interview with one of the amphipodologists – this year you can get to know Wolfgang Zeidler and his Hyperiidea better.

The next ICA? In two years we meet in Dijon, France! I am already excited – and maybe there will be mustard-coloured t-shirts in honour of the location (or burgundy-coloured t-shirts)?  What I know already, is that it is going to be like meeting family.

Anne Helene

AmphipodThursday: IceAGE-amphipods in the Polish woods

img_2610This adventure started 26 years ago, when two Norwegian benthos researchers (Torleiv Brattegard from University of Bergen and Jon-Arne Sneli from the University in Trondheim) teamed up with three Icelandic benthos specialists (Jörundur Svavarsson and Guðmundur V. Helgasson from University of Iceland and Guðmundur Guðmundsson from the Natural History Museum of Iceland) to study the seas surrounding the volcanic home of the Nordic sages. 19 cruises and 13 years later – and not least lots of exciting scientific findings and results the BioICE program was finished.

But science never stops. New methods are developed and old methods are improved – and the samples that were stored in formalin during the BioICE project can not be used easily for any genetic studies. They are, however, very good for examinations of the morphology of the many invertebrate species that were collected, and they are still a source of much interesting science.

Participants of the IceAGE workshop. Photo: Christian Bomholt (www.instagram.com/mcb_pictures)

Participants of the IceAGE workshop. Photo: Christian Bomholt (www.instagram.com/mcb_pictures)

The dream about samples that could be DNA-barcoded (and possibly examined further with molecular methods) lead to a new project being formed – IceAGE. A large inernational collaboration of scientists organised by researchers from the University of Hamburg (and still including researchers from both the University of Iceland and the University of Bergen) have been on two cruises (2011 and 2013) so far – and there is already lots of material to look at!


This week many of the researchers connected with the IceAGE project have gathered in Spała in Poland – at a researchstation in woods that are rumoured to be inhabited by bison and beavers (we didn´t see any, but we have seen the results of the beavers work). Some of us have discussed theories and technical stuff for the papers and reports that are to come from the project, and then there are “the coolest gang” – the amphipodologists. 10 scientists of this special “species” have gathered in two small labs in the field-station, and we have sorted and identified amphipods into the wee hours.

It is both fun and educational to work together. Everybody have their special families they like best, and little tricks to identify the difficult taxa, and so there is always somebody to ask when you don´t find out what you are looking at. Between the stories about amphipod-friends and old times we have friendly fights about who can eat the most chocolate, and we build dreams about the perfect amphipodologist holiday. Every now and then somebody will say “come look at this amazing amphipod I have under my scope now!” – we have all been treated to species we have never seen before, but maybe read about. We also have a box of those special amphipods – the “possibly a new species”- tubes. When there is a nice sample to examine, you might hear one of the amphipodologist hum a happy song, and when the sample is all amphipods but no legs or antennae (this can happen to samples stored in ethanol – they become brittle) you might hear frustrated “hrmpfing” before the chocolate is raided.

 

Isopodologists (Martina and Jörundur) visiting the amphipodologists... Photo: AH Tandberg

Isopodologists (Martina and Jörundur) visiting the amphipodologists… Photo: AH Tandberg

The samples from IceAGE are all stored in ethanol. This is done to preserve the DNA for molecular studies – studies that can give us new and exciting results to questions we have thought about for a long time, and to questions we maybe didn´t even know we needed asking. We can test if what looks like the same species really is the same species, and we can find out more about the biogeography of the different species and communities.

The geographical area covered by IceAGE borders to the geographical area covered by NorAmph and NorBOL, and it makes great sense to collaborate. This summer we will start with comparing DNA-barcodes of amphipods from the family Eusiridae from IceAGE and NorAmph. They are as good a starting-point as any, and they are beautiful (Eusirus holmii was described in the norwegian blog last summer).


Happy easter from all the amphiods and amphipodologists!

Anne Helene


Literature:

Brix S (2014) The IceAGE project – a follow up of BIOICE. Polish Polar Research 35, 1-10

Dauvin J−C, Alizier S, Weppe A, Guðmundsson G (2012) Diversity and zoogeography of Ice−
landic deep−sea Ampeliscidae (Crustacea: Amphipoda). Deep Sea Research Part I: 68: 12–23.

Svavarsson J (1994) Rannsóknir á hryggleysingjum botns umhverfis Ísland. Íslendingar og hafiđ.
Vísindafélag Íslendinga, Ráđstefnurit 4: 59–74.
Svavarsson J, Strömberg J−O,  Brattegard T (1993) The deep−sea asellote (Isopoda,
Crustacea) fauna of the Northern Seas: species composition, distributional patterns and origin. Journal of Biogeography 20: 537–555.

Door #22 A jolly, happy family?

Musculus discors hidden in Securiflustra securifrons. Photo: AHS Tandberg

Musculus discors hidden in Securiflustra securifrons. Photo: AHS Tandberg

At first glance, it can look like a seaweed. The depth, however, should start your alarm-bells for flora and point you towards fauna: the plantlike animal Securiflustra securifrons (Pallas, 1766) is a bryozoa – a collection of colonial filterfeeders less than 1 mm in size each. We are at 80-120 m depth in the cold Heleysundet – the sound between the two islands Spitsbergen and Barents Island in the eastern part of the Svalbard Archipelago. This is a sound famous among captains for its fast tidal streams, and the fast-flowing waters give the bryozoans a nice place to live. The colonies branch out to catch the most water-flow and the most food from the water.

Musculus discors. Photo: AHS Tandberg

Musculus discors. Photo: AHS Tandberg

Where the “branches”  form we see what might look like small hairy balls – these are the bivalve Musculus discors (L., 1767). The hairy look comes from their byssus threads – they produce and then use these threads to attach to the Securiflustra (and being packed in the threads they might get some camouflage from them).

 

Moving inside the molluscs we might find not only one, but two species of amphipods. In our samples from Heleysundet 14% of the Musculus had the carnivorous amphipod Anonyx nugax Ohlin, 1895 inside, and an astonishing 3 out of 4 Musculus had amphipods of the species Metopa glacialis (Krøyer, 1842) inside.  The system resembles a Russian doll – one species living inside another living inside yet another…

Anonyx affinis (large amphipod, upper left) and Metopa glacialis (small amphipod lower half og mussel) innside a Musculus discors. Photo: AHS Tandberg

Anonyx affinis (large amphipod, upper left) and Metopa glacialis (small amphipod lower half og mussel) innside a Musculus discors. Photo: AHS Tandberg

What reason can a small crustacean have to live inside the quite closed off world of a bivalve? The bivalve filters water actively – it pumps water over its gills, and then transports food-particles such as phytoplankton down the gills towards its mouth. Non-desirable particles are normally packed into mucus and transported out of the bivalve. Now imagine liking to eat some of those particles the bivalve finds non-desirable, and being placed on the gills of said bivalve. No need to hunt for the food – it will be coming on the conveyor-belt the gills are – and all you need to do is to eat. The bivalve does not seem to be troubled by this co-habitant – it does not eat the same food as the bivalve.

Not only does Musculus discors provide Metopa glacialis with food, the mantle cavity provides a luxury-shelter where the amphipod can raise a family! Amphipods, together with isopods, cumaceans, tanaidaeans and quite a few mysicadeans keep their offspring in a brood-pouch from the fertilisation of the eggs to the medium sized juveniles crawl out into the real world. Living inside a bivalve allows Metopa glacials to extend its child-care to young life outside the brood-pouch. Our examinations of the bivalves from Heleysundet showed us adult Metopa in the middle of the bivalve, with several juveniles “strategically placed” inbetween the two layers of gills in each shell-half. Surrounded by food, safe from most predators! (Predation of Metopa glacialis might be the main objective for Anonyx affinis, the food-source of the lysianassid needs to be established. It might also be the nice and fatty mollusk.)

 

Metopa glacialis innside a Musculus discors. Small arrows point to juveniles, large arrow to adult female. Photo: AHS Tandberg

Metopa glacialis innside a Musculus discors. Small arrows point to juveniles, large arrow to adult female. Photo: AHS Tandberg

Comparing with amphipods of the same size-range from the same areas, Metopa glacialis seems to have a safe life. Safe enough that they can manage to have several sets of offspring. We see that they don´t wait until´the first batch of kids are out of the “house” – we found one adult female with two size-groups of offspring and a fresh egg-filled brood-pouch!  Each batch can be 20 offspring, so that would mean one pregnant mom and 40 kids in one small house!

 

Many people travel to visit family during the holidays. Even when we cherish the time with our loved ones, filling the house with grandparents, aunts, uncles and cousins might cramp everybodys style slightly. Not so with Metopa glacialis. Measuring the size of all inhabitants show us that the kids stay home until they are adult and can move out to their own home. So when you can´t sleep because your younger cousin plays on her gamer all night, or because your old aunt snores when you come into your shared room, think how much more difficult life could have been if you were an amphipod. Happy holidays!

Anne Helene

PS: A slightly extended version in Norwegian (part of the TangloppeTorsdag blog) can be read here)


Literature:

Just J (1983) Anonyx affinis (Crust., Amphipoda: Lysianassidae), commensal in the bivalve Musculus laevigatus, with notes on Metopa glacialis (Amphipoda: Stenothoidae). Astarte 12, 69-74

Tandberg AHS, Schander C, Pleijel F (2010) First record of the association between the amphipod Metopa alderii and the bivalve Musculus. Marine Biodiversity Records 3:e5 doi:10.1017/S1755267209991102

Tandberg AHS, Vader W, Berge J (2010) Studies on the association of Metopa glacialis (Amphipoda, Crustacea) and Musculus discors (Mollusca, Mytilidae). Polar Biology 33, 1407-1418

Vader W, Beehler CL (1983) Metopa glacialis (Amphipoda, Stenothoidae) in the Barents and Beaufort Seas, and its association with the lamellibranchs Musculus niger and M. discors s. l. Astarte 12:57–61

Door #15 Twinkle, twinkle, little animal?

Yesterdays door of this calendar introduced the bioluminescent animals of the deep sea.
In the parts of the ocean where sunlight reaches (the photic zone), production of ones own light is not common. This is because it is costly (energetically), and when the surroundings already are light, the effect is almost inexistent. An exception to this is the use of counter-illumination that some animals have: lights that when seen from underneath the animal camouflages them against the downwelling light from above.

But what then with the ocean during the polar night? Last Thursdays blog told the story of the dark upper waters during the constant dark of the arctic winter, and how the quite scanty light of the moon is enough to initiate vertical mass movements. Another thing we see in the dark ocean is that processes that at other latitudes are limited to the deep sea come up nearly to the surface during the polar night.

So – in the Arctic winter we don´t have to use robots and remote cameras to observe biioluminescent animals: we can often observe them using normal sport diving equipment or even from above the surface. A very recent study (Cronin et al, 2016) has measured the light from different communities in the Kongsfjord of Svalbard during the polar night. They found that going from the surface and down, dinoflagellates produced most light down to 20-40 m depth, the lighting “job” was then in general taken over by small copepods (Metridia longa). Most light was produced around 80 m depth.

Bioluminescent dinoflagellates shining through the winter sea ice in Kongsfjorden. Photo: Geir Johnsen, NTNU

Bioluminescent dinoflagellates shining through the winter sea ice in Kongsfjorden. Photo: Geir Johnsen, NTNU

It is possible to recognise different species from the light they make; a combination of the wavelength, the intensity and the length of the light-production gives a quite precise “thumbprint”. If we know the possible players of the system in addition, an instrument registering light will also be able to give us information about who blinks most often, at what depths, etc. Cronin and her coauthors have made a map of the lightmakers in the Kongsfjord.

Bioluminescence profiles from Kongsfjord. Figure 3 from Cronin et al, 2016

Bioluminescence profiles from Kongsfjord. Figure 3 from Cronin et al, 2016

This is all well and good, but the next question is of course WHY. There can be several uses for light, and we can bulk the different reasons into 3 main groups: Defense, offense and recognition.

Different strategies for Bioluminescence. Fig 7 from Haddock (2010), redrawn for representation of the Polar night bioluminescence by Ola Reibo for the exhibition "Polar Night"

Different strategies for Bioluminescence. Fig 7 from Haddock (2010), redrawn for representation of the Polar night bioluminescence by Ola Reibo for the exhibition “Polar Night”

 

The bioluminescent cloud from an escaping krill. Kongfjorden, during the Arctic polar night. Photo: Geir Johnsen, NTNU

The bioluminescent cloud from an escaping krill. Kongfjorden, during the Arctic polar night. Photo: Geir Johnsen, NTNU

Defence has already been mentioned above: the counterillumination against downwelling light is helping an animal defend itself against predation. Some will leave a smokescreen, or even detach a glowing bodypart while swimming away in the dark, and others blink to startle the enemy or to inform their group-mates that an enemy is getting close.

 

 

Offense is mainly to use the light to get food (this is typical angler-fish-behaviour), and recognition is very often about flirting. Instead of flashing your eyelashes at your your chosen potential partner, you flash some light at him or her…

Thursdays are about amphipods in this blog, so here they come. Bioluminescent amphipods are present mainly in the hyperiid genera Scina (a Norwegian representative of this genus is Scina borealis (Sars, 1883).) Hyperiids are amphipods that swim in the free watermasses, like most other bioluminescent animals.

The bioluminescent amphipod Scina borealis (Sars, 1893). The added stars indicate where the bioluminescence occurs. Original figure: G.O.Sars, 1895.

The bioluminescent amphipod Scina borealis (Sars, 1893). The added stars indicate where the bioluminescence occurs. Original figure: G.O.Sars, 1895.

Crustacea use more different ways to produce bioluminescence than most other groups – this points to a possibility that the use of bioluminescence has evolved several independent times in this group. So the copepod Metridia longa will use a different chemical reaction than the krill, and the amphipods use again (several) different reactions. Some research on the bioluminescence of amphipods was undertaken already in the late 1960s, where P Herring collected several Scina species and kept them alive in tanks. There he exposed them to several luminescence-inducing chemicals and to small electrical shocks, to see where on the body light was produced and in what sort of pattern. He reported that Scina has photocytes (lightproducing cells) on the antennae, on the long 5th “walkinglegs”, and on the urosome and uropods. They would produce a nonrythmical rapid blinking for up to 10 seconds if attacked, and at the same time the animal would go rigid in a “defence-stance” with the back straight, the antennae spread out in front of the head, and the urosome stretched to the back. This definitely seems to be a defence-ligthing, maybe we should even be so bold as to say it would startle a predator?

Anne Helene


Literature:

Cronin HA, Cohen JH, Berge J, Johnsen G, Moline MA (2016) Bioluminescence as an ecological factor during high Arctic polar night. Scientific Reports/Nature 6, article 36374 (DOI: 10.1038/srep36374)

Haddock SHD, Moline MA, Case JF (2010) Bioluminescence in the Sea. Annual Review of Marine Science 2, 443-493

Herring PJ (1981) Studies on bioluminescent marine amphipods. Journal of the Marine biological Association of the United Kingdoms 61, 161-176.

Johnsen G, Candeloro M, Berge J, Moline MA (2014) Glowing in the dark: Discriminating patterns of bioluminescence from different taxa during the Arctic polar night. Polar Biology 37, 707-713.

Door #11 Invertebrately inspired art?

Scientific illustrations today are usually formed within quite strict limits. We use photographs or drawings of small details, and these are all connected to one specific specimen that preferably is to be found in a scientific collection.

But can other approaches also help us? The artist Pippip Ferner has long found her inspiration in nature, and especially the (marine) invertebrates. Maybe her pictures can inspire us to examine other details in our study-animals? Maybe a picture can inspire you to think more about nature, the sea, or invertebrates – their lives and lores? These are not pictures that are meant to be scientifically accurate, but rather fabulations inspired by the wild things that happen when evolution gets to do as it pleases…

Some of Pippis drawings are inspired from scientific drawings, both old and new, some are from animals we have looked at together.

Here are some of Pippips pictures from this year, and the animals that inspired them. These three pictures were chosen to be part of the Evolution and Art section of the international science conference Evolution this summer in Austin, TX.

"Tunicate anatomy" (c) Pippip Ferner

“Tunicate anatomy” (c) Pippip Ferner

Pippip says about this first picture:

“A scientific illustration of a TUNICATE is the inspiration for this work. Tunicates are sort of last stage before vertebrates. Clues for this is found in the larva that has a notochord, comparable to the spine of vertebrates. It has cerebral vesicle equivalent to a vertebrate’s brain, sensory organs that includes an eyespot to detect light and an otolith, which helps the animal orient to the gravity.
Fascinated by the thought of this “slimy blob” having many features similar to humans resulted in this quite complex outcome. The overload of insistent lines has given the tunicate quite a sophisticated system.”

Komodo National Park sea squirt (Polycarpa aurata). Photo: Nick Hobgood (wikipedia)

Komodo National Park sea squirt (Polycarpa aurata). Photo: Nick Hobgood (wikipedia)

On the left is a photo of a live tunicate. This photo is from Indonesia, but tunicates are common to find also in our colder waters. They can be solitary as this one, or colonial – where several tunicates form a colony together by budding, so that one large colony basically has the exact same DNA. Most tunicates are sessile (they sit attached to one place), but some live floating around in the water. The best known of these pelagic tunicates are the salps of the southern oceans.

 

Internal anatomy of a tunicate (Urochordata). Adapted, with permission, from an outline drawing available on BIODIDAC. (Wikipedia)

Internal anatomy of a tunicate (Urochordata). Adapted, with permission, from an outline drawing available on BIODIDAC. (Wikipedia)

A scientific illustration of a tunicate in a Biology textbook will look something like this:

 

 

 

 

 

 

Moving to other invertebrates, Pippip has worked with clams:

"Bivalve anatomy" (c) Pippip Ferner

“Bivalve anatomy” (c) Pippip Ferner

“In this image I question how the clam lives in symbiosis with other species as its shell gets weaker due to climate changes. The drawing might resemble the results of some kind of scientific inquiry with references to the anatomy of a clam (bivalve).
In my work I let my own artistic evolutionary process make the clam into something more abstract.”

(If you wait until door # 22, there might be a story that relates to bivalves that live with others…)

This is a Ctenophore, a comb jelly:

"Comb jelly anatomy" (c) Pippip Ferner

“Comb jelly anatomy” (c) Pippip Ferner

“The starting point of this work was a detailed illustration from biologist Ernst Haeckel’s (Artforms in Nature) of a comb jelly/ctenophorae. The comb jelly differs from other jellyfish with more sophisticated nervous system with both synapses and individual muscle cells.
The outcome of this drawing is a tribute to the beauty of the structure of this organism.”

Jelly fishes anf Comb jelly fishes. Illustration: Ernst Haeckel, Kunstformen der Natur 1904, plate 27

Jelly fishes anf Comb jelly fishes. Illustration: Ernst Haeckel, Kunstformen der Natur 1904, plate 27

Ctenophores are predatory planktonic jellies. The special thing about them, according to our Jelly-specialist Aino, is that they have a rotational symmetry. The diagnostic feature of comb jellies are their comb-rows that they use for swimming. The photos above represent the three groups of comb jellies – all of them are present in Norway.

 

To the right is the Haeckel-picture she started from, and here is a film of Comb jellies from the Chicago Shedd Aquarium.

 

 

 

Pippip, Anne Helene and Aino

 

 

Door #8: the ups and downs of a marine werewolf?

When we think about what drives the ecosystems, much of the initial responsibility is put on the sunlight. This is mainly because of the photosynthesis, and thus the basic pieces of almost all food-webs, but light is also important for the animals. Many animals use visual cues to find food, and whether you search for food or do not want to become food, the presence (or absence) of light will help you.

Themisto sp swims up into the dark night. Photo: Geir Johnsen, NTNU

Themisto sp swims up into the dark night. Photo: Geir Johnsen, NTNU

Seawater is a pretty good stopper of light. We don’t need to dive far down before we are in what we consider a dark place, and less and less light finds its way the deeper we come. We tend to call the depths between 200 and 1000 m “the twilight zone”: most light stops way before 200m and the last straggling lumens give up at 1000m.

Most places on earth has a daily division between a dark and a light period: night and day. This is the ultimate reason for what is often called “the largest motion on earth”: Millions of zooplankton hide out in the darker parts of the water column during the day, and then move up to feed on the plants living in the light-affected parts of the water during the night (when predators will have a hard time seeing them). This daily commute up and down is called Diel Vertical Migration (DVM).

Themisto sp among the many smaller particles. (The light in this picture is from a flash). Photo: Geir Johnsen, NTNU

Themisto sp among the many smaller particles. (The light in this picture is from a flash). Photo: Geir Johnsen, NTNU

But what about the waters north of the polar circle? These areas will for some time during the winter have days when the sun stays under the horizon the entire day – this is “the Dark time” (Mørketid). At higher latitudes, there will be several days, or even weeks or months when the sun is so far below the horizon that not even the slightest sunset-glow is visible at any time. In this region, we have long thought that the Dark time must be a dead or dormant time.

 

The acoustic signals that gave the first indications of LVM. Figure 2 from Last et al 2016.

The acoustic signals that gave the first indications of LVM. Figure 2 from Last et al 2016.

We could not have been more wrong! It turns out that during the polar night, the DVM moves from being on a 24 hr cycle (sunlight-induced), to a 24.8 hour cycle! What is now the driver? The moon !(The lunar day is 24.8 hrs). Another thing that shows us that the moon must give strong enough light that predators can hunt by it, is that every 29.5 days most of the zooplankton sinks down to a depth of 50m: this falls together with the moon being full. Researchers have started to call this LVM (Lunar-day Vertical Migration) to show the difference to the “normal” DVM. There are of course lots of complicated details such as the moons altitude above the horizon and its phase that influences the LVM, but in general we can say that during the polar night (the Very Dark time), the “day” as decided by light has become slightly longer than normal.

The full moon, photographed by the Apollo 11 crew after their visit. Photo: NASA, 1969

The full moon, photographed by the Apollo 11 crew after their visit. Photo: NASA, 1969

Themisto - the werewolf. Note that the whole head is dominated by eyes - this is a visual hunter! Photo: Geir Johnsen, NTNU

Themisto – the werewolf. Note that the whole head is dominated by eyes – this is a visual hunter! Photo: Geir Johnsen, NTNU

Some of the larger animals taking part in the LVM are the amphipods Themisto abyssorum and Themisto libellula. They are hunters – so their reason to migrate up in the water column is not the plants, but the animals eating the plants; their favourite food are copepods of the genus Calanus. These are nice and quite energy-rich small crustaceans that eat the microscopic plants in the upper water column. We have sampled both Themisto-species in the middle of the winter (january), and their guts were filled to the brim with Calanus, so we know that they continue hunting by moon-light. They are such voracious hunters that some researchers have started to call them marine werewolves: the moonlight transforms them from sedate crustaceans to scary killers…

 

But, if they are the hunters, why do they spend so much time in the deep and dark during the lighter parts of the day? The hunters are of course also hunted. Fish such as polar cod (Boreogadus saida),  birds such as little auk (Alle alle) and various seals like to have their fill of the Themisto species. So – life has its ups and downs, and the dance of hunter and hunted continues into the dark polar night…

Anne Helene


Literature:

Berge J, Cottier F, Last KS et al (2009) Diel vertical migration of Arctic zooplankton during the polar night. Biology Letters 5, 69-72.

Berge J, Renaud PE, Darnis G et al (2015) In the dark: A review of ecosystem processes during the Arctic polar night. Progress in Oceanography 139, 258-271.

Kintisch E (2016)  Voyage into darkness. Science 351, 1254-1257

Kraft A, Berge J, Varpe Ø, Falk-Petersen S (2013) Feeding in Arctic darkness: mid-winter diet of the pelagic amphipods Themisto abyssorum and T. libellula. Marine Biology 160, 241-248.

Last KS, Hobbs L, Berge J, Brierley AS, Cottier F (2016) Moonlight Drives Ocean-Scale Mass Vertical Migration of Zooplankton during the Arctic Winter. Current Biology 26, 244-251.