Tag Archives: Amphipoda

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 #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 #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.

Door #1 Gammarus wilkitzkii – closer than Santa to the North Pole?

We greet December with our 2016 edition of the invertebrate advent calendar, and will be posting a new blog post here every day from today until the 24th of December! Be sure to check in often! All posts of this year’s calendar will be collected here: 2016 calendar, and all of the post in last year’s event are gathered here in case you would like a recap: 2015 edition. First out is Anne Helene and a Northern amphipod:

December is over us, the Advent Calendar from the invertebrate section lets you open the first door today, and many children (both small and slightly older) are eagerly awaiting the answer to their letter to Santa Claus. Mr Claus is supposed to live on the North Pole, and many letters addressed there have been coming through different post-offices the last months.

Many of us are wondering if Santa Claus might be a Species dubius (a species it is slightly doubtful exists), but if he exists, his homestead is becoming endangered. We are seeing a rapid decline of the Arctic sea ice (here is a video from NOAA showing the extent and age of the icecap from 1987 to 2014), and this will undoubtedly have a large effect on the Earths climate.

A polar bear mother and cub walking on the top of the sea ice. Photo: AHS Tandberg

A polar bear mother and cub walking on the top of the sea ice. Photo: AHS Tandberg

In addition to the theoretical possibility of Santa, there are several true and precious species that depend on the sea ice for their life. Most probably think about polar bears and seals now, but there is an even more teeming abundance of life right under the ice, many of them live as the sea ice is an upside-down seafloor. The largest animal biomass of all the many invertebrate species connected to the sea ice (we call these sympagic species), comes form the amphipod Gammarus wilkitzkii Birula 1897.

Gammarus wilkitzkii is the largest of the invertebrates that hang out (literally) under the ice; they can reach almost 3 cm length. They are whitish-grey, with red-striped, long legs. The hind legs have hooks that allow them to easily attach to the sea ice, and hanging directly under the ice instead of swimming saves a lot of energy for them. This behaviour is so necessary to them that if we keep them in an aquarium, they need something to hang on to – be it the oxygen-pump, a piece of styrofoam, the hand of a researcher or the edge of the lid. There are a few observations of swimming G. wilkitzkii sampled from the middle of the water-column, but this seems to be specimens that have lost their hold in life – we do not think they can live long swimming around (that would take too much energy).

A male (white) Gammarus wilkitzkii holding a female (yellow) Gammarus wilkitzkii. The male is also holding on to the sea-ice with his hind legs. Photo: Bjørn Gulliksen, University of Tromsø and UNIS.

A male (white) Gammarus wilkitzkii holding a female (yellow) Gammarus wilkitzkii. The male is also holding on to the sea-ice with his hind legs. Photo: Bjørn Gulliksen, University of Tromsø and UNIS.

Being such large animals, and in such large abundance, G. wilkitzkii are preyed upon mostly by diving sea-birds, but they have also been found in the stomach-content of harp-seals and to a small degree the small and stealthy polar cod. Most of these animals are mainly found in what we call the marginal ice zone – where the sea ice meets the open water. This is also the place where G. wilkitzkii can find most of its own food: algae, other small invertebrates and ice-bound detritus.

A diver under the sea ice. Photo: Geir Johnsen, NTNU

A diver under the sea ice. Photo: Geir Johnsen, NTNU

G. wilkitzkii is also found in great quantities under the multi-year ice, where it probably leads a safer life. Being at the edge of the ice presents a problem: this is the ice that melts during the summer, and that will force the amphipods to move further into the ice as its habitats disappear. The underside of the ice is not a flat field – it is a labyrinth of upside-down mountains and valleys, with several small and large caves. Many nice hiding-places, but if you swim or crawl along the ice-surface, the distance is longer than we would measure it on the top of the ice.

Where the ice is thin, or where there is no snow covering the ice, some light will shine through. This means that the edge of the ice normally lets a lot more light through than the multi-year ice. We dont know what this does for G. wilkitzkii, but they have eyes that are of similar size and shape as the other species in the genus, so they possibly use their eyes for hunting for food or checking for enemies.


G. wilkitzkii is an animal that is accustomed to a tough life. The sea temperature right under the ice normally lies around -1.8ºC, (so below what we think of as “freezing”) this is because of the high salinity of the water. As sea-water freezes, the salt leaks out, and flows in tiny brine-rivers trough the ice and down into the water below.  They have specialised their life cycle to fit with the available food – so that their young are released when there is much food to be found, and they can live up to 6 years reproducing once every of the last 5 years, probably to make sure at least some of their offspring survive.

We have 24 more days before we find out if Santa “exists”, though this might not give us the answer to him having become a climate-refugee. Hopefully, we will have to wait much longer to find out what will happen with the many ice-dependent invertebrates, but becoming climate-refugees might not be easily accomplished for them.

Anne Helene


Literature:

Arndt C, Lønne OJ (2002) Transport of bioenergy by large scale arctic ice drift. Ice in the environment – Proceedings of the 16th IAHR International Symposium on Ice, Dunedin , NZ. p103-111.

Gulliksen B, Lønne OJ (1991) Sea ice macrofauna in the antarctic and the Arctic. Journal of Marine Systems 2, 53-61.

Lønne OJ, Gulliksen B (1991) Sympagic macro-fauna from multiyear sea-ice near Svalbard. Polar Biology 11, 471-477.

Werner I, Auel H, Garrity C, Hagen W (1999) Pelagic occurence of the sympagic amphipod Gammarus wilkitzkii in ice-free waters of the Greenland Sea – dead end or part of life-cycle? Polar Biology 22, 55-60.

Weslawski JM, Legezinska J (2002) Life cycles of some Arctic amphipods. Polish Polar Resarch 23, 2-53.

Amphipod-Thursday. WoRMS – (all) about amphipods

It is a sad fact, but a fact nonetheless. Most biologists are not taxonomists. Even so – the work many biologists do is based on knowing the species studied, and knowing the correct name is part of that important knowledge.

Screenshot from WoRMS-search: Andaniopsis lupus

Screenshot from WoRMS-search: Andaniopsis lupus

But how do we know what names are valid, and what species have been formally described within a group? Taxonomic revisions tend to have name-changes as a result, and new species are described all the time – for amphipods an average of 140 species new to science are described yearly…

Screenshot from World Amphipoda Database

Screenshot from World Amphipoda Database

This is where databases will be your best friend! For marine species, the World Record of Marine Species, WoRMS, database is used widely, with more than 200 000 visits every month. Here you can find not only current accepted names, but also information about synonymised names, taxonomic literature, and for some species information about distribution, ecological traits and links to other resources. The data have all been checked and edited by a world-wide team of taxonomic and thematic editors – all responsible for their special groups of organisms.


IMG_9037This week, 22 of the 34 taxonomic editors of the World Amphipoda Database, feeding WoRMS with all Amphipod-related information, gathered at the Flanders Marine Institute in Oostende, Belgium to learn about how to best edit the information about Amphipods. It was two days full of information about the database, but also of hands-on training and with the help of the nice people in the Data Management Team of WoRMS, we managed to get quite a lot of information added and edited on the database. Needless to say, with more than 9000 amphipod species accepted (and several of them with earlier names or alternate representations), we have not completely finished yet. The work on editing a database is continuous – and we have plans for adding more info for each species, including type-information, ecological information and links to identification keys.


The second best thing about going to workshops (the first being all the exciting new things we learn), is that we get to spend time with colleagues from far away. The people working on amphipods are in many ways my extended family – this is at least how it feels whenever we meet. News about both amphipods and life in general are exchanged, possible new projects are planned, and friendships continue to be reinforced over cups of coffee, early breakfasts and late dinners. And every time we leave each other, there is a hope that our next meeting might not be too far away.  My colleagues from Poland call this “the Amphipoda way of life”  – and this friendly, collaborate life is a good life to have as a researcher.

AHT_8164

Participants at the workshop. Photo: AHS Tandberg (with help from ? at VLIZ)

Anne Helene


Citations:

Horton, T.; Lowry, J.; De Broyer, C.; Bellan-Santini, D.; Coleman, C. O.; Daneliya, M.; Dauvin, J-C.; Fišer, C.; Gasca, R.; Grabowski, M.; Guerra-García, J. M.; Hendrycks, E.; Holsinger, J.; Hughes, L.; Jaume, D.; Jazdzewski, K.; Just, J.; Kamaltynov, R. M.; Kim, Y.-H.; King, R.; Krapp-Schickel, T.; LeCroy, S.; Lörz, A.-N.; Senna, A. R.; Serejo, C.; Sket, B.; Tandberg, A.H.; Thomas, J.; Thurston, M.; Vader, W.; Väinölä, R.; Vonk, R.; White, K.; Zeidler, W. (2016) World Amphipoda Database. Accessed at http://www.marinespecies.org/amphipoda on 2016-04-07

WoRMS-info on workshop: http://www.marinespecies.org/news.php?p=show&id=4531

Thursday Amphipod — Norwegian Marine Amphipoda

Amphipoda is an order of mainly small crustaceans living in the ocean, in lakes and rivers, in caves and in moist soil. They can be found worldwide, and the last count in the marine speciesdatabase WoRMS gives about 9 800 valid species. Most of the amphipod species are marine, with again most species connected to the sea-floor (benthic) – even if one of the suborders entirely lives in the watercolumn (pelagic).

The Norwegian Species-name List includes 561 amphipods in Norway, and the most recent listing of amphipods in the North-East Atlantic includes 850 species (Vader, 2007). How many amphipod species that do live in Norwegian waters is probably somewhere between these two numbers.

A collection of Norwegian Amphipoda. Photo: Katrine Kongshavn

A collection of Norwegian Amphipoda. Photo: Katrine Kongshavn

The Norwegian Species Initiative funded project “Norwegian Marine Amphipoda” (NorAmph) starting these days at the Universitymuseum has as one of its objectives to produce a better overview of what species are present in Norwegian marine waters. Utilising material from large projects such as MAREANO and GeoBio, from field-cruises with UNIS and not least the wonderful wealth of the Natural History Collections of the Universitymuseum of Bergen we hope to be able to give an answer to the question.

When a new species of any animal is described, it is mostly done on the basis of its morphology (how it looks). Lately we also add information about a small and species-specific part of the DNA, but for most species this is informations we don´t have yet. The project Barcode of Life aims to map this small part of every species´ DNA  as a tool for later identification – like the barcodes that are used in shops. Norway is participating in this project through the national node NorBOL – and another of the objectives of the NorAmph project is to try to DNA-barcode as many of the norwegian marine amphipod-species as possible. You can read more about the NorBOL work at our invertebrate lab here at her museum here.

One very important part of the NorAmph project is to present the amphipods to all you not working on this fascinating group. Maybe you played with sandhoppers during a beach-holiday, or hunted for sideswimmers under the cobbles on a rocky shore? You might even have been flyfishing with a “Gammarus”-fly? Follow our “TangloppeTorsdag” (in Norwegian) or ThursdayAmphipod (in English) tag. Everything we post under this project will be collected under the category “NorAmph”.

Anne Helene

Literature:
Vader, W. 2007 A checklist of the Marine Amphipoda of the North-East Atlantic and Norwegian Arctic. Published on Tromsø Amphipod Webpage

Door #19: The amphipods with the pointed hoods

Unravelling the mysteries of Amphipods

Unravelling the mysteries of Amphipods

This last week Ania and Anne Helene have been filling the lab with details about antennae, epimeral plates and hairs (setae) on all appendages imaginable and unimaginable. The first dive into the west-African amphipods has been made, and we chose to focus on a family that is easily distinguished from the rest of the amphipoda: the Phoxocephalidae.

This family was first described by G.O. Sars in 1891, and in the northern Atlantic it is a friendly group to examine – it does not have too many species. On a world-basis, however, there are 369 species of Phoxocephalide described, within 80 genera (as of dec 14 2015). The whole groups is easily recognized by their “pointed hoods” – the head is drawn forwards just like a hood that is pulled as far to the front as it goes.

 

Ania has much of her previous experience from the Antarctic and Anne Helene has worked in the Arctic, so west-African waters seemed a good place to meet – if not literally then thematically. Being physically in the same lab is probably the best way to collaborate on examining small animals, and we had a week of long and happy days in the lab.

A Basuto stimpsoni from Guinea Bissau. Photo A.H. Tandberg

A Basuto stimpsoni from Guinea Bissau. Photo A.H. Tandberg

Why did we think the Phoxocephalidae would be a good starting point for examining the amphipod-fauna of the West-African waters? There were moments during the last week we asked ourselves this question. There are some reasons, though. To be able to identify species of amphipods you normally have to examine a collection of characters such as the antennae, sections of the different legs (Amphipods do have a lot of legs!) and the different sideplates (for example the epimeral plates).

In difference with many other amphipod groups the Phoxocephalids do not have a lot of appendages that are sticking far out of the main body, so there are not so many pieces that break off ethanol-preserved specimens – and that gives us a bit easier job.

But there are not many studies of the smaller crustaceans from these waters previously, so we were not expecting to be able to put names on much of what we were looking at. This prediction proved true – we have found one already named species (Basuto stimpsoni Stebbing, 1908) in all our samples. In addition to this we have found what we think are 27 other species – but we do not have a name for most of them. For many we don´t even have a genus name.

How will we continue with this group? The first step is to see if our 28 putative species really are different – for this we will first map their DNA barcode (COI). Depending on what results this gives us, we will be able to see how many new species we end up with.

There is definitely more to come from this study, and we promise to write about it when we know more (that will, however, not be in this advent calendar)…

-Ania and Anne Helene

Door #6: Associated Amphipods

Amphipods are a group of small crustaceans where most of the species we know are benthic (bottom dwelling) and marine. But within the benthic habitat there are many niches, and one of the more intriguing is the many ways of living on or inside another benthic animal. A few species become parasitic (feeding on their host), but for the most species living like this, it does not look like eating the host is the main objective. In these cases we term the amphipods as “associated with a host”.

To document some of these associations, I have had a wonderful cooperation with an amazing underwater photographer this year. Lill Haugen has photographed amphipods associated with hydroids, and sampled the amphipods afterwards for us. Documenting this kind of association is almost impossible without the help of divers – if we are lucky enough to sample a hydroid with our normal sampling gear, the amphipods fall off. It is not easy spotting these small animals for a diver either, but Lill says that it becomes easier with practice.

An amphipod family at home. Photo by Lill Haugen, all rights reserved

An amphipod family at home. Photo by Lill Haugen, all rights reserved

This photo is from the Oslofjord, at 25 m depth. With the photos from Lill we are able to say that this particular amphipod (from the family Stenothoidae) looks like it keeps the hydroid as a family home. The parents sit on the “stem” of the hydroid, and their children sit on the tentacles of the “flower”. This might be both to provide extra protection and food for the amphipod-children. The adult amphipods are 5mm long, their children 3mm.

Earlier studies have shown that amphipods of the family Stenothoidae often associate with molluscs – we have found several different species living inside bivalves (shells). Other amphipods might associate with other crustaceans such as crabs, or with sponges, anemones or snails (gastropoda).

For most amphipod species we know nothing about their life-history and possible associations. But the more we examine them, the more we learn..

Suggested reading:

Tandberg, A.H., 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, A.H., 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., Tandberg, A.H. (2013) A survey of amphipods associated with mollusks. Crustaceana 86(7-8), 1038-1049

Vader, W., Tandberg, A.H. (2015) Amphipods as associates of other crustacea: a survey. Journal of Crustacean Biology 35(4), 522-532

-Anne Helene

Photo: AH Tandberg

Disko amphipod experiment

Saturday 14th of September, a day with a handful of events throughout history: Stephen V ends his reign as Catholic pope (891), The Netherlands and England sign a peace treaty (1662) and Walt Disney gets the Medal of Freedom at the White House (1964) to mention a few. Moving towards present day and we find scientist and researcher Anne Helene setting up her traps on an experiment to catch amphipods at the local harbor in Qeqertarsuaq, Greenland.

Photo: AH Tandberg

The amphipod trap team: Daniela, Henning and Anne Helene

With a warming sun and clear sky in the back she is assisted by enthusiastic students Henning and Daniela heading towards the chosen localities for the traps. To understand this experiment a little better we need to go back in time to the happy 90’s.

In 1990 Yves Scailteur and Claude De Broyer examined feeding in amphipods at the Arctic Station, Greenland from July 25th to August 18th. In one of the experiments traps were laid between 80 and 180m depth to catch the temperature and light sensitive amphipod Anonyx makarovi, in another experiment they examined the scavenging amphipods that were present at shallower depths.

Drawing: G.O. Sars

A scavenging amphipod (Onesimus sp.) – what we hoped to find. Drawing by G.O.Sars, 1891

23 years later scientist Anne Helene decided to set up a similar experiment to study scavenging amphipods. She made three homemade amphipod traps consisting of plumber tubes, plankton net, horse clamps and funnels and the result looked like this.

Photo: AH Tandberg

Traps “armed” with fresh seal blubber.

Photo: AH Tandberg

Preparing the blubber – the smell was quite intense… 😉

So on a sunny Saturday afternoon Anne Helene, Daniela and Henning set out to place these infamous traps to gather some amphipods for further examination. For bait the traps were fitted with fresh seal blubber straight from the fish market and a nice good chunk was put in to keep the amphipods well fed. There were chosen two localities for the experiment, the royal dock (actually just a floating dock with a bridge) by the museum of Qeqertarsuaq and at the harbor next to the research vessels docking point. The traps were hung with a solid rope roughly 2m down into the water with different colors to differentiate the two locations when collected; blue rope would indicate the dock and white would be the harbor.

Photo: AH Tandberg    Photo: AH Tandberg

Site 1: “The Royal Dock”                                        Site2: The harbor.

After 24 hours of exposure in the different sites, on a windy Sunday afternoon the three characters went to collect the traps, and to their relief they were still there! The traps were collected and on their way back to the Arctic Station they spotted a sunken ship, sledge dogs and friendly people greeting us as we passed by.

Photo: AH Tandberg

Retrieving the traps

So what was the outcome? Not a single amphipod…. Why? They really don’t know. It could be a number of factors from leaving them for a too short amount of time to feeding the scavenging munchkins something other than delicious seal fat. But wait! The traps weren’t completely empty! There were a couple of polychaetes  (Phyllodoce maculata) gathered around in one of them that seemed to be fascinated by the blubber and the blood. And even if the plan wasn’t to catch polychaetes, a failed attempt doesn’t have to mean that the findings don’t matter. In science we don’t discriminate!

Photo: AH Tandberg    Photo: AH Tandberg

The sampling result: a bucket of worms                  Empty seal blubber pieces and clean net

 

Photo: AH Tandberg

Our sampled species: Phyllodoce maculata (Linnaeus, 1767) with seal blood in the gut.

Written by: Henning (University of Bergen) and the girls (Daniela (Gothenburg University) and Anne Helene (Institute of Marine Research))