Tag Archives: Amphipoda

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

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.

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

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.

: Ice-floats and more permanent ice. Svalbard. Photo: AHS Tandberg

: A diver gets ready to sample Gammarus wilkitzkii under the sea ice. Photo: AHS Tandberg

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

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

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.

: Tammy and Mike getting ready for action! Photo: AHS Tandberg

: Thoughtful participants. Photo: AHS Tandberg

This 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.

: Amphipodologists waiting for the harbour ferry. Photo: AHS Tandberg

: Sunset in Oostende. Photo: AHS Tandberg

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.

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

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

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

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

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..

Disko amphipod experiment

Saturday 14^th 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.

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 25^th to August 18^th. 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.

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.

Traps “armed” with fresh seal blubber.

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.

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.

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!

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

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))

The Invertebrate Collections

The University Museum of Bergen

Tag Archives: Amphipoda

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

Amphipod-Thursday. WoRMS – (all) about amphipods

Thursday Amphipod — Norwegian Marine Amphipoda

Door #19: The amphipods with the pointed hoods

Door #6: Associated Amphipods

Disko amphipod experiment