Category Archives: sample sorting

Unravelling the diversity of Bivalve Molluscs of Western Africa

Tellina (Oudardia) compressa

Venus verrucosa

The study of the marine invertebrates of West Africa collected during the “Nansen Project” goes on and this year a second workshop was organized with a focus on the taxonomy of bivalves. Nine days of seclusion in our marine station at Espegrend on the surroundings of the city of Bergen allowed for the necessary tranquility to concentrate in the laborious work of sorting through and identifying thousands of specimens collected between Morocco and Angola by the Norwegian research vessel Dr. Fridtjof Nansen.

Abra alba

This year the “Molluscan” team was strengthen with two extra players; Sara Castillo, a PhD student from Spain enrolled at the University of Vigo and working on the marine fauna of Mauritania and Rudo von Cosel from the Paris Museum of Natural History a recognized authority on the taxonomy of bivalve molluscs.

Aequipecten flabellum

Atrina chautardi

Corbula cadenati

During last year workshop we have implemented a successful “conveyor-belt operation” where each of us was responsible for a specific task (identification, labelling, databasing, imaging, barcoding, etc.). The samples were first organized by morphotypes and then passed into the hands and eyes of our taxonomic experts; a new label with a museum voucher number, species name, locality, etc., was added, and the samples were then databased, photographed, and some selected for DNA barcoding. In parallel several invited participants received training in the various technical and scientific aspects of this operation.

Cuspidaria cuspidata

Falsolucinoma leloeuffi

This year we have again implemented the same successful strategy; Lena Ohnheiser (University Museum of Bergen) was responsible for the database, labelling, and “in between” automontage imaging, Rudo von Cosel, José Pedro Borges (Portuguese Institute of Malacology), Kouakou Kouadio (University of Nangui Abrogoua, Côte d’Ivoire), Sidi Moctar (Institut Mauritanien de Recherches Océanographiques et des Pêches), and Sara Castillo for the taxonomic identification, and the author of these lines was the responsible for general imaging of the specimens and overall coordination of the team-work. In parallel Trond Oskars (a PhD student at the University Museum of Bergen) and Endre Willassen (PI of the Marine Invertebrates of Western Africa project) have worked on the preparation of 95 samples for DNA barcoding.

Gari fervensis

Laevicardium senegalensis

Noetiella congoensis

Our colleague Rudo von Cosel has been working for more than 10 years on a comprehensive book about the bivalves from tropical western Africa.

Rudo brought the proofs of his book to the workshop and we can proudly claim to have been the first ones to have ever seen his book assembled! The species illustrations and descriptions were bind together by families and used as identification tools during the workshop. At the end of the week we have databased over 800 lots and identified approximately 125 species. It was very rewarding to realize that our joint effort rendered many new geographical records contributing to better understand the distribution of species and biogeographic processes along the coast of West Africa.

We are very thankful to all participants in the workshop; to all those mentioned along these lines and those who were not but were nonetheless crucial for the success of this very productive week helping with various technical and logistic aspects, contributing to the good atmosphere, and very important keeping everybody “bellies” happy with great demonstrations of cuisine masterskills!

Sinupharus bernardi

-Manuel

Pictures!

People are hard at work from early morning to late at night, and the amount of finished material is steadily increasing. We did lure our guests out on a little boat trip yesterday, which was very nice. Below are some photos of work in progress: discussions in the lab, identification work, drilling through mollusc shell to get to the tissue inside, piles of material and labels, and some snapshots of general life at the workshop.

Biodiversity in a dish

One of my (non-marine) colleagues asked me what I was planning on doing with the cartload of samples I was hauling into the lab – so I decided to write a little here, explaining what it is we do when we sort the samples.

R/V Dr Fridtjof Nansen

The first step is of course to aquire said samples. Ours have been collected from the West African continental shelf in agreement with the Guinea Current (GCLME) and Canary Current (CCLME) Large Marine Ecosystem projects.

The sampling has been done by the R/V Dr. Fridjof Nansen.

At present we house samples collected from close to 650 stations along the West African coast.

You will find all the stations and their associated metatdata in this interactive map – here’s a static version of the same:

Stations

Once the samples have arrived at the University Museum, we begin the laborious process of identifying the fauna within. The first step is – rather obviously – to separate the animals from the sediment. Whilst doing this, we also do a rough sorting of the animals to what we call the main groups: Echinoderms, Crustaceans, Polychaeta, Mollusca and so on.

Below are some pictures from the processing of a sample collected by use of a sledge at 106 m depth in the waters of Senegal in 2011.

$A 1 l container of decanted (= the most animal rich part of the sample) sample - from the same station we will have several bottles with different fractions of sample (decanted, 1 mm, 5 mm,...). Large or particularly conspicuos animals are picked out separately whilst processing the samples on board.$

A 1 liter container of decanted (= the most animal rich part of the sample) sample – from the same station we will have several bottles with different fractions (decanted, 1 mm, 5 mm,…). Large or particularly conspicuos animals are picked out separately whilst processing the samples on board.

Sorting using a dissecting microscope

A petri dish with two tea spoons worth of unsorted sample collected by sled (this is from a decanted fraction, though – not all containers will be this intensely populated!)

Zooming in..my, that’s a lot of animals!

At a glance..Ostracoda, Galatheidae, a Ebalia (the pink crab), isopods, amphipods and a lot of polychaeta.

Once the animals have been sorted to the main groups, they are passed on to the taxonomists, who will (do their best to) identify them to species. This is done to learn more about the rich species diversity of this region, and to compare it with the northern fauna. Some of the identified animals will be used as DNA barcode vouchers, helping us build a library of the genetic barcodes* of the marine invertebrates of western Africa.

*within the framework of the Barcode of Life Data Systems; “BOLD”

Snapshots

We’re nearing the end of our two weeks here at the research station, but work is still continuing at full speed. Below are some snapshots from life in the lab.

Science in action

Sorting the snails

Mollusca sorted for species identification

When samples are sorted to main groups of taxa, individuals can also be separated into “morphotypes” based on their general appearence, Morphotypes may or may not correspond to species and this has to be decided by more thorough examination for species identification.