Diving into an octocoral world with Naturalis Museum

It is intrinsically born in each and every one of us the curiosity to explore the natural world. As babies, step by step, we start learning how to walk. First at home and then exploring outside: fields, streets, beaches. When names and language come along the first thing we ask after pointing is “what”? We do it again and again until we do learn the names of each object and animal. As complex knowledge is acquired we tend to follow distinct questions like “when”, “why” or “how”? However, these questions can only be answered after we know the main one: What is that? What is there? What was there in the first place? What will be there? We, the explorers of the natural world, can spend a life time just answering the same main question to complete the Encyclopaedia of Life on Earth while being taxonomists*. Therefore, we can keep asking what is that during years and years when identifying animals and describing new species.

For 300 years we have only identified around 10% of the life forms that inhabit our planet. The other 90% are still waiting for a name. Deep underwater, below 200 meters depth, is an inaccessible world full of life that looks and behaves much differently than what we commonly see in our daily environment. Deep-sea exploration started during the 19th and 20th centuries when scientific expeditions went through the oceans of the world to discover that the Azoic hypothesis, which stated that marine life was inexistent below 550 m depth, was wrong. Later on, during the late 20th Century, the Dutch dressed in their diving suits and picked up a few gears to go aboard HNLMS Onversaagd, HNLMS Tydeman and RV Tyro. The CANCAP and Mauritania II projects have explored the southern NE Atlantic Ocean during expeditions that took more than a decade, between 1976 and 1988. CANCAP indicates its researched area: (CAN)arian - (CAP)e Verdean Deep-sea Basin. Several scientific expeditions occurred at the Macaronesian archipelagos of Portugal and Spain: Azores, Madeira, Selvagens and the Canary Islands. Then they followed to Africa visiting the islands of Cape Verde and the west coast of Africa off Morrocos and Mauritania, because many of its islands and seamounts have not been studied before.

Though these adventures in the Atlantic Ocean took place forty years ago, you can still be an explorer of their accomplishments by visiting the picturesque Dutch city of Leiden. At the Naturalis Biodiversity Center, the National Natural History Museum sits with animals collected from the surface and the deep sea during several expeditions. Back in 2016, there was a tower building filled with the natural treasures. Each floor gathers collections of distinct animals. My own favourite group, the octocorals, resides on the 18th floor. Octocorals are animals that build forests underwater. They form colonies of numerous polyps with forms that are similar to trees, mushrooms or even feathers. And those colonies can form habitats for a great variety of other species like fish, echinoderms, etc. My soon to be published results about CANCAP octocorals can be found in Zookeys journal (Sampaio et al. 2019).

When I went on the elevator up and up towards their own Naturalis floor, not were only CANCAP deep sea souvenirs discovered, but there were also some relics of the Challenger expedition the worldwide expedition that marked the basis of modern oceanography. There were also Mediterranean species presenting deep life lessons, Clavularia carpediem. Moreover, I had in my own hands the type of individual species described by Gustav Stiasny which are the unique representatives of these animals from the unknown African deep sea. Each jar had its own mysteries and some have unique life forms not found in any other place.

While passing through the research facilities and going in and out of the collections and laboratories, I could observe the natural curiosity of adults and kids through a big pane of glass. The reverse was also possible. They could observe the passing-by of a scientist or a curator as if looking to a longitudinal cut of a busy anthill. From the scientist’s perspective, this was like a window to the evolution of life on Earth; a beautiful display of animals placed in a big room with vertebrates and invertebrates from the floor to the ceiling. However, this building was soon closed for a major renovation. A new and better museum for the natural heritage of the Netherlands is under construction. It is almost ready so we need to stay tuned in their website: https://www.naturalis.nl/en/practical-info

The new museum is easily found at the Darwinweg 2, relatively close to Leiden Central train station. If the restaurant and museum shop are similar to the old one, I can assure you great meals and nature souvenirs. Just take a quick look on their website to be enchanted with the architecture of the new building where nine exhibition galleries and three learning areas are announced. All visitors will be able to explore “in the museum, in nature and in the classroom.” I am already eager to visit it next October for the Biodiversity Next conference (https://biodiversitynext.org). What about you?

*a biologist that groups organisms into categories, identifies and describes species.


Sampaio Í, Carreiro-Silva M, Freiwald A , Menezes G, Grasshoff M. in press. Natural history collections as a basis for sound biodiversity assessments: Plexauridae (Octocorallia: Holaxonia) of the Naturalis CANCAP and Tyro Mauritania II expeditions Zookeys

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Íris Sampaio

Íris Sampaio is a PhD Candidate to Ocean Sciences, Marine Ecology at MARE & DOP, University of the Azores and Senckenberg am Meer, Wilhelmshaven supervised by Dr. Marina Carreiro-Silva, Prof. Dr. André Freiwald and Dr. Gui Menezes.