Media

August 30th 2024

How a salt giant radically reshaped Mediterranean marine biodiversity

A new study paves the way to understanding biotic recovery after an ecological crisis in the Mediterranean Sea about 5.5 million years ago. An international team led by Konstantina Agiadi from the University of Vienna and with the participation of the curator Danae Thivaiou from Natural History Museum Basel has now been able to quantify how marine biota was impacted by the salinization of the Mediterranean: Only 11 percent of the endemic species survived the crisis, and the biodiversity did not recover for at least another 1.7 million years. The study was just published in the renowned journal Science.

Lithospheric movements throughout Earth history have repeatedly led to the isolation of regional seas from the world ocean and to the massive accumulations of salt. Salt giants of thousands of cubic kilometers have been found by geologists in Europe, Australia, Siberia, the Middle East, and elsewhere. These salt accumulations present valuable natural resources and have been exploited from antiquity until today in mines around the world (e.g. at the Hallstatt mine in Austria or the Khewra Salt Mine in Pakistan).

The Mediterranean salt giant is a kilometer-thick layer of salt beneath the Mediterranean Sea, which was first discovered in the early 1970s. It formed about 5.5 million years ago because of the disconnection from the Atlantic during the Messinian Salinity Crisis. In a study published in the journal Science, an international team of researchers led by Konstantina Agiadi from University of Vienna – comprising 29 scientists from 25 institutes across Europe which also includes Danae Thivaiou from the Natural History Museum Basel – now was able to quantify the loss of biodiversity in the Mediterranean Sea due to the Messinian crisis and the biotic recovery afterwards.

Huge impact on marine biodiversity
After several decades of painstaking research on fossils dated from 12 to 3.6 million years found on land in the peri-Mediterranean countries and in deep-sea sediment cores, the team found that almost 67% of the marine species in the Mediterranean Sea after the crisis were different than those before the crisis. Only 86 of 779 endemic species (living exclusively in the Mediterranean before the crisis) survived the enormous change in living conditions after the separation from the Atlantic. The change in the configuration of the gateways, which led to the formation of the salt giant itself, resulted in abrupt salinity and temperature fluctuations, but also changed the migration pathways of marine organisms, the flow of larvae and plankton and disrupted central processes of the ecosystem. Due to these changes, a large proportion of the Mediterranean inhabitants of that time, such as tropical reef-building corals, died out. After the reconnection to the Atlantic and the invasion of new species like the Great White shark and oceanic dolphins, Mediterranean marine biodiversity presented a novel pattern, with the number of species decreasing from west to east, as it does today.

Recovery took longer than expected
Because peripheral seas like the Mediterranean are important biodiversity hotspots, it was very likely that the formation of salt giants throughout geologic history had a great impact, but it hadn’t been quantified up to now. “Our study now provides the first statistical analysis of such a major ecological crisis”, explains Konstantina Agiadi from the Department of Geology. Furthermore, it also quantifies for the first time the timescales of recovery after a marine environmental crisis, which is actually much longer than expected: “The biodiversity in terms of number of species only recovered after more than 1.7 million years,” says the geoscientist. The methods used in the study also provide a model connecting plate tectonics, the birth and death of the oceans, Salt, and marine Life that could be applied to other regions of the world.

“The results open a bunch of new exciting questions,” states Daniel García-Castellanos from Geosciences Barcelona (CSIC), who is the senior author of this study: “How and where did 11% of the species survive the salinization of the Mediterranean? How did previous, larger salt formations change the ecosystems and the Earth System?” These questions are still to be explored, for instance also within the new Cost Action Network “SaltAges” starting in October, where researchers are invited to explore the social, biological and climatic impacts of salt ages.

Publication
Agiadi et al. (2024) The marine biodiversity impact of the Late Miocene Mediterranean salinity crisis.
Paper Science

July 3rd 2024 (short version)
No more flirting in Natural History Museum Basel

The special exhibition «SEXY - Driving Force of Life» at the Natural History Museum Basel closed its doors on 30 June 2024. Over 60,000 people visited the exhibition. The educational programmes for school classes were particularly popular. A total of 245 school classes used the special exhibition as an extracurricular learning centre. The exhibition was based on objects from the special exhibition «Sexperten» by Liechtensteinisches Landesmuseums as well as Amt für Umwelt Liechtenstein and was further developed by the Basel exhibition team.

Exclusive new Special Exhibition
The international competition for nature photography Wildlife Photographer of the Year celebrates its 60th anniversary this autumn. The Natural History Museum Basel is showing the 100 best nature photographs in the world exclusively in Switzerland. A jury in London will select the 100 most outstanding images from tenthousands submitted photographs and present these award-winning pictures in an exhibition. The Natural History Museum Basel will open this show on Thursday, 7 November 2024 with a public opening. The pictures will be on display until 27 April 2025, and the museum will be holding its own very popular nature photography competition, Snapshot, as an accompanying event.

Apr 2nd 2024 (short version)
Natural History Museum Basel extends exhibition «SEXY - Driving Force of Life»

The special exhibition «SEXY - Driving Force of Life» at the Natural History Museum Basel will be extended and remains on display until Sunday, June 30th, 2024. The topic of reproduction in the animal kingdom is very popular, especially for schoolchildren. The extension makes it possible to offer school classes of all levels additional school workshops and guided tours.
The special exhibition focuses on the question of which strategies animals use in the fight for the object of their desire. It shows that animal behavior, mating types and family models are extremely diverse because of the existence of gender.

Nov 14th 2023
Novartis loans an impressive dinosaur skeleton to the Natural History Museum Basel

The skeleton of an Allosaurus fragilis, which has been on display at the Novartis Campus since 2015, is to be exhibited in the new building of the Natural History Museum Basel in St. Johann. This will bring the skeleton more into the public domain and make it more accessible for scientific research. Until such a time, the skeleton will remain in its current location at the Novartis Campus. Novartis permanently loans the impressive dinosaur skeleton to the museum.

There are new opportunities for collaborative work with the opening of the Novartis Campus and the construction of the new Natural History Museum in the immediate vicinity of Novartis on Vogesenplatz. This will be an striking addition for the museum: The Allosaurus fragilis, a kind of pop star among dinosaurs that has been owned by Novartis for over a decade, is given a new home and moves into the Natural History Museum Basel. In doing so, Novartis makes this rare skeleton more accessible to the world of science and the general public. Novartis is donating the piece to the museum on the basis of a permanent loan. The “relocation” of the skeleton will take place as soon as the new museum is completed and ready for occupancy. Until then, the Allosaurus will remain at the Novartis Campus where it cannot be viewed the public.

A special skeleton
The approximately ten metres long and 2.8 metres high skeleton of an Allosaurus fragilis was found in Wyoming, USA, where it was embedded for millions of years in the well-known Morrison Formation comprising mainly of sandstone. It was discovered near the site where the long-necked dinosaur was excavated, which was acquired by the Natural History Museum Basel in 2019.
The Allosaurus skeleton, presumed to be a female, is around 150 million years old and up to 70% complete.

Predators from the Jurassic period
150 million years ago, 75 million years before the T. rex dinosaur species came on the scene, the Allosaurs were the top of their food chain, the most feared predators. Stegosaurus, young Diplodocids or other dinosaurs were among their favourite prey. The Allosaurus lived in dry, warm climates, often in swampy areas with floodplain forests.

08 Nov 2023
Drives, dances, and dalliances in the animal kingdom

The new special exhibition “SEXY – The Driving Force of Life” at the Natural History Museum Basel is all about reproduction in the animal kingdom. Animals are endowed with various features to win their mate through the art of seduction and/or warfare. There is a whole wealth of different animal behaviour patterns, pairings and family models. But why? Because of the sexes. This exhibition is designed for families and adults. It was inspired by the “Sexperten” exhibition of the Liechtenstein Office for the Environment and then further developed by the Basel exhibition team.

The animal kingdom is vibrant and diverse. Why is this? One reason is the pairing of different sexes in order to reproduce. They are very different in terms of their biological characteristics and interests. Whether it’s in their choice of partner, competition between the sexes, mating or the role of parents, gender differences in animals drive evolution forwards producing a world filled with diversity.

Gender as a pacemaker
The special exhibition “SEXY – The Driving Force of Life” illustrates this diversity and reveals the role gender plays in it. You will discover that: Some animals have two genders, others none and some even have several. There are animals that can change their gender and some that can have two genders at the same time. But they all have one thing in common: they want to reproduce. Through astonishing stories, impressive specimens, and interactive elements, we show the lengths animals will go to to breed. They turn on the charm with their best displays and most splendid plumage. In the survival of the fittest, animals fearlessly fight off the competition with the ultimate aim of becoming attentive parents who watch over their young. But there isn’t a clear pattern to their roles: The animal kingdom is ahead of its time and has always had different family models.

Family exhibition with an in-depth level for adults
This exhibition is exciting for kids and adults. While we grown-ups can marvel at the many different types of pairing and the desires and frustrations of animals’ mating rituals, kids can find out how it feels to grow up protected by a womb, pouch or even ice. We use a variety of young animal specimens to show how they started life and who smoothed their pathway to adulthood.

This exhibition is based on objects and the basic idea of the special exhibition “Sexperten” by Liechtenstein National Museum and Liechtenstein Office for the Environment.

The Clever Clogs Club and other surprise features for an engaging programme
The special exhibition at the Natural History Museum also offers a varied programme of events. In addition to the regular guided tours for adults and families, visitors can enjoy a family Sunday outing or inclusivity offers, or show off their knowledge, no holds barred, in the Clever Clogs Club. This competition is held in front of an audience and the participant with the most convincing and best presented scientific argument scores points.

Thanks to the museum’s cooperation with Basel Zoo, there are two focus tours in dialogue between curators from the zoo and the museum, and another guided tour with an external expert, biologist Daniel Haag-Wackernagel, the “advocate of female desire”. The dancer Armando Braswell is also on hand with his Braswell Arts Center. He invites visitors to dance in a video installation in the exhibition, and delights visitors by performing a dance during the opening event.

After Hours in the Museum
The programme also offers the chance for AFTER HOURS sweet talk once a month from December 2023 to May 2024. Here the special exhibition can be visited free of charge on these evenings until 11 pm. Plus, an exhibition space within the museum is transformed into a lively bar where you can enjoy your evening with some uplifting tunes and in good company.

05. Oct. 2023

Explosion of biodiversity thanks to the recycling of genetic material

What usually takes aeons happened in a relative flash in Lake Victoria: Over 500 new species evolved from three stem species of cichlids in just 16,000 years. A study published in the renowned journal Science, to which David Marques from the Natural History Museum Basel contributed, provides an explanation: This explosion in biodiversity is the result of the existing genetic material being repeatedly reshuffled.

Why do some species in the animal kingdom tend to speciate quickly while others do not? This was the question investigated by a team led by Ole Seehausen and Joana Meier from the Swiss Federal Institute of Aquatic Science and Technology (eawag) and the University of Bern, together with the Natural History Museum Basel. Their work focused on the cichlids of Lake Victoria, which are known for having formed new species the fastest and most extensively. In a recent study published in the scientific journal Science, the research team provide answers to how this could have happened.

It all started with a disaster
Towards the end of the last ice age, around 20,000 years ago, Lake Victoria in East Africa dried up. Only a few isolated wetlands remained from what was once the largest lake in Africa, now a large savannah. When the former lake basin refilled with water 16,000 years ago, its survivors returned: three lineages of cichlids from the lake’s inflows and outflows, as well as from the Great Lakes of the East African Rift. When they repopulated Lake Victoria 16,000 years ago, they interbred. This mixed their genetic material. Again, because their common ancestor was itself a mixture between cichlid species from the upper reaches of the Congo and Nile 350,000 years earlier.

Genetic analysis throws light on what happened
To reconstruct the evolutionary history of cichlids in Lake Victoria, Joana Meier analysed over 460 genomes of East African cichlids for the new Science study. 288 genomes came from 120 species, representing all but one known cichlid genera and ecological roles in Lake Victoria. Genomes of other cichlid species from the African Great Lakes region were also included. The analysis revealed new findings: The vast diversity of species is the result of repeated recycling of genetic material. Lake Victoria’s current biodiversity did not immigrate from other lakes. Instead, it 2 | 2 dates back to the interbreeding of the survivors from the lake’s early day inhabitants 16,000 years ago. As a result of this reshuffling of genetic material found in the three stem species, about 500 new species have formed in this short period of time.

Recombination instead of random mutation
Although all cichlid species in Lake Victoria are closely related, they have become specialists in a wide variety of feeding styles and habitats, and occupy various ecological niches. The repeat fusion and splitting of species played a key role in this process. The mixing of large predators with small plankton feeders, for example, gave rise to a new way of life, that of dwarf predators, which include many species today. “This repeat fusion of species and splitting of species helped them conquer ever new, more extreme ecological niches,” says David Marques from the Natural History Museum Basel and coauthor of the study. Genomic mixing did away with the wait for random, new mutations when adapting to new niches. “So many new, specialist species emerged very quickly,” Marques explains.

Genomic recycling makes it possible
The repeated fusion and splitting (350,000 years ago between the Congo and Nile, by survivors after the dry season 16,000 years ago, and within Lake Victoria since then) explains why this lineage of cichlids became a master of rapid speciation. Not only in Lake Victoria, but also in the nearby African Great Lakes, the majority of fish diversity originates from the genomic recycling among these cichlids.

Publications: Meier, J. I.; McGee, M. D.; Marques, D. A.; Mwaiko, S.; Kishe, M.; Wandera, S.; Neumann, D.; Mrosso, H.; Chapman, L. J.; Chapman, C. A.; Kaufman, L.; Taabu-Munyaho, A.; Wagner, C. E.; Bruggmann, R.; Excoffier, L.; Seehausen, O. (2023) Cycles of fusion and fission enabled rapid parallel adaptive radiations in African cichlids, Science Vol. 381, Issue 6665

Paper Science online