Interviews

Paleoclimate research: Back to the future

Ulrich Kotthoff looks into the past to gain insights for the future. Pollen grains and single-celled organisms from marine and lake deposits, fossil insects and living creatures preserved in amber provide the head of the Museum of Nature - Geology at the LIB with detailed reports on life in past Earth eras such as the Eocene. This allows him to reconstruct past ecosystems and determine past climate changes.

• The Eocene dates back more than 33 million years. How accurately can paleontologists study life so long ago?

From a geoscientist's perspective, the Eocene is not that far back. We therefore have relatively many "shop windows" into that time. These include deep-sea deposits, but also sedimentary rocks from earlier lakes that can be studied through research drilling. The Messel pit near Darmstadt is a good example of such a lake. Large-scale research excavations can also be carried out there.

• What clues do boreholes and excavations give you about the structure of ecosystems at that time?

To stay with the Messel example: In the sedimentary rocks, we researchers can find pollen grains and remains of other plant as well as microorganisms. These allow us to reconstruct the vegetation around the former lake as well as the microflora and fauna within the former water body. Since usually the older deposits are at the bottom, we get an overview of what the flora and fauna looked like at what time. During excavations, we paleontologists can also find larger fossils of plants and animals and thus obtain the comprehensive picture of an ecosystem - from the lurking crocodile and the small prehistoric horse to the vine and the freshwater algae.

• What insights do amber provide you in addition to the fossils from Messel?

In Europe, for example also in Bitterfeld, we have some large amber deposits, which are probably only a little younger than the fossils from Messel. Danilo Harms from the Arachnology Department and I are currently examining these deposits for the arachnids they contain as part of a project. In amber, evidence of larger creatures is rare, but very well preserved smaller animals, plant remains and fungi can be discovered. In addition, amber again contains animals that tend not to be found in lake deposits. So amber represents another important showcase into the ecosystems of the past.

• Why are you studying arachnids in particular?

Some arachnid groups preserved in amber have not yet been studied in detail. Thanks to a cooperation with the German Electron Synchrotron DESY, we now have high-resolution scans that provide us with completely new insights. For example, using these three-dimensional images, we have already been able to identify a family of spiders that was previously only known from the present day - now we know that they already existed in the Eocene. Some arachnids have very specific requirements for ecosystems and climate. Therefore, they can help us to test and, if necessary, optimize climate reconstructions, for example, for the Eocene, and to better understand the development of habitats.

• And what can we now learn from the Eocene with regard to current climate warming?

Paleoclimate researchers arrive at congruent conclusions via very different reconstruction methods: In the Eocene, especially the early Eocene, we had significantly warmer conditions coupled with higher levels of atmospheric CO2 and other greenhouse gases. Sea level was about 50 to 100 meters higher than today. Northern Germany was at least partially covered by the precursor of today's North Sea. We had rather subtropical to tropical conditions here. For example, crocodiles and heat-loving turtles lived in the Messel area. So with the Eocene, we have a possible scenario of how the world might evolve if we are not careful with greenhouse gas emissions. However, it is important to keep in mind that the continents were arranged somewhat differently in the Eocene. In addition, some of the current human-influenced changes are occurring very rapidly.

Ulrich Kotthoff is a paleontologist and director of the Museum of Nature - Geology at LIB.

Exhibition Design: Between Facts and Fantasies

The Eocene is a bygone age that ended about 34 million years ago. How do you bring the nature of this time to life for an exhibition? How do you succeed in astonishing visitors with scientific findings, fossils and fragments? Julia Pawlowski is an exhibition designer and, together with the scientific curators, has given the Eocene exhibition its face.

Julia Pawlowski in an interview:

• How do you bring a long-gone age of the earth to us in the present?

In order to do this, I first had to consciously break with the usual visual habits. Visitors are immersed not only in fossil grays and browns, but also in an extremely colorful world of colors. The exhibition is visually divided into three parts: Blue stands for the cosmic catastrophe of the meteorite impact, without which the Eocene would not have existed at all. Green stands for the diverse jungle world that characterized the landscape in Eocene Germany. Dark red rounds off the exhibition. In this, the large amber inclusions, the "sunstones," come into their own. "Eocene" means new beginning, but it can also stand for "dawn" or "daybreak."

• To what extent does an exhibition help us understand scientific relationships?

Paleontologists have a lot of background knowledge about fossils and the other objects from the Eocene that they can call up and visualize directly in their minds. But when visitors look at a fossil skeleton in a museum, they often lack this contextualization; they might miss the sensation. As a communication designer, I have the task of making as much of this knowledge and the associated research questions visible as possible. Therefore, the exhibition is very rich in images and colorful - in every corner hides an image of a creature from the Eocene. The diversity of living creatures as well as the mosaic-like piecemeal nature of scientific work are symbolized here by photographs or illustrations, for example. The exhibition is thus, in a sense, a visualization of the current state of research.

• What is the arc of tension that leads the most diverse visitors through the exhibition?

Visitors can get to know the world of the Eocene from very different perspectives: While the Jungle Room, like a journey through time, is primarily about the former Messel Lake and the living environment in Eocene Germany, the Amber Room offers the opportunity to take on the perspective of science: How are amber inclusions studied? And what do researchers see when they look into a microscope? For each perspective, exhibits, texts and also visual focal points have been chosen accordingly. In the discovery line, children and their companions are also taken by the hand by our "Forscherchen", a little mascot, and playfully guided through the exhibition.

Julia Pawlowski is a designer with a focus on visual science communication. She works as an exhibition designer, graphic artist and as a consultant for the visual presentation of research.

Knowledge transfer: Creating diverse access points with "Aha!" moments

Conveying knowledge to a diverse audience in a variety of ways is a very important concern for the entire LIB and especially for A. Marie Rahn, Deputy Head of Scientific Education, a very important concern. The department's collaboration on permanent and special exhibitions, the team's wealth of experience, and their diverse didactic offerings ensure that a visit becomes even more of an exciting and lasting experience for different visitor groups and ages.

An interview with A. Marie Rahn:

• There is a "EntdeckerSpur" in the Eocene - what is behind it and who is it for?

In all parts of the exhibition, our "EntdeckerSpur" creates alternative access points to a living world that lies so far back in time that it is difficult for us humans to imagine it today. The separate stations are primarily aimed at families with children - but have something to offer for all ages. Each one stimulates different senses, closer observation and reflection, and also provides an opportunity for cross-generational discussion. Together, we will explore the question of what science can teach us and where its limits lie.

• What other possibilities does the Eocene exhibition offer for conveying knowledge?

The original objects, illustrations and references to the current state of research form an ideal basis for a wide variety of educational formats - depending on the motivation, previous knowledge and interests of our audience. With guided tours, workshops, analog as well as digital additional offers, we can in principle shed more light on all partial aspects and every living being shown, show further connections and include new perspectives in direct exchange - this way it becomes even more lively!

• The special exhibition has only a limited duration - are there also longer-term and supra-regional effects?

With every conception, we learn for and through our audience and expand our offerings. The pandemic experience also underscores our desire to make more details available online, both spatially and temporally unlimited - such as the comic drawn especially for us, which offers a small foretaste. Moreover, this exhibition could not have been created without the cooperation of various sponsors, partners and lenders. We look forward to the always productive exchange in the far-reaching, often long-standing networks behind it in the future as well!

A. Marie Rahn is associate director of science education and visitor management. With over 20 years of experience as a museum educator and exhibition curator, she now communicates LIB's knowledge, research, and collections to the general public.

Biodiversity research: When the end is an evolutionary beginning

After the dinosaurs died out at the end of the Earth's Middle Ages, new species of birds and mammals "conquered" the Earth. Matthias Glaubrecht, professor of animal biodiversity at the University of Hamburg, looks in his book "The End of Evolution. Humans and the Destruction of Species" into an almost equally abrupt end to the heyday of biodiversity. This time, humans are the cause of the species decline through the ongoing destruction of natural habitats.

• Are we in the midst of a mass extinction and is "The End of Evolution" still avertable?

In fact, species extinction began in the second half of the 20th century, largely unnoticed by us. It has been accelerating for two, three or four decades, the more humans we become. For the coming decades, experts expect, on the one hand, two to three billion more people, all of whom will have to be fed and thus increase the pressure on natural habitats. On the other hand, studies by the World Biodiversity Council IPBES predict that up to one million species will become extinct. Only by giving more space to other species and giving it back will this be stopped.

• The dinosaurs became extinct before the Eocene. What has remained of them in evolutionary terms?

The group of dinosaurs was tremendously successful for over 150 million years. They didn't go extinct because their time was up or they were poorly adapted, as is always mistakenly assumed. Most lineages ultimately died out because 66 million years ago the impact of a meteorite destroyed the Earth's habitats. Of the species of that time, only the ancestors of today's birds have survived. These include the Gastornis of the Eocene - a flightless goose relative, as we also show in the exhibition. For a long time, it was assumed to have lived a predatory lifestyle like that of earlier dinosaurs, but it could very well have been a sedate herbivore.

• What special feature does the Eocene age stand for and what fascinates you as an evolutionary biologist?

After the catastrophe that brought an end not only to the dinosaurs but also to the majority of the flora and fauna of the time, it took many millions of years for biodiversity to recover. Only with the therefore aptly named Eocene - the age of the "dawn" that began about 56 million years ago - did new and species-rich life forms emerge again, for example among mammals and birds. This coming and going of the animal world in the course of evolution fascinates me - and at the same time it should be an instructive example for our handling of today's biodiversity.

Prof. Dr. Matthias Glaubrecht is evolutionary biologist and Professor of Animal Biodiversity.