Amber forests

With a bit of luck, you might find amber whilst walking along the Baltic Sea coast. These fossilised lumps of resin are often washed ashore following stormy winter days with onshore winds. A team of researchers from the Museum für Naturkunde Berlin is bringing ancient forests back to life using plant inclusions found in amber. In doing so, they are making use of the museum’s amber collection, amongst other sources.

Past ecosystems

“The aim is to identify plant inclusions in amber and draw conclusions about the ecosystem from which the plants originated,” says palaeobotanist Eva-Maria Sadowski. 

Some of the plant parts – mostly leaves, flowers or seeds less than a centimetre in size – that were trapped in flowing resin millions of years ago are well preserved in terms of their shape and cell structure. 

“We can use these finds to draw conclusions about the distribution patterns and morphological evolution of plant families,” says Sadowski. Further questions concern the resin itself. In the case of Baltic amber, it is unclear which plant produced such large quantities of resin and what factors triggered this massive resin production. The first step in the investigations is to find suitable specimens. “We are very fortunate to be able to work with pre-sorted collections, including those from private individuals,” says Sadowski. 

In Baltic amber, only about one in every thousand pieces contains an inclusion. And only two to three out of every hundred inclusions consist of plant material. And only a small proportion of these is suitable for detailed analysis. In a project funded by the German Research Foundation, Sadowski, together with her PhD student Simon Beurel, investigated amber inclusions from Myanmar and China. The finds date from the Middle Cretaceous, around 98 million years ago, and the Middle Miocene, around 15 million years ago. 

The newly discovered finds from both countries have so far been little studied for traces of past plant communities. The new findings from this project contribute, among other things, to our understanding of the rapid spread and diversification of flowering plants during the Cretaceous period. Furthermore, they provide insights into the resin-producing forests of that time, their biodiversity and habitats.

Promising analyses 

Some of the amber specimens are cut and polished in the museum’s amber laboratory for examination, to obtain the best possible view of the inclusions. In the next step, the amber inclusions are examined and photographed under a light microscope. In some cases, small samples are taken from the inclusions for electron microscopic imaging. 

To record the internal structure of the plant inclusions, the palaeobotanist and her team use micro-computed tomography at the museum and at the German Electron Synchrotron (DESY, Hamburg). The museum houses one of the largest and most significant collections of Baltic and Bitterfeld amber in Europe. Many of the specimens have so far been examined only once, and some of the publications are over 150 years old. Scientifically, they are therefore often outdated, yet continue to be cited. 

“Revising these initial descriptions using new techniques and the current state of knowledge is, of course, very promising,” says Sadowski. In a new project funded by the German Research Foundation, Sadowski and her PhD student Josephine Franke are researching these historical specimens. The focus is on the flowering plants in Baltic amber. They are further pieces of the puzzle that will help us better understand the original forest from which this amber originated. This is because neither its plant diversity nor its climate has yet been comprehensively analysed. “New insights into the plant communities of the Baltic amber forest are also essential for understanding the habitat of the thousands upon thousands of insects and arachnids known to have been preserved in this amber,” says Sadowski.

DFG projects

• Reconstruction of fossil-rich amber forests of East Asia based on seed plant inclusions (project number 423862824) 
• Towards a holistic reconstruction of the “Baltic Amber Forest” – The diversity of flowering plants and their palaeoecological significance (project number 535296903)