Why the discovery of amber in Antarctica matters

Sticking with ancient fossilised relics from the past, scientists in Germany say they have discovered the first documented deposits of amber in Antarctica. It means that the resin has now been found on every continent on the planet, and it paints a picture of a heavily forested Antarctic continent millions of years ago. Here’s Johann Klages at the Alfred-Wegener Institute…

Johann - We found for the first time amber in Antarctica. Fossilised resin that trees exude when they try to seal injuries, for example. That was really the first time in Antarctica. So far, on all continents, Amber was found and discovered, but not in Antarctica. That was really exciting for us.

Chris - Where did you find it?

Johann - We found it in a marine sediment core, which is very unusual because normally you don't find these things in a marine sediment core, but at the time, when the resin deposited, it was a terrestrial ecosystem, so on land. And therefore it is a direct indication and direct evidence for us that a forest must have existed in the location where we drilled.

Chris - You don't think the amber could have got there via another route? Perhaps an animal took it, or currents took it, something like that?

Johann - No, because we know exactly what this environment was about because we published another paper in 2020 where we reconstructed a temperate rainforest in the same location, and sediments were completely undisturbed and pristinely preserved. We have a root system in there. We have pollen and spores from these plants back then. So we know that the sediments were pristinely preserved. We looked a little closer in the particular layer of that sediment core, and there we found this amber. The first direct evidence for the presence of resin producing trees in that particular location.

Chris - Critically, when does that date from, then?

Johann - In between, let's say, 93 to 82 million years. This is the time the dinosaurs lived. We call that the mid Cretaceous, which is about 90 million years ago.

Chris - Why was Antarctica so different then compared to how it is now?

Johann - Interestingly, the location of Antarctica was not so much different. The location where we drilled today is on 73 degrees South, which is pretty far South, but back then it was on 82 degrees South, so only 900 kilometres away from the South Pole. But, and this is a big but, the continent of Antarctica was still connected to the other continents in the Southern hemisphere, so South America, South Africa, and also Australia, New Zealand. There were land connections in between those continents and it was the final breakup of those continents from Antarctica, the final days of the super continent, and we call that Gondwana, and that was about 90 million years ago.

Chris - Why though is it now so cold, and back then it was much warmer, despite being in the same geographical position, warm enough to sustain a big rainforest?

Johann - That is a very good question, and we know exactly why that is. The continents were connected back then, also ocean currents and atmospheric currents, winds, were able to reach the Antarctic continent and transport warm water and air masses towards the continent much further south than can be done today. If you go back further in time, 34 million years before, then we had a time where those continents of South America, Africa and Australia were already very far away because of continental drift from Antarctica. Therefore an ocean current could evolve in between Antarctica and the other currents and we know that today as the circumpolar arctic current. Not only that, also at this time, 34 million years ago, the CO2 content globally in the atmosphere dropped significantly. Those two things together, and they're of course also connected to those things, they led to a significant cooling of the entire planet.

Chris - If Antarctica was connected to these other continents to create not just those climate effects, but also to allow other things to get there, does that mean there were animals down there as well then in much greater profusion than just the very specialist species that we see today?

Johann - Definitely. From the Antarctic Peninsula we have much evidence for the presence of, for example, dinosaurs. We also have evidence for insects and also frogs a little bit later in the Eocene. But still, it must have been a very diverse environment down there. Just imagine, on 82 degrees South, we had a temperate rainforest environment that could survive in those conditions, even though we also back then of course had almost four months total darkness because of the polar night.