Exquisite Fossils Show an Entire Rain Forest Ecosystem

Foulden Maar is located on New Zealand's South Island and is one of the most significant but troubled fossil sites. This shallow-sided volcanic crater lake was formed in a violent explosion 23 million years ago when the climate in this part of the world was much warmer and wet than it is today.

The rain forest was around the lake for over a century. In its waters, tiny single-celled algae called diatoms bloomed and then died. The diatoms are the most important fossils because without them, other fossils wouldn't have been preserved.

The other fossil plants and animals are amazing. Lee and her colleagues were able to get a good look at the entire system, which was found in the rock.

Climate scientists were able to analyze the leaves' structure and chemical composition to discover that atmospheric carbon dioxide reached a level similar to those predicted for Earth by the end of the 20th century.

Lee and her colleagues published scientific papers, but they didn't talk much about the site. She says that they didn't give the site the public recognition it deserved because they were trying to keep on good terms with the mining companies.

When a leaked document revealed Plaman Resources was going to dig up the entire site and export the diatomite as an animal food supplement, Lee was galvanized into activism. She spoke at meetings about Foulden Maar. She started working on a book with two other people. An illustrated guide to the site's history, science and fossil discoveries is available in the US this December. If we have to the point where this whole site might be destroyed, we need to get this story out there.

Foulden Maar has no formal protection despite the public pressure that helped Plaman Resources abandon its mining plans. The company appointed to manage Plaman's business affairs has been locked in negotiations with the city council for three years. The parties wouldn't comment on the progress of the talks. Scientists are not allowed to visit the site.

Lee spoke with Scientific American about the fossils of Foulden Maar, what they reveal about our planet's past, and her hopes for the site's future.

The transcript of the interview has been changed.

This place is told in the book. Why does it matter so much?

It has the best preservation of fossils in the world. There are a few sites in the world that have Lagersttte preservation. Soft parts of fossils, such as eyes and skin and flowers with petals and pollen, are almost never preserved in other places. Foulden gives a snapshot of the world's flora and fauna.

We have two ecosystems that are preserved. It was a small lake with a few hundred meters deep and a kilometer across. Everything that lived in the lake and fell to the bottom is preserved in liquid.

Every leaf, every flower, every insect is preserved around the lake. We have a year-by-year record of it. This kind of preservation is possible because it was a closed system and small.

It's very, very unusual to have this combination of factors all coming together at this one site, and it means we can build up a detailed and accurate picture just by taking a walk through the forest and diving into the lake.

Tell me about the fossils that have been found there. There have been a lot of things. There was more discovered.

There were a lot of fish in the lake. Uwe discovered the first one. He went back to the pile that the digger had pulled out and searched for a few days until he found the other bits that matched the one he thought was a fish. Until we found more of them, this was the only fossil from the Southern Hemisphere. It changed the way we view freshwater edins.

You have mentioned that you found a really nice fish.

This was the best fossil I've found. You can cut diatomite with a spade or a chainsaw. My colleague developed a way to cut blocks with a chainsaw, and then the rest of us would split them. I split a block and it split the fish in half as if it had been cut open.

You can count its bones, but you can't see them. It is different from any other fish. It was named Galaxias effusus, which means it's better than before.

You might want to go back and check out what else is on the site. Can you not?

Every time we went, we found something new. The receiver said nobody could go there. They've been absolutely adamant despite many pleas to take groups of students and bring scientists from overseas to visit Foulden Maar. The gate isn't open. We can't do anything except look over the fence.

Your dream for Foulden Maar is a World Heritage site where children and students can learn about geology, fossils and Earth's climate history. Is this something you will see in your life?

I hope that's the case. It would be great if everyone could go to Foulden Maar to see what the book is all about. It's the best way to explain the science.

Foulden has a lot of different stories about the lake, the rain forest, and the climate. You can see the mountains in the background, but they weren't there when the maar was formed, and there was snow in the hills back then.

This is a place of fossils, just as a museum is full of fossils, and they belong to everyone.