Teen SciCafe: Microfossils and Big Clues to Reconstructing the Past

BUSHRA HUSSAINI (Senior Museum Specialist, Division of Paleontology): I was fascinated when I saw them under the microscope. I was fascinated by the structures, the different orientations. Just they’re absolutely beautiful. So, I found forams interesting from a purely aesthetic point of view. But now I’m hooked. Because I see how important they are.

I am Bushra Hussaini and I take care of the fossil invertebrate collection.  

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ELLEN THOMAS (Senior Research Scientist, Earth and Planetary Science, Yale University): Micropaleontology just means small paleontology—fossil objects that are so small that you cannot really study them with the naked eye. 

I’m Ellen Thomas and I’m a research associate at the American Museum of Natural History.

I myself study foraminifera. By far, by very far, the most species of foraminifera live on the sea floor. Your average period after a sentence on a piece of paper is a nice size for a foram. They are unicellular organisms, which belong in that large group of things called Protista, which are not animals. Although my husband always calls them “beasties.”

What we recognize as foraminifera goes back about 650 million years ago. The interesting thing is that although foraminifera are only one cell, they make shells. That’s what, of course, makes it possible for them to become fossilized.  

NEIL LANDMAN (Curator, Division of Paleontology): We have a very important foram collection here, because in the mid-20^th century, the American Museum was the focus of foram studies. 

I’m Neil Landman and I’m a curator in the Division of Paleontology.  

Forams reflect environmental changes. They’re very sensitive indicators of environmental change. 

THOMAS: One way in which foraminifera can tell us something is by chemical analysis of the shells. We can look at the isotopic composition of the oxygen and the carbon and trace element concentrations in the shell.  That means that we can say things about direct temperature of the past. It can tell us sort of the size of the polar ice caps. It can tell us something about how much photosynthesis was going on in the surface of the ocean. And that can tell us something about the CO2 levels in the atmosphere.

If you look at reconstructions of climate, if you just look at climate change in Wikipedia, for instance, then you’ll see wiggly lines that tell you something about the climate of, say, the last 70 to 100 million years or so. Those wiggly lines are all derived from the analysis of foraminifera.

I hope you’re impressed by foraminifera.

LANDMAN: So, we have this very important foram collection that was developed in the mid-20^th century and, you know, everything changes and curators come and go. And so, it’s really our obligation to rehouse and recurate the collection of microfossils, because it’s so important.

THOMAS: Scientists here at the Museum in cooperation with me started to write a proposal to the National Science Foundation. 

HUSSAINI: So, we received a grant. The main goal of this project is to rehouse the specimen slides. The other objective is to create a digital catalog— you know, enter them into a database, photograph them, and then also to create about 50 CT scans.

SHAUN MAHMOOD (Curatorial Assistant, Department of Earth and Planetary Sciences): Forams are cool because they’re such tiny objects, yet they have so many complex features. You can see something the size of a grain of rice suddenly has a hundred chambers that you didn’t even know were there. 

I’m Shaun Mahmood. I was part of a group of interns working on the microfossil digitization and rehousing project. 

So, we had to come up with some way to scan something so tiny. It’s quite difficult to mount these specimens because if you poke it too hard with the brush it will actually shatter.  

So, now we have the specimen in the pipette tip and we want to drop it in this little vial. We label and bag the specimen. And we take this off to the CT lab and they’ll scan it for us.

The way that a CT scanner works is it will create these 2D slices that we put together and create a 3D object of that specimen.  

HUSSAINI: We had this one specimen, you know, that on the outside looked like it was completely eroded and we just didn’t think you would be able to see anything. But we CT scanned it, and lo and behold, the internal structure was absolutely beautiful.

MAHMOOD: We can extract the 3D model and make it available for researchers to observe, make measurements, and everything that you would with a normal specimen. We can print out a 3D object. Instead of it being a tenth of a millimeter, we can actually have something that will fit in the palm of your hand.

THOMAS: Our project in rehousing the collection has been amazingly important because what we can do with the geological past is say, “Okay, Nature has made those experiments. It has done global warming.” Okay, let’s use Earth’s history and foraminifera in the Earth’s history to learn how life on Earth reacted to those events in the past, to help to predict how we are dealing with the future.