Thursday, July 10, 2014

Interlude: Why are microfossils important? What are these things?

Most people think of huge dinosaurs and mammoths when they think of paleontology, not tiny one-celled organisms with a calcite "test" (like a shell), or miniature crustaceans that can only be seen under a microscope. While these microscopic fossils may seem less exciting than a dinosaur or an ancient fish, they actually are in many ways more important to the paleontologist's quest to chronicle the history of life on earth. These tiny animals incorporate carbon in their tests and inadvertently preserve information about a host of environmental conditions while they are alive. When interpreted by paleogeochemists, the tests of foraminifers can be used to extract information about temperature, salinity, and facies changes. Their tests, while beautiful, are also quite useful in informing us of change on geological time scales. Similarly, the shells of ostracods are used in paleoclimate studies.

In addition to being useful for paleoclimate reconstruction, microfossils have been useful in industrial settings as indicator fossils. Because many species are short lived and environment specific, paleontologists use them to determine the geological age and environment in which the foram was deposited. Oil companies often employ paleontologists to determine when an oil bearing rock layer has been reached. Because of this industrial use for forams, many of the collections we are working with were collected as part of oil drilling operations. More about forams from UCMP

Extant analogs

Some of the organisms we encounter in the invertebrate paleontology lab have extant analogs that are studied by ecologists. Knowledge of habitats and behavior of certain genera in modern settings can help us to interpret the fossil record. Here are some videos that show some of the animals that are in the invertebrate fossil collections .

Live Ostracods

Video credit: nymdevente (youtube user)

Live Foram feeding

Video credit: foraminiferal (youtube user)

What are we contributing?

This conservation and rehousing project will make the microfossil collections of the American Museum of Natural History more easily accessible to researchers and the general public. Of over 7,000 specimen lots in the AMNH microfossil collections, most specimens are types. By photographing type specimens, we are making it possible for researchers to see images of specimens before they decide to come to the museum in person.

Before this project started, many specimens were difficult to locate in their storage spaces at the museum. We are ensuring that specimens are correctly associated with the publications that describe them, and that their storage location and other important data are entered in an electronic database.

Another important part of this project is rehousing the specimens. Many older slides were housed vertically, allowing for fossils to fall out of the slides when the adhesive holding them in place decayed. We are rehousing slides in metal holders with glass cover slips. The slides are then stored horizontally in boxes according to the publication they are associated with.
Work desk. At left is an original wooden slide box.

Specimens in their new home.
Hopefully, our efforts will contribute to the creation of an accessible collection for the use of researchers and microfossil enthusiasts around the world.

We hope this interlude helped you understand the fossils we work with and the importance of this project. Look forward to our next weekly update: The Adventures of Week 4.

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