Image of the diatom, Stenopterobia curvula.
Click on image for full size
Courtesy of Peter Siver, Connecticut College
Microscopic Fossils Offer Big Clues to Earth's Climate
News story originally written on January 7, 2009
Some scientists look for fossils that are so small they need an electron microscope to find them. The fossils may be small, but what they can tell us about the climate of ancient Earth can be huge.
These tiny fossils are diatoms, microbes that are each made of just a single cell. Diatoms are still found in lakes and the ocean today. They are related to algae and are in the Domain Eukaryota and Kingdom Protista.
Scientist Peter Siver has been looking for diatoms for 20 years. He has found diatoms all over North America and has discovered 60 species – including diatoms that are living today and ones that were fossilized long ago. He finds them in the mud at the bottom of lakes or in rock formed from mud.
He found fossil diatoms in 48 million years old rocks in the cold tundra of northern Canada. Looking at these diatoms under an electron microscope, he discovered that they were the same type that live in the tropics today. So, these tiny fossils tell us that that the chilly Arctic used to be quite warm 48 million years ago.
"By knowing the different species and being able to tell them apart, we can better tell how water bodies are being affected and changing. This has huge implications for understanding climate change," Siver said.
Before the invention of the electron microscope, it wasn’t easy to identify diatom species. Under the electron microscope, Peter Siver can see differences in microbes that wouldn't have been visible to scientists a century ago. An electron microscope can magnify an image to 100,000 times its size. In comparison, most light microscopes can only magnify objects 1,000 times. This makes the electron microscope an excellent tool for fossil hunting, at least if you are looking for fossil microbes!
Last modified March 6, 2009 by Lisa Gardiner.
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, as well as books
on science education!
You might also be interested in:
Fossils are evidence of ancient life preserved in sedimentary rocks. On Earth, they are clues to what living things, ecosystems, and environments were like in the past. The oldest fossils are from mats...more
Members of the Kingdom Protista are the simplest of the eukaryotes. Protists are an unusual group of organisms that were put together because they don't really seem to belong to any other group. Some protists...more
The Arctic tundra, vast plains filled with grasses, flowers, mosses and lichen, is located north of the taiga forests in Earth’s north polar region. Like all types of tundra, this is a very cold and windy...more
North of the Arctic Circle (at 66.5°N latitude) you will find the Arctic Ocean surrounded by the continents of Europe, Asia, and North America. You will find the geographic North Pole and the magnetic...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more
Some geologic faults that appear strong and stable, slip and slide like weak faults, causing earthquakes. Scientists have been looking at one of these faults in a new way to figure out why. In theory,...more