Foraminifera

Microscopic, single-celled organisms called foraminifera have a fossil record that extends from today to more than 500 million years ago. Although each foram is just a single cell, they build complex shells around themselves from minerals in the seawater. These shells have accumulated in layers of sediment below the seafloor of the open ocean and in regions where the ocean once flooded the continents for millions of years. By examining the shell chemistry of these ancient forams, scientists can learn about Earth's climate long before humans ever walked the planet—and get insight into how climate changed in the past. Take a closer look at a few members of this fascinating life form.

Tags: 
Microorganisms, Under the microscope

Foraminifera

Credit: Noora Al-Meer, Flickr

Shallow Coral Reef Foraminifers

In this photo of a shallow coral reef in the Pacific there are three species of forams. Their colors come from the symbiotic algae that live inside the foram shells.

Credit: Pamela Hallock/University of South Florida

Star Sand Grains Collected from Southern Japan

Star shaped grains of sand collected from southern Japan are the shells of microscopic foraminifera.

Credit: Flickr User Mouser NerdBot

A Colorful Foram: Globigerinoides ruber

The central dark area of this foram (Globigerinoides ruber) is the shell surrounded by spines. The tiny yellow dots are symbiotic algae, which live in the protoplasm of the host organism.

Credit: Howard J. Spero/University of California, Davis

Globotruncana falsostuarti

This foram Globotruncana falsostuarti) lived about 75 million years ago. Using shell chemistry, scientists can estimate sea surface temperatures at the time when these organisms lived and learn more about our changing climate. For this specimen, they calculate that it lived in 28°C (82°F) seawater.

Credit: Brian T. Huber/Smithsonian Institution

Hedbergella sliteri

This Hedbergella sliteri specimen was taken from a drill core near Antarctica dating back 71-66 million years ago, a time when the south polar region was warm enough for the Antarctic continent to have forests and dinosaurs.

Credit: Brian T. Huber/Smithsonian Institution

Hantkenina mexicana

Hantkenina mexicana is a foram with elongated shell chambers that lived between 45-49 million years ago, during the Eocene Epoch. This specimen is from marine sediments that were drilled in the southeast coastal region of Tanzania.

Credit: Helen G. Coxall/Cardiff University

Lenticulina secans

This foram (Lenticulina secans) lived on the Tanzania seafloor more than 92 million years ago when both the polar regions and the deep ocean were much warmer than they are today, an era known as the "Cretaceous Supergreenhouse." Scientists estimate that in this region at that time, the temperature of the ocean bottom at 600 meters was about 20°C. Present day temperatures at that depth average about 12°C.

Credit: Ines Wendler/University of Bremen

Post new comment