Thiomargarita namibiensis
Brandie Amsden

Thiomargarita namibiensis is a very unique bacteria because not only does it live where most bacteria can not survive it is the largest bacteria ever found. It took the record of the largest bacteria from Epulopiscium fishelsoni by being one hundred times larger. These prokaryotic, spherical bacteria are about 0.75 millimeters in diameter, which allows it to be visible by the naked eye. It is generally found in chains of ten or more. It is also very easy to notice because it shines like a pearl. The pearl color gives it the name “Sulfur Pearl of Namibia”. The rest of its name comes from the fact that it eats sulfur and that it was found off of the coast of Namibia.

Heide Schulz is from the Max Planck Institute for Marine Microbiology and with the help of her colleagues they stumbled across this fascinating microbe deep down on the ocean floor. They were on the Russian research vessel Petr Kottsov looking for Thioploca and Beggiatoa off the coast of Namibia when the whiteness from this microbe caught their eye. Heide Schulz knew right away that this new discovery was a microorganism but it took a little more to convince the others that she was right. So far this is the only species in this genus and there have not been any pure cultures made outside of the original environment. They have been able to bring the microorganism back to the lab for research but it must be maintained in its environment. Trying to get a pure culture has been a challenge because other bacteria are colonizing on the mucous sheath since it is so big.

The giant size of this microorganism comes from the large vacuole that is inside of it. The vacuole takes up about ninety eight percent of the interior. There are a few sulfur globules and the cytoplasm that fill the remainder of the space. It needs the large vacuole in order to store the nitrate it needs for survival because it can not move. Since they can not move they wait for what nitrate they are given. Each time there is a storm the ocean floor is stirred up and the mucous sheath that links the cells together catch the nitrate. The amount of nitrate that they capture allows them to go for about three months before they will die of starvation. They type of environment that they are in allows them to obtain the sulfur they need to break down the nitrate which keeps them alive.

They are still trying to learn more about this microorganism currently but they hope that it can be use to clean up the ocean waters where there is a lot of runoff. With more research they can also look further into how the nitrogen and sulfur cycle work together. This organism and others like it also help keep the ocean from smelling like rotten eggs. For the moment they are very curious about how Thiomargarita namibiensis is able to store large amounts of nitrate over a period of time.


Henahan, Sean. Giant Bacteria Discovered. 16 April 1999.

Travis, J. Pearl like bacteria are largest ever found. Science News Online. 17 April 1999. Scientist discover biggest bacteria ever. 15 April 1999.

The Worlds Largest Bacteria. Woods Hole Currents.

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.


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