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Arkansas Endemic: cyanobacterium

 ONLY in Arkansas: It’s not a plant. It’s not an animal! This endemic is an organism, a species of cyanobacterium called “Phormidium treleasei.” In the 1970s, scientists determined that cyanobacteria (formerly known as blue-green algae) have physical features that make them more closely related to bacteria than to algae.

Although the exact classification of cyanobacteria is still under debate, some scientists now classify cyanobacteria as “prokaryotes”- mostly tiny, single celled organisms whose genetic material is loose in the cell. The genetic material of plants, animals, and other “eukaryotes” on the other hand, is held in the cell's nucleus. Cyanobacteria are widely distributed over land and water, often in environs where no other life can exist. They can tolerate temperatures in the range of 158 to 163 degrees F. The blue-green color of the cells of cyanobacteria (cyan means blue-green) is due to the combination of green chlorophyll pigment and a unique blue pigment (phycocyanin). However, not all “blue-green algae” are actually blue-green. Their pigmentation includes yellow-green, green, grey-green, grey-black, and even red specimens. The Red Sea derives its name from occasional blooms of a species of scillatoria that produces large quantities of a unique pigment called phycoerythrin. Cyanobacteria are microscopic life forms that exhibit several different types of organization. Some grow as single cells enclosed in a sheath of slime-like material, or mucilage. The cells of others, including Phormidium treleasei, aggregate into colonies. Phormidium usually forms flat, slimy mats of tangled filaments attached deep under water which can detach and float to the surface. Examples of the unique Phormidium treleasei, as well as other organisms adapted to life at high temperatures, can be seen in the pools and springs at Hot Springs National Park, where the water temperature averages 143 degrees F. Learn more about Arkansas endemics at the Arkansas Natural Heritage Commission.