Life Cycle of Blue Green Algae

Blue green algae, also known as cyanobacteria, are both helpful and harmful organisms. They have been called the "architect's of Earth's atmosphere" for their role in creating the oxygen-based atmosphere we now know. They are also an important part of the nitrogen cycle. However, algal blooms in recreational and drinking water can be very harmful to humans and pets.

Reproduction

Cyanobacteria reproduce asexually through binary fission, wherein the cell copies and divides itself to create two cells.

Photosynthesis

Cyanobacteria are photosynthetic, meaning they make their own food using sunlight. Various species are able to adapt their pigmentation to the available light. Therefore, some species of cyanobacteria can thrive in very low light. The only waters unlikely to experience a bloom are those where light is nearly absent.

Survival

Cyanobacteria can produce a type of cell called an akinete. Akinetes are thick-walled cells that store reserve nutrients and enable cyanobacteria to survive adverse conditions. These akinetes are likely responsible for cyanobacteria's ability to colonize even volcanic rock.

Movement

Most cyanobacteria possess gas vesicles. These vesicles allow the bacteria to float to the surface when they need more light. Also, some varieties flagellate or undulate to move slowly.

Blooms

In the presence of nutrient-rich waters, especially nitrogen- and phosphorus-loaded waters, blue green algae can bloom until light or temperature become limiting. Temperatures of more than 82 degrees Fahrenheit promote blooms.

Death

Blue green algae create dangerous toxins when they die. These toxins can create unpleasant taste and odor in drinking water; irritate skin, eyes and throats; cause liver and nerve damage; headache; nausea; and even death.

References

• World Health Organization
• Indiana Department of Natural Resources
• Encyclopedia Britannica

Resources

• University of California Museum of Paleontology