Growth found in extreme conditions.

In some of the most extreme environments on Earth, hidden deep within caves in Greece, unexpectedly scientists have discovered that life is flourishing in the form of cyanobacteria.

In a lecture at Mount Allison University last week, Professor Athena Economou-Amilli of the University of Athens, revealed surprising information about the diversity of life in the underground cave ecosystems.

Cyanobacteria are more commonly known to the public as green or blue-green algae and are found worldwide. The wide variety of uses for cyanobacteria include pharmaceuticals, food, and biofuel. One of the key characteristics of cyanobacteria is the ability to ‘fix’ nitrogen gas from the atmosphere into a form of ammonia or nitrates that plants are then able to absorb.

Athough cyanobacteria are known to live in some of the most extreme conditions on Earth they do perform oxygenic photosynthesis.

Economou-Amilli and her team studied three cave environments around Greece: an open-air cave, a cave exposed to salt spray, and a typical limestone cave. Caves are exemplified by a stable temperature and high relative humidity, leading some to describe them as extreme environments. Economou-Amilli disagrees with this assessment, based on her research. Cyanobacteria were uncovered in the farthest reaches of the caves known as the dim light zone where lack of light is the limiting factor in the growth of most species. The cyanobacteria is also found growing within the rocks, hidden from light, in the entrance zone of caves.

When Economou-Amilli and her team discovered new taxa of cyanobacteria, they encountered some difficulty in the naming, as the scientific community does not have a perfect method for it. The taxonomy used to identify the vast quantity of cyanobacteria lacks cohesion as the botanical and bacterial nomenclature differs. The classical method of naming new species usually relies on morphology of cells. Newer molecular taxonomy uses the growth of bacterial cultures in a laboratory setting. Since some cyanobacteria have not been successfully cultured, it adds another level of difficulty when naming a new species or genus.

Further areas of research into cyanobacteria may compare the morphology and speciation between terrestrial species and those found in cave environments. Caves, some of the most extreme environments on Earth, support life and favour speciation in unexpected ways with cyanobacteria paving the way for increased growth and development of other species.

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