algae

Algae are organisms which are classified by certain shared characteristics.

They live predominantly in water and constantly produce oxygen through photosynthesis.
All organisms which are today considered to be algae have a nucleus inside a membrane, and chloroplasts within one or more membranes. They belong to the group of eukaryotes and are also known as eukaryotic algae.

Algae without a nucleus, like cyanobacteria, (referred to as the blue-green algae) were formerly classified as algae, but now they are usually classified as prokaryotes.

Eukaryotes are divided into green algae, brown algae (phaeophyceae), red algae (rhodophyta), dinoflagellates, cryptophytes, diatoms and many more; eukaryotic algae represent some of the oldest plant groups known today.

Most types of algae live in freshwater,  but also started to live on dry land 400 million years ago. Algae can be found in all damp areas: in hot springs, arctic lakes, glaciers, and also in the air. With the help of the sun, algae and cyanobacteria have been converting large amounts of carbon dioxide (CO²) into oxygen for millions of years, and have created most of the oxygen on earth and in the water, establishing the basis for our existence.

Our life is therefore intrinsically tied to the photosynthesis of algae and their capacity to produce organic carbon dioxide compounds from inorganic carbon dioxide matter, generating oxygen in the process.

80,000 types of algae have been classified and an estimated 400,000 populate our planet.

Up till now most of the algae with applied uses are marine algae, which are used for nutrition. Microalgae are also used to deal with sewage and to produce high grade biomass.

The use of algae for energy has been much under discussion in recent years, due to the rise in oil and food prices. There are, however, hardly any plant processors which have passed the pilot stage.

According to the endosymbiotic theory, a bacterium is engulfed and retained by a free living eukaryote and a symbiosis results between the two (primary endosymbiosis). This product can again be engulfed and retained by another eukaryote (secondary endosymbiosis). If secondary endosymbiosis takes place many times, other types of algae and eukaryotes can develop. Evidence suggests that, in this way, higher, specialised flora evolves.