Introduction

Algae is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular microalgae, such as Chlorella, Prototheca and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 metres (160 ft) in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, Spirogyra and stoneworts.

Algae are a diverse group of aquatic organisms that have the ability to conduct photosynthesis. Certain algae are familiar to most people; for instance, seaweeds (such as kelp or phytoplankton), pond scum or the algal blooms in lakes. However, there exists a vast and varied world of algae that are not only helpful to us, but are critical to our existence.

Habitat

The majority of algae live in aquatic habitats (Current Biology, 2014). Yet, the word "aquatic" is almost limited in its ability to encompass the diversity of these habitats. These organisms can thrive in freshwater lakes or in saltwater oceans. They can also endure a range of temperatures, oxygen or carbon dioxide concentrations, acidity and turbidity. Algae are also able to survive on land. Some unexpected places where they grow are tree trunks, animal fur, snow banks, hot springs (according to "Algae") and in soil, including desert crusts (Current Biology, 2014).

Mostly, algae live independently in their various growth forms (single cells, colonies, etc.), but they can also form symbiotic relationships with a variety of non-photosynthetic organisms including ciliates, sponges, mollusks and fungi (as lichens). One of the benefits of such relationships is that they enable algae to broaden the horizons of their habitats.

The algae are not closely related in an evolutionary sense, and the phylogeny of the group remains to be delineated. Specific groups of algae share features with protozoa and fungi that, without the presence of chloroplasts and photosynthesis as delimiting features, make them difficult to distinguish from those organisms. Indeed, some algae appear to have a closer evolutionary relationship with the protozoa or fungi than they do with other algae.

Diatoms, a type of algae, are found floating in the phytoplankton of the seas. Their cell walls contain a hard substance called silica. When the diatoms die they sink to the floor. Their soft parts decay and the silica cell wall remains. Over time the pressure of the seawater pushes the silica together to form one large layer. This silica is mined from the seabed, crushed and used in abrasives and polishes such as toothpaste.

Importance

Probably the most important contribution of algae to our environment and well-being is the generation of oxygen through photosynthesis. "Algae are indispensable because they produce about half the oxygen in Earth's atmosphere," Graham told LiveScience.

The journal of “Medical Microbiology & Diagnosis” is a peer reviewed medical journal that includes a wide range of topics in this fields including Bacteriology, Clinical and Medical Diagnostics, Parasitology, Bacterial Infections and creates a platform for the authors to make their contribution towards the journal. The editorial office promises a thorough peer review of the submitted manuscripts to ensure quality.

Best Regards,

Mary Wilson,

Associate Managing Editor,

Medical Microbiology & Diagnosis

E-mail: microbiology@jpeerreview.com