19 Facts About Brown algae

Brown algae, comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere.

Brown algae are the major seaweeds of the temperate and polar regions.

Brown algae belong to the group Heterokontophyta, a large group of eukaryotic organisms distinguished most prominently by having chloroplasts surrounded by four membranes, suggesting an origin from a symbiotic relationship between a basal eukaryote and another eukaryotic organism.

Brown algae are unique among heterokonts in developing into multicellular forms with differentiated tissues, but they reproduce by means of flagellated spores and gametes that closely resemble cells of other heterokonts.

Whatever their form, the body of all brown algae is termed a thallus, indicating that it lacks the complex xylem and phloem of vascular plants.

Related searches

But, because some botanists define "true" stems, leaves, and roots by the presence of these tissues, their absence in the brown algae means that the stem-like and leaf-like structures found in some groups of brown algae must be described using different terminology.

Brown algae include the largest and fastest growing of seaweeds.

Growth in most brown algae occurs at the tips of structures as a result of divisions in a single apical cell or in a row of such cells.

Specifically, the cellulose synthases seem to come from the red alga endosymbiont of the photosynthetic stramenopiles ancestor, and the ancestor of brown algae acquired the key enzymes for alginates biosynthesis from an actinobacterium.

Closest relatives of the brown algae include unicellular and filamentous species, but no unicellular species of brown algae are known.

DNA sequence comparison suggests that the brown algae evolved from the filamentous Phaeothamniophyceae, Xanthophyceae, or the Chrysophyceae between 150 and 200 million years ago.

Fossils comparable in morphology to brown algae are known from strata as old as the Upper Ordovician, but the taxonomic affinity of these impression fossils is far from certain.

Between generations, the Brown algae go through separate sporophyte and gametophyte phases.

Certain species of brown algae can perform asexual reproduction through the production of motile diploid zoospores.

Brown algae have adapted to a wide variety of marine ecological niches including the tidal splash zone, rock pools, the whole intertidal zone and relatively deep near shore waters.

Brown algae growing in brackish waters are almost solely asexual.

Brown algae produce a specific type of tannin called phlorotannins in higher amounts than red algae do.

All brown algae contain alginic acid in their cell walls, which is extracted commercially and used as an industrial thickening agent in food and for other uses.

Brown algae including kelp beds fix a significant portion of the earth's carbon dioxide yearly through photosynthesis.