Stackhouse (Lat. Cystoseira barbata). It is brown algae characterized by highly differentiated basal and apical regions and the presence of catenate pneumatocysts (air-vesicles). The aerocyst or air vesicles keep the organism erect, by causing it to float in strong currents. It provides an essential habitat for many epiphytes, invertebrates, and fish. It depends on good water quality, so can be used for bioindication. It is an edible brown seaweed, traditionally used in the Black Sea area as functional food. Both alginate and brown seaweed biomass are well known for their potential use as adsorbents for heavy metals from the intestinal system which is related to organism detoxification. One of the main active components of edible brown seaweed is alginate, a polysaccharide composed of two different uronic acids, mannuronic and guluronic. Due to the fact that alginates are not digested by human enzymes, they act as prebiotics, supporting the production of short-chain fatty acids, and as potential immunomodulators.