Seaweed
Seaweed or macroalgae refers to several species of macroscopic, multicellular, marine algae. The term includes some types of red, brown, and green macroalgae. Marine algae species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; ocean algae species from seaweeds to planktons play a vital role in carbon capture, producing up to 90 percent of the planet's oxygen. Understanding these roles provides guiding principles for conservation and sustainable use of seaweeds to take precedence over industrial exploitation. Mechanical dredging of kelp, for instance, destroys the resource and dependent fisheries. Certain species of seaweed are valuable for nutrition, biomedicine, bioremediation, and other uses.
Gelidium amansii
Gelidium amansii, also known as umutgasari, is an economically important species of red algae commonly found and harvested in the shallow coast (3 to 10 m or 10 to 33 ft of depth below the water) of many East Asian countries including North and South Korea, China, Japan, Singapore, and northeast Taiwan. "G. amansii" is an important food source in East Asian countries and has been shown to have medicinal effects on dieting. Hence, in folklore medicine "G. amansii" is used to treat constipation. This algae is used to make agar, whose components are the polysaccharide agarose and agaropectin, from the large amount of algin which is located in the algae's cell wall, as well it is sometimes served as part of a salad, puddings, jams, and other culinary dishes in producing regions. Agar is a gelatinous substance that is commercially used as an incubation matrix for microbes and other products that require an ecologically friendly gelatinous matrix. "G. amansii" can be purple, red, to yellowish-red because it contains the class of pigments known as phycobiliprotein. Its branching body is cartilaginous and can grow up to a height of 8 to 30 cm or 3 to 12 in. "G. amansii" may have four or five opposite, compound-lobed, pinnate leaves on each branch. It is uniaxial with an apical cell and whorled cells coming from the axial towards the exterior of the algae. The pith is compacted with apical cells and the epidermis is formed by rounded whorled cells. "G. amansii" is being studied as a cheap biofuel.