Algae (sing. alga) are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions The largest and most complex marine forms are called seaweeds. Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae. They are photosynthetic, like plants, and "simple" because they lack the many of the distinct organs found in land plants. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. The embryophytes are the most familiar group of Plants They include Trees Flowers Ferns Mosses and various other green Though the prokaryotic cyanobacteria (commonly referred to as blue-green algae) were traditionally included as "algae" in older textbooks, many modern sources regard this as outdated and restrict the term algae to eukaryotic organisms. The prokaryotes (proʊˈkærioʊts singular prokaryote /proʊˈkæriət/ are a group of Organisms that lack a Cell nucleus (= karyon or any other Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex  All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis.  Algae constitute a paraphyletic and polyphyletic group: they do not represent a single evolutionary direction or line, but a level or grade of organization that may have developed several times in the early history of life on Earth. In Phylogenetics, a group of organisms is said to be paraphyletic if the group contains its most recent common ancestor but does not contain all In Phylogenetics, a Taxon is polyphyletic ( Greek for "of many races" if the trait its members have in common evolved separately in different This timeline of the evolution of life outlines the major events in the development
Algae lack the various structures that characterize land plants, such as phyllids and rhizoids in nonvascular plants, or leaves, roots, and other organs that are found in tracheophytes. In Botany, a leaf is an above-ground Plant organ specialized for Photosynthesis. ROOT is an object-oriented program and library developed by CERN. In Biology, an organ ( Latin: organum, "instrument tool" from Greek όργανον - organon "organ instrument Vascular plants (also known as tracheophytes or higher plants) are those Plants that have lignified tissues for conducting They are distinguished from protozoa in that they are photosynthetic. Protozoa (in Greek πρῶτον proton "first" and ζῷα zoia "animals" are unicellular Eukaryotes (singular Many are photoautotrophic, although some groups contain members that are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. An autotroph (from the Greek autos = self and trophe = nutrition is an Organism that produces complex Organic compounds from simple A mixotrophic organism is one that obtains its electrons from an inorganic electron source ( Hydrogen-sulfide, Ammonium, Hydrogen) but uses organic matter Osmotrophy is the uptake of dissolved Organic compounds by Osmosis for nutrition Myzocytosis (from Greek: myzein, () meaning "to suck" and kytos () meaning "container" hence referring to "cell" Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole Some unicellular species rely entirely on external energy sources and have reduced or lost their photosynthetic apparatus. In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank.
All algae have photosynthetic machinery ultimately derived from the cyanobacteria, and so produce oxygen as a byproduct of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The purple sulfur bacteria are a group of Proteobacteria capable of Photosynthesis, collectively referred to as Purple bacteria. The green sulfur bacteria are a family of obligately anaerobic Photoautotrophic bacteria.
Algae are most prominent in bodies of water but are also common in terrestrial environments. However, terrestrial algae are usually rather inconspicuous and far more common in moist, tropical regions than dry ones, because algae lack vascular tissues and other adaptations to live on land. The Tropics are centered on the Equator and limited in Latitude by the Tropic of Cancer in the northern hemisphere at approximately 23°26' (23 This is an article about vascular tissue in plants For transport in animals see Circulatory system. Algae are also found in other situations, such as on snow and on exposed rocks in symbiosis with a fungus as lichen. Watermelon snow, also called snow algae, is Snow that is reddish or pink in color with the slight scent of a fresh Watermelon. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek Lichens (ˈlaɪkən or /lɪtʃən/ are symbiotic associations of a Fungus (the mycobiont with a photosynthetic partner (the photobiont also known as
The various sorts of algae play significant roles in aquatic ecology. Microscopic forms that live suspended in the water column (phytoplankton) provide the food base for most marine food chains. Phytoplankton are the Autotrophic component of the Plankton community Food chains, also called food networks and/or trophic networks, describe the feeding relationships between species within an Ecosystem. In very high densities (so-called algal blooms) these algae may discolor the water and outcompete, poison, or asphyxiate other life forms. An algal bloom is a rapid increase in the population of Algae in an aquatic system Seaweeds grow mostly in shallow marine waters, however some have been recorded to a depth of 300 m. Some are used as human food or harvested for useful substances such as agar, carrageenan, or fertilizer. Agar or agar agar is a Gelatinous substance derived from Seaweed. Carrageenans or carrageenins (ˌkærəˈgiːnənz are a family of linear sulphated Polysaccharides extracted from red Seaweeds The name is derived from
The study of marine and freshwater algae is called phycology or algology. Phycology (from Greek grc φύκος phykos, "seaweed" and grc -λογία -logia) or algology (from Latin
The US Algal Collection is represented by almost 300,000 accessioned and inventoried herbarium specimens. 
While Cyanobacteria have been traditionally included among the algae, referred to as the Cyanophytes or blue-green algae, recent works on algae usually exclude them due to large differences such as the lack of membrane-bound organelles, the presence of a single circular chromosome, the presence of peptidoglycan in the cell walls, and ribosomes different in size and content from eukaryotes . Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy A chromosome is an organized structure of DNA and Protein that is found in cells. Not to be confused with Glycoprotein. Peptidoglycan, also known as murein, is a Polymer consisting of sugars and amino Rather than in chloroplasts, they conduct photosynthesis on specialized infolded cytoplasmic membranes called thylakoid membranes. A Thylakoid is a membrane-bound compartment inside Chloroplasts and cyanobacteria. Therefore, they differ significantly from the algae despite occupying similar ecological niches.
By modern definitions algae are eukaryotes and conduct photosynthesis within membrane-bound organelles called chloroplasts. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex Chloroplasts are Organelles found in Plant cells and eukaryotic Algae that conduct Photosynthesis. Chloroplasts contain circular DNA and are similar in structure to cyanobacteria, presumably representing reduced cyanobacterial endosymbionts. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known The endosymbiotic theory concerns the origins of mitochondria and Plastids (e The exact nature of the chloroplasts is different among the different lines of algae, reflecting different endosymbiotic events. The table below lists the three major groups of algae and their lineage relationship is shown in the figure on the left. Note many of these groups contain some members that are no longer photosynthetic. Some retain plastids, but not chloroplasts, while others have lost them entirely.
|Cyanobacterium||These algae have primary chloroplasts, i. An endosymbiont is any Organism that lives within the body or cells of another organism i The Archaeplastida or Primoplantae are a major line of Eukaryotes comprising the land plants green and Red algae and a small The Archaeplastida or Primoplantae are a major line of Eukaryotes comprising the land plants green and Red algae and a small Chlorophyta, a division of Green algae, of mostly aquatic Photosynthetic Eukaryotic organisms The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater microscopic Algae. e. the chloroplasts are surrounded by two membranes and probably developed through a single endosymbiotic event. The chloroplasts of red algae have chlorophylls a and d (often), and phycobilins, while those of the green alga have chloroplasts with chlorophyll a and b. Phycobilins (from Greek: (phykos meaning "alga" and from Latin: bilis meaning "bile" are Chromophores (light-capturing Higher plants are pigmented similarly to green algae and probably developed from them, and thus Chlorophyta is a sister taxon to the plants; sometimes they are grouped as Viridiplantae. A taxon (plural taxa) or taxonomic unit, is a name designating an organism or a group of Organisms In Biological nomenclature according to Plants are living Organisms belonging to the kingdom Plantae.|
Excavata and Rhizaria
These groups have green chloroplasts containing chlorophylls a and b . In the classification of Eukaryotes (living organisms with a cell nucleus Cabozoa is a Taxon proposed by Cavalier-Smith. The excavates are a major assemblage of Protists often known as Excavata. The Rhizaria are a species-rich supergroup of Protists They vary considerably in form but for the most part they are Amoeboids with filose reticulose or microtubule-supported Chlorarachniophytes are a small group of Algae occasionally found in tropical oceans The euglenids (or euglenoids) are one of the best-known groups of Flagellates commonly found in freshwater especially when it is rich in organic materials with a Their chloroplasts are surrounded by four and three membranes, respectively, and were probably retained from an ingested green alga.
Chlorarachniophytes, which belong to the phylum Cercozoa, contain a small nucleomorph, which is a relict of the alga's nucleus. The Cercozoa are a group of Protists including most Amoeboids and Flagellates that feed by means of filose pseudopods Nucleomorphs are small reduced eukaryotic nuclei found in certain Plastids So far only two groups of organisms are known to contain a nucleomorph the Cryptomonads The term relict is used to refer to surviving remnants of natural phenomena In Cell biology, the nucleus (pl nuclei; from Latin la ''nucleus'' or la ''nuculeus'' "little nut" or kernel is a membrane-enclosed
Euglenids, which belong to the phylum Euglenozoa, live primarily in freshwater and have chloroplasts with only three membranes. The Euglenozoa are a large group of Flagellate protozoa They include a variety of common free-living species as well as a few important parasites some of which infect humans It has been suggested that the endosymbiotic green algae were acquired through myzocytosis rather than phagocytosis. Myzocytosis (from Greek: myzein, () meaning "to suck" and kytos () meaning "container" hence referring to "cell" Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole
Chromista and Alveolata
These groups have chloroplasts containing chlorophylls a and c, and phycobilins. Chromalveolata is a Eukaryote supergroup first proposed by Thomas Cavalier-Smith as a refinement of his kingdom Chromista, which was first The Chromista are a eukaryotic supergroup probably Polyphyletic, The alveolates ("with cavities" are a major line of Protists There are three phyla, which are very divergent in form but are now known to be close relatives The Chromista are a eukaryotic supergroup probably Polyphyletic, The heterokonts or stramenopiles are a major line of Eukaryotes presently containing about 10500 known species The haptophytes, classed either as the Prymnesiophyta or Haptophyta are a Phylum of Algae The Chloroplasts are pigmented similarly to those of the The cryptomonads are a small group of Flagellates most of which have Chloroplasts They are common in freshwater and also occur in marine and brackish habitats The dinoflagellates are a large group of Flagellate Protists Most are marine Plankton, but The latter chlorophyll type is not known from any prokaryotes or primary chloroplasts, but genetic similarities with the red algae suggest a relationship there.
In the first three of these groups (Chromista), the chloroplast has four membranes, retaining a nucleomorph in cryptomonads, and they likely share a common pigmented ancestor.
The typical dinoflagellate chloroplast has three membranes, but there is considerable diversity in chloroplasts among the group, as some members have acquired theirs from different sources. The Apicomplexa, a group of closely related parasites, also have plastids called apicoplasts. Plastids are major Organelles found in plants and algae Plastids often contain pigments used in photosynthesis and the types of pigments present can change Apicoplasts are not photosynthetic but appear to have a common origin with dinoflagellates chloroplasts.
It was W.H.Harvey (1811 — 1866) who first divided the algae into four divisions based on their pigmentation. William Henry Harvey ( February 5, 1811 &ndash May 15, 1866) was an Irish Botanist who specialised in Algae. This is the first use of a biochemical criterion in plant systematics. Harvey's four divisions were: red algae (Rhodophyta), brown algae (Heteromontophyta), green algae (Chlorophyta) and Diatomaceae (Dixon, 1973 p. 232). 
Most of the simpler algae are unicellular flagellates or amoeboids, but colonial and non-motile forms have developed independently among several of the groups. A microorganism (also spelled micro organism or micro-organism and also called a microbe) is an Organism that is Microscopic (usually Flagellates are cells with one or more whip-like organelles called flagella. Amoeboids are Unicellular lifeforms that mainly consist of Contractile vacuoles, a nucleus, and cytoplasm as their basic structure Some of the more common organizational levels, more than one of which may occur in the life cycle of a species, are
In three lines even higher levels of organization have been reached, with full tissue differentiation. A life cycle is a period involving 1 Generation of an Organism through means of Reproduction, whether through Asexual reproduction or Sexual Mucilage is a gooey polar Glycoprotein; an exopolysaccharide; a Polymer produced by most plants and some microorganisms For the chronologer/historian occasionally mentioned in the works of early Christian writers see Thallus (historian. These are the brown algae —some of which may reach 50 m in length (kelps)—the red algae , and the green algae . The Phaeophyceae or brown algae, (singular alga is a large group of mostly marine multicellular Algae including many Seaweeds of colder Kelp are large Seaweeds ( Algae) belonging to the Brown algae and classified in the order Laminariales The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are The green algae (singular green alga) are the large group of Algae from which the Embryophytes (higher plants emerged The most complex forms are found among the green algae (see Charales and Charophyta), in a lineage that eventually led to the higher land plants. The Charales are Algae in the division Charophyta. They are green plants believed to be the closest relatives of the green land plants. The Charophyta are a division of Green algae, including the closest relatives of the Embryophyte plants The embryophytes are the most familiar group of Plants They include Trees Flowers Ferns Mosses and various other green The point where these non-algal plants begin and algae stop is usually taken to be the presence of reproductive organs with protective cell layers, a characteristic not found in the other alga groups.
The first plants on earth evolved from shallow freshwater algae much like Chara some 400 million years ago. These probably had an isomorphic alternation of generations and were probably heterotrichous. Fossils of isolated land plant spores suggest land plants may have been around as long as 475 million years ago.
Some species of algae form symbiotic relationships with other organisms. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek In these symbioses, the algae supply photosynthates (organic substances) to the host organism providing protection to the algal cells. This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek The host organism derives some or all of its energy requirements from the algae. Examples include
Rhodophyta, Chlorophyta and Heterokontophyta, the three main algal Phyla, have life-cycles which show tremendous variation with considerable complexity. The red algae (Rhodophyta ˌroʊdəˈfaɪtə roʊˈdɒfɨtə from Greek: ῥόδον (rhodon = rose + φυτόν (phyton = plant thus red plant are Chlorophyta, a division of Green algae, of mostly aquatic Photosynthetic Eukaryotic organisms The heterokonts or stramenopiles are a major line of Eukaryotes presently containing about 10500 known species A phylum ( Plural: phyla) is a Taxonomic rank between Kingdom and above Class. In general there is an asexual phase where the seaweed's cells are diploid, a sexual phase where the cells are haploid followed by fusion of the male and female gametes. "Haplo" redirects here For the fictional character see The Death Gate Cycle. "Haplo" redirects here For the fictional character see The Death Gate Cycle. A gamete (from Ancient Greek γαμέτης; translated gamete = wife gametes = husband is a cell that fuses with another gamete Asexual reproduction is advantageous in that it permits efficient population increases, but less variation is possible. Sexual reproduction allows more variation but is more costly because of the waste of gametes that fail to mate, among other things. Often there is no strict alternation between the sporophyte and gametophyte phases and also because there is often an asexual phase, which could include the fragmentation of the thallus. 
In the British Isles the UK Biodiversity Steering Group Report estimated there to be 20,000 algal species in the UK, freshwater and marine, about 650 of these are seaweeds. In Phycology, conceptacles are specialised cavities of Seaweeds that contain the reproductive organs Another checklist of freshwater algae reported only about 5000 species. It seems therefore that the 20,000 is an overestimate or an error (John, 2002 p. 1). 
The Smithsonian collection of algae has over 300,000 specimens. 
World-wide it is thought that there are over 5,000 species of red algae, 1,500 — 2,000 of brown algae and 8,000 of green algae. In Australia it is estimated that there are over 1,300 species of red algae, 350 species of brown algae and approximately 2,000 species of green algae totalling 3,650 species of algae in Australia. 
669 marine species have been described from California (U. S. A. ). 
642 entities are listed in the check-list of Britain and Ireland (Hardy and Guiry, 2006). 
No publication has been found which attempts to discuss the general distribution of algae in the seas world-wide. However, notes and comments have been made by some authors. The floristic discontinuities may appear to determined by geographical features such as Antarctica, long distances of ocean or general land masses. However, the distances between Norway, the Faroes and Iceland do not show great changes in distribution. 
There has been dispersal in some species by ships, water currents and the like; further, some algae can quickly become entangled and make drifting mats.  Two red species have been introduced from the Pacific to Europe and the Mediterranean: Bonnemaisonia hamifera Hariot and Asparagopsis armata Harvey, A. The Pacific Ocean is the largest of the Earth 's Oceanic divisions armata is a native of Australia. For a topic outline on this subject see List of basic Australia topics. Colpomenia peregrina is a native of the Pacific but has also invaded Europe. Colpomenia peregrina (Sauvageau Hamel is a Seaweed ( Alga) not native to the British Isles but recorded in Ireland since 1934
For centuries seaweed has been used as a fertilizer; Orwell writing in the 16th Century referring to drift weed in South Wales: "This kind of ore they often gather and lay in heaps where it heats and rots, and will have a strong and loathsome smell; when being so rotten they cast it on the land, as they do their muck, and thereof springeth good corn, especially barley" and "After spring tides or great rigs of the sea, they fetch it in sacks on horse brackets, and carry the same three, four, or five miles, and cast it on the lande, which doth very much better the ground for corn and grass" (Chapman p. Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae. 35). 
Algae are used by humans in many ways. They are used as fertilizers, soil conditioners and are a source of livestock feed.  Because many species are aquatic and microscopic, they are cultured in clear tanks or ponds and either harvested or used to treat effluents pumped through the ponds. Algaculture on a large scale is an important type of aquaculture in some places. See also Algae Algaculture is a form of Aquaculture involving the farming of species of Algae. Aquaculture is the farming of freshwater and saltwater organisms including Molluscs Crustaceans and aquatic plants
Maerl is commonly used as a soil conditioner, it is dredged from the sea floor and crushed to form a powder. Maerl is a collective name for two or three Species of Red algae in the Corallinacease  It is still harvested around the coasts of Brittany in France and off Falmouth, Cornwall (also extensively in western Ireland) and is a popular fertilizer in these days of organic gardening investigated Falmouth maerl and found that L. Brittany (Breizh bʁejs Bretagne; Gallo: Bertaèyn) is a former independent Celtic kingdom and Duchy, now incorporated into This article is about the country For a topic outline on this subject see List of basic France topics. Falmouth (Aberfal is a town Civil parish and Port on the River Fal on the south coast of Cornwall, England, UK. corallioides predominated down to 6 m and P. calcareum from 6-10 m (Blunden et al. , 1981). 
Chemical analysis of maerl showed that it contained 32. 1% CaCO3 and 3. 1% MgCO3 (dry weight).
Chondrus crispus, (probably confused with Mastocarpus stellatus, common name: Irish moss), is also used as "carrageen". Chondrus crispus, known under the common name Irish moss, or carrageen moss ( Irish carraigín, "little rock" is a species Mastocarpus stellatus, also called Clúimhín Cait Puff Carragheen or Carrageen Moss is closely related to Irish Moss, or Chondrus crispus Chondrus crispus, known under the common name Irish moss, or carrageen moss ( Irish carraigín, "little rock" is a species The name carrageenan comes from the Irish Gaelic for Chondrus crispus. It is an excellent stabiliser in milk products - it reacts with the milk protein caesin, other products include: petfoods, toothpaste, ice-creams and lotions etc.  Alginates in creams and lotions are absorbable through the skin. 
Seaweeds are an important source of food, especially in Asia; They are excellent sources of many vitamins including: A, B1, B2, B6, niacin and C. For the similarly spelled pyrimidine see Thymine Thiamin or thiamine, also known as Vitamin B1 Riboflavin ( E101) also known as vitamin B2, is an easily absorbed Micronutrient with a key role in maintaining Health Vitamin B6 is a water-soluble Vitamin. Pyridoxal phosphate (PLP is the active form and is a cofactor in many reactions of Amino acid metabolism including Niacin, also known as vitamin B3, is a water-soluble vitamin which prevents the deficiency disease Pellagra. Vitamin C or L-ascorbate is an Essential nutrient for a large number of higher primate species a small number of other Mammalian They are rich in iodine, potassium, iron, magnesium and calcium. Iodine (ˈaɪədaɪn ˈaɪədɪn or /ˈaɪədiːn/ from ιώδης iodes "violet" is a Chemical element that has the symbol I and Atomic Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 
Algae is commercially cultivated as a nutritional supplement. One of the most popular microalgal species is Spirulina (Arthrospira platensis), which is a Cyanobacteria (known as blue-green algae), and has been hailed by some as a superfood. Spirulina is the common name for human and animal food supplements produced primarily from two species of Cyanobacteria (also known as blue-green algae Arthrospira Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy  Other algal species cultivated for their nutritional value include; Chlorella (a green algae), and Dunaliella (Dunaliella salina), which is high in beta-carotene and is used in vitamin C supplements. Chlorella is a Genus of single- celled green Algae, belonging to the phylum Chlorophyta. In taxonomy, Dunaliella is a genus of Algae, specifically of the Dunaliellaceae. Beta-carotene is an Organic compound - a Terpenoid, a red-orange pigment abundant in plants and fruits
In China at least 70 species of algae are eaten as is the Chinese "vegetable" known as fat choy (which is actually a cyanobacterium). Fat choy ( Nostoc flagelliforme) also known as faat choy, black moss, hair moss or hair weed is a terrestrial Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy Roughly 20 species of algae are used in everyday cooking in Japan. 
Certain species are edible; the best known, especially in Ireland is Palmaria palmata (Linnaeus) O. Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously Kuntze, also known as Rhodymenia palmata (Linnaeus) Kuntze, common name: dulse). Palmaria palmata (L Kuntze also called dulse, dillisk, dilsk or creathnach, is a Red alga ( Rhodophyta) previously  This is a red alga which is dried and may be bought in the shops in Ireland. Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world It is eaten raw, fresh or dried, or cooked like spinach. Similarly, Durvillaea antarctica  is eaten in Chile, common name: cochayuyo. 
Porphyra (common name: purple laver), is also collected and used in a variety of ways (e. Porphyra is a foliose Red algal genus of laver, comprising approximately 70 species Laver is an edible Seaweed that has a high Mineral salt content particularly Iodine and Iron. g. "laver bread" in the British Isles). In Ireland it is collected and made into a jelly by stewing or boiling. Preparation also involves frying with fat or converting to a pinkish jelly by heating the fronds in a saucepan with a little water and beating with a fork. It is also collected and used by people parts of Asia, specifically China, Korea (gim) and Japan (nori) and along most of the coast from California to British Columbia. Gim ( 김) sometimes spelled kim, is a Korean -style edible Seaweed in the genus Porphyra, similar Nori (海苔 ( 김 kim or gim) is the Japanese name for various edible Seaweed species of the Red alga Porphyra California ( is a US state on the West Coast of the United States, along the Pacific Ocean. British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C The Hawaiians and the Maoris of New Zealand also use it. New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island
One particular use is in "instant" puddings, sauces and creams. Ulva lactuca (common name: sea lettuce), is used locally in Scotland where it is added to soups or used in salads. Alaria esculenta (common name: badderlocks or dabberlocks), is used either fresh or cooked, in Greenland, Iceland, Scotland and Ireland. Alaria esculenta is an edible Seaweed, also known as dabberlocks or badderlocks, or winged Kelp. Greenland (Kalaallit Nunaat meaning "Land of the Greenlanders" Grønland is a self-governing Danish Province located between the Iceland, officially the Republic of Iceland ( ( Ísland or Lýðveldið Ísland ( Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain.
The oil from some algae have high levels of unsaturated fatty acids. Arachidonic acid (a polyunsaturated fatty acid), is very high in Parietochloris incisa, (a green alga) where it reaches up to 47% of the triglyceride pool (Bigogno C et al. Arachidonic acid (AA sometimes ARA is an Omega-6 fatty acid 204(ω-6 Phytochemistry 2002, 60, 497).  
It is a known fact that fish oil contains the omega-3 fatty acids docosahexaenoic acid, commonly known as DHA and eicosapentaenoic acid, or EPA; but The Martek Biosciences Corporation who discovered the source of DHA to be from algae manufactures DHA from algae, which is where fish get their DHA, explains J. Casey Lippmeier, Martek's senior scientist.
The algae are eaten by smaller marine life such as copepods, "and those are eaten by slightly larger fish," says Lippmeier. The DHA gets passed along the food chain, all the way up to the biggest fish, but the original source is the algae.
You can refer to the following npr. org link for an article on algae and omega-3 fatty acids; http://www.npr.org/templates/story/story.php?storyId=15823852.
There are also commercial uses of algae as agar. 
The natural pigments produced by algae can be used as an alternative to chemical dyes and coloring agents. For the drug referred to as "pigment" see Black tar heroin. A dye can generally be described as a Colored substance that has an affinity to the substrate to which it is being applied  Many of the paper products used today are not recyclable because of the chemical inks that they use, paper recyclers have found that inks made from algae are much easier to break down. There is also much interest in the food industry into replacing the coloring agents that are currently used with coloring derived from algal pigments. Algae can be used to make pharmaceuticalsSewage can be treated with algae as well Some cosmetics can come from microalgae as well. In Israel, a species of green algae is grown in water tanks, then exposed to direct sunlight and heat which causes it to become bright red in color. For a topic outline on this subject see List of basic Israel topics. It is then harvested and used as a natural pigment for foods such as Salmon. 
Between 100,000 and 170,000 wet tons of Macrocystis are harvested annually in California for alginate extraction and abalone feed. Macrocystis is a genus of Kelp ( Algae) This genus contains the largest of all the Phaeophyceae or Brown algae. California ( is a US state on the West Coast of the United States, along the Pacific Ocean.  
Seaweed specimens can be collected and preserved for research. Such preserved specimens will keep for two or three hundred years. Those of Carl von Linné (1707 — 1778) are still available for reference, and are used. Carl Linnaeus (Latinized as Carolus Linnaeus, also known after his ennoblement as, May 23 new style (13 May old style 1707 who laid the foundations for Specimens may be collected from the shore; those below low tide must be collected by diving or dredging. The whole algal specimen should be collected, that is the holdfast, stipe and lamina. A holdfast is a Root -like structure that anchors aquatic Sessile organisms such as Seaweed, other sessile Algae, stalked Specimens of algae reproducing will be the more useful for identification and research. When collected the details of the location and site should be noted. They can then be preserved pressed on paper or in a preserving liquid such as alcohol or solution of 5 per cent formalin/seawater. However, formalin is reported to be carcinogenic. 
The ecology of the shores of the British Isles, including a discussion of the different shores from sheltered to exposed along with an exposure scale, is given by Lewis (1964).  An exposure scale of five stages is given:- Very Exposed Shores; Exposed Shores; Semi-exposed Shores; Sheltered Shores and Very Sheltered Shores. Factors indicating the differences between these exposure scales are detailed. Very Exposed Shores have a wide Verrucaria zone entirely above the upper tide level, a Porphyra zone above the barnacle level and Lichina pygmaea is locally abundant. The eulittoral zone is dominated by barnacles and limpets with a coralline belt in the very low littoral along with other Rhodophyta and Alaria in the upper sublittoral. A barnacle is a type of Arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence distantly related to The name Limpet is used for many kinds of mostly saltwater but also freshwater Snails specifically those that have a simple shell which is more or less broadly conical Brown algae, in the Kingdom Chromista, Order Laminariales and Family Alariaceae there are up to 14 Species Exposed shores show a Verrucaria belt mainly above the high tide, with Porphyra and Lichina pygmaea. The mid shore is dominated by barnacles, limpets and some Fucus. Some Rhodophyta. Himanthalia and some Rhodophyta such as Mastocarpus and Corallina are found in the low littorral with Himanthalia, Alaria and Laminaria digitata dominant in the upper sublittoral. Brown algae, in the Kingdom Chromista, Order Laminariales and Family Alariaceae there are up to 14 Species Laminaria is a Genus of 31 Species of Brown algae ( Phaeophyceae) all sharing the common name " Kelp " The semi-exposed shores show a Verrucaria belt just above high tide with clear Pelvetia in the upper-littoral and Fucus serratus in the lower-littoral. Limpets, barnacles and short Fucus vesiculosus midshore. Fucus serratus with Rhodophyta, (Laurencia, Mastocarpus stellatus, Rhodymenia and Lomentaria). Mastocarpus stellatus, also called Clúimhín Cait Puff Carragheen or Carrageen Moss is closely related to Irish Moss, or Chondrus crispus Laminaria and Saccorhiza polyschides and small algae common in the sublittoral. The sheltered shores show a narrow Verrucaria zone at high water and a full sequence of fucoids: Pelvetia, Fucus spiralis, Fucus vesiculosus, Fucus serratus, Ascophyllum nodosum. Laminaria digitata is dominant the upper sublittoral. The very sheltered shores show a very narrow zone of Verrucaria, the dominance of the littoral by a full sequence of the fucoids and Ascophyllum covering the rocks. Laminaria saccharina, Halidrys, Chondrus and or Furcellaria.