Algae

For other uses, see Algae (disambiguation).

Algae
Laurencia, a marine genus of Red Algae from Hawaii.
Scientific classification
Domain:	Eukaryota
Groups included
Apicomplexa Axodines Bolidomonas Brown algae Charophyta Cryptomonads Diatoms Dinoflagellates Euglenids Eustigmatophytes Glaucophytes Golden algae Green algae Heterokonts Pelagophyceae Phaetothamniophyceae Pinguiophyceae Prymnesiophyta Raphidophytes Red algae Synurids Yellow-green algae others... please help complete this list
Cladistically included but traditionally excluded taxa
Cyanobacteria Plantae

The lineage of algae according to Thomas Cavalier-Smith. The exact number and placement of endosymbiotic events is not yet clear, so this diagram can be taken only as a general guide. Endosymbiotic events are noted by dotted lines.

Algae (a Latin plural) are a large and diverse paraphyletic group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. For that reason they are currently excluded from being considered plants.

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to as Blue-green Algae) were traditionally included as "Algae" in older textbooks, many modern sources regard this as outdated and restrict the term Algae to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and chloroplasts bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group, as they do not all descend from a common algal ancestor, although their chloroplasts seem to have a single origin.

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. 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. Some unicellular species rely entirely on external energy sources and have limited or no photosynthetic apparatus.

All algae have photosynthetic machinery ultimately derived from the Cyanobacteria, and so produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria.

Study of algae

The singular alga is the Latin word for a particular seaweed and retains that meaning in English. The etymology is obscure. Although some speculate that it is related to Latin algēre, "be cold", there is no known reason to associate seaweed with temperature. A more likely source is alliga, "binding, entwining." Since Algae has become a biological classification, alga can also mean one individual of any of the classifications under Algae; however, the meaning of subclassification is excluded.

The ancient Greek word for seaweed was φῦκος (fūkos or phykos), which could mean either the seaweed, probably Red Algae, or a red dye derived from it. The Latinization, fūcus, meant primarily the cosmetic rouge. The etymology is uncertain, but a strong candidate has long been some word related to the Biblical פוך (pūk), "paint" (if not that word itself), a cosmetic eye-shadow used by the ancient Egyptians and other inhabitants of the eastern Mediterranean. It could be any color: black, red, green, blue.

Accordingly the modern study of marine and freshwater algae is called either phycology or algology. The name Fucus appears in a number of taxa.

Classification

While Cyanobacteria have been traditionally included among the Algae, recent works 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 those of the Eukaryotes.. Rather than in chloroplasts, they conduct photosynthesis on specialized infolded cytoplasmic membranes called thylakoid membranes. 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. Chloroplasts contain circular DNA and are similar in structure to Cyanobacteria, presumably representing reduced cyanobacterial endosymbionts. The exact nature of the chloroplasts is different among the different lines of Algae, reflecting different endosymbiotic events. The table below describes the composition of the three major groups of Algae. Their lineage relationships are shown in the figure in the upper right. Many of these groups contain some members that are no longer photosynthetic. Some retain plastids, but not chloroplasts, while others have lost plastids entirely.

Supergroup affiliation	Members	Endosymbiont	Summary
Primoplantae/ Archaeplastida	Chlorophyta Rhodophyta Glaucophyta	Cyanobacteria	These Algae have primary chloroplasts, i.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 Green Algae have chloroplasts with chlorophyll a and b. 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.
Excavata and Rhizaria	Chlorarachniophytes Euglenids	Green Algae	These groups have green chloroplasts containing chlorophylls a and b . Their chloroplasts are surrounded by four and three membranes, respectively, and were probably retained from ingested Green Algae. Chlorarachniophytes, which belong to the phylum Cercozoa, contain a small nucleomorph, which is a relict of the algae's nucleus. Euglenids, which belong to the phylum Euglenozoa, live primarily in freshwater and have chloroplasts with only three membranes. It has been suggested that the endosymbiotic Green Algae were acquired through myzocytosis rather than phagocytosis.
Chromista and Alveolata	Heterokonts Haptophyta Cryptomonads Dinoflagellates	Red Algae	These groups have chloroplasts containing chlorophylls a and c, and phycobilins. 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, although other evidence casts doubt on whether the Heterokonts, Haptophyta, and Cryptomonads are in fact more closely related to each other than to other groups. The typical dinoflagellate chloroplast has three membranes, but there is considerable diversity in chloroplasts within the group, and it appears there were a number of endosymbiotic events. The Apicomplexa, a group of closely related parasites, also have plastids called apicoplasts. Apicoplasts are not photosynthetic but appear to have a common origin with Dinoflagellate chloroplasts.

W.H.Harvey (1811 — 1866) was the first to divide the Algae into four divisions based on their pigmentation. This is the first use of a biochemical criterion in plant systematics. Harvey's four divisions are: Red Algae (Rhodophyta), Brown Algae (Heteromontophyta), Green Algae (Chlorophyta) and Diatomaceae.

Relationship to higher plants

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.

Morphology

The kelp forest exhibit at the Monterey Bay Aquarium. A three-dimensional, multicellular thallus.

A range of algal morphologies are exhibited, and convergence of features in unrelated groups is common. The only groups to exhibit three dimensional multicellular thalli are the reds and browns, and some chlorophytes. Apical growth is constrained to subsets of these groups: the florideophyte reds, various browns, and the charophytes. The form of charophytes is quite different to those of reds and browns, because have distinct nodes, separated by internode 'stems'; whorls of branches reminiscent of the horsetails occur at the nodes. Conceptacles are another polyphyletic trait; they appear in the coralline algae and the Hildenbrandiales, as well as the browns.

Most of the simpler algae are unicellular flagellates or amoeboids, but colonial and non-motile forms have developed independently among several of the groups. Some of the more common organizational levels, more than one of which may occur in the life cycle of a species, are

• Colonial: small, regular groups of motile cells
• Capsoid: individual non-motile cells embedded in mucilage
• Coccoid: individual non-motile cells with cell walls
• Palmelloid: non-motile cells embedded in mucilage
• Filamentous: a string of non-motile cells connected together, sometimes branching
• Parenchymatous: cells forming a thallus with partial differentiation of tissues

In three lines even higher levels of organization have been reached, with full tissue differentiation. These are the brown algae,—some of which may reach 50 m in length (kelps)—the red algae, and the green algae. 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 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.

Symbiotic Algae

Some species of Algae form symbiotic relationships with other organisms. In these symbioses, the algae supply photosynthates (organic substances) to the host organism providing protection to the algal cells. The host organism derives some or all of its energy requirements from the algae. Examples include

• lichens: a fungus is the host, usually with an alga of the Green Algae or a bacterium of the Cyanobacteria as its symbiont. Both fungal and algal species found in lichens are capable of living independently, although habitat requirements may be greatly different from those of the lichen pair.
• corals: algae known as zooxanthellae are symbionts with corals. Notable amongst these is the dinoflagellate Symbiodinium, found in many hard corals. The loss of Symbiodinium, or other zooxanthellae, from the host is known as coral bleaching.
• sponges: Green Algae live close to the surface of some sponges, for example, breadcrumb sponge (Halichondria panicea). The alga is thus protected from predators; the sponge is provided with oxygen and sugars which can account for 50 to 80% of sponge growth in some species.

Life-cycle

Rhodophyta, Chlorophyta and Heterokontophyta, the three main algal Phyla, have life-cycles which show tremendous variation with considerable complexity. 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. 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.

Further information: Conceptacle

Numbers

The Algal Collection of the U.S. National Herbarium (located in the National Museum of Natural History) consists of approximately 320500 dried specimens, which, although not exhaustive (no exhaustive collection exists), gives an idea of the order of magnitude of the number of algal species (that number remains unknown). Estimates vary widely. For example, according to one standard textbook, in the British Isles the UK Biodiversity Steering Group Report estimated there to be 20000 algal species in the UK. Another checklist reports only about 5000 species. Regarding the difference of about 15000 species, the text concludes: "It will require many detailed field surveys before it is possible to provide a reliable estimate of the total number of species ...."

Regional and group estimates have been made as well: 5000 — 5500 species of Red Algae worldwide, "some 1300 in Australian Seas," 400 seaweed species for the western coastline of South Africa, 669 marine species from California (U.S.A.), 642 in the check-list of Britain and Ireland, and so on, but lacking any scientific basis or reliable sources, these numbers have no more credibility than the British ones mentioned above. Most estimates also omit the microscopic Algae, such as the phytoplankta, entirely.

Distribution

The topic of distribution of algal species has been fairly well studied since the founding of phytogeography in the mid-19th century AD. Algae spread mainly by the dispersal of spores analogously to the dispersal of Plantae by seeds and spores. Spores are everywhere in all parts of the Earth: the waters fresh and marine, the atmosphere, free-floating and in precipitation or mixed with dust, the humus and in other organisms, such as humans. Whether a spore is to grow into an organism depends on the combination of the species and the environmental conditions.

The spores of fresh-water Algae are dispersed mainly by running water and wind, as well as by living carriers. The bodies of water into which they are transported are chemically selective. Marine spores are spread by currents. Ocean water is temperature selective, resulting in phytogeographic zones, regions and provinces.

To some degree the distribution of Algae is subject to floristic discontinuities caused by geographical features, such as Antarctica, long distances of ocean or general land masses. It is therefore possible to identify species occuring by locality, such as "Pacific Algae" or "North Sea Algae". When they occur out of their localities, it is usually possible to hypothesize a transport mechanism, such as the hulls of ships. For example, Ulva reticulata and Ulva fasciata travelled from the mainland to Hawaii in this manner.

Mapping is possible for select species only: "there are many valid examples of confined distribution patterns." For example, Clathromorphum is an arctic genus and is not mapped far south of there. On the other hand, scientists regard the overall data as insufficient due to the "difficulties of undertaking such studies."

Ecology

Algae are prominent in bodies of water, common in terrestrial environments and are found in unusual environments, such as on snow and on ice. Seaweeds grow mostly in shallow marine waters, under 100 metres (330 ft); however some have been recorded to a depth of 360 metres (1,180 ft)

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. In very high densities (algal blooms) these algae may discolor the water and outcompete, poison, or asphyxiate other life forms.

Algae are variously sensitive to different factors, which has made them useful as biological indicators in the Ballantine Scale and its modifications.

Uses

Seaweed is used as a fertilizer.

Fertilizer

For centuries seaweed has been used as a fertilizer; George Owen of Henllys writing in the 16th century referring to drift weed in South Wales:

This kind of ore they often gather and lay on great heapes, where it heteth and rotteth, and will have a strong and loathsome smell; when being so rotten they cast on the land, as they do their muck, and thereof springeth good corn, especially barley ... After spring-tydes or great rigs of the sea, they fetch it in sacks on horse backes, and carie the same three, four, or five miles, and cast it on the lande, which doth very much better the ground for corn and grass.

Today Algae are used by humans in many ways; for example, as fertilizers, soil conditioners and livestock feed. Aquatic and microscopic species are cultured in clear tanks or ponds and are 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. Maerl is commonly used as a soil conditioner.

Energy source

Algae are processed to make various chemical fuels.

Main articles: Algae fuel, Biological hydrogen production, Biohydrogen, Biodiesel, Bioethanol, Biobutanol, and Vegetable oil

Pollution control

• Algae are used in wastewater treatment facilities, reducing the need for greater amounts of toxic chemicals than are already used.
• Algae can be used to capture fertilizers in runoff from farms. When subsequently harvested, the enriched algae itself can be used as fertilizer.
• Algae Bioreactors are used by some powerplants to reduce CO₂ emissions.

Stabilizing substances

Chondrus crispus is used as a stabiliser in milk products.

Main article: Carrageen

Nutrition

Naturally growing seaweeds are an important source of food, especially in Asia. They provide many vitamins including: A, B1, B2, B6, niacin and C, and are rich in iodine, potassium, iron, magnesium and calcium. In addition commercially cultivated microalgae, including both Algae and Cyanobacteria, are marketed as nutritional supplements, such as Spirulina, Chlorella and the Vitamin-C supplement, Dunaliella, high in beta-carotene.

Algae are national foods of many nations: China consumes more than 70 species, including a Cyanobacterium considered a vegetable: fat choy; Japan, over 20 species; Ireland, dulse; Chile, cochayuyo. Laver is used to make "laver bread" in the British Isles; in Korea, gim; in Japan, nori and aonori. It is also used along the west coast of North America from California to British Columbia, in Hawaii and by the Maoris of New Zealand. Sea lettuce and badderlocks are a salad ingredient in Scotland, Ireland, Greenland and Iceland.

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. Phytochemistry 2002, 60, 497).

Some varieties of algae are a vegetarian / vegan / plant based source of long chain essential omega-3 fatty acids Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) in addition to vitamin B12. Fish oil contains the omega-3 fatty acids, but the original source is algae, which are eaten by marine life such as copepods and passed up the food chain.

Alginates

Between 100,000 and 170,000 wet tons of Macrocystis are harvested annually in California for alginate extraction and abalone feed.

Other uses

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. 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. It is then harvested and used as a natural pigment for foods such as Salmon.

Collecting and preserving specimens

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. 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. 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.

Bibliography

General

• Chapman, V.J. (1950). Seaweeds and their Uses. London: Methuen & Co. Ltd.
• Guiry, M.D. (1991). Seaweed Resources in Europe: Uses and Potential. John Wiley & Sons. ISBN 0471929476. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Lembi, C.A. (1988). Algae and Human Affairs. Cambridge: Cambridge University Press. ISBN 0521321158. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Round, F E (1981). The Ecology of Algae. London: Cambridge University Press. ISBN 0521225833.

Identification

• Abbott, I.A. (1976). Marine Algae of California. California: Stanford University Press. ISBN 0804708673. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Brodie, J.A. (2003). Seaweeds of the British Isles. Vol. 1 Part 3B. London: The Natural History Museum. ISBN 1898298874. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Burrows, E.M. (1991). Seaweeds of the British Isles. Vol. 2. London: British Museum (Natural History). ISBN 0565009818.
• Christensen, T. (1987). Seaweeds of the British Isles. Vol. 4, Tribophyceae. London: British Museum (Natural History). ISBN 056500980X.
• Dixon, P.S. (1977). Seaweeds of the British Isles. Vol. 1, Part 1, Introduction, Nemaliales, Gigartinales. London: British Museum (Natural History). ISBN 0565007815. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Greeson, Phillip E. (1982). An annotated key to the identification of commonly occurring and dominant genera of Algae observed in the Phytoplankton of the United States. Washington, D.C.: U.S. Department of the Interior, Geological Survey. Retrieved 2008-12-19.
• Irvine, L.M. (1983). Seaweeds of the British Isles. Vol. 1, Part 2A. London: British Museum (Natural History). ISBN 0565008714.
• Irvine, L.M. (1994). Seaweeds of the British Isles. London: The Natural History Museum. ISBN 0113100167. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |vo;ume= ignored (help)
• Fletcher, R.L. 1987. Seaweeds of the British Isles. Volume 3 Part 1. British Museum (Natural History), London. ISBN 0-565-00992-3
• John, D.M. (2002). The Freshwater Algal Flora of the British Isles. Cambridge University Press, UK. ISBN 0521770513. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Stegenga, H. (1997). Seaweeds of the South African West Coast. Bolus Herbarium, University of Cape Town. ISBN 079921793x. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Taylor, W.R. 1957. Marine algae of the north-eastern coasts of North America. Revised edition. University of Michigan Press. Ann Arbor.

Uses

• Guiry, M D and Blunden, G (Eds) (1991) Seaweed Resources in Europe: Uses and Potential. John Wiley & Sons. ISBN 0-471-92947-6
• Mumford, T F and Miura, A (1988) 4. Porphyra as food: cultivation and economics. p.87 — 117. In Lembi, C.A. and Waaland, J.R. (Ed.) Algae and Human Affairs. 1988. Cambridge University Press. ISBN 0 521 32115 8

Regional

Britain and Ireland

• Hardy, F G and Guiry, M D (2006) A Check-list and Atlas of the Seaweeds of Britain and Ireland. British Phycological Society, London. ISBN 3 906166 35 X
• Cullinane, J P (1973) Phycology of the South Coast of Ireland. The Cork University Press, University College Cork.
• Hardy, F G and Aspinall, R J (1988). An Atlas of the Seaweeds of Northumberland and Durham. Northumberland Biological Records Centre. The Hancock Museum. The University Newcastle upon Tyne. Special publication: 3. ISBN 0 9509680 5 6
• Morton, O (1994) Marine Algae of Northern Ireland. Ulster Museum, Belfast. ISBN 0 900761 28 8
• Morton, O. The marine macroalgae of County Donegal, Ireland. Bull. Ir. biogeog. Soc. 27:3 - 164.
• Knight, M and Park, M W (1931) Manx algae. An algal survey of the south end of the Isle of Man. L.M.B.C. Mem. Typ. Br. Mar. Pl. 390: 1 - 155.

Australia

• Huisman, J M (2000). Marine Plants of Australia. University of Western Australian (UWA) Press. ISBN 1876268336.

New Zealand

• Lindauer, V W; Chapman, V J and Aiken, M (1961) The Marine Algae of New Zealand. Part II. Phaeophyta. Nova Hedwigia 3: 129 - 350.
• Chapman, V J (1969) The Marine Algae of New Zealand. Part III issues 1. Lehre: J. Cramer, 1 - 113.
• Chapman, V J and Dromgoole, F I (1970) The Marine Algae of New Zealand. Part III issues 2. Lehre: J.Cramer, 115 - 154.
• Chapman, V J and Parkinson, P G (1974) The Marine Algae of New Zealand. Part III issues 3. Lehre: J.Cramer,155 - 278.
• Chapman, V J (1979) The Marine Algae of New Zealand. Part III issues 4. Lehre: J.Cramer, 279 - 420.

Europe

• Cabioc'h, J; Floc'h, J Y; Le Toquin, A; Boudouresque, C F; Meinesz, A and Verlaque, M (1992) Guide des algues des mers d'Europe. Delachaux et Niestlé, Switzerland.
• Gayral, P (1958) Algues de la Côte Atlantique Marocaine. Rabat.
• Gayral, P (1966) Algues des Côtes Françaises. Paris.

Arctic

• Kjellman, F R (1883) The algae of the Arctic Sea. K. sevenka. VetenskAkad. Handl. 20: 1 - 350.

Greenland

• Lund, S (1959) The Marine Algae of East Greenland. I. Taxonomical part. Meddr. Grønland 156: 1 - 247.

Faroe Islands

• Borgesen, F (1903) Marine Algae, pp.339 - 532. In, Warming, E. (Ed.), Botany of the Faröes Based Upon Danish Investigations. Part II. Copenhagen. [reprint 1970]

Canary Islands

• Borgesen, F (1925) Marine algae from the Canary Islands, especially from Tenerife and Gran Canaria. I. Chlorophyceae. Biol. Meddr 5: 1 - 113.
• Borgesen, F (1926) Marine algae from the Canary Islands especially from Tenerife and Gran Canaria. II. Phaeophyceae. Biol. Meddr 6: 1 - 112.
• Borgesen, F (1927) Marine algae from the Canary Islands. III. Rhodophyceae. Part I, Bangiales and Nemalionales. Biol. Meddr 6: 1 - 97.
• Borgesen, F (1929) Marine algae from the Canary Islands. III Rhodophyceae. Part II. Cryptonemiales, Gigartinales and Rhodymeniales. Biol. Meddr 8: 1 - 97.
• Borgesen, F (1930) Marine algae from the Canary Islands. III Rhodophyceae. Part II. Cryptonemiales, Gigartinales and Rhodymeniales. Biol. Meddr 9: 1 - 159.

South Africa

• Stegenga, H Bolton, J J and Anderson, R J (1997) Seaweeds of the South African West Coast. Bolus Herbarium Number 18, Publication jointly financed by the Fourcade Bequest and the Research Committee of the University of Cape Town and the Foundation for Research Development.

North America

• Taylor, W R (1957) Marine Algae of the Northeastern Coast of North America. University of Michigan Press, Ann Arbor.
• Abbott, I A and Hollenberg, G J (1976) Marine Algae of California. Stanford University Press, California.
• Wehr, J D and Sheath, R G (2003) Freshwater Algae of North America: Ecology and Classification. Academic Press, USA.

See also

• AlgaeBase
• Microphyte
• Nutrition

External links

• "Algae Research" (html). National Museum of Natural History, Department of Botany. 2008. Retrieved 2008-12-19.
• Anderson, Don (2007). "Harmful Algae" (html). U.S. National Office for Harmful Algal Blooms. Retrieved 2008-12-19. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• "Australian Freshwater Algae (AFA)" (html). Department of Environment and Climate Change NSW Botanic Gardens Trust. Retrieved 2008-12-19.
• "Monterey Bay Flora" (html). Monterey Bay Aquarium Research Institute (MBARI). 1996–2008. Retrieved 2008-12-20.{{cite web}}: CS1 maint: date format (link)
• Silva, Paul (1997–2004). "Index Nominum Algarum (INA)" (html). University Herbarium, University of California. Retrieved 2008-12-19. {{cite web}}: Unknown parameter |city= ignored (|location= suggested) (help)CS1 maint: date format (link)