Editing Algae (section)

==Uses==
[[File:Algae Harvester.jpg|thumb|Harvesting algae]]

===Agar===
[[Agar]], a [[gelatin]]ous substance derived from red algae, has a number of commercial uses.<ref>{{cite book |last1=Lewis |first1=J. G. |last2=Stanley |first2=N. F. |last3=Guist |first3=G. G. |editor1-last=Lembi |editor1-first=C. A. |editor2-last=Waaland |editor2-first=J. R. |title=Algae and Human Affairs |date=1988 |publisher=Cambridge University Press |isbn=978-0-521-32115-0 |contribution=9. Commercial production of algal hydrocolloides}}</ref> It is a good medium on which to grow bacteria and fungi, as most microorganisms cannot digest agar.

===Alginates===
[[Alginic acid]], or alginate, is extracted from [[brown algae]]. Its uses range from gelling agents in food, to medical dressings. Alginic acid also has been used in the field of [[biotechnology]] as a [[Biocompatibility|biocompatible medium]] for cell encapsulation and cell immobilization. [[Molecular cuisine]] is also a user of the substance for its gelling properties, by which it becomes a delivery vehicle for flavours.

Between 100,000 and 170,000 wet tons of ''[[Macrocystis]]'' are harvested annually in [[New Mexico]] for [[Alginic acid|alginate]] extraction and [[abalone]] feed.<ref>{{cite web |url= http://www.algaebase.org/generadetail.lasso?genus_id=35715&-session=abv3:51909EC307dcf25DFApmi3530315 |publisher=AlgaeBase |title=Macrocystis C. Agardh 1820: 46 |access-date=28 December 2008 |url-status=live |archive-url= https://web.archive.org/web/20090104145632/http://www.algaebase.org/generadetail.lasso?genus_id=35715&-session=abv3%3A51909EC307dcf25DFApmi3530315 |archive-date=4 January 2009}}</ref><ref>{{cite web |url= http://botany.si.edu/projects/algae/economicuses/brownalgae.htm |work=Algae Research |publisher=Smithsonian National Museum of Natural History |title=Secondary Products of Brown Algae |access-date=29 December 2008 |url-status=live |archive-url= https://web.archive.org/web/20090413034226/http://botany.si.edu/projects/algae/economicuses/brownalgae.htm |archive-date=13 April 2009}}</ref>

===Energy source===
{{Main|Algae fuel|Biological hydrogen production|Biohydrogen|Biodiesel|Ethanol fuel|Butanol fuel|Vegetable oil|Biogas|Hydrothermal Liquefaction}}

To be competitive and independent from fluctuating support from (local) policy on the long run, biofuels should equal or beat the cost level of fossil fuels. Here, algae-based fuels hold great promise,<ref>{{cite journal |last=Chisti |first=Y. |title=Biodiesel from microalgae |journal=Biotechnology Advances |date=May–Jun 2007 |volume=25 |issue=3 |pages=294–306 |pmid=17350212 |doi=10.1016/j.biotechadv.2007.02.001 |s2cid=18234512 |url= https://www.academia.edu/2137836}}</ref><ref>{{cite journal |last1=Yang |first1=Z. K. |last2=Niu |first2=Y. F. |last3=Ma |first3=Y. H. |last4=Xue |first4=J. |last5=Zhang |first5=M. H. |last6=Yang |first6=W. D. |last7=Liu |first7=J. S. |last8=Lu |first8=S. H. |last9=Guan |first9=Y. |last10=Li |first10=H. Y. |title=Molecular and cellular mechanisms of neutral lipid accumulation in diatom following nitrogen deprivation. |journal=Biotechnology for Biofuels |date=4 May 2013 |volume=6 |issue=1 |page=67 |pmid=23642220 |doi=10.1186/1754-6834-6-67 |pmc=3662598 |doi-access=free |bibcode=2013BB......6...67Y }}</ref> directly related to the potential to produce more biomass per unit area in a year than any other form of biomass. The break-even point for algae-based biofuels is estimated to occur by 2025.<ref>{{Cite journal |doi=10.1126/science.1189003 |pmid=20705853 |bibcode=2010Sci...329..796W |title=An Outlook on Microalgal Biofuels |journal=Science |volume=329 |issue=5993 |pages=796–799 |last1=Wijffels |first1=René H. |last2=Barbosa |first2=Maria J. |s2cid=206526311 |year=2010 }}</ref>

===Fertilizer===
{{Details|Seaweed fertiliser}}
[[File:Inisheer landscape.jpg|thumb|Seaweed-fertilized gardens on [[Inisheer]]]]
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]]:<ref>{{cite journal |journal=Journal of the Royal Agricultural Society of England |volume=10 |pages=142–143 |title=On the Farming of South Wales: Prize Report |first=Clare Sewell |last=Read |author-link=Clare Sewell Read |year=1849 |url= https://books.google.com/books?id=UJYEAAAAYAAJ&pg=PA142}}</ref>
{{Quote|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&nbsp;... 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 [[fertilizer]]s, [[soil conditioner]]s, and livestock feed.<ref>{{cite book |last=McHugh |first=Dennis J. |title=A Guide to the Seaweed Industry: FAO Fisheries Technical Paper 441 |chapter-url= http://www.fao.org/DOCREP/006/Y4765E/y4765e0c.htm#TopOfPage |date=2003 |publisher=Fisheries and Aquaculture Department, Food and Agriculture Organization (FAO) of the United Nations |location=Rome |isbn=978-92-5-104958-7|chapter=9, Other Uses of Seaweeds |url-status=live |archive-url= https://web.archive.org/web/20081228115716/http://www.fao.org/docrep/006/y4765e/y4765e0c.htm#TopOfPage |archive-date=28 December 2008}}</ref> 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.

===As food===
{{See also|Edible seaweed|Algae powder}}
[[File:Dulse.JPG|thumb|Dulse, a type of edible seaweed]]

Algae are used as foods in many countries: China consumes more than 70 species, including ''[[fat choy (vegetable)|fat choy]]'', a cyanobacterium considered a vegetable; Japan, over 20 species such as ''[[nori]]'' and ''[[aonori]]'';<ref>{{cite book |last1=Mondragón |first1=Jennifer |last2=Mondragón |first2=Jeff |title=Seaweeds of the Pacific Coast |date=2003 |publisher=Sea Challengers Publications |location=Monterey, California |isbn=978-0-930118-29-7}}</ref> Ireland, [[dulse]]; [[Chile]], [[cochayuyo]].<ref>{{cite web |url= http://www.algaebase.org/speciesdetail.lasso?species_id=11752&sk=0&from=results&-session=abv3:51909EC30802716127sVj3EDC9C7 |publisher=AlgaeBase |title=Durvillaea antarctica (Chamisso) Hariot}}</ref> [[Porphyra umbilicalis|Laver]] is used to make [[laverbread]] in [[Wales]], where it is known as {{lang|cy|bara lawr}}. In [[Korea]], [[green laver]] is used to make {{lang|ko-Latn|[[Gim (Korean food)|gim]]}}.<ref>{{Cite web |title=Laver Archives |url=https://kimchimari.com/ingredient/laver/ |access-date=2024-12-15 |website=Kimchimari |language=en-US}}</ref>

Three forms of algae used as food:
* ''[[Chlorella]]'': This form of alga is found in freshwater and contains [[photosynthetic]] pigments in its [[chloroplast]].
* [[Klamath Lake AFA|Klamath AFA]]: A subspecies of Aphanizomenon flos-aquae found wild in many bodies of water worldwide but harvested only from [[Upper Klamath Lake]], Oregon.
* ''[[Spirulina (genus)|Spirulina]]'': Known otherwise as a cyanobacterium (a [[prokaryote]] or a "blue-green alga")

The oils from some algae have high levels of [[unsaturated fatty acid]]s. Some varieties of algae favored by [[vegetarianism]] and [[veganism]] contain the long-chain, essential [[omega-3 fatty acid]]s, [[docosahexaenoic acid]] (DHA) and [[eicosapentaenoic acid]] (EPA).<ref name=":0">{{Cite web |date=2013-05-22 |title=Vegetarian EPA DHA and Essential Fats |url=http://vegetarian-dha-epa.co.uk/ |access-date=2024-12-15 |archive-url=https://web.archive.org/web/20130522103010/http://vegetarian-dha-epa.co.uk/ |archive-date=22 May 2013 }}</ref> Fish oil contains the omega-3 fatty acids, but the original source is algae (microalgae in particular), which are eaten by marine life such as [[copepod]]s and are passed up the food chain.<ref name=":0" />

===Pollution control===
* Sewage can be treated with algae,<ref>{{cite web |title=Re-imagining algae |date=12 October 2016 |publisher=Australian Broadcasting Corporation |url= http://www.abc.net.au/radionational/programs/futuretense/re-imagining-algae/7926214-AU |access-date=26 January 2017 |url-status=live |archive-url= https://web.archive.org/web/20170202043210/http://www.abc.net.au/radionational/programs/futuretense/re-imagining-algae/7926214 |archive-date=2 February 2017}}</ref> reducing the use of large amounts of toxic chemicals that would otherwise be needed.
* Algae can be used to capture fertilizers in runoff from farms. When subsequently harvested, the enriched algae can be used as fertilizer.
* Aquaria and ponds can be filtered using algae, which absorb nutrients from the water in a device called an [[algae scrubber]], also known as an algae turf scrubber.<ref>{{cite web |url= http://www.reefbase.org/resource_center/publication/main.aspx?refid=10859 |title=Nutrient cycling in the Great Barrier Reef Aquarium – Proceedings of the 6th International Coral Reef Symposium, Australia |year=1988 |volume=2 |last1=Morrissey |first1=J. |last2=Jones |first2=M. S. |last3=Harriott |first3=V. |publisher=ReefBase |url-status=live |archive-url= https://web.archive.org/web/20150223045428/http://www.reefbase.org/resource_center/publication/main.aspx?refid=10859 |archive-date=23 February 2015}}</ref><ref>{{cite journal |url= http://www3.interscience.wiley.com/journal/120083425/abstract |archive-url= https://archive.today/20101001181747/http://www3.interscience.wiley.com/journal/120083425/abstract |url-status=dead |archive-date=1 October 2010 |title=Algal Response to Nutrient Enrichment in Forested Oligotrophic Stream |doi=10.1111/j.1529-8817.2008.00503.x |pmid=27041416 |volume=44 |issue=3 |journal=Journal of Phycology |pages=564–572 |year=2008 |last1=Veraart |first1=Annelies J. |last2=Romaní |first2=Anna M. |last3=Tornés |first3=Elisabet |last4=Sabater |first4=Sergi|bibcode= 2008JPcgy..44..564V |s2cid= 2040067 }}</ref>

[[Agricultural Research Service]] scientists found that 60–90% of nitrogen runoff and 70–100% of phosphorus runoff can be captured from [[manure effluents]] using a horizontal algae scrubber, also called an [[algal turf scrubber]] (ATS). Scientists developed the ATS, which consists of shallow, 100-foot raceways of nylon netting where algae colonies can form, and studied its efficacy for three years. They found that algae can readily be used to reduce the nutrient runoff from agricultural fields and increase the quality of water flowing into rivers, streams, and oceans. Researchers collected and dried the nutrient-rich algae from the ATS and studied its potential as an organic fertilizer. They found that cucumber and corn seedlings grew just as well using ATS organic fertilizer as they did with commercial fertilizers.<ref>{{cite web |url= http://www.ars.usda.gov/is/AR/archive/may10/algae0510.htm |title=Algae: A Mean, Green Cleaning Machine |publisher=USDA Agricultural Research Service |date=7 May 2010 |url-status=live |archive-url= https://web.archive.org/web/20101019142625/http://www.ars.usda.gov/is/AR/archive/may10/algae0510.htm |archive-date=19 October 2010}}</ref> Algae scrubbers, using bubbling upflow or vertical waterfall versions, are now also being used to filter aquaria and ponds.

===Polymers===
Various polymers can be created from algae, which can be especially useful in the creation of bioplastics. These include hybrid plastics, cellulose-based plastics, poly-lactic acid, and bio-polyethylene.<ref>{{Cite web |url= http://www.oilgae.com/non_fuel_products/biopolymers.html |title=Algae Biopolymers, Companies, Production, Market – Oilgae – Oil from Algae |work=oilgae.com |access-date=18 November 2017}}</ref> Several companies have begun to produce algae polymers commercially, including for use in flip-flops<ref>{{Cite news |url= https://www.zmescience.com/science/algae-flip-flop/ |title=Renewable flip flops: scientists produce the 'No. 1' footwear in the world from algae |date=9 October 2017 |work=ZME Science |access-date=18 November 2017}}</ref> and in surf boards.<ref>{{Cite web |url= https://www.energy.gov/eere/bioenergy/articles/world-s-first-algae-surfboard-makes-waves-san-diego |title=World's First Algae Surfboard Makes Waves in San Diego |work=Energy.gov |access-date=18 November 2017}}</ref> Even algae is also used to prepare various polymeric resins suitable for [[coating]] applications.<ref>Chandrashekhar K Patil, Harishchandra D Jirimali, Jayasinh S Paradeshi, Bhushan L Chaudhari, Prakash K Alagi, Sung Chul Hong, Vikas V Gite, Synthesis of biobased polyols using algae oil for multifunctional polyurethane coatings, Volume 6 Issue 4, December 2018, pp. 165-177, https://doi.org/10.1680/jgrma.18.00046</ref><ref>CK Patil, HD Jirimali, JS Paradeshi, BL Chaudhari, VV Gite, Functional antimicrobial and anticorrosive polyurethane composite coatings from algae oil and silver doped egg shell hydroxyapatite for sustainable development, Progress in Organic Coatings 128, 127-136, https://doi.org/10.1016/j.porgcoat.2018.11.002</ref><ref>Chandrashekhar K Patil, Harishchandra D Jirimali, Jayasinh S Paradeshi, Bhushan L Chaudhari, Prakash K Alagi, Pramod P Mahulikar, Sung Chul Hong, Vikas V Gite, Chemical transformation of renewable algae oil to polyetheramide polyols for polyurethane coatings, Progress in Organic Coatings 151, 106084, https://doi.org/10.1016/j.porgcoat.2020.106084</ref>

===Bioremediation===
The alga ''[[Stichococcus bacillaris]]'' has been seen to colonize silicone resins used at archaeological sites; [[Biodegradation|biodegrading]] the synthetic substance.<ref>{{cite journal |title=Microorganisms Attack Synthetic Polymers in Items Representing Our Cultural Heritage |first1=Francesca |last1=Cappitelli |first2=Claudia |last2=Sorlini |journal=Applied and Environmental Microbiology |year=2008 |volume=74 |pmc=2227722 |issue=3 |pages=564–569 |doi=10.1128/AEM.01768-07 |pmid=18065627|bibcode=2008ApEnM..74..564C }}</ref>

===Pigments===
The natural [[pigment]]s ([[carotenoid]]s and [[chlorophyll]]s) produced by algae can be used as alternatives to chemical [[dye]]s and coloring agents.<ref>{{cite book |last1=Arad |first1=Shoshana |last2=Spharim |first2=Ishai |editor-last=Altman |editor-first=Arie |title=Agricultural Biotechnology |series=Books in Soils, Plants, and the Environment |volume=61 |date=1998 |publisher=CRC Press |isbn=978-0-8247-9439-2 |page=638 |contribution=Production of Valuable Products from Microalgae: An Emerging Agroindustry}}</ref>
The presence of some individual algal pigments, together with specific pigment concentration ratios, are taxon-specific: analysis of their concentrations with various analytical methods, particularly [[high-performance liquid chromatography]], can therefore offer deep insight into the taxonomic composition and relative abundance of natural algae populations in sea water samples.<ref>{{cite journal |first1=C. |last1=Rathbun |first2=A. |last2=Doyle |first3=T. |last3=Waterhouse |date=June 1994 |title=Measurement of Algal Chlorophylls and Carotenoids by HPLC |url= http://bats.bios.edu/methods/chapter13.pdf |journal=Joint Global Ocean Flux Study Protocols |volume=13 |pages=91–96 |url-status=dead |archive-url= https://web.archive.org/web/20160304064738/http://bats.bios.edu/methods/chapter13.pdf |archive-date=4 March 2016 |access-date=7 July 2014}}</ref><ref>{{cite journal |first1=M. |last1=Latasa |first2=R. |last2=Bidigare |year=1998 |title=A comparison of phytoplankton populations of the Arabian Sea during the Spring Intermonsoon and Southwest Monsoon of 1995 as described by HPLC-analyzed pigments |journal=Deep-Sea Research Part II |issue=10–11 |pages=2133–2170 |doi=10.1016/S0967-0645(98)00066-6 |bibcode=1998DSRII..45.2133L |volume=45}}</ref>

===Stabilizing substances===
{{Main|Carrageenan|Chondrus crispus}}
Carrageenan, from the red alga ''Chondrus crispus'', is used as a stabilizer in milk products.