Algal bloom
47473
222286646
2008-06-28T14:51:11Z
76.170.199.157
deleted doubtful statement
{{generalize}}
[[Image:River algae Sichuan.jpg|right|thumb|Algal blooms can present problems for ecosystems and human society]]
An '''algal bloom''' or '''marine bloom''' or '''water bloom''' is a rapid increase in the population of [[alga]]e in an aquatic system. Algal blooms may occur in freshwater as well as marine environments. Typically only one or a few [[phytoplankton]] species are involved, and some blooms may be recognized by discoloration of the water resulting from the high density of pigmented cells. Although there is no officially recognized threshold level, algae can be considered to be blooming at concentrations of hundreds to thousands of cells per milliliter, depending on the severity. Algal bloom concentrations may reach millions of cells per milliliter. Colors observed are green, yellowish-brown, or red. Bright green blooms may also occur. These are a result of blue-green algae, which are actually bacteria ([[cyanobacteria]]). Blooms may also consist of macroalgal, not phytoplankton, species; these blooms are recognizable by large blades of algae that may wash up onto the shoreline.
Some algal blooms are the result of an excess of nutrients (particularly [[phosphorus]] and [[nitrogen]]) into waters and higher concentrations of these nutrients in water cause increased growth of algae and green plants. As more algae and plants grow, others die. This dead organic matter becomes food for bacteria that decomposes it. With more food available, the bacteria increase in number and use up the dissolved oxygen in the water. When the dissolved oxygen content decreases, many fish and aquatic insects cannot survive. This results in a dead area.
Algal blooms may also be of concern as some species of algae produce [[neurotoxin]]s. At the high cell concentrations reached during some blooms, these toxins may have severe biological impacts on wildlife. Algal blooms composed of phytoplankters known to naturally produce biotoxins are often called Harmful Algal Blooms, or HABs.
[[Image:Coccolithophore bloom.jpg|right|thumb|200px|Satellite image of a large [[coccolithophore]] bloom in the [[Bering Sea]] in [[1998]].]]
Algal blooms are monitored using biomass measurements coupled with the examination of species present. A widely-used measure of algal and cyanobacterial biomass is the [[chlorophyll]] concentration. Peak values of chlorophyll ''a'' for an [[oligotrophic lake]] are about 1-10 µg/l, while in a [[eutrophic lake]] they can reach 300 µg/l. In cases of [[Hypereutrophic|hypereutrophy]], such as [[Hartbeespoort Dam]] in [[South Africa]], maxima of chlorophyll a can be as high as 3,000 µg/l.<ref>{{cite journal
|last=Zohary|first=T.
|coauthors=and R. D. Roberts
|title= Hyperscums and the population dynamics of ''Microcystis aeruginosa''
|journal=J. Plankton Res.|issn=0142-7873|year=1990|volume=12|issue=2|pages=423–432|doi=10.1093/plankt/12.2.423}}
</ref>
<ref>{{cite book
|last=Bartram|first= J.
|coauthors=Wayne W. Carmichael, Ingrid Chorus, Gary Jones, and Olav M. Skulberg
|chapter=Chapter 1. Introduction
|title=Toxic Cyanobacteria in Water: A guide to their public health consequences, monitoring and management
|publisher=[[World Health Organization]]
|year=1999|isbn=0-419-23930-8
|url=http://www.who.int/water_sanitation_health/resourcesquality/toxicyanbact/en/|accessdate=2007-06-09}}
</ref>
==Black water==
So-called '''black water''' is a dark discoloration of sea water, first described in the [[Florida Bay]] in January 2002.<ref>{{cite web
|title = Black water status report|date=2002, May 4
|publisher=Florida Marine Research Institute
|url=http://www.floridamarine.org/features/view_article.asp?id=15348||accessdate=2007-06-09}}
</ref><ref>[http://apod.nasa.gov/apod/ap020402.html Mysterious Black Water in Florida Bay ] Astronomy Picture of the Day, NASA, 2002-04-02</ref>
==Water treatment==
Algal blooms sometimes occur in drinking water supplies. In such cases, toxins from the bloom can survive standard water purifying treatments. Researchers at [[Florida International University]] in [[Miami, FL|Miami]] are experimenting with using 640-kilohertz [[ultrasound]] waves that create micropressure zones as hot as 3,700 °C. This breaks some water molecules into reactive fragments that can kill algae.<ref>{{cite journal
|last=Song|first=W.
|coauthors=Teshiba T., Rein K., and O'Shea K. E.
|title=Ultrasonically induced degradation and detoxification of microcystin-LR (cyanobacterial toxin)
|journal=Environmental Science & Technology|year=2005|volume=39|issue=16|pages=6300–6305|doi=10.1021/es048350z}}
</ref>
==See also==
{{Commonscat|Algal blooms}}
*[[Ciguatera]]
*[[Cultural eutrophication]]
*[[Dead zone (ecology)]]
*[[Dinoflagellate]] (see "neurotoxins" and "red tide" under [[dinoflagellate#Ecology and fossils|Ecology and fossils]] and see "phosphate" under [[dinoflagellate#Cautions|Cautions]])
*[[Domoic acid]]
*[[Eutrophication]]
*[[Red tide]]
==References==
{{reflist}}
==External links==
* [http://research.myfwc.com/redtide Harmful Algal Bloom information] from the Florida Fish and Wildlife Conservation Commission [http://research.myfwc.com/ Fish and Wildlife Research Institute]
*[http://www.whoi.edu/institutes/coi/viewTopic.do?o=read&id=112 Harmful Algae and Red Tide Information from the Coastal Ocean Institute], [[Woods Hole Oceanographic Institution]]
*[http://www.fathom.com/course/10701012/index.html Toxic Blooms: Understanding Red Tides], a seminar by the [[Woods Hole Oceanographic Institution]]
*[http://www.tulane.edu/~bfleury/envirobio/enviroweb/DeadZone.htm Gulf of Mexico Dead Zone and Red Tides]
*[http://www.whoi.edu/redtide/illness/illness.html Human Illness caused by Algae], an excellent summary.
*[http://redtideflorida.org/pages/index.php/florida-red-tide-report/ Red Tide Report] A Compilation of citizen based, media and official reports of the locations and severity of current Red Tide Blooms.
*[http://redtideflorida.org Florida Red Tide Coalition] A citizen based group dedicated to raising awareness of Red Tide, debunking myths, educating the public and taking action to promote our oceans' health and help stop red tide.
*[http://isurus.mote.org/~mhenry/rtupdate.phtml Red Tide updates for the Gulf Coast of Florida] provided by [[Mote Marine Laboratory]] in [[Sarasota, FL]]
*[http://www.ncddc.noaa.gov/habsos Harmful Algal Blooms Observing System (HABSOS)]
*[http://www.bblooms.ulg.ac.be/ The Belgian Blooms Monitoring project]
*[http://www.ncdc.noaa.gov/oa/esb/?goal=ecosystems&file=events/algae/ Social & Economic Costs of Harmful Algal Blooms] from "NOAA Socioeconomics" website initiative
[[Category:Algae]]
[[Category:Biological oceanography]]
[[Category:Aquatic ecology]]
[[Category:Fisheries]]
[[de:Algenblüte]]
[[es:eflorescencia algal]]
[[et:Veeõitseng]]
[[fr:Efflorescence algale]]
[[is:Þörungablómi]]
[[nl:Algenbloei]]
[[ja:水の華]]
[[pl:Zakwit wody]]
[[sv:Algblomning]]
[[zh:水华]]