View source for Biology:Black band disease

{{short description|Coral disease}}
[[Image:Black Band Disease.JPG|thumb|300px|Example of black band disease progression on a colony of ''Diploria strigosa''.]]

'''Black band disease''' is a coral disease in which corals develop a black band. It is characterized by complete tissue degradation due to a pathogenic [[Biology:Microbial consortium|microbial consortium]].<ref>{{cite journal |title=First aid for massive corals infected with black band disease, Phormidium corallyticum: An underwater aspirator and post-treatment sealant to curtail reinfection. |journal=In: Hallock and French (Eds). Diving for Science...2000 |volume=Proceedings of the American Academy of Underwater Sciences |issue=20th annual Scientific Diving Symposium |year=2000 |url=http://archive.rubicon-foundation.org/6627 |archive-url=https://archive.today/20120701134146/http://archive.rubicon-foundation.org/6627 |url-status=usurped |archive-date=July 1, 2012 |access-date=2008-06-16 |author=Hudson, JH }}</ref> The mat is present between apparently healthy coral tissue and freshly exposed coral skeleton.

==Appearance==
[[Image:Koral mozgovity hranica.jpg|thumb|left|Black band disease on a [[Biology:Brain coral|brain coral]] in Caribbean Sea near Bahia de la Chiva on the island of Vieques, Puerto Rico]]

Black band disease was first observed on reefs in Belize in 1973 by A. Antonius, who described the pathogen he found infecting corals as ''Oscillatoria membranacea'', one of the [[Biology:Cyanobacteria|cyanobacteria]].<ref name=Antonius>{{cite journal |author=Antonius, A. |year=1973 |title=New observations on coral destruction in reefs. |journal=10th Meeting Assoc. 1st. Mar. Lab. Carib. |volume=10 |issue=3 (abstract)}}</ref> The band color may be blackish brown to red depending on the vertical position of a cyanobacterial population associated with the band. The vertical position is based on a light intensity-dependent photic response of the [[Biology:Cyanobacteria|cyanobacteria]]l filaments, and the color (due to the cyanobacterial pigment [[Biology:Phycoerythrin|phycoerythrin]]) is dependent on the thickness of the band. The band is approximately {{convert|1|mm|in|sp=us|2}} thick and ranges in width from {{convert|1|mm|in|sp=us|2}} to {{convert|7|cm|in|sp=us}} White specks may be present on surface, at times forming dense white patches. The pathogenic [[Biology:Microbial mat|microbial mat]] moves across coral colonies at rates from {{convert|3|mm|in|sp=us}} to {{convert|1|cm|in|sp=us|1}} a day. Tissue death is caused by exposure to a [[Medicine:Hypoxia (medical)|hypoxic]], [[Chemistry:Sulfide|sulfide]]-rich microenvironment associated with the base of the band.

==Composition==
[[File:Black band disease - brain coral.jpg|right|thumb|Buck Island Reef National Monument, 2010]]
The black band microbial consortium consists of an assortment of [[Earth:Photosynthesis|photosynthetic]] and non-photosynthetic [[Biology:Bacteria|bacteria]] that co-exist [[Biology:Synergy|synergistically]]. The consortium has three functionally and physically dominant members as well as numerous [[Biology:Heterotroph|heterotroph]]ic members whose role in the disease is as yet unknown. The three functionally dominant members are populations of cyanobacteria and sulfide-oxidizing and sulfate-reducing bacteria. The black band disease microbial consortium is structurally and functionally identical to cyanobacterial-dominated microbial mats found in other illuminated, sulfide-rich environments<ref>{{cite journal |first= L.L |last= Richardson |author2=R.G. Carlson | title= Behavioral and chemical aspects of Black Band disease of corals: An in situ field and laboratory study |journal = In: Heine and Crane (Eds). Diving for Science...1993. Proceedings of the 13th Annual Scientific Diving Symposium |publisher=American Academy of Underwater Sciences |date=1993|pages=107–116|url=http://archive.rubicon-foundation.org/6331 |archive-url=https://archive.today/20130920193523/http://archive.rubicon-foundation.org/6331 |url-status=usurped |archive-date=September 20, 2013 |access-date=2013-09-20 }}</ref><ref name=richardson1997>{{cite journal |first= L.L |last= Richardson |title= Occurrence of the Black Band disease cyanobacterium on healthy corals of the Florida Keys |journal= Bulletin of Marine Science |volume=61|issue=2|pages=485–490|date=1997 |url=http://www.ingentaconnect.com/content/umrsmas/bullmar/1997/00000061/00000002/art00017?crawler=true |access-date=2013-09-20 }}</ref>

==Taxonomy==
Several species of cyanobacteria have been found associated with black band disease,<ref name="Frias-Lopez_et_al_2002"/><ref name="Cooney et al.2002"/> the most well-known of which is ''Phormidium corallyticum''.<ref>{{cite journal |author=Riitzler, K. and D.L. Santavy. |year=1983 |title=The Black Band disease of Atlantic reef corals. I. Description of the cyanophyte pathogen |journal=P.S.Z.N.I. Mar. Ecol. |volume=4 |pages=301–319 |doi=10.1111/j.1439-0485.1983.tb00116.x |issue=4}}</ref> Sulfide-oxidizing bacteria, dominated by ''[[Biology:Beggiatoa|Beggiatoa]]'' spp.,<ref name="Ducklow&Mitchell1979">Ducklow and Mitchell, 1979. "Observations on naturally and artificially diseased tropical corals:scanning electron microscope study". ''Microbial Ecology'', Vol.5, pp.215-223</ref> are present in well-developed bands and exhibit visible vertical migrations within the band matrix (Richardson, 1996; Viehman and Richardson, 2006). When present on the band surface ''Beggiatoa'' appears white due to intracellular inclusions of stored elemental [[Chemistry:Sulfur|sulfur]]. Sulfate-reducing bacteria dominated by ''[[Biology:Desulfovibrio|Desulfovibrio]]'' spp.<ref name="Frias-Lopez_et_al_2002"/><ref name="Cooney et al.2002"/><ref name="Ducklow&Mitchell1979"/> are present at the base of the band and are responsible for producing high concentrations of sulfide within the band matrix.<ref>Carlton, R.G. and L.L. Richardson, 1995. "Oxygen and sulfide dynamics in a horizontally migrating cyanobacterial mat: Black band disease of corals". ''FEMS Microbiology Ecology'', Vol18, pp. 155-162.</ref> [[Engineering:Microscope|Light microscopic]] observation of black band reveals motile (gliding) filaments of ''P. corallyticum'' that are 4&nbsp;mm wide, with one round end and one narrow (sharply tapering) end. Also present are gliding ''Beggiatoa'' filaments (1–4&nbsp;mm wide) that are non-pigmented but contain highly refractive intracellular granules of elemental sulfur. Numerous gram-negative bacteria (small rods) are also present but not identifiable using light microscopy. The bacterial population has been characterized using molecular techniques and was found to contain over 500 species of bacteria that are different from bacterial communities found in the water column, healthy coral tissue, or dead coral skeleton.<ref name="Frias-Lopez_et_al_2002">Frias-Lopez, J., A. Zerkle, G. Bonheyo and B. Fouke (2002). "Partitioning of bacterial communities between seawater and healthy, black band diseased and dead coral surfaces". ''Applied and Environmental Microbiology'', Vol. 68, pp 2214-2228</ref><ref name="Cooney et al.2002">Cooney, R.P., O. Pantos, M. D. A. Le Tissier, M. R. Barer, A. G. O´Donnell, and J. C Bythell (2002) "Characterization of the bacterial consortium associated with black band disease in coral using molecular microbiological techniques". ''Environmental Microbiology'', Vol 4 (7), pp 401, Jul 2002.</ref> The functional role of this diverse population of bacteria is not known.

Black band disease affects 42 species of coral in a worldwide distribution. The only known reservoir is within cyanobacterial [[Earth:Biofilm|biofilm]]s that are present on sediments in depressions of healthy black band disease susceptible corals.<ref name=richardson1997/>

Black band disease significantly affects boulder star coral in the reef ecosystem, allowing for more staghorn coral to grow.

== See also ==
* [[Medicine:Aspergillosis|Aspergillosis]], caused by the fungus ''Aspergillus sydowii'', affects [[Biology:Gorgonian|Gorgonian]] soft corals commonly known as sea fans.
* [[Biology:White pox disease|White pox disease]], caused by [[Biology:Serratia marcescens|Serratia marcescens]]
* Black necrosing syndrome, or Dark spots disease, probably fungal.
* Brown band disease, or Red band disease, probably caused by [[Biology:Protozoa|protozoa]] (possibly ''Helicostoma nonatum'') and [[Biology:Cyanobacteria|cyanobacteria]].
* Rapid Wasting, possibly caused by a fungus growing on areas damaged by the feeding of the [[Biology:Stoplight parrotfish|Stoplight parrotfish]].
* White band disease, the cause of this disease remains unknown.
* White plague, caused by the bacterium ''[[Biology:Aurantimonas coralicida|Aurantimonas coralicida]]''.
* Skeletal Eroding Band, caused by the protozoan ''[[Biology:Halofolliculina corallasia|Halofolliculina corallasia]]''.
* [[Earth:Yellow-band disease|Yellow-band disease]], possibly caused by an unidentified species of ''[[Biology:Vibrio|Vibrio]]''

== References ==
{{Reflist}}

==External links==
* [https://web.archive.org/web/20050905140609/http://www.coral.noaa.gov/coral_disease/black_band.shtml NOAA website on coral (public domain)]
* [https://www.unep-wcmc.org/resources-and-data/global-coral-disease-database World Conservation Monitoring Centre Global Coral Disease Database]

{{corals}}

{{DEFAULTSORT:Black Band Disease}}
[[Category:Animal bacterial diseases]]

{{Sourceattribution|Black band disease}}