Didymosphenia geminata

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Didymosphenia geminata
Didymo from the Mararoa River in New Zealand.

Didymo from the Mararoa River in New Zealand .

Systematics
without rank: Bacillariophytina
without rank: Diatoms (Bacillariophyceae)
Order : Cymbellales
Family : Gomphonemataceae
Genre : Didymosphenia
Type : Didymosphenia geminata
Scientific name
Didymosphenia geminata
( Lyngbye ) M. Schmidt , 1899

Didymosphenia geminata ( Syn. Echinella geminata Lyngbye, 1819 , Syn. Gomphonema geminatum (Lyngbye) C. Agardh, 1824 ), English didymo , in New Zealand also called rock snot ("Felsenrotz"), is a species of diatoms thatgrowsin warm, shallow water thrives. If it spreads excessively, it can form large mats at the bottom of lakes and rivers. Although the species poses no health risks, its overgrowth destroys the ecosystem and food sources of the fish and makes recreational activities unattractive. The invasive species can be carried into a body of water in a single drop of water.

biology

Silica cell wall of D. geminata. The scale measures 50 μm.

Didymosphenia geminata is a diatom, a unicellular alga with a cell wall reinforced with silica . Diatoms have vegetative and sexual reproduction cycles , although the sexual reproduction of the species has been little explored.

Although the species has only one plane of symmetry, which is typical for gomphonemoid diatoms, the species belongs to the cymbelloid diatoms, which typically have two axes of symmetry. The cells have a raphe , which allows them to move on surfaces, and at the top a pore field from which a stem consisting of mucopolysaccharides is secreted.

With the help of this stem, the alga can stick to rocks, plants and other surfaces under water. When diatoms reproduce vegetatively, the stalk is also divided, eventually forming a mass of branched stems. These slimy stems lead to the annoying effects of the algae. The stems consist mainly of polysaccharides and proteins and form complex, multilayered structures that are difficult to rot.

distribution

Warning sign with instructions against the spread of Didymo in New Zealand.

The species is native to cooler regions of the northern hemisphere, including the forest and alpine regions of Europe, Asia and parts of North America. Before it first appeared in New Zealand , the species was unknown in the southern hemisphere. Over the past two decades, the species has slowly spread outside of its original range and has also led to mass reproductions within natural habitats, where it was otherwise only found in small quantities.

New Zealand

In 2004 D. geminata was discovered in New Zealand, for the first time in the southern hemisphere. In order to prevent further spread, protective measures were put into effect for the entire South Island in September 2005 . Despite intensive efforts to raise public awareness of the problem, the species spread to other rivers.

South America

In Chile , the United States Geological Survey found the species in large quantities in rivers in the Región de los Lagos near Esquel in the Argentine province of Chubut . The algal bloom occurred in the Espolon River and Futaleufú River over a length of more than 35 miles. This find was confirmed by the Chilean Centro de Investigacion en Ecosistemas de la Patagonia (CIEP) on May 28, 2010.

North America

Confirmed Finds of Didymosphenia geminata in the US and Canada. EPA 2007

Didymosphenia geminata was first detected in disruptive amounts in the late 1980s on Vancouver Island , British Columbia . Since then, there has been a mass increase both on the island and on the mainland. Early reports of algal blooms in Alberta exist as far back as the mid-1990s, from the upper reaches of the Bow River in Banff National Park . Algae and algal blooms have been recorded in most of the rivers in the South Saskatchewan River basin since 2005 .

The species has been reported in Rapid Creek, South Dakota since at least 2005 and is believed to be responsible for a significant decline in brown trout populations. The alga is also present in the area in smaller quantities. Also in 2005, Didymo was found in the drains of the Norris , Cherokee , Wilbur and South Holston dams . This was the first find in the USA east of the Mississippi River . Didymo was found in western Virginia in the summer of 2006 in Smith River , Jackson River, and Pound River .

In June 2007 the alga was found in the Connecticut River , near Bloomfield in Vermont , for the first time in the northeastern United States. Also in 2007 the species was found in New Hampshire in the Connecticut River near Pittsburg. In August 2007, the diatom was first detected in New York State in a section of the Batten Kill in Washington County . It was also found in Esopus Creek in the Catskills . In May 2008 the species was detected in the Gunpowder River in Baltimore County , Maryland .

Countermeasures

In New Zealand, as a countermeasure, it is recommended that visible clumps of algae are removed after leaving water and left on site; residues discovered later should not get into the sewer system, but rather be treated using one of the following methods: Treatment for at least one minute at 60 ° C Water, 2% bleach or 5% saline solution , disinfectant or detergent. If this is not practicable, as is the case with animals, dehydration should be ensured for at least 48 hours before a non-infested body of water is sought.

New Zealand and the US states of Alaska and Vermont have banned the use of felt-soled shoes by anglers. Maryland is considering this too.

Web links

Commons : Didymosphenia geminata  - collection of images, videos and audio files

Individual evidence

  1. ^ Sarah Spaulding, Leah Elwell: Increase in nuisance blooms and geographic expansion of the freshwater diatom Didymosphenia geminata. (PDF; 1.72 MB) United States Environmental Protection Agency , January 2007, accessed July 31, 2007 .
  2. Is didymo an exotic species? (No longer available online.) In: biosecurity.govt.nz. Biosecurity New Zealand, August 2007, archived from the original on December 3, 2013 ; Retrieved July 15, 2011 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.biosecurity.govt.nz
  3. Invasive Algae Species Discovered In Chile's Patagonia Region. In: The Santiago Times. Retrieved June 1, 2010 (registration required.).
  4. ^ Didymo Identified in Chile. In: usgs.gov. United States Geological Survey (USGS), accessed May 17, 2010 .
  5. Centro de Investigacion en Ecosistemas de la Patagonia (CIEP): Se Identifica Presencia de Alga Invasora Didymo en Rio Futaleufu ( Memento of July 7, 2011 in the Internet Archive )
  6. Distribution map - Confirmed presence of D. geminata in the United States and Canada. (PDF; 723 kB) In: epa.gov. US Environmental Protection Agency, accessed June 16, 2007 .
  7. Game, Fish and Parks news releases for July 14, 2006. (No longer available online.) South Dakota Game, Fish and Parks, July 14, 2006, archived from the original on January 20, 2015 ; Retrieved July 15, 2011 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / listserv.state.sd.us
  8. Owen Schroeder: Invasive algae 'Didymo' found in Tennessee River. (No longer available online.) In: homestead.com. Tennessee Wildlife Resources Agency, September 1, 2005, archived from the original June 23, 2007 ; Retrieved July 16, 2007 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.homestead.com
  9. ^ Didymo (Invasive Freshwater Algae) in Virginia. (No longer available online.) In: dgif.virginia.gov. Virginia Department of Game and Inland Fisheries, archived from the original September 20, 2008 ; Retrieved October 13, 2008 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.dgif.virginia.gov
  10. ^ ANR Confirms First Northeastern US Infestation of "Didymo". (No longer available online.) In: anr.state.vt.us. Vermont Agency of Natural Resources, July 6, 2007, archived from the original August 17, 2013 ; Retrieved July 16, 2007 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.anr.state.vt.us
  11. FAQs about Rock Snot in New Hampshire. (PDF; 216 kB) (No longer available online.) In: des.nh.gov. New Hampshire Department of Environmental Services, archived from the original on April 3, 2009 ; Retrieved October 13, 2008 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / des.nh.gov
  12. ^ New York State Department of Environmental Conservation: NYSDEC Announces Didymo Found in Lower Section of Batten Kill ( Memento of December 28, 2009 in the Internet Archive )
  13. Invasive Algae Found In Maryland. (No longer available online.) In: dnr.state.md.us. Maryland Department of Natural Resources, May 8, 2008, archived from the original June 12, 2008 ; Retrieved September 21, 2008 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.dnr.state.md.us