Zostera

Eelgrass ( Zostera spp.)

The plant genus seagrasses ( Zostera ) belongs to the family of seagrass plants ( Zosteraceae ). It comprises of about twelve species of the few submerse living in the seas flowering plants species. You can grow submerged to a depth of 15 meters. Also similar-looking species of other genera and families are called " seaweeds ".

• 5.1 Notes and references

Description

Zostera species grow as perennial herbaceous plants. They act grassy and are submerged living ( submerged ) aquatic plants. They are anchored in the seabed with adventitious roots at a monopodial rhizome. The alternate and distichous arranged leaves have linealische leaf blades.

Zostera species are monoecious getrenntgeschlechtig ( monoecious ). The functionally unisexual flowers have no perianth or bracts and are in two rows on either side of a flattened ears axis (the spadix ) and included in the heyday into a single bract ( spathe that ). The male flower has a stamen. The flower contains only a superior ovaries consisting of two, but apparently only one carpel. Pollination is over the water with thread pollen.

Seagrasses form of small nut fruits which are cylindrical in shape and have a two-column style on top.

• Dwarf eelgrass ( Zostera noltii ).
• Ordinary seagrass ( Zostera marina).

Dissemination

The approximately twelve Zostera species thrive in cold, cool and warm, but not warm tropical coastal waters nearly worldwide. Most often they are found on coastlines in temperate regions of the Northern Hemisphere. Five species are known from Chinese and two species of North American seashores. They are found only in the seas and grow mostly forming stands in seagrass beds.

System

The genus Zostera was erected in 1753 by Carl Linnaeus in Species Plantarum with the type species Zostera marina. The genus name Zostera is the Greek word " zoster " ajar, which translates as "belt" means and refers to the flat, ribbon-like leaves.

The genus Zostera contains about twelve species are known:

• Zostera angustifolia ( Hornem. ) Rchb.
• Zostera asiatica Miki
• Zostera caespitosa Miki
• Zostera capensis Setch.
• Zostera Capricorni Asch.
• Zostera caulescens Miki
• Zostera japonica Asch. & Graebn.
• Ordinary eelgrass ( Zostera marina L.)
• Zostera mucronata Hartog
• Zostera muelleri Irmisch ex Asch.
• Dwarf eelgrass ( Zostera noltii Hornem. ), Comes on the coasts of Europe. Africa and Asia before.
• Zostera novazelandica Setch.
• Zostera tasmanica M.Martens ex Asch.

Use

Since seaweed - along with algae and other plant debris - on the beaches of the North and Baltic Sea as flotsam represents a large amount of biomass, there are different concepts of use. Landed On European tourism beaches seaweed is so far collected and either disposed of in landfills or occasionally plowed on fields as fertilizer. In Denmark there is also recovered as an insulating material and for the renovation of the famous sea grass roofs on Laesoe.

Material use

Dried seaweed was formerly used as upholstery material for sofas and the like, mattresses and as a packaging material ( however, the use is similar quaking grass - sedge was referred to as " seaweed "). In today's "classic padding " the palm fiber ( Afrique ) has replaced the seaweed. The first refrigerator was used seaweed as an insulating layer. The South Pole explorer Robert Falcon Scott has insulated his research station with seaweed. In New York, the Radio City Music Hall and Rockefeller Center with Seegrasdämmmatten Cabot 's quilt -insulated ( seaweed engl. Eelgrass ).

By-products such as cat litter and erosion control mats seagrass showed an efficient ecological insulation material which can be processed both as a mat as well as a bed. Meanwhile, seaweed is recognized by the German Institute for Building Technology as an insulating material. Seagrass have insulation as a bed a WLG- value of 045, store heat very well ( heat capacity of 2.0 kJ / (kg · K) ), have relatively good Entfeuchtungseigenschaften and are inherently flame resistant. In addition, seaweed is also vermin resistant (mites, insects, mice, etc. ) and therefore suitable as cushioning material particularly suitable for house dust allergy. Seaweed, like all other natural insulation, protecting roof spaces against overheating in summer. It provides good sound insulation. 1997 in the Official Klützer angle was founded the project " disposal by recycling ," should tap the potential uses of overburden. In Germany Seegrasdämmmatten were made on this basis until 2006/2007, production came to a halt now.

Since 2012 in round bales pressed seaweed as insulation back on the market.

Investigations of the use of seaweed as additives for cosmetics, spa treatments, products for the food industry and pharmaceuticals are also being planned.

Energy Use

Also known as biogas substrate is basically seaweed can share with the algae. The problem with this, however, the low biogas yield 8-20 m3 from a ton of algae seaweed mixture and with up to 50 percent very high sand content of the collections made. In a long-term test of the Hanseatic Umwelt GmbH, the fermentation properties of algae seaweed mixture and other landscape maintenance biomass of the coastal region were examined, a pilot plant is planned for 2010.

Swell

• Robert R. Haynes: Zosteraceae. In: Flora of North America Editorial Committee ( eds.): Flora of North America North of Mexico. Volume 22: Magnoliophyta: Alismatidae, Arecidae, Commelinidae ( in part), and Zingiberidae, Oxford University Press, New York / Oxford et al 2000, ISBN 0-19-513729-9, pp. 90-94 ( limited preview in Google Book Search ). , online ( Description section ).
• Youhao Guo, Robert R. Haynes, C. Barre Hellquist: Zosteraceae. In: Wu Zheng -yi, Peter H. Raven, Deyuan Hong (eds.): Flora of China. Volume 23: Acoraceae through Cyperaceae, Science Press / Missouri Botanical Garden Press, Beijing / St. Louis 2010, ISBN 978-1-930723-99-3, pp. 106, online, PDF file (Section Description, systematics and distribution ).
• Leslie Watson: Zosteraceae. In: Western Australian Herbarium (ed.): Flora Base. The Western Australian Flora. Department of Environment and Conservation 2008, online ( Section Description )
• SWL Jacobs, DH Les: New Combinations in Zostera ( Zosteraceae ). In: Telopea. Volume 12, No. 3, 2009, pp. 419-423. ISSN 0312-9764 PDF file.
• Walter Erhardt, Erich Götz, Nils Boedeker, Siegmund Seybold: The big walleye. Encyclopedia of plant names. Volume 2 species and varieties. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5406-7.