Posidonia oceanica
Neptune grass ( Posidonia oceanica )
The Neptune grass ( Posidonia oceanica ) is a plant from the family of seagrass plants ( Posidoniaceae ). This water plant thrives in the saltwater. She is - as the only way of otherwise completely native to Australia genus Posidonia - Mediterranean home. The seagrass meadows formed by it there are the basis of important marine ecosystems. They are known for losses resulting from them friend clear sea balls.
Description
The seagrass is a submerged living ( submerged ), perennial herbaceous plant. Its compact and branched rhizomes have a diameter 5-10 mm and their internodes are only 0.5 to 2 millimeters long. The highly branched roots have a length of up to 40 centimeters and a diameter of 3 to 4 millimeters.
Most four to six, rarely up to ten leaves are in bunches together at the end of the branches. The leaf sheath is 3-5 inches long and 10 to 12 millimeters wide, ears missing, the age they tear along and form a brush-like bundles of stiff fibers. The simple, flat leaf blade is linear and nicked at a length of 40 to 50 centimeters and a width of 5 to 9 mm at its tip to butt. There are 13 to 17 veins present.
The flowering period extends from May to June (Malta). It is made of a 7 to 15 cm long inflorescence stem of 4 to 6 inches long and 0.5 to 0.8 centimeters wide, foliage leaf-like bracts. The ähriger inflorescence is 2.5 to 4.5 inches long. The bracts are smaller than the bracts. Each inflorescence contains three to seven hermaphrodite flowers, the terminal flower is always functionally male. A perianth is lacking. There are three stamens present, the reddish, 2 to 4.5 mm long anthers are sessile. The seated scars are filled with star-shaped papillae. The egg-shaped fruit, up to 10 millimeters long.
Ecology
Growth
With other seaweeds of the genera Zostera or Cymodocea the main growth takes place in the summer. In Posidonia oceanica but new leaves are blowing out only in the fall and winter. This is done by use of starch reserves in the rhizome and roots. These reserves are exhausted in the spring and will be replenished in the most productive months of April and May. In the spring a few new leaves are only created and the growth in the summer, due to the high coverage of the leaves with epiphytes, complete set. Only in August and September appear first new leaves that grow in the protection of old leaves. The old leaves fall off in October. This Produktionsryhtmus is explained as an adaptation to the growth of epiphytes, as Posidonia oceanica probably mainly absorbs nutrients through the leaves and thus is the epiphytes in competition. Thus, by the use of the winter nutrient supply and the conversion of carbohydrates thus effectively leaf biomass are built, while epiphytes and phytoplankton are still limited by the low light intensity. The leaves grow from a basal meristem itself and die by the blade tip her off ( " conveyor system " ), which is also interpreted with an adjustment to Epiphytenwachstum.
Propagation
Posidonia oceanica flowers only very rarely. Usually only one flower per 10 m² per year is low (less than 3 % of the newly formed sprouts ). In warmer years, however, can be propagated flowers form (more than 10 % of the newly formed sprouts ). Seedlings that emerged from seeds, are found only rarely. Posidonia oceanica reproduces mainly vegetatively via branches of the rhizome.
In the genetic analysis of seagrass in the Mediterranean have up to 15 km extended (genetically identical ) clones found Sophie Amaud - Haond among others, by DEEP - Centre de Brest in Plouzané. From this length and the growth rates, the researchers derive an age of up to 80,000 years, which this could be the oldest living thing in the world.
Occurrence
Unlike all other species of the genus Posidonia, the Neptune grass is exclusively in the Mediterranean. It occurs in shallow waters to 40 meters depth before, with very clear water well to a depth of 50 to 60 meters. It settled moved to slightly protected sites in fine sand with good water circulation, such as open coasts or the tips of tongues of land and there is often forming stands. Posidonia oceanica also settled, larger boulders, where the roots are formed into adhesive discs. The plants require oxygen-rich water without large salinity ( 33-40 ppt) or temperature fluctuations. At a water temperature above 20 ° to 22 ° C, the plants die, at temperatures below 10 ° C as well.
Benefit
Plays an important role Posidonia oceanica for the climate. The Spanish marine biologist Carlos Duarte from the Mediterranean Institute of the Balearic Islands in Esporles / Mallorca found that seagrass beds can save twice as much CO2 as eg an equal area of rainforest. Posidonia oceanica is also a breeding area for many fish and habitat for snails. It also protects coasts from erosion and thus contributes to the fact that beaches are not removed. In addition, the seaweed takes many of the rivers into the sea flushed nutrients and protects the sea against over-fertilization and keeps the water clear and clean.
Duarte estimates that occurring in the Mediterranean seagrass, but there is a maximum of 50 years.
Dead Neptune grass can also be used as insulation material. Inventor of the Karlsruhe architecture professor Richard Meier, who had patented NeptuTherm ® as an insulating material. In addition to high thermal insulation and easy recyclability this insulation must be added any additives to achieve the statutory fire protection due to the silicate-containing fiber structure of Neptune grass.
Damage
First, the seaweed is severely damaged by the increasing climate change and ocean warming. On the other Posidonia oceanica is torn out and destroyed by ships at anchor from the seabed. Between the Balearic islands Formentera and Ibiza since 1999, recognized by UNESCO and led to the UNESCO list of World Heritage natural park of the ' Parque Natural de Ses Salines d' Eivissa i Formentera '. The largest contiguous areas located there on Posidonia oceanica are significantly damaged and reduced each year by heavy motorboat traffic and at anchor yachts. The marine biologist Manu San Felixe from Formentera filmed in the summer of 2011 as the 100 -meter motor yacht ' Turama ' in a single day an acre of seagrass destroyed. Here the seaweed could be gone during sustained injury in three years.
Systematics and botanical history
The seagrass was first described in 1767 by Carolus Linnaeus as Zostera oceanica. Charles Dietrich Eberhard Koenig described as a separate genus Posidonia 1805 and described the seagrass Posidonia under the name caulini as type species. However, the species name was not valid, so Alire Raffeneau oceanica Delile described the way again in 1813 and now also valid as Posidonia.