Electra posidoniae | |
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Electra posidoniae on Posidonia oceanica , Sardinia, Italy | |
Scientific classification | |
Kingdom: | Animalia |
Clade: | Lophophorata |
Phylum: | Bryozoa |
Class: | Gymnolaemata |
Order: | Cheilostomatida |
Family: | Electridae |
Genus: | Electra |
Species: | E. posidoniae |
Binomial name | |
Electra posidoniae | |
Electra posidoniae is a species of bryozoan in the family Electridae. It is endemic to the Mediterranean Sea, [1] and is commonly known as the Neptune-grass bryozoan because it is exclusively found growing on seagrasses, usually on Neptune grass ( Posidonia oceanica ), but occasionally on eelgrass ( Zostera marina ). [2]
Electra posidoniae is a white bryozoan forming encrusting colonies of zooids on the leaves of seagrasses. The colonies consist of irregularly branching ribbons formed from a single layer of zooids, up to four zooids wide, neatly arranged in parallel rows along the length of the leaf blade. The colonies can reach 10 cm (4 in) in length; they are poorly calcified which makes the colony flexible and able to bend as the leaf moves in the water. This species could be confused with Electra pilosa , which also grows in the Mediterranean, but that species tends to grow in star-shaped colonies that have a rough or bristly appearance. [2]
Electra posidoniae is endemic to the Mediterranean Sea where it grows on Posidonia oceanica and occasionally Zostera marina . These seagrasses grow in soft sediment at depths down to about 35 m (115 ft). They have rhizomes sending up tufts of leaves of new leaves and losing their old foliage in the autumn. Electra posidoniae is the most common bryozoan on P. oceanica in the Mediterranean in the depth range 15 to 30 m (50 to 100 ft). It has a life cycle synchronised with that of the grass. [3]
Bryozoans feed on diatoms and organic particles which the lophophores extract from the water flowing past. The food particles are passed to the central mouth and used by the colony for maintenance and growth. The colony grows by budding off new zooids. There are also specialised reproductive zooids, with male and female units, and occasionally hermaphrodites, in the same colony. The embryos are brooded in a membranous pouch inside the zooid for a while and then have a planktonic larval stage lasting several months, during which they can disperse widely. Very few colonies are present on Posidonia oceanica during the winter, with recruitment occurring in the early spring, at a time when the seagrass is beginning to grow new foliage and there is an increased availability of phytoplankton on which the colonies can feed. [3] Bryozoans tend to dominate the epiphytic growth on seagrass in the first part of the year, but by late summer, the availability of phytoplankton is lower, and macroalgae are more abundant and competing for space, and the number of bryozoan colonies decrease. [3] The nudibranch Polycera quadrilineata is a specialised feeder, grazing on Electra posidoniae and other bryozoans. [2]
Seagrasses are the (only) flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families, all in the order Alismatales. Seagrasses evolved from terrestrial plants which recolonised the ocean 70 to 100 million years ago.
Zostera is a small genus of widely distributed seagrasses, commonly called marine eelgrass or simply eelgrass and also known as seaweed by some fishermen and recreational boaters including yachtsmen. The genus Zostera contains 15 species.
A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and long green, grass-like leaves. They produce seeds and pollen and have roots and rhizomes which anchor them in seafloor sand.
Posidonia is a genus of flowering plants. It contains nine species of marine plants ("seagrass"), found in the seas of the Mediterranean and around the south coast of Australia.
Posidonia oceanica, commonly known as Neptune grass or Mediterranean tapeweed, is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free floating and known in Italy as "the olive of the sea". Balls of fibrous material from its foliage, known as egagropili, wash up to nearby shorelines.
The Seagrasses of Western Australia are submerged flowering plants found along the coast, around islands, and in Estuaries of Western Australia. The region contains some of the largest seagrass meadows in the world, and is the most diverse in the number of species. The variety of habitats along its western and southern coasts is often soft sands in shallow subtropical waters, ideal for these plants.
Smaragdia viridis. common name the "emerald nerite" is a species of small, green sea snail, a marine gastropod mollusk in the family Neritidae, the nerites.
Zostera marina is a flowering vascular plant species as one of many kinds of seagrass, with this species known primarily by the English name of eelgrass with seawrack much less used, and refers to the plant after breaking loose from the submerged wetland soil, and drifting free with ocean current and waves to a coast seashore. It is a saline soft-sediment submerged plant native to marine environments on the coastlines of northern latitudes from subtropical to subpolar regions of North America and Eurasia.
Cymodocea nodosa is a species of seagrass in the family Cymodoceaceae and is sometimes known as little Neptune grass. As a seagrass, it is restricted to growing underwater and is found in shallow parts of the Mediterranean Sea and certain adjoining areas of the Atlantic Ocean.
Amathia vidovici is a species of colonial bryozoans with a tree-like structure. It is found in shallow waters over a wide geographical range, being found in both the Atlantic and Pacific Oceans and adjoining seas.
Zostera noltii is a species of seagrass known by the common name dwarf eelgrass. It is found in shallow coastal waters in north western Europe, the Mediterranean Sea, Black Sea, Caspian Sea and Aral Sea and on islands in the Atlantic off the coast of northwest Africa. It is an important part of the intertidal and shallow subtidal ecosystems of estuaries, bays and lagoons.
Zoobotryon verticillatum, commonly known as the spaghetti bryozoan, is a species of colonial bryozoans with a bush-like structure. It is found in shallow temperate and warm waters in the western Atlantic Ocean and the Caribbean Sea and has spread worldwide as a fouling organism. It is regarded as an invasive species in some countries.
Conopeum seurati is a species of colonial bryozoan in the order Cheilostomatida. It is native to the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea. This species has been introduced to New Zealand and Florida.
Zostera japonica is a species of aquatic plant in the Zosteraceae family. It is referred to by the common names dwarf eelgrass or Japanese eelgrass, and is native to the seacoast of eastern Asia from Russia to Vietnam, and introduced to the western coast of North America. It is found in the intertidal zone and the shallow subtidal, and grows on sandy, muddy and silty substrates.
Electra pilosa is a species of colonial bryozoan in the order Cheilostomatida. It is native to the northeastern and northwestern Atlantic Ocean and is also present in Australia and New Zealand.
Clavularia crassa is a species of colonial soft coral in the family Clavulariidae. It is found in the eastern Atlantic Ocean and the Mediterranean Sea. It was first described in 1848 by the French zoologist Henri Milne-Edwards from a specimen collected off the coast of Algeria.
Cryptosula pallasiana is a species of colonial bryozoan in the order Cheilostomatida. It is native to the Atlantic Ocean where it occurs in northwestern Europe and northern Africa, and the eastern seaboard of North America. It has been accidentally introduced to the western coast of North America and to other parts of the world.
Watersipora subtorquata, commonly known as the red-rust bryozoan, is a species of colonial bryozoan in the family Watersiporidae. It is unclear from where it originated but it is now present in many warm-water coastal regions throughout the world, and has become invasive on the west coast of North America and in Australia and New Zealand.
Zoothamnium niveum is a species of ciliate protozoan which forms feather-shaped colonies in marine coastal environments. The ciliates form a symbiosis with sulfur-oxidizing chemosynthetic bacteria of the species "Candidatus Thiobios zoothamnicoli", which live on the surface of the colonies and give them their unusual white color.
Callopora lineata is a species of colonial bryozoan in the family Calloporidae. It is found on rocky shores in the Atlantic Ocean and the Mediterranean Sea.