Cymodocea nodosa | |
---|---|
Blossoming Cymodocea nodosa off the coast of Corsica | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Monocots |
Order: | Alismatales |
Family: | Cymodoceaceae |
Genus: | Cymodocea |
Species: | C. nodosa |
Binomial name | |
Cymodocea nodosa | |
Synonyms [3] | |
Cymodocea aequoreaK.D.Koenig Contents |
Cymodocea nodosa is a species of seagrass in the family Cymodoceaceae [3] and is sometimes known as little Neptune grass. [4] 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.
C. nodosa has light green or greyish-green leaves. They are very narrow but may be up to forty centimetres long. Each leaf has seven to nine veins running along its length. The plant produces rhizomes which are only 1 mm in diameter and have leaf scars at intervals. [5] Inconspicuous grass-like flowers are sometimes produced at the end of long stems in the spring when water temperatures begin to rise after their winter minimum. The pollen is liberated into the sea and the seeds remain dormant until the following spring. [6]
This seagrass is found in shallow parts of the Mediterranean Sea and the adjoining parts of the Atlantic Ocean, the coasts of Portugal, Mauritania and Senegal and round the Canary Islands, Madeira and the islands of Cape Verde. [2] It grows at depths of down to nineteen [7] metres in sandy sediments in sheltered locations and needs clear waters for photosynthesis. [4] Off the Catalan coast in the western Mediterranean, a single meadow of this grass covering at least 800 hectares (2,000 acres) has been discovered. [8]
Cymodocea nodosa grows in meadows on the seabed [9] and is sometimes associated with the other seagrasses, Zostera noltei and Posidonia oceanica and the seaweeds Caulerpa prolifera and Caulerpa racemosa . Although it is adversely affected by mechanical disturbance such as trawling and by pollution, and although it is in competition with other seagrass species, C. nodosa is not considered to be threatened. [1]
In the Canary Islands, fifty-three species of epiphytic algae were found to grow on the leaves and rhizomes of C. nodosa. Many of these were encrusting species of Corallinaceae. [10]
Seagrass meadows have high biological productivity and are rich, biodiverse habitats. Fish species associated with C. nodosa in a coastal lagoon in south east Spain include Atherina boyeri , Pomatoschistus marmoratus , Liza aurata , Liza saliens , Syngnathus abaster and Aphanius iberus . The meadows are an important rearing ground for juvenile fish. [11] Invertebrates associated with seagrass meadows include polychaete worms, [12] amphipods, isopods, decapods and molluscs. [13]
C. nodosa tends to grow in patches. This is because it favours unstable sandy sediments and subaqueous dunes tend to move over time. If the sand accretion is not too fast, the stolons can grow vertically through it, but the seagrass can be overwhelmed by rapid accretion. Patch death was mostly caused by erosion as roots were uncovered, encrusting and drilling organisms increased and plants were swept away. The dune movement cycle tended to take two to six years, which gives the seagrass time to recolonise bare areas. Sand accretion also stimulates flowering and dormant seeds can enable recolonisation when conditions allow it. [14]
The fact that the pattern of C. nodosa growth changes as sand is deposited provides a means of measuring the travel of subaqueous dunes. In the Alfacs Bay in the northwest Mediterranean Sea, it was found that the rate of dune advance averaged 13 metres per year, and that the seagrasses could be used to monitor movement rates ranging from 0.15 metres to 980 metres per year. [15]
The invasive alga Caulerpa taxifolia is often associated with C. nodosa. It has an extensive rhizoidal system that anchors it to a sandy substrate. The alga is better able to extract nutrients from the substrate than can the seagrass. A study was undertaken near the island of Elba, Italy, in which slow release fertiliser sticks were added to test plots of the seabed where the seagrass and alga both grew. It was found that although both species responded with increased growth rates, the seagrass was relatively disadvantaged in that increased growth of the alga restricted the amount of sunlight reaching the seagrass whereas the alga was less constrained by limited light. [16]
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.
Caulerpa taxifolia is a species of green seaweed, an alga of the genus Caulerpa, native to tropical waters of the Pacific Ocean, Indian Ocean, and Caribbean Sea. The species name taxifolia arises from the resemblance of its leaf-like fronds to those of the yew (Taxus).
Caulerpa is a genus of seaweeds in the family Caulerpaceae. They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world.
Caulerpa racemosa is a species of edible green alga, a seaweed in the family Caulerpaceae. It is commonly known as sea grapes and is found in many areas of shallow sea around the world. Despite the name, it is not related to grapes. There are a number of different forms and varieties, and one that appeared in the Mediterranean Sea in 1990, which is giving cause for concern as an invasive 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.
Cymodocea is a genus in the family Cymodoceaceae described as a genus in 1805. It includes four species of sea grass distributed in warm oceans.
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 or Neptune balls, wash up to nearby shorelines.
The Islets of Ksamil, consist of four rocky islets located in the direct proximity to the Ionian Sea in Southern Albania. The village of Ksamil, after whom the islets are named, is located to the east of the islets. Furthermore, the islands are situated within the boundaries of the Butrint National Park.
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.
Caulerpa prolifera is a species of green alga, a seaweed in the family Caulerpaceae. It is the type species of the genus Caulerpa, the type location being Alexandria, Egypt. It grows rapidly and forms a dense mass of vegetation on shallow sandy areas of the sea.
Paracentrotus lividus is a species of sea urchin in the family Parechinidae commonly known as the purple sea urchin. It is the type species of the genus and occurs in the Mediterranean Sea and eastern Atlantic Ocean.
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.
Thalassodendron ciliatum, the sickle-leaved cymodocea, is a species of plant in the Thalassodendron genus of seagrasses in the family Cymodoceaceae.
Zostera novazelandica Setchell is a species of seagrass in the family Zosteraceae found on the shores of New Zealand. It is regarded as a distinct species by some authors but considered as a synonym of Zostera muelleri Irmisch ex Ascherson by others. The Maori names for Zostera novazelandica are karepō, nana, rehia, and rimurehia.
Zostera muelleri is a southern hemisphere temperate species of seagrass native to the seacoasts of South Australia, Victoria and Tasmania. and New Zealand. Today, Zostera muelleri can be found in regions of Australia, New Zealand, and Papua New Guinea, as well as areas of the eastern Indian Ocean, and the southwest and western central Pacific Ocean. Zostera muelleri is a marine angiosperm, and is commonly referred to as eelgrass or garweed. It is a fast growing and readily colonizing species that serves as a feeding ground for wading birds and aquatic animals, and a breeding ground for juvenile fish and shrimp species.
Codium bursa is a green marine algae of medium size.
Syringodium isoetifolium, commonly known as noodle seagrass, is a species of flowering plant in the family Cymodoceaceae, growing underwater in marine habitats. It forms seagrass meadows in shallow sandy or muddy locations in the Indian and Pacific Oceans.
Electra posidoniae is a species of bryozoan in the family Electridae. It is endemic to the Mediterranean Sea, and is commonly known as the Neptune-grass bryozoan because it is exclusively found growing on seagrasses, usually on Neptune grass, but occasionally on eelgrass.