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 seagrass or 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.
Halophila johnsonii, or Johnson's seagrass, is a small, asexual seagrass in the family Hydrocharitaceae. It occurs only on the southeastern coast of Florida, and was the first marine plant listed on the United States endangered species list, though it was removed from listing in April 2022. Female flowers have been observed, but even with decade long observational studies, neither male flowers nor seed have ever been observed.
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.
Lacuna vincta, commonly known as northern lacuna, wide lacuna, northern chink shell, or banded chink shell, is a species of sea snail, a marine gastropod mollusk in the family Littorinidae, the winkles or periwinkles. It is found intertidally and in shallow waters in both the northern Atlantic Ocean and the northern Pacific Ocean. It is a herbivore, feeding on seaweed and diatoms with its toothed radula.
Thalassia testudinum, commonly known as turtlegrass, is a species of marine seagrass. It forms meadows in shallow sandy or muddy locations in the Caribbean Sea and the Gulf of Mexico. Turtle grass and other seagrasses form meadows which are important habitats and feeding grounds. The grass is eaten by turtles and herbivorous fish, supports many epiphytes, and provides habitat for juvenile fish and many invertebrate taxa.
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.
Halophila decipiens, commonly known as Caribbean seagrass or paddle grass, is a seagrass in the family Hydrocharitaceae. It grows underwater on sandy or muddy sea floors in shallow parts of tropical seas.
Syringodium filiforme, commonly known as manatee grass, is a species of marine seagrass. It forms meadows in shallow sandy or muddy locations in the Caribbean Sea and the Gulf of Mexico, and is also found in the Bahamas and Bermuda. It occurs to a depth of about 20 m (66 ft), and even deeper where water is very clear.
Plasmodiophora bicaudata is a marine pathogen, an obligate parasite of seagrass of the genus Zostera and the causal agent of wasting disease in the genus. These marine plants grow in fine sediment in shallow seas and the pathogen seems to have a worldwide distribution.
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 capensis is a species of dwarf eelgrass growing along the shores of the Indian and Atlantic oceans on the African coast. Its range extends from southern Kenya, through Tanzania, Mozambique, Madagascar, and South Africa up to Angola. This species is the dominant seagrass species in South Africa, occurring as fragmented populations along the coast and occupying subtidal and intertidal habitats in shallow bays, estuaries and lagoons. The two largest meadows in South Africa are present in the Knysna lagoon and Berg river estuary. When last mapped in 2007, Zostera capensis cover in the Berg river estuary was estimated at 206 hectares, while in 2019 the Knysna lagoon was mapped at 316 hectares. Further north in its distribution, Maputo bay in Mozambique is an important habitat for this species, containing approximately 4016 hectares of mixed Zostera capensis and Halodule wrightii on muddy flats. Over its total distribution, this species is estimated to occupy less than 2000 km².
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.
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.
Polly A. Penhale is an American biologist and Environmental Officer at the National Science Foundation. She is a leading figure in Antarctic research, and has been recognized for contributions to research, policy, and environmental conservation. Penhale Peak in Antarctica is named for her.
Velma is a Venetian dialect term derived from "melma" (mud). It is also used by Italian scientists to refer to lagunar mudflats, such as those found in the Lagoon of Venice. They are areas of shallow lagunar bottoms which are normally submerged, but emerge at low tides. They are generally without vegetation. Only associations of Zostera noltii can be found. They originate from sediments carried by sea and stronger currents which are deposited on the lagoon bottom. They often surround the edges of the lagoon's barene.
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.
