What is seagrass?
Seagrass is a flowering grass with long, narrow leaves of green. Growing in shallow, aquatic meadows; seagrass is a flowering grass with long, narrow leaves of green. It has many amazing functions, and it’s meadows are filled with biodiversity. “They contain literally thousands of creatures in one square meter.”1 These organisms can range from small shrimp, predatory fish, and sea turtles, to even seahorse and sea dragons. Seagrass not only provides protective shelter and nursery for marine organisms, but the detritis or dead plants provide a source food. In addition to providing a protective habitat and food source, seagrass has many other important functions, it protects the coast line from currents; thereby reducing erosion. Secondly, it reduces eutrophication and improves water clairty. The water claity is improved because the dense root system reduces sedimentation by trapping sediments between the blades of grass. It reduces nutrients from land runoff because the seagrass uptakes
Tough and hardwearing, seagrass is collected from a tall plant having grass-like stems that thrive in wet lands. The distinctive features of this plant are its grassy appearance, hay-like scent and coloring, which dissipates over a certain period. Seagrass has a surface that is impermeable to water because of its inherent smooth texture. Tough and rigid, seagrass is one of the most durable natural fibers. Colors range from sage green hues to olive-like shades.
Five seagrass genera occur in Texas. These species represent highly specialized marine flowering plants (but not actually true grasses) that grow rooted and submersed in the higher salinity waters of most Texas bays and estuaries. The well-known annual species, widgeon grass (technically not a seagrass because it tolerates very low salinity, even fresh water) and the perennial, shoal grass often occur mixed in the higher salinity parts of all Texas bays and estuaries except for Sabine Lake. Shoal grass, a subtropical species, is the most abundant seagrass coast wide, with the most extensive beds in Upper Laguna Madre. The tropical species, turtle grass and manatee grass, for all practical purposes occur only as far north as Aransas Bay, and are most abundant in the Lower Laguna Madre or Corpus Christi Bay area. Star grass typically grows in higher salinity waters, interspersed in shoal grass and manatee grass beds. This dominance of seagrass habitat makes Texas, in the western Gulf of
Seagrass is an unusual example of an entirely aquatic marine flowering plant. It grows in large meadows in areas of shallow water, providing a habitat to numerous species from all phyla, including free-living macroalgae and microalgae, bristle worms, mollusks, nematodes, and many fish, especially white-spotted puffers. Its green meadows are either monospecific (containing one species) or multispecific (many). Temperate meadows are more likely to be dominated by one or a few species, while tropical meadows, like those in the Philippines, may have as many as 13 or more. It is estimated that there are about 60 species of seagrass worldwide. Like other grasses, to which they are not closely related, seagrasses are monocots, the smaller and simpler group of flowering plants. Seagrass is a fairly recent evolutionary innovation, having evolved from saltwater-tolerant land plants, especially mangroves, which are believed to be its immediate ancestor. Seagrass didn’t likely exist prior to about
Since the time of the dinosaurs, three groups of flowering plants (angiosperms) colonised the oceans. Known as ‘seagrasses’, they are the only flowering plants that can live underwater. More closely related to terrestrial lilies and gingers than to true grasses, they grow in sediment on the sea floor with erect, elongate leaves and a buried root-like structure (rhizome). Seagrasses live in the coastal waters of most of the worlds’ continents. They are the main diet of dugongs and green turtles and provide a habitat for many, smaller marine animals, some of which, like prawns and fish, are commercially important. They also absorb nutrients from coastal run-off and stabilise sediment, helping to keep the water clear. Seagrasses are unique amongst flowering plants, in that all but one genus can live entirely immersed in seawater. Enhalus plants are the exception, as they must emerge to the surface to reproduce; all others can flower and be pollinated under water. Adaptation to a marine en
