Why seagrass

Human disturbances like eutrophication, mechanical destruction of habitat, overfishing and release of nutrients play havoc on seagrasses. Siltation, trawling, coastal engineering construction, pollution, etc, are considered to be significant causes for the deterioration of seagrasses. Sea Cow Dugong and Green Turtle that depend on seagrass for their food also face a severe threat.

The International Union for the Conservation of Nature should intervene immediately and study the status of the different seagrass species before they become extinct. Restoration of seagrasses has been attempted at the global level. Restoration of seagrasses has been taken up by the Tamil Nadu Forest Department in the Gulf of Mannar also and the results have been found to be encouraging. If seagrass habitats are lost, the marine organisms that depend on them for their survival may also face extinction, resulting in the loss of marine ecosystem productivity.

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Please use a genuine email ID and provide your name. Ecosystem engineers Seagrasses are known for providing many ecosystem services. There is an urgent need to take earnest measures to conserve seagrasses and their habitats. Subscribe to Weekly Newsletter :. Donate Now. Post a Comment. These leaves form large, dense meadows under the sea. Globally, estimates suggest we lose an area of seagrass around the same size as two football pitches every hour.

Protecting what is left is vital. Seagrasses occupy 0. Seagrass meadows, mangroves and coastal wetlands capture carbon at a rate greater than that of tropical forests. Seagrass meadows support communities and livelihoods. Over 30 times more animals live within seagrass compared to adjacent sandy habitats. Learn More CLimate Seagrass absorbs vast amounts of Carbon, helping in the fight against climate change. Some marine protected areas, such as in Wakatobi island and Buton regency in Southeast Sulawesi province, have been successful in increasing the seagrass cover in those areas.

Marine protected areas MPAs are not necessarily effective in managing programs to protect seagrass as it failed to predict threats when they are designed. Majority of threats to the marine ecosystem come from outside of the protected areas, for instance sedimentation from runoffs resulted from coastal development and rapid population growth.

Read more: No-take marine areas help fishers and fish far more than we thought. Other issues, pollutants and debris such as plastic to fisheries activities also harm seagrass ecosystem.

Fishing activities, at a certain level, could damage seagrass. Anchors, propellers, and fishing gears often cut the leaves or uprooted the whole plant. Lack awareness and knowledge from MPAs authorities complicates the effort to protect seagrass ecosystem. This resulted to managers of MPAs with insufficient knowledge to construct effective conservation management program for seagrass ecosystem.

Seagrass is home to marine animals, both for endangered animals such as dugong , sea turtle , seahorse , tiger shark and economically targeted animals such as snappers and emperor fishes , sea cucumber , molluscs , crabs.

Some of these living and dead seagrass blades are also washed to other areas of the ocean, feeding organisms in ecosystems as far as the deep sea. Small invertebrates, such as these crustaceans left and gastropods right , can help keep seagrasses clean by consuming epiphytic algae. Seagrasses are capable of capturing and storing a large amount of carbon from the atmosphere. Similar to how trees take carbon from the air to build their trunks, seagrasses take carbon from the water to build their leaves and roots.

As parts of the seagrass plants and associated organisms die and decay, they can collect on the seafloor and become buried, trapped in the sediment. It has been estimated that in this way the world's seagrass meadows can capture up to 83 million metric tons of carbon each year.

The carbon stored in sediments from coastal ecosystems including seagrass meadows, mangrove forests and salt marshes is known as " blue carbon " because it is stored in the sea.

While seagrasses occupy only 0. One acre of seagrass can sequester pounds of carbon per year 83 g carbon per square meter per year , the same amount emitted by a car traveling around 3, miles 6, km. Unfortunately, seagrasses are in trouble.

Seagrass coverage is being lost globally at a rate of 1. That amounts to about 2 football fields of seagrass lost each hour. It's estimated that 29 percent of seagrass meadows have died off in the past century.

In a assessment, nearly one quarter of all seagrass species for which information was adequate to judge were threatened endangered or vulnerable or near threatened using the International Union for the Conservation of Nature IUCN Red List criteria.

This is especially worrying because seagrass losses are projected to have severe impacts on marine biodiversity, the health of other marine ecosystems, and on human livelihoods. Additionally, some threatened marine species such as sea turtles and marine mammals live in seagrass habitats and rely on them for food.

For every seagrass species there is on average more than one associated threatened marine species. In fact, the only marine plant listed as endangered in the United States is a seagrass Halophila johnsonii found in Florida. Seagrasses are vulnerable to physical disturbances, such as wind-driven waves and storms.

Some animals, such as skates and rays, disturb the rhizomes and roots of seagrasses, ripping up the seagrass as they forage for buried clams and other invertebrates. However, the direct and indirect effects of human activities account for most losses of seagrass beds in recent decades. Some fast growing seagrass meadows are able to rebound from disturbances, but many grow slowly over the course of centuries and are likely to be slow to recover and are thus most vulnerable.

Nutrients, such as those from fertilizers and pollution , wash off the land and into the water, causing algal blooms that block sunlight necessary for seagrass growth. Sediment washing into the water from agriculture and land development can also damage seagrass beds by both smothering the seagrass and blocking sunlight. Similarly, dredging can both directly remove seagrass plants and cause lower light levels because of increased amounts of sediments in the water.

Boat anchors and propellers can leave "scars" in a seagrass bed—killing sections of the seagrass and fragmenting the habitat. This fragmentation of seagrass beds can increase erosion around the edges, as well as influence animal use and movement within the seagrass bed. Disease has also devastated seagrasses. In the early s, a large die-off of up to 90 percent of all eelgrass Zostera marina growing in temperate North America was attributed to a "wasting disease".

This die-off was so severe that a small snail specialized to live on eelgrass went extinct as a result. The disease was caused by the slime mold-like protist, Labyrinthula zosterae , which also ravaged eelgrass populations in Europe. This disease still affects eelgrass populations in the Atlantic and has contributed to some recent losses, though none as catastrophic as in the s. Eelgrass leaves that are weak or stressed are more susceptible to the disease, developing brown spots and lesions that reduce the plant's ability to photosynthesize, eventually killing the plant.

Healthy plants are thought to be resistant to the disease, indicating importance of reducing other stressors like pollution. Lower seawater salinity may also increase susceptibility to the Labyrinthula pathogen. Episodes of warm seawater temperatures can also damage seagrasses. Temperature affects how enzymes and metabolism work, influencing how organisms grow.

Rising water temperatures tend to increase rates of seagrass respiration using up oxygen faster than rates of photosynthesis producing oxygen , which makes them more susceptible to grazing by herbivores. Increased temperature also increases seagrass light requirements, influences how quickly seagrasses can take up nutrients in their environment, and can make seagrasses more susceptible to disease.

Removal of fish can also lead to seagrass death by disrupting important components of the food web. When large predators are removed, intermediate predators can become more abundant, and they in turn cause the decline of the smaller organisms that keep the blades of the seagrasses clean.

This has been observed most strikingly in the Baltic sea with the disappearance of cod due to overfishing and corresponding increases in smaller fishes and crustaceans which limited epiphyte-grazing invertebrates, resulting in seagrass decline. In addition to the small epiphytic algae, larger algae also compete with seagrasses, and introduced invasive seaweed species can displace native seagrass species. One important example is the invasion of Caulerpa taxifolia , a seaweed nicknamed "the killer algae.

Since then, invasive Caulerpa has been found in California and southwestern Australia where eradication programs are in place to prevent its spread.

Most management that protects seagrasses focuses on maintaining their biodiversity and the services these habitats provide for humans and ecosystems. There is no international legislation for seagrasses, and so protection typically occurs by local and regional agencies.