What is seagrass?
Since the time of the dinosaurs, four groups of flowering plants (angiosperms) colonised the oceans. Known as ‘seagrass’, they are the only flowering plants that can live underwater. More closely related to 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).
Seagrass live in near-shore 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.
Where Does Seagrass Grow?
A number of environmental parameters are critical to whether seagrass will grow and persist. These include physical parameters that regulate the physiological activity of seagrasses (temperature, salinity, waves, currents, depth, substrate and day length), natural phenomena that limit the photosynthetic activity of the plants (light, nutrients, epiphytes and diseases), and anthropogenic inputs that inhibit access to available light for growth (nutrient and sediment loading). Various combinations of these parameters will permit, encourage or eliminate seagrass from a specific location.
Seagrasses occupy a variety of coastal habitats. Seagrass meadows typically occur in most shallow, sheltered soft-bottomed marine coastlines and estuaries. These meadows may be monospecific or may consist of multispecies communities, sometimes with up to 12 species present within one location.
The depth range of seagrass is usually controlled at its deepest edge by the availability of light for photosynthesis. Exposure at low tide, wave action and associated turbidity and low salinity from fresh water inflow determine seagrass species survival at the shallow edge. Seagrasses survive in the intertidal zone especially in sites sheltered from wave action or where there is entrapment of water at low tide, (e.g., reef platforms and tide pools), protecting the seagrasses from exposure (to heat, drying) at low tide.
Why Conserve Seagrass?
The habitat complexity within seagrass meadows enhances the diversity and abundance of animals. Seagrasses on reef flats and near estuaries are also nutrient sinks, buffering or filtering nutrient and chemical inputs to the marine environment. They also stabilise coastal sediments.
They also provide food and shelter for many organisms, and are a nursery ground for commercially important prawn and fish species. The high primary production rates of seagrasses are closely linked to the high production rates of associated fisheries. These plants support numerous herbivore- and detritivore-based food chains, and are considered very productive pastures of the sea. The associated economic values of seagrass meadows are very large, although not always easy to quantify.
Seagrass/algae meadows are rated the 3rd most valuable ecosystem globally (on a per hectare basis), only preceded by estuaries and wetlands. The average global value of seagrasses for their nutrient cycling services and the raw product they provide has been estimated at 1994US$ 19,004 ha-1 yr-11.. This value would be significantly greater if the habitat/refugia and food production services of seagrasses were included.
Many people find comfort with nature and prefer to have their home filled with items made from natural materials. Products made from bamboo, coir, jute, hemp, and seagrass are a few to name. Seagrasses are unique marine flowering plants that live underwater. They grow in large meadows resembling grassland. The strong and non porous surface of the plant gives them a lustrous look, and smooth texture. They are durable, rigid, and stain resistant by nature.
Seagrasses are harvested, and the long reeds are dried, and spun into yarns. These yarns are woven into pretty designs with a smooth broadloom with long lasting finishes. These are an affordable and durable option with a wide range of applications. They can be woven into attractive patterns and made into rugs, carpets, baskets, chairs etc. Carpets can be woven with natural latex backing to enable more durability and to avoid slipping. These carpets can be used throughout the home and is a great alternative for synthetic carpeting which depends on oil industry. These carpets and rugs can be cut into any desired shape, and size such as oval, L shape, circles to fit into the environment.
Sea grasses are 100% natural, and involve both ecological and economic value. They contain low dust, and non-allergic in nature. Due to its impermeable nature, it is impossible to dye. They are available in various shades of green, olive, and beige which are its natural color that gets a brownish tint with age. It is a sustainable resource carrying hay like scent which dissipates over time. With its warm hues, seagrass products make attractive interiors. Due to its strong nature, seagrass rugs, and carpets last from 5 to 15 years.
Commercial viability of the marine treasures:
On an average, a single acre of seagrass can produce more than 10 tons of leaves a year. Global production of natural fibres is estimated to be around 30 million tons. Woven seagrass can be used profitably in a wide range of products such as carpets, baskets, etc. Rugs from seagrass make an affordable option. Non-absorbent, and stain resistant, dirt can be easily brushed from them. Combined with the virtues of low price, and high quality, seagrass products make profitable items. Popularly grown in the coastal regions of China, and India, seagrass makes the most versatile and natural floor covering. They are grown in the paddy fields of China also. The highest concentration of species occurs in the Indo-West Pacific region.
Seagrass fibres make an important component for clothing, upholstery, and many other textiles. They contribute to a greener environment, and generate employment opportunities to many people. Seagrasses are also labeled as ecosystem engineers. One square meter of seagrass produces up to 10 litres of oxygen per day. They provide fishing grounds, oxygen production, wave protection, and coastal erosion protection. Oceans absorb 25% of the total global carbon emissions. Seagrass meadows account for 15% of the oceans total carbon storage. Seagrass fibres make interesting products having a life of their own.