Seagrass meadows produce massive volumes of sediment that may construct coral reef island shorelines, rising the resilience of low-lying reef island nations to future sea degree rise, in accordance with new analysis.
The brand new research, from Northumbria College, amd printed in Nature Communications Earth and Atmosphere, gives seemingly the primary proof of the quantity of sediment produced by a seagrass meadow in a reef island setting.
It has lengthy been recognized that seagrass gives many helpful societal advantages. Seagrass meadows are biodiversity hotspots, gradual local weather change by storing carbon, and defend land from coastal erosion.
Researchers have now highlighted an extra profit offered by seagrass meadows: they’re essential sources of sediment that may each construct and preserve coral reef islands.
Seagrass leaves have tiny residing creatures often known as epibionts residing on them. These epibionts are manufactured from calcium carbonate which creates sand when the seagrass leaves die or when the epibionts fall off the leaves. This sediment is then transported by waves and may be deposited on close by islands.
A analysis group, led by Dr Holly East from Northumbria College’s Division of Geography and Environmental Sciences, studied seagrass meadows and epibionts within the southern Maldives.
Utilizing satellite tv for pc imagery, the group mapped the completely different areas of the seagrass meadow after which manually counted the variety of seagrass leaves in grids positioned on the ocean ground to precisely set up the densities of seagrass leaves within the space.
They then analysed lots of of seagrass leaves of their lab and had been in a position to calculate the scale and mass of the epibionts residing inside the meadow and the way a lot sediment they might create.
They found that one sq. kilometre of seagrass produced greater than 700 tonnes of sediment per yr, two thirds of which was sand-sized and of the precise measurement for island constructing.
Primarily based on the quantity of sediment produced, the researchers say {that a} one sq. kilometre meadow might produce sufficient sediment to construct an island the scale of its neighbour, Faathihutta, in lower than 20 years.
Dr East defined: “Seagrasses might not appear to be superheroes, however these underwater meadows present essential advantages to society.
“Seagrass meadows are generally discovered near reef islands, however their potential position as sources of reef-island constructing sediments has been neglected. Our findings quantify the speed of sediment manufacturing from seagrass meadows, and the proportion of that sediment that’s of the precise kind to contribute to coral reef island constructing.”
Dr East added that tropical seagrass meadows might assist to guard coral reef islands from the impacts of local weather change, equivalent to sea-level rise, which is a transparent hazard to low-lying coral reef island nations, together with the Maldives.
“The power of seagrass meadows to provide sediments that may construct and preserve coral reef island shorelines might assist the islands to develop and stay resilient to rising sea ranges. Their very survival could also be depending on the sand produced by these unbelievable underwater seagrass meadows.”
She added that the findings strengthened the necessity for governments to work with the vacationer business to preserve seagrass meadows.
“Seagrasses are actively eliminated by the vacationer business in lots of areas as pristine white sands are thought-about extra aesthetically interesting than seagrass meadows,” she mentioned.
“It is a false expectation and deprives guests from experiencing the pure magnificence that comes with the big variety of wonderful marine life that decision seagrass meadows their residence, equivalent to unbelievable faculties of child fish, seahorses and turtles.
“Our findings current a brand new and compelling geomorphic argument for seagrass conservation.”
