1st of June 2022 – written by Stacey Bondareva
Researchers have made a fascinating new discovery: a species of seagrass called Poseidon’s ribbon weed (Posidonia australis), which is now considered the largest plant in the world, reaching a whopping 180 kilometers or 112 miles long.
A Nice Suprise…
The research team at the University of Western Australia and Flinders University recently set out to measure a field of seagrass meadows in Australia’s Shark Bay World Heritage Area. They sampled seagrass shoots from several areas across the bay and compared their DNA “fingerprint” using genetic markers, with the goal of determining which plants should be collected for ecological restoration.
To the researcher’s surprise, the entire seagrass meadow turned out to be clones of a single seagrass seedling; in other words, one big plant.
Let Us Tell You A Bit More About Poseidon’s Ribbon Weed
Poseidon’s ribbon weed reproduces asexually by cloning itself, extending rhizomes horizontally below the sediment surface and pushing out roots and shoots from underground. Some other marine seagrasses reproduce sexually, forming seedlings and pollen which are carried by the current to fertilize female flowers. This is a strategy that promotes genetic diversity in the seagrass population, which Poseidon’s ribbon weed may be lacking, since each of its plants is an exact genetic copy. This means that it could be more susceptible to diseases.
On the other hand, clonal reproduction has allowed for Poseidon’s ribbon weed to grow rapidly over a large surface area and survive in conditions more extreme than usual seagrass habitat. This includes the saltier water, high light levels and wide temperature fluctuations of Shark Bay.
Why Seagrass Is Important For The Health Of Our Oceans
Seagrasses are vital to shallow coastal ecosystems, providing food sources, habitats and ideal nursery locations to an abundance of marine animals. They also release oxygen into water through photosynthesis and help improve water quality by trapping or stabilizing sediments and absorbing nutrients.
As a result of their nutrient pumping abilities, seagrasses including Poseidon’s ribbon weed are extremely sensitive to marine pollution. Even though the seagrass meadows in Shark Bay are an estimated 4500 years old, one tenth of its population has already been killed in the past few years.
Now that we know more about this ancient and massive seagrass species, it is important that we continue to push for seagrass research and conservation efforts in Shark Bay. The growth of Poseidon’s ribbon weed and other seagrasses throughout the world, big or small, is vital to the health of our oceans.