BRUSSELS, Feb 1 — Like coral reefs, seagrass beds are key ecosystems for maintaining biodiversity. Although these underwater meadows have been in sharp decline for several decades, a recent study demonstrates the ability of certain species to survive in extreme environmental conditions.
The flowering plants that flourish in the oceans (known as seagrasses or seagrass beds) are full of virtues: they protect coastal areas from erosion, serve as a source of food and refuge for aquatic animals, and have significant carbon storage capacities. Their conservation is therefore just as crucial as that of coral reefs. To determine how seagrass is resisting global warming, an international group of 38 researchers sequenced and analysed the genomes of three of the most important seagrass species: Neptune grass (Posidonia oceanica), endemic to the Mediterranean, the broadly distributed Little Neptune grass (Cymodocea nodosa) and turtlegrass (Thalassia testudinum), endemic to the Caribbean.
One of the main findings of this research is that seagrasses have been able to adapt radically through genome duplication, which is often a sign of severe environmental stress. “Comparison of the three independent seagrass lineages, including freshwater sister lineages, revealed a shared ancient whole genome triplication at about 86 million years. This was quite exciting because large parts of the ocean were oxygen-free at that time and it’s also a uniting event involving the three lineages,” explains study co-author, Professor Yves Van de Peer of Ghent University, Belgium, quoted in a news release.
The researchers also found that the three seagrass species studied were able to withstand several threats, such as high salinity or low light levels. “Evolutionary changes have also provided different species with the ability to withstand different environments,” notes study co-author Dr. Gabriele Procaccini. “These new genomes will accelerate functional studies and solutions, as continuing losses of the ‘savannas of the sea’ are of major concern in times of climate change and loss of biodiversity,” the researchers conclude.
In April 2023, the Cornwall Wildlife Trust revealed the presence of a 359-hectare seagrass bed located in St Austell Bay (Cornwall, England), home to 122 different species of plants and animals (including seahorses and scallops), and which acts as a “highly effective carbon store.” This is an important discovery insofar as the storage capacity of this “blue carbon sink” has drastically declined since the pre-industrial period, “when our seas were far richer in marine life,” explain the authors of a report published by the NGO. — ETX Studio
