It appeared on Earth over 140 million years ago, yet we still know very little about it. Celebrated on March 1st, World Seagrass Day is a great opportunity to learn more about the incredible potential of underwater meadows, their significance for marine ecosystems, climate change, and even modern architecture!
Less and less seagrass
On May 27, 2022, the UN General Assembly decided that seagrass deserved its own dedicated day. This decision reflects alarming facts - since the late 19th century, we have lost over 30% of global seagrass resources, and each year an additional 7% disappears. The main threat, of course, is human activity, particularly pollution entering the seas, coastal development, seabed dredging, and unregulated shipping and fishing.
Today, there are about 60 species of seagrass worldwide - 21% of them are classified by the International Union for Conservation of Nature (IUCN) as near-threatened, vulnerable, or endangered. The scale of the crisis is closely linked to climate change - on one hand, rising ocean temperatures are destroying underwater vegetation; on the other, seagrass is one of the most crucial elements of the natural carbon sequestration system. It is estimated that up to 18% of the world’s carbon stocks may be stored in underwater meadows!
photo: franciscojrg / adobe stock An extraordinary ecosystem with dozens of functions
Seagrasses are the only flowering plants that complete their entire reproductive cycle underwater. Their adaptation to salty environments is fascinating - according to the latest research, it results from a unique chemical composition of cell walls made of structural polysaccharides. It’s no surprise that centuries ago, the Danes used Zostera seagrass washed ashore to thatch roofs. Today, there is talk of reusing seagrass as a component of eco-friendly concrete with exceptionally high functional properties.
However, seagrass primarily serves as a habitat for thousands of underwater species - up to 20% of the world’s fisheries are closely linked to marine meadows. These habitats are home to eels, cod, parrotfish, grunts, seahorses, as well as sharks, sea turtles, dugongs, octopuses, snails, sea urchins, shrimp, and many more. In shallow waters covered with seagrass, herons and cormorants wade in search of prey, while dead blades of seagrass are broken down by a host of bacteria and fungi, which in turn produce food for phytoplankton and zooplankton - the foundation of the marine food chain.
It is safe to say that seagrass meadows are to the underwater world what forests are to the land. Additionally, thanks to their strong roots, they prevent coastal erosion and absorb the impact of destructive waves. As if that weren’t enough, they also act as natural filters, reducing ocean acidificatioCan we save seagrass?
World Seagrass Day aims to raise awareness about the dangers of underwater meadow destruction and to encourage people to take action. What can be done?
Many environmental organizations are already actively working on restoring seagrass ecosystems, for example, in the southern Baltic Sea and along the southern coast of England. Supporting them financially is a great way to help. Another approach is to make conscious consumer choices - when choosing resorts, dive centers, and boat charters, opt for those operating under sustainable development principles with respect for the natural environment.
Seagrass can also be supported politically by signing petitions and voting for representatives who understand the importance of ecosystems hidden beneath the water’s surface.
Source: wodnesprawy.pl
