Poseidon’s grass
By Katerina Tsamarda, Geologist, MSc Sustainable Development-Environmental Management
April 3rd, 2023
In our sea there are areas with posidonia meadows, a priceless treasure on a global scale. Poseidon’s grass is the familiar seaweed, which is not a seaweed.
It is perennial higher plant and has roots, leaves, flowers and fruits, just like land plants. The Italians call posidonia “the olive of the sea”, which proves its enormous contribution to the marine environment and beyond.
It’s value
Poseidon’s grass is found only in the Mediterranean Sea and covers less than 0.2% of the global seabed. One hectare of this ancient plant can absorb 35 times more carbon dioxide than a tropical forest of the same size. It releases valuable oxygen, and therefore limits the effects of climate change.
The underwater posidonia meadows are among the most productive marine ecosystems of the Mediterranean. They host more than 1300 species of fauna and flora, among them many fish of fishery importance.
They also have a role of cleaning the marine ecosystem from plastics. In the Mediterranean Sea, they capture up to 867 million pieces of plastic a year. In addition, they act as a natural fence as they prevent beach erosion.
Its contribution also extends to underwater cultural wealth because it acts a protective shield for underwater antiquities, such as sunken states and ancient shipwrecks.
Poseidon’s grass has considerable economic value. According to relevant research, the value of its services is estimated to reach €150,000,000/Km2. Therefore, the benefits of protecting and preserving the posidonia meadows are multiple.
The pressures
Poseidon’s grass is precious, but under constant threat. The human activity of the last 50 years is responsible for the reduction of the posidonia meadows in the Mediterranean in a percentage that exceeds 34%. Uncontrolled mooring, destructive fishing practices, eutrophication, coastal infrastructure and activities as well as intensive fish farming near the meadows are some of the main burden factors. The burden of intensive fish farming on the posidonia meadows is one of the reasons why Katheti is against the development of industrial fisheries at Poros.
The destruction of a posidonia meadow implies the annihilation of an entire ecosystem, but also the re-release of all the amount of stored “blue carbon”.
It takes more than 100 years for a damaged meadow to recover. This disaster comes with significant impacts on our health, fisheries and tourism. It degrades the environment we live in, reduces the productivity of fishing and intensifies the effects of beach erosion.
The future
This damage is still reversible. Some of the most important posidonia meadows in the Mediterranean remain in the Greek seas. Some of these tracts are in our area. Furthermore, we have the chance, not only to protect them, but also to multiply them.
Researchers of the Institute of Marine Conservation “Archipelagos” have proceeded with experimental replanting of posidonia meadows, in collaboration with specialized European universities, with very good results.
Poseidon’s grass, this wonderful and unique plant that drifted to the bottom of the sea thousands of years ago and managed to survive underwater, is the guardian angel of our sea. Every step we take, every choice we make has consequences. There are two ways to survive and grow financially. One is gentle, sustainable and ensures the good life for many generations after us. The other is aggressive and turns against us.
What shall we choose?
Read more about industrial fisheries here.
Read more about industrial fisheries at Poros here.
Let’s state our position with a signature here.
Featured image source: ertnews.gr
Photograph 1- T. Tsimpidis (source: Archipelagos)
Photograph 2- source naturagraeca
Photograph 3- G. Skoufas (source: dasarxeio.com)
Photograph 4- J. Le Coz (source: Archipelagos)
