This is the 13090th most frequent Spanish word.
posidonia
Posidonia: A genus of seagrass found in the Mediterranean Sea, important for marine ecosystems.
In this context, 'posidonia' is used as a noun referring to the ecological organism itself.
La posidonia es una planta marina esencial para los ecosistemas mediterráneos.
The posidonia is a marine plant essential for Mediterranean ecosystems.
Here, 'posidonias' is used in plural to describe the physical presence of these organic entities in a natural scene.
Estuvimos nadando entre posidonias en nuestra última excursión a la playa.
We swam among posidonias on our last trip to the beach.
Here, 'posidonia' is used again as a singular noun, emphasizing its ecological importance as a grouping or substratum.