Seagrasses: the great (un)known

March has been internationally established as the seagrass awareness month. This fact is indicative of the existing need to make seagrasses better known to society, being the perfect example of something that even being close to us keeps unknown. Thus, seagrasses could be compared (if we are discussing the general knowledge that society has about them) to the neighbor of the fifth floor: you have crossed many times, sometimes you have even interacted, but you really do not know each other.

Neptune seagrass flower. Photo SUBMON.

To change this relationship, it is important to start from the beginning: what are seagrasses? The answer is simple, they are marine plants that form meadows. In fact, they are plants originally from the terrestrial environment that tens of millions of years ago adapted to live in the marine environment. For this reason, they maintain a complex structure, made up of roots, rhizomes, and leaves, and they can produce flowers, fruits, and seeds. This fact distinguishes them from other less complex organisms such as algae. Therefore, the first noteworthy aspect about seagrasses (unknown to much of society) is that they are superior plants, NOT algae.

Globally, it is considered that there are around 60 species of these marine plants, and in our closest environment, we can find 4 different species: Posidonia oceanica (a species that is only found in the Mediterranean Sea, being, therefore, endemic), Cymodocea nodosa, Zostera noltei and Zostera marina.

Why is it important to make society aware of them?

A moray eel observing from the refuge of a Neptune seagrass. Photo: SUBMON.

Once this general explanation about seagrasses has been made, it is time to talk about their importance… Why is it important to make society aware of them? This answer could be very long since they provide multiple goods and services, so these are some examples:

1- They are habitat-forming species, which means that lots of marine organisms live in the meadows they create, being especially important as a nursery (where juveniles develop) for many species, finding refuge among their leaves.

2- They are great producers of oxygen, on which we depend to live.

Snakelocks anemonea in a Neptune seagrass meadow. Photo: SUBMON

3- They represent a key element to mitigate the effects of climate change, by capturing large amounts of CO₂ and burying it in the sediment or by slowing down hydrodynamism, protecting the coastline from the effects of storms.

Finally, knowing that seagrasses play a key role both for the proper functioning of the marine environment and for our own interests, it is important to note that as a society we should be aware of seagrasses and ensure their conservation every day of the year, and not only during March.