
What are marine caves?
Marine caves, also known as sea caves or littoral caves, are underwater environments that additionally serve as habitats for a large variety of species. More than 3000 marine caves are located in the Mediterranean Sea.
According to the U.S. National Park Service, marine caves are formed in the process of erosion. Though typically scarce in nutrients and low in sunlight, many vulnerable species find a way to reside in these dark submerged caves. Typical sea cave-dwelling species include sponges, arthropods, echinoderms, molluscs and fish. Certain mammals, like Mediterranean monk seals, also find solace in sea caves that are only partially underwater. These dwellings are also of historical importance as they contain formations and fossils.

What endangers life within underwater and dark habitats?
There are a few threats to these biodiverse and submerged habitats. Pollution, heatwaves, invasive species like lionfish, and human activity including tourism, are damaging to these environments.
Specific recreational human activities, such as frequent tourism and fishing, have been found to be damaging to sea caves. One study that took place in Kakoskali Cave, within the Mediterranean region, found that the resulting issue was mainly litter and physical damage to biostructures and living organisms. This is a result of exploration backed by indifference or inexperience, and could be reduced with greater awareness of marine life and conservation methods as well as efforts.
How can others help to preserve life and nature within submerged caves?
According to a few research publications on marine caves, diverse life within the caves are insufficiently studied, and some suggest that it would be beneficial to conduct more research in hopes of increasing knowledge of the many species in these regions where the caves are located.
As for human activity, a possible solution could be the implementation of a course or training requirement that would describe standards and policies on preserving marine life. If it were easily accessible to the public and those interested in recreation, it could increase the strength of conservation efforts, while simultaneously allowing humans to continue appreciating and exploring the vast sea and its vulnerable caves.

Where can readers find further information on marine caves?
While sponges and algae cover the cave walls inside and out, many other species use the environment as either a permanent dwelling or place of temporary protection and shelter. Within submerged caves, there are fish like the Lipophrys nigriceps, seals like Monachus monachus, and plenty of invertebrate inhabitants such as lobsters, sponges, coral, mussels, and urchins.
If you would like to learn more about marine caves, see the U.S. National Park Service’s article titled “Sea/Littoral Caves”, which can be found under Park Resources on the homepage.
For further information on another type of danger to life in dark habitats, see Project Manaia’s projects page on invasive species and view the subsection on Lionfish, Pufferfish, Rabbitfish, and Cornetfish.
Written by Miette Broussard
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