The loneliness and vastness of terrestrial deserts have attracted explorers since ancient times, succumbing to their bleakness. But I never imagined deserts like this could exist underneath the surface of the ocean.

Between 2005 and 2006 I was living in the Canary Islands where I first heard about urchin barrens. It was a major issue for the community that were already running culling programs to control urchin expansion. At that time I was not aware of the scale of the problem. It was later on in 2011-2012 when I started my research in the Mediterranean. I figured out that deserts where more dominant than I had previously expected, and they seemed to be expanding. I started studying barrens, reading the work of experts on the issue from different angles (overfishing, invasive species, climate change, etc.). These people inspired my research from the beginning and now, we are joining efforts to deepen our understanding of the problem.

One of the greatest threats that the ocean has to resist is also one of its beauties. We call them hidden deserts, because not many people are aware of their existence. The bright, mirror-like surface of the sea acts, for many, as an impenetrable layer that isolates the terrestrial world from an unknown vastness. It wasn’t that long ago when marine explorers and researchers first broke this barrier, discovering an exciting and completely new world, vital to humanity. Hidden deserts are a sign of an ocean in trouble. When seaweed forests collapse, bare rock takes over. These deserts are very resilient and stable, which makes the recovery of the previously existing marine forest very tricky. What lasts is an unproductive seascape, with a catastrophically depleted diversity and with merely no associated services.

For example, Bondi Beach is one of the most popular corners of Australia, attracting tourists and surfers all year around. But what many people don’t know is that a huge desert expands below the crowded breaks. Sometime during the 1980s, seaweeds collapsed. The emblematic ‘crayweed’ forests dominating underwater Sydney was wiped away, most probably as a consequence of reduced water quality, which gave way to large bare rock seascapes. Deserts similar to Bondi’s are found all around the globe, especially in temperate waters. Losing underwater forests has important implications for us all. The structure they generate, similar to terrestrial forests, gives life to a great diversity of organisms including the fish we eat. Losing kelp forests means also eroding the planet’s resilience to climate change.