New Caledonia Expedition: Green Umbrellas in the Reef

By Kike Ballesteros

Imagine you’re on the first day of vacation, arriving in the Florida Keys, Cozumel, Cabo Pulmo, the Bahamas or another beautiful beach destination. Now it’s time to go swimming and sunbathing on the beach, but you have to be careful. To protect against a sunburn you may need the help of some lotion, the shadow of a palm tree, or even better, the protection of an umbrella.

Umbrellas absorb most of the sun’s radiation; they have been designed for this purpose. Strangely, though, it’s hard to find these kinds of structures in the natural world – even on a planet where most organic matter is obtained by plants with the help of the sun’s rays! Sunlight is pivotal to maintaining life on Earth. Terrestrial plants, for instance, are always trying to get it. This explains the existence of trees. They struggle to be higher and to display an “antenna” that captures most of the light, but evolution has not created an umbrella-like tree, probably because of mechanical constraints.

In the ocean, however, there are some kinds of organisms that need light for growth and have adopted the shape of an umbrella. Good examples are plate corals, whose colonies project over the sea bottom like a table with one central leg. I had never seen this umbrella shape in an algae even though I have been studying seaweeds for more than thirty years in most of the world’s oceans.

Pitcairn Islands Expedition Photos: Strange and Beautiful Algae

This is why I was so excited when I first saw some tiny green umbrellas growing in some areas of the reef, together with other common tropical algae. My diving buddies were recording and filming the high coral diversity, the large amount of sharks and the colorful life of the reef. “Important and relevant” things, yes, but I was so happy with this small encounter that I asked our cameraman, Manu San Felix, to take my picture with the precious gift the reef had given to me. Manu, a bit surprised, stopped filming the astonishing reef life and took the picture I wanted. Sometimes you enjoy small organisms because of their rarity or because finding them is unexpected or just because, as in this case, they fill an “evolutionary” gap. For me, I had found a naturally designed light-gatherer: the green umbrella.

Click here to view all New Caledonia expedition blog posts.

This expedition is led by National Geographic in collaboration with the Institute de Recherche pour le Development (IRD) of New Caledonia and the Waitt Institute.

Thanks to Pristine Seas sponsors Blancpain and Davidoff Cool Water.

Changing Planet

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Meet the Author
Marine ecologist Dr. Enric Sala is a National Geographic Explorer-in-Residence who combines science, exploration and media to help restore marine life. Sala’s scientific publications are used for conservation efforts such as the creation of marine protected areas. 2005 Aldo Leopold Leadership Fellow, 2006 Pew Fellow in Marine Conservation, 2008 Young Global Leader at the World Economic Forum.