When you think of corals, you might imagine gracefully curving lobes, textured blobs or branching antlers reaching up toward the water's surface. They are colorful and diverse. They are at once animal, plant and mineral. And, not surprisingly, they are the building blocks of coral reefs. As Dr. Randi Rotjan, coral biologist at the New England Aquarium, explains in a podcast on Encyclopedia of Life, corals build little cities.



Corals provide habitats to reef animals large and small. But around the world, corals are under threat. Overfishing, pollution and rising ocean temperatures are just some of the pressures facing these rich marine ecosystems. Aquarium scientists are studying the corals and animals in a very special corner of the globe—the Phoenix Islands Marine Protected Area (PIPA). Dr. Rotjan explains in the podcast just why PIPA is so special.

Have a listen! And while you're tuned in, scroll through these images of coral reefs  in the Phoenix Islands Protected Area and meet some of the animals that live there. Can't get enough corals? Come check out our IMAX film The Last Reef 3D and you'll get to see some supersized corals on the largest movie screen in New England!

Underwater photographer Keith Ellenbogen traveled to the Phoenix Island in 2012. See more of his pictures.

Randi photographed and blogged extensively during the 2009 expedition to the Phoenix Islands

Corals up close from the 2012 expedition to PIPA, more pictures by K. Ellenbogen

More corals up close, more pictures by K. Ellenbogen

Some of the larger fishes Randi saw in the Phoenix Islands

Sharks are a sign of a healthy ecosystem, see more shark pictures

Many tiny animals call the coral reef home. See more pictures like this

Even at night the reef is alive. See more pictures like this

See more pictures like this

The Aquarium's PIPA blog is chock full of expedition pictures (from 2009 to 2012), history of the remote atolls (who knew the logbooks of Yankee whalers from the 1800s would be important for science today?) and important discussions about marine protection areas. Go ahead, take a trip to one of the world's largest MPAs and you'll know why it's so important to protect special habitat like this.