coral

However, they are also among its most vulnerable, with areas of coral reefs, mangrove forests and seagrass beds under increasing threat from a wide range of human activities.

Yet as coral reef ecologist Alexandra Dempsey explored the atolls’ beautiful coral reefs in 2015, she nevertheless found signs of human pollution.

The mega coral - which is a collection of many connected, tiny creatures that together form one organism rather than a reef - could be more than 300 years old.

California moray eels live in coral reefs from Point Conception in Santa Barbara County to southern Baja California in Mexico, according to the Monterey Bay Aquarium.

On the deep seafloor, rough volcanic terrain harbors corals, sponges and fish.