Two Views of Coral Reefs: Thriving and Threatened
Coral reefs are beautiful, vibrant ecosystems that house roughly one quarter of all marine species and provide billions of dollars in products and services to humans each year. But they are also vulnerable to human activities – both direct disturbances and small, indirect effects that build up over time. Read about why it's important for coral to be resistant and resilient, in a blog post by Smithsonian marine scientist Dr. Nancy Knowlton.
Hawaii’s Maro Coral Reef
A bluefin trevally swims in Hawaii’s Maro Coral Reef, part of the Papahānaumokuākea Marine National Monument.
©James D. Watt/Ocean Stock
Bleached Corals, Pacific Ocean
Compare the healthy coral on the left with the bleached coral on the right.
Close-up of a Coral Polyp
The brownish-green specks are the zooxanthellae that most shallow, warm-water corals depend on for much of their food.
© osf.co.uk. All rights reserved.
Corals Threatened by Acid Seas
A single bleached coral polyp foretells a grim future for this colony. In the 2011 issue of National Geographic, writer Elizabeth Kolbert tells the story of how scientists are trying to address ocean acidification before it's too late.
Andy (Flickr user amell)
Deep-Sea Coral Habitat
Rockfish, anemones, and other invertebrates inhabit this deep-sea coral reef in Cordell Bank National Marine Sanctuary off the coast of California.
Jodi Pirtle/Cordell Bank National Marine Sanctuary
Dead Coral Overgrown with Algae
These corals are dead—smothered in sediments and overgrown with algae.
Kingman’s Reef, Line Islands
A red snapper hunts for prey on Kingman’s Reef, a healthy reef in the Line Islands.
Brian Skerry/National Geographic
Unhealthy Coral Reef, Kiritimi, Line Islands
Algae has overtaken this coral reef off heavily populated Kiritimati, or Christmas Island.
Jennifer E. Smith/Scripps Institution of Oceanography
Indonesian Coral Reef
A variety of organisms make their home on this tropical coral reef in Indonesia.
© Chris Newbert/Minden Pictures
These bleached corals in the Gulf of Mexico are the result of increased water temperatures.
Diver Cleaning Up Reef
A diver cares for the reef by cleaning up discarded fishing gear and garbage.
Amos Nachoum 2005/Marine Photobank