17 January 2023 | 4 minutes.

Mapping Corals

Trillions of coral polyps exist in the ocean, forming coral by secreting skeletons of calcium carbonate. Image: Greg Asner


Take to the sky to see corals like never before.

Launched in 2006, the Global Airborne Observatory (GAO), formerly known as the Carnegie Airborne Observatory (CAO), is an airborne laboratory developed by Dr. Greg Asner that uses cutting-edge technology to make advanced sensor mappings of Earth. Through its Airborne Taxonomic Mapping Systems (AToMS), Asner and his team are able to map ecosystems around the world: from the Bornean rainforest where they discovered the world’s tallest tree to the tropical reefs of the Dominican Republic that helped spearhead conservation of marine areas.

Occupying less than 1% of the ocean floor, coral reefs are home to more than 25% of all marine life. Corals are under pressure from a range of threats, from overfishing and pollution, to coral bleaching and ocean acidification due to warming global temperatures. Over 200 coral species are listed as threatened with extinction, according to the IUCN Red List, highlighting the need for efforts to protect corals as hotspots of biodiversity.

This VIEWS captures seafloor species, including corals and macroalgae, bringing to light a colorful collage of biodiversity.

Housed on a highly modified Dornier 228-202 aircraft. Image: Greg Asner

If no action is taken, models predict that 70% to 90% of coral reefs will be lost by 2050. Image: Greg Asner

The GAO is regarded as one of the most advanced mapping technologies operating in the civil sector. Image: Greg Asner

This image on the left is captured in “natural color” as you might see it from the window in an airplane. To the left of the island a noticeably sandy area is accompanied by a coral reef that forms a ring around the island. Tragically enough, as shown in the image to the right, 90% of the Dominican Republic’s coral reefs have been destroyed, having detrimental impacts to the entire coastal ecosystem.

The Florida Reef Tract is home to over 6,000 species of plants, fishes, and invertebrates. This mapping reveals a range of habitats on the seafloor: dark green is seagrass ecosystem, blues are different sand-dominated ecosystems (each with different types of algae), and very light green-to-yellow colors are different groups of corals commonly found in Floridian reefs.

Located on the Kona coast of Hawai‘i, the diversity is captured in natural colors. Mapping the biodiversity and functioning coral reefs is critical to understanding how best to conserve and manage them.

Asner Lab’s Coral Haven Project deploys a team of highly trained ecologists using deep diving techniques to explore, survey, measure, and document the efficacy of artificial reefs with a focus on shipwrecks that can support future coral biodiversity. Image: Greg Asner

This tiny island is the top of an extinct volcano and one of only three volcanic calderas worldwide. Corals of all types inhabit the interior and exterior around the bit of volcanic cone that still protrudes from the ocean.

This is Buck Island off the northern coast of St. Croix Island. Buck Island is shaped like an arrowhead, with the point of the land and reef shaped by continuous currents and waves coming from the east (left side of image). Like a boat moving through water, Buck Island’s reefs have arranged themselves into this arrowhead shape.

A coral reef restoration project. The Dominican Republic has lost 90% of its coral reefs. Image: Greg Asner

Coral polyps, the building blocks of coral reefs. Image: Greg Asner

Coral reefs surround Oʻahu, although active live coral growth is limited to the leeward sides of the island or in sheltered areas on the windward coasts. Here you see Kaneohe Bay, a calm lagoon-like place where large circular coral reefs have formed over millennia. These coral reefs are mostly two species, so each one has the same color in the GAO AToMS data – the hot pink color.

Located off the Island of Hawai‘i, in 2011 the fishponds of Kiholo Bay were donated to the Nature Conservancy. Restoration efforts have benefited the 3-5 million gallons of submarine groundwater that flow from these ponds into the coastal waters each day, boosting the productivity of surrounding coral reefs and reef fisheries. In this biodiversity map, red is sand and purple is dead coral resulting from a recent marine heatwave, but rest of the colors are different groups of Hawaiian corals that are alive and well.

Coral polyp in Belize. Image: Greg Asner