Hundreds of low-lying islands make up the Florida Keys

Today’s Image of the Day from NASA Earth Observatory features the Florida Keys, which are visited by several million tourists each year. The Keys have a population of more than 80,000 people across 30 populated islands.

“The chain of hundreds of low-lying islands, also called cays or keys, that extend from southern Florida are relics of a time when global sea levels were higher than today. About 125,000 years ago, during a warm interglacial period, water covered the area,” explains NASA.

“However, the sea was shallow enough that big communities of coral flourished just below the surface and built up reefs. As time passed and an ice age took hold, sea levels dropped and the tops of some reefs—as well as some sand bars—began to poke above the water surface. Over time, material from these exposed reefs and sand bars hardened and fossilized, forming the sedimentary rocks that make up the modern Florida Keys.”

Many of the Florida Keys are located within the boundaries of national parks, including the Florida Keys National Marine Sanctuary. Several of the northern keys are in Biscayne National Park, and most of the islands within Florida Bay are part of Everglades National Park.

“Still, some parts of Big Pine Key and several other islands retain patches of pine rockland, an unusual ecosystem found exclusively in southern Florida. In these areas, scattered slash pine soars over an understory of palms, palmettos, berries, grasses, and several types of herbaceous plants,” says NASA.

“While falling sea levels brought the Florida Keys into existence, rising seas now pose a threat to their long-term existence. Sea level rise projections from the Interagency Sea Level Rise Scenario Tool (published by NASA’s Sea Level Change Team) indicate that Key West could experience between 0.45 and 2.16 meters (1 and 7 feet) of sea level rise by 2100.”

The image was captured on March 30, 2022 by the Operational Land Imager (OLI) on Landsat 8.

Image Credit: NASA Earth Observatory 

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By Chrissy Sexton, Earth.com Editor

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