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St. Petersburg Coastal and Marine Science Center > Effects of African Dust on Coral Reefs and Human Health

The Effects of African Dust on Coral Reefs and Human Health

Photo Gallery - Five Decades of Change

Eugene Shinn took the photographs in this gallery over a period of about fifty years at two locations, Grecian Rocks and Carysfort Reef, in the Key Largo Coral Reef Marine Sanctuary in Florida.

At Grecian Rocks, and at Carysfort Reef about 15 kilometers to the north, clear evidence can be seen of the changes affecting these corals.

In some of the earlier photos the aftermath of Hurricane Donna is apparent in the damage that can be seen at some locations. Donna was a Category 4 hurricane when it made landfall in Florida in 1960.

In 1978-79, staghorn and elkhorn corals suffered an extensive die-off in Florida. This change can be seen clearly in the first and last star coral photo sets at Grecian Rocks, and in the brain coral photo set from Carysfort Reef.

By the late 1990s, some of the corals that remained at these locations were afflicted with black band disease, algal infestation, or coral bleaching.

USGS scientists are investigating whether or not the greater amounts of dust and concentrations of chemicals in that dust coming out of Africa are factors in the large scale changes in Caribbean coral reefs.

Grecian Rocks

Grecian Rocks Star Coral 1961-2009: This star coral (Montastraea faveolata) was tagged with stainless steel pins for a growth-rate experiment following devastation of the area by Hurricane Donna in 1960. A sediment trap is in the cement block in background. Staghorn coral (Acropora cervicornis, at right) grew at a rapid rate and encroached the star coral (see photos for years 1971 and 1976). The staghorn began dying in 1979 and most had died by 1980. All staghorn by 1988 was dead and by 2004 the misshapen star coral remains and is surrounded by sea fans and sea whips. Click on a thumbnail image or year to see a larger version of the image.

Grecian Rocks Brain Coral 1959-1998: Photo of a large Colpophyllia natans (a type of brain coral) with a star coral attached at left and a species of Diploria on the right as in 1959. In 1988, the star coral was missing (note cavity in foreground) but Diploria remained. Hurricane Donna impacted the area after the 1959 photography. In 1998, the head coral was mostly dead and encrusted with sea whips and the Diploria at right was bleached white. Click on a thumbnail image or year to see a larger version of the image.

Grecian Rocks Star Coral 1988-2009: This large star coral (Montastraea faveolata) was being attacked by black-band disease (the white part was dead) in 1988. By 2004, some living tissue remained at the lower right, and two heads of Porities astreoides are growing on the dead surface. Such successions can be seen in fossil coral reefs such as at Windley Key Fossil Reef State Park in the Florida Keys. Click on a thumbnail image or year to see a larger version of the image.

Grecian Rocks Star Coral 1961-2004: This large Montastraea sp. head was being encroached by elkhorn and staghorn coral in 1961 following devastation by Hurricane Donna in 1960. In 1974, there was abundant growth of these corals around the head coral. Elkhorn and staghorn were dead in 1988. The orginal head coral is just below the diver's hand. The head coral was not visible in 1998 and 2004, and the area has been taken over by sea fans and whips. Click on a thumbnail image or year to see a larger version of the image.

Carysfort Reef

Carysfort Reef Star Coral 1960-2004: A large star coral (Montastraea faveolata) in 1960. Arrow points to a spike used to measure growth rate. The series shows changes in the same coral up to 2004 when erosion after death in the early 1980s changed its shape. Only small parts are still living. Click on a thumbnail image or year to see a larger version of the image.

Carysfort Reef Brain Coral 1960-2009: In 1960, this brain coral (Diploria sp) was tagged with stainless steel pins (shown by arrows). By 1971, it was surrounded by staghorn coral. By 1986, the staghorn was dead, broken, and covered by fleshy algae. The brain coral continued to die and by 2004 only a small portion was living. Click on a thumbnail image or year to see a larger version of the image.


St. Petersburg Coastal and Marine Science Center > Effects of African Dust on Coral Reefs and Human Health

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