African dust and the demise of Caribbean coral reefs

The vitality of Caribbean coral reefs has undergone a continual state of de cline since the late 1970s, a period of time coincidental with large increa ses in transatlantic dust transport. It is proposed that the hundreds of mi llions of tons/year of soil dust that have been crossing the Atlantic durin g the last 25 years could be a significant contributor to coral reef declin e and may be affecting other ecosystems. Benchmark events, such as near syn chronous Caribbean-wide mortalities of acroporid corals and the urchin Diad ema in 1983, and coral bleaching beginning in 1987, correlate with the year s of maximum dust flux into the Caribbean. Besides crustal elements, in par ticular Fe, Si, and aluminosilicate clays, the dust can serve as a substrat e for numerous species of viable spores, especially the soil fungus Aspergi llus. Aspergillus sydowii, the cause of an ongoing Caribbean-wide seafan di sease, has been cultured from Caribbean air samples and used to inoculate s ea fans.