A study of marine fossils by an international team of scientists has shown that there have been at least three biodiversity ‘hotspots’ in the past 50 million years, including the Mediterranean and an area between the Arabian Peninsula and India. The creation of such hotspots coincided with the movement of plates in the Earth’s crust, during which continents collide, producing shallow seas where thousands of species of fish and coral can flourish.

The research was published in the journal Science, where the scientists wrote: ‘They [hotspots] have moved almost across half the globe, with their timing and locations coinciding with major tectonic events.’ For example, some corals off Australia were found to have evolved from species found near the Middle East.

The Mediterranean was connected to what is now the Indian Ocean 40 million years ago, but its hotspot status died off as the African continent shifted north, resulting in the creation of the Alps from previously underwater areas. The Middle Eastern region then took over as the primary hotspot.

Willem Renema of the Dutch National Museum of Natural History, the report’s lead author, said that the current Indonesia–Australia hotspot could be past its peak, as the Australian landmass slowly drifts north towards Asia. The two continents moved closer over the past five million years, creating mountain ranges across New Guinea and lifting huge corals out of the sea around Sulawesi.

The next hotspot is likely to occur off southern or eastern Australia in about 25 million years.

November 2008