Underwater paradise discovered in London

01 August 2008

Tropical lagoons teeming with unusual sea life covered London and northwest Europe 50 million years ago, according to an international team, including Natural History Museum scientists.

The study published today in the journal Science reveals that these areas of exceptionally high marine diversity moved to different places around the world over time.

The movements happened as the global climate changed but also coincided with the movements of the Earth's tectonic plates.

'Fifty million years ago, a shallow tropical sea covering London, Brussels and Paris contained the most diverse sea life on Earth,' explains Dr Jon Todd, fossil expert (palaeontologist) at the Natural History Museum.

Marine biodiversity hotspots (from top to bottom) in the Eocene, Miocene and Recent times.

Marine biodiversity hotspots (from top to bottom) in the Eocene, Miocene and Recent times.

Marine biodiversity hotspots (from top to bottom) in the Eocene, Miocene and Recent times.

'This changed completely over the following 30 million years. The variety of tropical marine creatures around Europe gradually dropped as global climate cooled and as the Mediterranean became isolated from the Indian Ocean as tectonic movement created mountains in the Middle East.'

Fossil evidence

The team studied fossils that are millions of years old. They can tell what species of molluscs, coral and other marine life was living at different times in the Earth's history by identifying the remains left behind as fossils.

They combined studies of Museum specimens with previous DNA analyses to identify when and where selected organisms comprised the greatest number of different species.

'Collections of fossils at the Natural History Museum proved to be a critical piece in the puzzle,' says Dr Ken Johnson, Museum fossil expert (palaeontologist).

'They allowed us to map out the changing geographical spread of tropical biodiversity as the hotspot hopped a third of the way around the world.'

Marine biodiversity hotspot

The current hotspot for marine diversity is in southeast Asia. The rich variety of plants and animals are critical resources for many people who live along these coastlines.

Some scientists believe the marine diversity in southeast Asia developed only in the past few million years in response to climate and sea-level changes caused by the Ice Ages. 

But this new research shows that the region has had an exceptional variety of sea life for at least 25 million years. This long period of high diversity has coincided with increased tectonic activity in the region.

Future conservation

Southeast Asia's coral reefs are among the world's most threatened because the region is so densely populated.

Gaining a better understanding of the history of this unique environment will help conservation efforts during the coming decades of global environmental change caused by humans.