Sea Level and Biogeography
Monday, 9. March 2009, 20:22:25
An ancient seaway between the Gulf of Thailand and the Andaman Sea was once thought have split the peninsula in two, allowing separated populations of animals to diverge. But a recent revision of the history of sea levels reveals that the ocean hasn’t cut through the peninsula in the past 40 million years. More than 58 rapid sea level rises of more than 40 m in the last 5 million years could account for the shift by crowding out species, particularly at the narrowest part of the peninsula called the Isthmus of Kra.For most of the past few million years, the shallow ocean shelf surrounding the peninsula and islands of Malaysia and Indonesia has been exposed, creating a land area about the size of Europe. That habitat shrank dramatically each time sea levels rose.
The map shows the situation sixteen thousand years ago, when surrounding seas were 110 meters lower than today. Massive ice sheets covered parts of North America, northern Europe, and several other regions during the last ice age. This huge volume of ice lowered global sea level by around 120 meters as compared to today. After the ice sheets began to melt and retreat, sea level rose rapidly, with several periods of even faster spurts.
The figure shows a generalised curve of sea level rise since the last ice age.
• http://www3.interscience.wiley.com/journal/122217747/abstract
• http://www-biology.ucsd.edu/news/article_030509.html
• http://www.giss.nasa.gov/research/briefs/gornitz_09/
The closing of the “Indonesian Seaway” (east of Borneo/Kalimantan) has by the way been seen as triggering the Ice Ages.
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