Oceanography in the 21st Century - An Online Textbook
navigation bar for the online textbook

 

Dustiest Places on Earth–Dead and Dying Seas

Introduction

Climate change and the diversion of rivers for use by cities and agriculture in arid lands produces dead and dying seas. Winds blowing over the former seabeds have produced the dustiest places on earth.

The Dustiest Place on Earth: the Bodélé Depression in the Sahel

The dustiest place on earth is the Bodélé Depression in the Sahel. It is the remains of a much larger sea formed when the Sahel and the Sahara were much wetter thousands of years ago. Read Dustiest Place on Earth, a 904-KB pdf file, about the Bodélé Depression in the Sahel, from Nature.

dustiest place on earth
Image from Dustiest Place on Earth article.

Owens Valley

The dustiest place in North America is the Owens Valley. It is the single largest source of PM-10 dust in the United States. The story begins with the Metropolitan Water District of Southern California obtaining water rights to almost all water in the Owens Valley during the early 20th century to ensure an adequate water supply for the fast growing Los Angeles. This led to the dessication of Owens Lake.

owens valley seen from space
All that is left of the original Owens Lake in Owens Valley, California east of the Sierra Nevada mountains. Click on image for a zoom.
From NASA Earth Observatory.

Dust from the lake has a high salt content, and it includes important concentrations of arsenic, cadmium, nickel, and chromium. For more information read Owens (Dry) Lake, California: A Human-Induced Dust Problem by Marith C. Reheis of the U.S. Geological Survey.

Recently the district has been required to allow enough water to flow into Owens Lake to reduce the amount of particulates picked up by winds in the area. See A Century Later, Los Angeles Atones for Water Sins in the New York Times. Photos of the partly restore lake bed are published by Metropolis Magazine.

Dying Seas—The Aral Sea

The demand for water for irrigating crops has led to large-scale diversion of water from rivers. In central Asia, the Syr Darya and Aru Darya feed the Aral Sea. The diversion led to perhaps the most notorious ecological catastrophe of human making. The Aral Sea was once the 4th largest lake in the world.

map of Aral Sea area in central Asia.
Map of Aral Sea area in central Asia.
From the World Bank.

Aral Sea in 1989 and 2003 as seen from space.
Aral Sea as observed from space. From NASA Earth Observatory.

Aral Sea in 2007, source of a dust storm.
The remnants of the Aral Sea in 2007.

From NASA Earth Observatory.

Read Coming to Grips With the Aral Sea's Grim Legacy, a Science article by Stone (1999). There's no undoing this sea's demise, but scientists are hoping to soften the impact.

beached ships, Aral Sea
Beached. A Soviet decision to divert river water to cotton farming hastened the Aral Sea's retreat. From Pala (2005).

Aral Sea - To save a Vanishing Sea, a Science article by Pala (2005).
A project backed by the World Bank aims to reverse the Aral Sea's rapid decline, but it could also increase traffic to an abandoned bioweapons testing site.

The northern portion of the Aral Sea is slowly being brought back to life. A dike supported by the World Bank and repairs along the banks of the Syr Darya River have increased the water level dramatically. An article in Science by Pala (2007).

Dying Seas—The Salton Sea

Salton Sea: Battle Over a Dying Sea, a Science article by Kaiser (1999).
Scientists are at odds over whether to save the Salton Sea, an engineering mistake that has become a deathtrap for wildlife; the remedy they choose could influence how environmental debacles are dealt with around the world.

Revised on: 5 January, 2009

navigation bar for the online textbook
Copyright and contact information for Our Ocean Planet
click here to get back to the schedule page click here to go to the next page