The Danube River is the largest in the European Union, its
watershed draining 801,463 square kilometers (309,447 square miles) of land
across 19 countries. Where that great river reaches the Black Sea, a remarkable
delta has formed—the “Everglades” of Europe. The Danube Delta is home to more
than 300 species of bird and 45 species of freshwater fish.
The Danube Delta has been home to human settlements since the
end of the Stone Age (the Neolithic Period), and the ancient Greeks, Romans,
and Byzantines all built trading ports and military outposts along this coast.
Today, the border between Romania and Ukraine cuts through the northern part of
the delta. The area is a United Nations World Heritage Site, both for its
natural and human history, and for the traditional maritime culture that persists
in its marshes. All the while, the landscape has been shaped and re-shaped by
nature and man.
The image above was acquired on February 5, 2013, by the
Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1)
satellite. The Danube Delta has a number of lobes formed over the past several
thousand years, and this image is focused largely on the northernmost Chilia
(or Kilia) lobe. It is the youngest section of the delta—somewhere between 300
to 400 years old—and lies mostly within Ukraine. Much of the land in the image
above is officially considered part of the Danube Biosphere Reserve. (To see
more about how the delta formed, click
here.)
Near the center of the image, the small city of Vylkove is known
as the “Ukranian Venice,” due to its canals. To the lower left, the older
Sulina lobe of the delta stretches to the south and further inland into
Romania. White and brown curved lines reveal beach ridges and former
shorelines, with the whiter ridges composed almost entirely of pure quartz sand
in high dunes. To the east of the ridges, most of the landscape is flat
marshland that is mostly brown in the barren days of winter.
The Bystroye Canal through the center of the Chilia lobe has
been the subject of heated debate over the past two decades. Over the
centuries, damming and channeling of the Danube throughout Europe has reduced
its water flow and sediment load to roughly 30 percent of what it once was,
according to coastal geologist Liviu Giosan of the Woods Hole Oceanographic
Institution. In recent years, the Ukrainian government has dredged some delta
channels (including Bystroye) and proposed extensive dredging of others in
order to provide navigational channels for large ships. Proponents argue for
the economic needs of water transportation routes. Opponents note that deeper,
faster channels mean less mud and sand is deposited in the delta; in some
places, more is carried away by swifter currents. Both affect the sensitive
ecosystems and the ability of the delta to restore itself and grow.
In a 2012 report led by Giosan, scientists noted that the shape,
water chemistry, and biology of Danube Delta was being altered long before the
modern Industrial Era. Land use practices—particularly farming and forest
clearing—added significant amounts of nutrients into the water and reduced
salinity in the Black Sea, changing the dominant species of phytoplankton and
sending a ripple of effects through the entire food web.
1. Related Reading
2.
Carlowicz, M.J.,
(2005, July 11) The
Once and Future Danube River Delta. Oceanus. Accessed
February 15, 2013.
3.
Der Spiegel (2007, October 4) The
Shipping News: Construction Threatens Danube’s Natural Paradise. Accessed February 15, 2013.
4.
Giosan, L. et al. (2012) Early Anthropogenic
Transformation of the Danube-Black Sea System. Scientific Reports 2,
582.
5.
International
Commission for the Protection of the Danube River.Working for Danube River Basin
and Its People. Accessed
February 15, 2013.
NASA Earth Observatory image by Jesse Allen and Robert Simmon,
using EO-1 ALI data provided courtesy of the
NASA EO-1 team and
the U.S. Geological Survey. Caption by Mike Carlowicz.
Congratulations to Kevin
Martin,CEO/senior meteorologist for TheWeatherSpace.com, for being the
first person to solve the puzzler.
Instrument:
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