The Green Sahara, A Desert In Bloom

Science News, ScienceDaily ^ | September 30, 2008 | Christian-Albrechts-Universitaet zu Kiel

[SunkenCiv]

Reconstructing the climate of the past is an important tool for scientists to better understand and predict future climate changes that are the result of the present-day global warming. Although there is still little known about the Earth's tropical and subtropical regions, these regions are thought to play an important role in both the evolution of prehistoric man and global climate changes.

New North African climate reconstructions reveal three 'green Sahara' episodes during which the present-day Sahara Desert was almost completely covered with extensive grasslands, lakes and ponds over the course of the last 120.000 years. The findings of Dr. Rik Tjallingii, Prof. Dr. Martin Claussen and their colleagues will be published in the October issue of Nature Geoscience.

Scientists of the... Center for Marine Environmental Research in Bremen... and the Alfred-Wegener-Institute in Bremerhaven... studied a marine sediment core off the coast of Northwest Africa to find out how the vegetation cover and hydrological cycle of the Sahara and Sahel region changed. The scientists were able to reconstruct the vegetation cover of the last 120.000 years by studying changes in the ratio of wind and river-transported particles found in the core...

The scientists explain these periods by an increase of the precipitation that resulted in a much larger vegetation cover resulting in less wind dust and stronger river activity in the Sahara region...

The computer model simulation shows three periods with an almost completely vegetated Sahara at the same time as seen in the geological record. This supports the interpretation of geologists and, in turn, demonstrates the value of computer model results. Additionally, the computer model indicates that only a small increase in precipitation is sufficient to develop a vegetation cover in the Sahara.

[SunkenCiv]

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Just updating the GGG info, not sending a general distribution. Evolution in Your Face by Patrick Huyghe Omni Lake Victoria, Africa's largest lake, is home to more than 300 species of cichlids. These fish, which are popular in aquariums, are deep-bodied and have one nostril, rather than the usual two, on each side of the head. Seismic profiles and cores of the lake taken by a team headed by Thomas C. Johnson of the University of Minnesota, reveal that the lake dried up completely about 12,400 years ago. This means that the rate of speciation of cichlid fishes has been extremely rapid: something on average of one new species every 40 years! 12,400 years ago? Hydrologic cycle came to a screeching whoa for some reason, hmm, what could it have been? To all -- please ping me to other topics which are appropriate for the GGG list.

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The African Source Of The Amazon’s Fertilizer
Science News Magazine ^ | 11-18-2006 | Sid Perkins
Posted on 11/18/2006 7:22:58 PM by blam
http://www.freerepublic.com/focus/news/1740969/posts

[SunkenCiv]

Evolution in Your Face
by Patrick Huyghe
Omni

Lake Victoria, Africa's largest lake, is home to more than 300 species of cichlids. These fish, which are popular in aquariums, are deep-bodied and have one nostril, rather than the usual two, on each side of the head. Seismic profiles and cores of the lake taken by a team headed by Thomas C. Johnson of the University of Minnesota, reveal that the lake dried up completely about 12,400 years ago. This means that the rate of speciation of cichlid fishes has been extremely rapid: something on average of one new species every 40 years!

[SunkenCiv]

Ancient lakes of the Sahara
Innovations Report | Jan 19, 2006 | University of Reading
Posted on 1/21/2006 7:14:03 AM by Tyche
http://www.freerepublic.com/focus/news/1562135/posts