Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Drastic Desertification

21.08.2012
Over the past 10,000 years, climate changes in the Dead Sea region have led to surprisingly swift desertification within mere decades.
This is what researchers from the University of Bonn and their Israeli colleagues found when analyzing pollen in sediments and fluctuations in sea levels, calling the findings 'dramatic.' They are presented in the current issue of the international geosciences journal "Quaternary Science Reviews," whose print version is published on 23 August.

The Dead Sea, a salt sea without an outlet, lies over 400 meters below sea level. Tourists like its high salt content because it increases their buoyancy. "For scientists, however, the Dead Sea is a popular archive that provides a diachronic view of its climate past," says Prof. Dr. Thomas Litt from the Steinmann-Institute for Geology, Mineralogy and Paleontology at the University of Bonn.

Using drilling cores from riparian lake sediments, paleontologists and meteorologists from the University of Bonn deduced the climate conditions of the past 10,000 years. This became possible because the Dead Sea level has sunk drastically over the past years, mostly because of increasing water withdrawals lowering the water supply.

Oldest pollen analysis

In collaboration with the GeoForschungsZentrum Potsdam (German Research Centre for Geosciences) and Israel's Geological Service, the researchers took a 21 m long sediment sample in the oasis Ein Gedi at the west bank of the Dead Sea. They then matched the fossil pollen to indicator plants for different levels of precipitation and temperature. Radiocarbon-dating was used to determine the age of the layers. "This allowed us to reconstruct the climate of the entire postglacial era," Prof. Litt reports. "This is the oldest pollen analysis that has been done on the Dead Sea to date."

In total, there were three different formations of vegetation around this salt sea. In moist phases, a lush, sclerophyll vegetation thrived as can be found today around the Mediterranean Sea. When the climate turned drier, steppe vegetation took over. Drier episodes yet were characterized by desert plants. The researchers found some rapid changes between moist and dry phases.

Transforming pollen data into climate information

The pollen data allows inferring what kinds of plants were growing at the corresponding times. Meteorologists from the University of Bonn took this paleontological data and converted it into climate information. Using statistical methods, they matched plant species with statistical parameters regarding temperature and precipitation that determine whether a certain plant can occur. "This allows us to make statements on the probable climate that prevailed during a certain period of time within the catchment area of the Dead Sea," reports Prof. Dr. Andreas Hense from the University of Bonn's Meteorological Institute.

The resilience of the resulting climate information was tested using the data on Dead Sea level fluctuations collected by their Israeli colleagues around Prof. Dr. Mordechai Stein from the Geological Services in Jerusalem. "The two independent data records corresponded very closely," explains Prof. Litt. "In the moist phases that were determined based on pollen analysis, our Israeli colleagues found that water levels were indeed rising in the Dead Sea, while they fell during dry episodes." This is plausible since the water level of a terminal lake without an outlet is exclusively determined by precipitation and evaporation.

Droughts led to the biblical exodus

According to the Bonn researchers' data, there were distinct dry phases particularly during the pottery Neolithic (about 7,500 to 6,500 years ago), as well as at the transition from the late Bronze Age to the early Iron Age (about 3,200 years ago). "Humans were also strongly affected by these climate changes," Prof. Litt summarizes the effects. The dry phases might have resulted in the Canaanites' urban culture collapsing while nomads invaded their area.

"At least, this is what the Old Testament refers to as the exodus of the Israelites to the Promised Land."

Dramatic results

In addition, this look back allows developing scenarios for potential future trends. "Our results are dramatic; they indicate how vulnerable the Dead Sea ecosystems are," says Prof. Litt. "They clearly show how surprisingly fast lush Mediterranean sclerophyll vegetation can morph into steppe or even desert vegetation within a few decades if it becomes drier." Back then, the consequences in terms of agriculture and feeding the population were most likely devastating. The researchers want to probe even further back into the climate past of the region around the Dead Sea by drilling even deeper.

Publication: Holocene climate variability in the Levant from the Dead Sea pollen record, Quaternary Science Reviews 49 (August 2012)

Contact:

Prof. Dr. Thomas Litt
Steinmann Institute for Geology, Mineralogy and Paleontology
Ph. 0228/732736
Email: t.litt@uni-bonn.de

Prof. Dr. Andreas Hense
Meteorological Institute
Ph.: 0228/735184
Email: ahense@uni-bonn.de

Johannes Seiler | idw
Further information:
http://www.uni-bonn.de
http://www3.uni-bonn.de/Pressemitteilungen/207-2012
http://dx.doi.org/10.1016/j.quascirev.2012.06.012

More articles from Earth Sciences:

nachricht Responses of benthic foraminifera to changes of temperature and salinity
14.01.2019 | Science China Press

nachricht 'Realistic' new model points the way to more efficient and profitable fracking
14.01.2019 | DOE/Los Alamos National Laboratory

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

Im Focus: Mission completed – EU partners successfully test new technologies for space robots in Morocco

Just in time for Christmas, a Mars-analogue mission in Morocco, coordinated by the Robotics Innovation Center of the German Research Center for Artificial Intelligence (DFKI) as part of the SRC project FACILITATORS, has been successfully completed. SRC, the Strategic Research Cluster on Space Robotics Technologies, is a program of the European Union to support research and development in space technologies. From mid-November to mid-December 2018, a team of more than 30 scientists from 11 countries tested technologies for future exploration of Mars and Moon in the desert of the Maghreb state.

Close to the border with Algeria, the Erfoud region in Morocco – known to tourists for its impressive sand dunes – offered ideal conditions for the four-week...

Im Focus: Programming light on a chip

Research opens doors in photonic quantum information processing, optical signal processing and microwave photonics

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new integrated photonics platform that can...

Im Focus: Physicists uncover new competing state of matter in superconducting material

A team of experimentalists at the U.S. Department of Energy's Ames Laboratory and theoreticians at University of Alabama Birmingham discovered a remarkably long-lived new state of matter in an iron pnictide superconductor, which reveals a laser-induced formation of collective behaviors that compete with superconductivity.

"Superconductivity is a strange state of matter, in which the pairing of electrons makes them move faster," said Jigang Wang, Ames Laboratory physicist and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

 
Latest News

Scientists coax proteins to form synthetic structures with method that mimics nature

15.01.2019 | Life Sciences

Next generation photonic memory devices are light-written, ultrafast and energy efficient

15.01.2019 | Information Technology

Viennese scientists develop promising new type of polymers

15.01.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>