One African valley provides half Amazon's fertilizing dust

Scientists from Israel, UK, US and Brazil discover that 50 million tons of dust make their way from Africa to the Amazon region every year.

chad 88 (photo credit: )
chad 88
(photo credit: )
More than half of the dust needed for fertilizing the Brazilian rainforest is supplied by a valley in northern Chad, according to an international research team headed by Dr. Ilan Koren of the Weizmann Institute of Science's department of environmental sciences and energy research. In a study published recently in Environmental Research Letters, the scientists have explained how the Bodele valley's unique features might be responsible for making it such a major dust provider. It has been known for more than a decade that the Amazon rainforest depends for its existence on a supply of minerals washed off by rain from the soil in the Sahara and blown across the Atlantic by dust. By combining various types of satellite data, Koren and colleagues from Israel, the United Kingdom, the US and Brazil have now for the first time managed to obtain quantitative information about the weight of this dust. Analyses of dust quantities were performed near the Bodele valley itself, on the shore of the Atlantic and at an additional spot above the ocean. The data revealed that some 56 percent of the dust reaching the Amazon forest originates in the Bodele valley. They also showed that a total of some 50 million tons of dust make their way from Africa to the Amazon region every year, a much higher figure than the previous estimates of 13 million tons. The new estimate matches the calculations on the quantity of dust needed to supply the vital minerals for the continued existence of the Amazon rainforest. The researchers suggest that the Bodele valley is such an important source of dust due to its shape and geographic features: It is flanked on both sides by enormous basalt mountain ridges, which create a cone-shaped crater with a narrow opening in the northeast. Winds that "drain" into the valley focus on this funnel-like opening similarly to the way light is focused by an optical lens, creating a large wind tunnel of sorts. As a result, gusts of surface wind that are accelerated and focused in the tunnel lift the dust from the ground and blow it toward the ocean, allowing the Bodele valley to export the vast amount of dust that makes a life-sustaining contribution to the Amazon rainforest. NEW SCIENCE ACADEMY MEMBERS Six distinguished new members have joined the Israel Academy of Sciences and Humanities. Chosen in the academy's general meeting on the basis of recommendations from its humanities and natural sciences branches, they are Prof. Moshe Oren, senior molecular biologist of the Weizmann Institute of Science; Prof. Moshe Idel, a leading Jewish philosophy expert at the Hebrew University; Prof. Gedeon Dagan, emeritus professor in Tel Aviv University's engineering faculty; Prof. Sergiu Hart, one of the world's leading mathematical economists from the Hebrew University; Prof. Shulamit Volkov, an expert in comparative European history at Tel Aviv University; and Hebrew University Prof. David Kazhdan, one of the world's most prominent mathematicians. BRING IN THE GIRLS Thirty 15-year-old girls from Beersheba have won a prize - a course for developing computer software that will lead to them becoming certified by Microsoft International as application developers. Beersheba's Sami Shamoon College of Engineering, in cooperation with the Ministry of Science and Technology, the Beersheba Municipality and Microsoft-Israel launched the program recently in a festive ceremony. The aim is to raise the number of women who go into scientific and engineering fields in higher education and the job market. The municipality chose the pupils among 60 studying four and five units of mathematics who took a qualifying exam. Each of the winners will be matched with female students at the college who will advise them and give them support during the 20-month course. The high-school pupils will also go on tours in industry and technological bases of the Israel Defense Forces and meet with female officers enrolled in the IDF's Atuda program. College president Prof. Yehuda Haddad said that the course will integrate the girls into academic engineering studies and help them reach the right places in their military service and in industry. Dr. Shaul Yanai of the Science Ministry's "1,000 Scholarships" program to encourage women said that "unfortunately, the potential of half of the country's population is being wasted because few young women go into technological fields." He noted that Microsoft-Israel's Forum for Young Developers has included 800 youths, of them only two women, so far. The new Shamoon project will change this. TAU AIMS FOR THE STARS Tel Aviv University, in collaboration with several other Israeli universities, plans to join a large telescope facility outside Israel in a astronomical research project that will advance their researchers' ability to study the origin of galaxies and the universe, black holes, super-novae, planets and faraway stars. The exact location of the telescope has not yet been announced. Called "New Horizons in Astronomy," the TAU effort is aimed at attracting the attention of the general public to science and talented young people to the Ramat Aviv campus, which recently hosted the British astrophysicist Prof. Stephen Hawking. Much stress will be on biological physics, which deals with physical principles underlying biological processes and molecules such as DNA, lipids and proteins.