來(lái)自非洲撒哈拉/薩赫勒地區(qū)的塵埃排放是氣候系統(tǒng)中的一個(gè)重要因素，但非洲塵埃之產(chǎn)生的長(zhǎng)期歷史仍然在很大程度上不為人們所知,，部分原因是,，人類對(duì)非洲塵埃排放的貢獻(xiàn)是一個(gè)有爭(zhēng)議的問(wèn)題。
現(xiàn)在,，通過(guò)研究位于西非塵埃柱下一個(gè)海洋點(diǎn)上所沉降的沉積物的化學(xué)組成及顆粒大小分布,，Mulitza等人構(gòu)建了關(guān)于非洲西北塵埃沉降的一個(gè)3200年的記錄。他們的發(fā)現(xiàn)數(shù)據(jù)顯示,，由人類誘導(dǎo)的塵埃排放在距今約200年前的商業(yè)化農(nóng)業(yè)生產(chǎn)發(fā)端期間開(kāi)始對(duì)總塵埃預(yù)算有較大貢獻(xiàn),，并且從此以后一直在繼續(xù)增加。 (生物谷Bioon.net)
生物谷推薦原文出處：
Nature doi:10.1038/nature09213
Increase in African dust flux at the onset of commercial agriculture in the Sahel region
Stefan Mulitza,David Heslop,Daniela Pittauerova,Helmut W. Fischer,Inka Meyer,Jan-Berend Stuut,Matthias Zabel,Gesine Mollenhauer,James A. Collins,Henning Kuhnert& Michael Schulz
The Sahara Desert is the largest source of mineral dust in the world1. Emissions of African dust increased sharply in the early 1970s (ref. 2), a change that has been attributed mainly to drought in the Sahara/Sahel region2 caused by changes in the global distribution of sea surface temperature3, 4. The human contribution to land degradation and dust mobilization in this region remains poorly understood5, 6, 7, 8, 9, 10, 11, owing to the paucity of data that would allow the identification of long-term trends in desertification12. Direct measurements of airborne African dust concentrations only became available in the mid-1960s from a station on Barbados2 and subsequently from satellite imagery since the late 1970s: they do not cover the onset of commercial agriculture in the Sahel region ~170 years ago11, 13, 14. Here we construct a 3,200-year record of dust deposition off northwest Africa by investigating the chemistry and grain-size distribution of terrigenous sediments deposited at a marine site located directly under the West African dust plume. With the help of our dust record and a proxy record for West African precipitation15 we find that, on the century scale, dust deposition is related to precipitation in tropical West Africa until the seventeenth century. At the beginning of the nineteenth century, a sharp increase in dust deposition parallels the advent of commercial agriculture in the Sahel region. Our findings suggest that human-induced dust emissions from the Sahel region have contributed to the atmospheric dust load for about 200 years.
