Palaeo-dust records in sediments and ice cores show that wind-borne mineral aerosol ('dust') is strongly linked with climate state. During glacial climate stages, for example, the world was much dustier, with dust fluxes two to five times greater than in interglacial stages. However, the influence of dust on climate remains a poorly quantified and actively changing element of the Earth's climate system. Dust can influence climate directly, by the scattering and absorption of solar and terrestrial radiation, and indirectly, by modifying cloud properties. Dust transported to the oceans can also affect climate via ocean fertilization in those regions of the world's oceans where macronutrients like nitrate are abundant but primary production and nitrogen fixation are limited by iron scarcity. Dust containing iron, as fine-grained iron oxides/oxyhydroxides and/or within clay minerals, and other essential micronutrients (e.g. silica) may modulate the uptake of carbon in marine ecosystems and, in turn, the atmospheric concentration of CO2. Here, in order to critically examine past fluxes and possible climate impacts of dust in general and iron-bearing dust in particular, we consider present-day sources and properties of dust, synthesise available records of dust deposition at the last glacial maximum (LGM); evaluate the evidence for changes in ocean palaeo-productivity associated with, and possibly caused by, changes in aeolian flux to the oceans at the LGM: and consider the radiative forcing effects of increased LGM dust loadings. (C) 2010 Elsevier B.V. All rights reserved.
- EQUATORIAL PACIFIC-OCEAN
- CHINESE LOESS PLATEAU
- LONG-RANGE TRANSPORT
- GREENLAND ICE CORE
- DISSOLVED IRON CONCENTRATIONS
- NORTH-ATLANTIC OSCILLATION
- BUENOS-AIRES PROVINCE
- EAST-ASIAN MONSOON
- SUB-ARCTIC PACIFIC
- PAST 800,000 YEARS
[Maher, B. A.] Univ Lancaster, Lancaster Environm Ctr, Ctr Environm Magnetism & Palaeomagnetism, Lancaster LA1 4YQ, England; [Prospero, J. M.] Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA; [Mackie, D.] Univ Otago, Dept Chem, Dunedin, New Zealand; [Gaiero, D.] Univ Nacl Cordoba, Fac Ciencias Exactas Fis & Nat, Ctr Invest Geoquim & Proc Superficie, RA-5000 Cordoba, Argentina; [Hesse, P. P.] Macquarie Univ, Dept Geog & Environm, Sydney, NSW 2109, Australia; [Balkanski, Y.] Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France
Maher, BA (reprint author), Univ Lancaster, Lancaster Environm Ctr, Ctr Environm Magnetism & Palaeomagnetism, Lancaster LA1 4YQ, England.