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The recent upsurge in research attention to aeolian dust has shown that dust transport systems operate on very large spatial and temporal scales, and involve much larger quantities of sediment than was previously realized. An inevitable consequence of this is that researchers from a range of neighbouring disciplines, including ecology, are beginning to realize that this new knowledge has important implications for their study areas. In the present paper, we examine the ecological implications (real and potential) of this expanding knowledge of dust transport systems, with a particular emphasis upon the Australian dust transport system. We track these ecological effects from source to sink. At source, wind erosion–soil–vegetation...
The forest-alpine tundra ecotone in the Front Range of Colorado typically occurs as a gradual transition from the treeless tundra to the closed canopy coniferous subalpine forest. We evaluated the patterns of snow, deposition inputs, and soil properties at three spatial scales: across the entire ecotone, with distance from tree limit in the transitional krummholz zone, and around individual trees. Snow depth was deepest in the krummholz zone and lowest in the alpine tundra and upwind of trees near tree limit, but was not predictive of most soil properties except for surface litter decomposition. Inorganic deposition ranged from 0.7 to 7.7 g m−2 yr−1 across the ecotone and tended to be higher downwind than upwind...
This article presents a simple physical concept of aeolian dust accumulation, based on the behaviour of the subprocesses of dust deposition and dust erosion. The concept is tested in an aeolian dust wind tunnel. The agreement between the accumulation curve predicted by the model and the accumulation curve obtained in the experiments is close to perfect and shows that it is necessary to discriminate between the processes of aeolian dust deposition and aeolian dust accumulation. Two important thresholds determine the accumulation process. For wind speeds below the deflation threshold, the aeolian accumulation of dust increases linearly with the wind speed. For wind velocities between the deflation threshold and the...
This study investigates how dust deposition samplers affect the grain size characteristics of the sediment they catch. Sediment samplers act as obstacles in the flow and their collection efficiency varies with the grain size and other factors. Some particle fractions are collected more efficiently than others, resulting in a modification of the original grain size distribution of the sediment. This paper presents wind tunnel results for five dust deposition samplers and five wind velocities ranging from 1 to 5 m s− 1. The catcher's effect on the grain size was apparent in all experiments. Dust accumulated in a catcher is finer than undisturbed dust. For the dust used in the tests the difference (in median grain...