The origins of dust in Antarctica Figure 3: Map of South America showing the locations of dust and loess sampled for lead isotopes as possible sources of dust deposited in Antarctic ice cores. The lead isotopes of these samples were then compared with previous results from dust trapped in Antarctic ice cores and dust sources collected from Australia. To do this, they collected samples of dust and loess (a rock formed by dust deposits) across a north-south transect of South America (Figure 3). Gili and her colleagues analyzed the lead isotopes of potential dust sources in much greater detail. Previous studies using lead isotopes were inconclusive because the differences between the sources were small and subtle. ![]() If even a tiny bit of dust from the lab gets in the ice core sample, the contamination ruins the measurement. Few studies have used this sort of fingerprint because it’s hard to make a measurement without contamination. Dust sources on different continents have subtly different fingerprints, so examining the lead isotopes of dust particles trapped in ice cores can be used to determine the relative contributions of the different sources. This study uses lead isotopes to identify the “fingerprint” of dust sources in different regions. The chemical composition of dust particles is used to track their source, because their composition is preserved during transport and reflects their origins. This is important for understanding past changes in ocean iron availability which, as you can imagine, is not easy to figure out! Tracing dust origins with lead isotopes The glaciers have been accumulating for the last 800,000 years, so examining the origins of dust particles trapped in ice cores can provide a massive historical record of dust transport and deposition. Without any way to directly measure how the world worked hundreds of thousands of years ago, we rely on oblique clues like ice core records to gradually piece together the puzzle of the prehistoric earth system. In addition, Antarctic ice cores provide a window into dust deposition in the distant past. Most dust therefore comes from atmospheric transport across the ocean, providing an opportunity to examine wind patterns. The continent is covered in snow and ice, so exposed mountain faces are the only significant local dust sources. Antarctica is a particularly interesting place to study dust deposition because it produces little dust of its own. By determining the origin of deposited dust, we can reconstruct the wind patterns required to get it from its origin to its destination. ![]() Dust blowing off the Sahara over the Atlantic Ocean (NASA)ĭust can provide interesting insights into the patterns of wind currents and atmospheric circulation. Dust plumes blowing off the Saharan desert (shown below) have been shown to fertilize algae growth in the eastern Atlantic Ocean, and can even provide nutrients to the Amazon rain forest. For example, see this post! Dust is very rich in iron, and dust deposition represents the only source of iron to some remote ocean ecosystems. This process can be critical for life in the ocean because in much of the ocean (especially the southern ocean surrounding Antarctica) the productivity of the ecosystem is limited by iron availability. Picked up by wind and trapped in the atmosphere, then transported halfway around the world in wind currents. Microscopic particles of soil or rock can be The tiniest of particles can have a huge impact on the ocean ecosystem. Kaplan (2016), Provenance of dust to Antarctica: A lead isotopic perspective, Geophysical Research Letters, 43, 2291–2298, doi:10.1002/ 2016GL068244 Dust and ocean productivity Microscope image of dust particles (Creative Commons) ![]() Lucky for them, the rest of the world wasn’t as unforgiving and quickly embraced Queen once again when they retreated to somewhat more familiar (though no less eclectic) hard rock territory with 1984’s The Works.Gili, S., D. The most blatant and negative of these was their decision to commit the bulk of their next effort, 1982’s Hot Space, to experimental, dancey funk and electrified soul – a catastrophic move which alienated many longtime fans and effectively killed the band’s career in America. pushed the members of Queen into some questionable musical decisions in the near future. The song became a hit in 17 countries, but nowhere larger than in the United States, where it became the biggest-selling Queen record ever, topping both the Pop and Disco charts, as well as reaching #2 on the Soul chart.Ĭomposed by bassist John Deacon, the song features an instantly recognizable funk bass riff, and high energy, bordering on manic, vocals by Freddie Mercury.Īccording to Eduardo Rivadavia of AllMusic, this surprise crossover hit was responsible for a change in the band’s musical style. “Another One Bites the Dust” took the world by storm.
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