Reconstructing atmospheric particulate loads over the north-western Pacific Ocean during the mid to late Holocene: volcanism, dust and human perturbation of regional aerosol loads/composition.
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Date
2022-12-06
Journal Title
Journal ISSN
Volume Title
Publisher
Australasian Quaternary Association
Abstract
Atmospheric particulate transport over the North Pacific Ocean is known to be significant for regional biogeochemical processes and climate. For example, dust aerosol is known to fertilize phytoplankton, increasing the effectiveness of the biological C pump. Despite its importance, there has been little work tracing the changing sources and relative loads of particulate aerosols in this key region over the Holocene. The deserts of northern East Asia are the 2nd largest global dust source, while the eastern extent of East Asia forms part of the Pacific ring of fire, indicating tephra forms a significant, albeit episodic component of atmospheric particulate loads. Critically, East Asia has also undergone a significant transformation over recent decades, with widespread agricultural intensification and a massive increase in industrial activity, especially following China’s Great Leap Forward from late 1950s. This has likely perturbed regional atmospheric aerosol characteristics. In this study, we use peat mires from the Daisetsuzan Mountains in central Hokkaido, Japan, to reconstruct the history of atmospheric particulate deposition over the mid to late Holocene. Results show that over the past 4 kyr mineral flux was relatively low and dominated by dust input from mainland China, as evidenced by the rare earth element (REE) and eNd composition of sediments deposited in the mire. Within the last millennium, particulate fluxes changed more significantly, with the deposition of at least two major tephras. Further dramatic changes are recorded in the very top sections of the peat mire, where Chinese dust input becomes more geochemically significant. At the same time, the onset of nascent particulate matter is recorded by increasing concentrations of ‘industrial’ metals such as Pb and Cu. Collectively, this demonstrates the vast scale of human perturbation of atmospheric particulate, even within a region where the atmosphere is loaded with ‘natural’ particulate aerosol.
Description
Keywords
Pacific Ocean, Climates, Dusts, China Sea, Mountains, Particulates, Aerosols
Citation
Marx, S., Hooper, J., Irino, T., Seki, O., Stromsoe, N., Saunders, K., Zawdzki, A., Dosseto, A., & Jacobson, G. (2022). Reconstructing atmospheric particulate loads over the north-western Pacific Ocean during the mid to late Holocene: volcanism, dust and human perturbation of regional aerosol loads/composition. Paper presented to the AQUA 2022 Conference, 6-8th December, Adelaide (pp. 127-128). Retrieved from: https://aqua.org.au/conference/aqua-2022/aqua-2022-conference-program-and-abstracts/