Investigating Australia’s southeast dust path as a source of essential trace elements to the Southern Ocean

Supervisory Team:

• Prof Andrew Bowie
• Dr Scott Meyerink (AAPP, IMAS, University of Tasmania)

Research advisors:

• Dr Krystyna Saunders (ANSTO)
• Dr Morgane Perron (IUEM, France)

Brief project description:

The atmosphere transports mineral dust, bushfire particles and anthropogenic emissions from terrestrial and human sources. These aerosols contain micronutrients and pollutants which can stimulate or limit marine productivity and impact marine ecosystems. This project aims to quantify the atmospheric deposition of trace metals and nutrients contained in aerosols transported to the oceans southeast of Australia. We will use samples collected from a unique archive from two different study sites, the first from Lord Howe Island in the Tasman Sea to the east of Australia and the second from Macquarie Island in the subantarctic Southern Ocean to the southeast of Tasmania.

We will focus on lithogenic trace elements (e.g., Al, Fe, Th, Ti) and micronutrients needed for biological productivity (e.g., Fe, Zn, Mn), and how the transport of these elements may vary seasonally and interannually, whilst also obtaining important information on pollutant aerosols (e.g., Pb, Cu, V, Cu). If time allows, we will also examine major ions (e.g., macronutrients, oxalate, sulfate) and biomass burning tracers (e.g., levoglucosan) in the samples.

The project will compare the new data with existing aerosol data collect by our lab from kunanyi/Mount Wellington (Tasmania) (Perron et al., 2022) and Gingin (Western Australia) (Strzelec et al., 2020), and also on voyages of RV Investigator to the east of Australia and in the Southern Ocean (Perron et al., 2020). The aerosol data will be interpreted in the context of remotely sensed aerosol deposition and atmospheric transport models.

Specific questions addressed by the project:

1. How does the particle concentration and chemical composition of trace elements vary seasonally and interannually at Lord Howe Island and Macquarie Island?

2. What are regional sources of aerosols to the Tasman Sea and the subantarctic Southern Ocean and how are they modified along the atmospheric transport pathway?

3. How do the new data from Lord Howe Island and Macquarie Island compare with our existing time-series from Tasmania and WA, and also from our shipboard aerosol program on RV Investigator?

References:

Perron et al., 2020. Origin, transport and deposition of aerosol iron to Australian coastal waters. Atmospheric Environment 228, 117432, https://doi.org/10.1016/j.atmosenv.2020.117432.

Perron et al., 2022. Trace elements and nutrients in wildfire plumes to the southeast of Australia. Atmospheric Research 270, 106084, https://doi.org/10.1016/j.atmosres.2022.106084.

Strzelec et al., 2020. Atmospheric Trace Metal Deposition from Natural and Anthropogenic Sources in Western Australia. Atmosphere 11, 474. https://doi.org/10.3390/atmos11050474

Skills students will develop during this research project:

The student will learn laboratory skills and techniques including acid digestion and ICP-MS trace metal analysis following GEOTRACES clean protocols. The student will also learn data processing techniques, including script-based methods (Matlab, R) associated with these analytical methods and with the analysis of remotely-sensed environmental data.

The student will also participate in field sampling at the kunanyi/Mt Wellington sampling site. The student will need to be comfortable working in a clean lab, have exceptional record keeping skills and attention to detail, and be familiar with basic concepts in environmental and analytical chemistry.