“As a result of Patrick’s initiative over the last three decades, we now have a better understanding of the history of our oceans, in particular during the last climatic cycle spanning the last 150,000 years. This is particularly relevant as we now know how our oceans respond to climatic signals, allowing us to better predict the future.” – Professor Peter Gell, Federation University

The Council of the Royal Society of Victoria is delighted to announce that Professor Patrick De Deckker AM FAA has been selected to receive the RSV’s 2023 Medal for Excellence in Scientific Research, which recognises peak research career achievements and outstanding leadership in research by scientists working in southeastern Australia. For 2023, the Medal is awarded in Category III – the Earth Sciences.

Professor Patrick De Deckker’s remarkable career spans four decades, making enormous contributions to the fields of palaeoclimatology, palaeolimnology, palaeoceanography and environmental science. His dedication to unravelling the mysteries of our planet’s past has significantly contributed to our understanding of global and regional climatic variability.

Born in Belgium, Patrick undertook his first studies in geology at the Université de Lausanne in 1969, followed by a BA (1971) and then MSc (1976) in Geology and Micropalaeontology at Macquarie University in New South Wales following immigration to Australia. He attained his PhD in Zoology at the University of Adelaide in 1981 and was conferred a Doctor of Science (DSc) for his work in Australian Quaternary Studies by the same university in 2002. He conducted postdoctoral work at a number of Australian and Belgian research institutions, including the University of Newcastle, the University of Louvain, the Australian National University (ANU) and Monash University. Today he is an Emeritus Professor in the Climate and Ocean Geoscience Cluster at ANU and continues to publish research in the areas of palaeoclimate studies, airborne dust and climate change.

From Land to Sea

Since completing his PhD studies in 1980, Patrick commenced a productive career studying Australian salt lakes and the climate history recorded in sediments of numerous crater (most in Victoria) and large lakes in the arid and semi-arid regions of Australia. He then moved on and developed interest in the field of Quaternary oceanography and co-led an impressive nine sea-going scientific expeditions studying marine sedimentary systems, all in the southern hemisphere.

Patrick dedicated almost three decades of research on our oceans. He founded the Australian Marine Quaternary Program that attracted numerous postdoctoral fellows, international visitors and many postgraduate students, a truly international group originating from a wide range of nations. From these studies he co-authored an extraordinarily large number of high-impact publications, notably on the role of the Southern Ocean and the Indo-Pacific Warm Pool in modulating past global climate change. To date, De Deckker has published thus far 100 papers in refereed international journals on the subject of palaeoceanography, with additional papers in the process of publication.

Throughout his career he developed a great interest in linking terrestrial and marine records of climate change and studied archives of environmental change in many different sedimentary settings, including river palaeochannels, crater lakes, large playas and dunes.

New Techniques, New Discoveries

De Deckker brought innovations to the discipline of palaeoceanography through the examination of terrestrial archives (of environmental change) stored in deep-sea cores, such as airborne dust and vegetation records through pollen distribution, in addition to the geochemical signals registered in riverine clays transported at sea.

Major discoveries in palaeoceanography made by Patrick and his associates are:

1. oceanic fronts south of Australia did wax and wane through time, and the timing and rates are now well established;
2. ocean temperatures fluctuated much, with values down to 9°C during the last glacial maximum, and this is matched by equivalent temperatures on land;
3. oceanic currents, such as the Leeuwin Current that parallels the Western Australian and southern Australian coasts frequently changed intensity and vanished at times;
4. detailed documentation and timing of the onset of ENSO in the Australian region based on marine records; and
5. succinct documentation and mapping of deep-sea canyons offshore South Australia and Victoria.

Tales from the Abyss

In addition, Patrick, with others, successfully completed the mapping of the some of the deep-sea canyons offshore southern Australia that was commenced by French vessels in 1999/2001 and 2003 respectively. As a result, we now have a high-resolution map of the Sprigg Canyon and the Murray Canyons Group. He also identified that some of the conduits [channels] in several of the canyons are definitely transporting upper slope material down to the abyss. Recently, he described with Rachel Nanson some of the deep-sea canyons offshore Victoria and extrapolated that their generation is caused by groundwater seeps at sea and on the possibility of the undersea slides associated with the canyons generating tsunamis. During the investigations of the Murray canyons, Patrick and others identified ancient courses of the River Murray formed during periods of low sea levels.

A Quintessence of Dust

In parallel with the studies referenced above, Patrick worked with an Australian and international team to conduct a series of novel studies on Australian airborne dust that included, for the first time, comprehensive analyses of microbes in dust. The geochemical fingerprinting of airborne dust carried out by this team enabled them to determine the origin of major dust events in Australia. They were also able to determine that an Australian dust component is found in Antarctic ice cores, thus enabling us to determine the pathways of dust transport in the Southern Hemisphere. This work was summarised in two major single-authored papers published by Patrick in 2019 and 2020.

Curious to the Core – Microfossils as Indicators of Past Conditions

Patrick De Deckker’s forte has been to use microfossils and their chemistry to reconstruct past environments. Patrick commenced his career using calcareous microfossils called ostracods (microcrustaceans) drawn from core samples to determine past conditions in lakes, such as salinity and temperature. For the latter, he pioneered with Professor Allan Chivas the concept of using trace elements such as magnesium and strontium in ostracod shells to reconstruct past environmental changes in lakes. This was commenced with in vitro experiments which were then applied to Quaternary fossil material. This technique is now used by numerous laboratories worldwide. The lacustrine palaeoenvironmental conditions were also reconstructed using an array of microfossils such as charophyte algae, diatoms, gastropods, cladoceran and fish remains, as well as pollen.

When Patrick turned his interests to marine cores, he used the same approach to gather information from microfossils such as foraminifera, pteropods, diatoms, radiolarians, often in collaboration with postgraduate and postdoctoral fellows. This work led to a better understanding of the distribution and (palaeo)ecology of those organisms.

Funding the Work

In order to achieve this work Patrick De Deckker was successful in obtaining numerous research grants form a variety of sources, (totalling > 5 million dollars from the ARC, AINSE, ANU small grants scheme etc.) as well as secured ship time (>2 million dollars) from the Australian National Marine Facility and the French Polar Institute.

Contributions to Science Community and Awards:

In addition to his exceptional research, Patrick has been a committed mentor, inspiring younger scientists and actively participating in numerous academic organisations. His commitment to interdisciplinary collaboration is evident in his editorial roles and long-standing contributions to renowned scientific journals.

He is a recipient of the Royal Society of South Australia’s Verco Medal (1992), the Australian Society for Limnology Medal (2005), the Christoffel Plantin Medal (Belgium, 2008), the Australian Academy of Science’s Mawson Medal (2010), and the Micropalaeontological Society’s Brady Medal (2019). He was appointed as a Member of the Order of Australia (AM) in 2007, elected a Fellow of the Australian Academy of Science in 2012 and an Honorary Fellow of the Geological Society of London in 2014, and was made an Officer in the Order of Leopold II by the Kingdom of Belgium in 2018.

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The Royal Society of Victoria proudly honours Professor Patrick De Deckker AM FAA with the 2023 Medal for Excellence in Scientific Research. We convey our warmest congratulations on his lifetime of significant contributions to science and the global scientific community.

Professor De Deckker will be presented with the 2023 RSV Medal for Excellence in Scientific Research following a public lecture on his work at the Royal Society of Victoria on the evening of Thursday, 18th April, 2024. Full details and registrations are available at https://rsv.org.au/events/holocene-climatic-fluctuations/.

References

[i] Schmidt, Sabine & De Deckker, P. & Etcheber, H. & Caradec, S. (2010). Are the Murray Canyons offshore southern Australia still active for sediment transport? Geological Society of London Special Publications. 346. 43-55. 10.1144/SP346.4.