Research website of Dr Gilbert Price

Tall Poppy Awards

One of the things that I really enjoy about my work is telling people about it! I mean, who doesn’t love a good yarn about an Ice Age cold case featuring some of the coolest, biggest and meanest beasts that ever walked the planet! It’s an easy sell too- most people know a little about dinosaurs, but when you tell them that there were giant wombats, massive kangaroos, and marsupial lions living alongside Australia’s earliest peoples… well, their jaws just drop!

I was recently invited to attend the awards ceremony of the Queensland Young Tall Poppies. The awards are an initiative of the Australian Institute of Policy and Science, or AIPS. Each year, AIPS celebrates and recognises the achievements of young scientists across Australia as part of their Tall Poppy Campaign. Their ultimate aim is to strive towards the building of more engaged scientific leadership across Australia, and that by necessity, means scientific communication, not just between scientists, but with the general public alike.

Tall Poppy Awards

Discussing my research at the 2013 Queensland Tall Poppy Awards (it’s not often that you’ll find me this clean and wearing a suit!)

The awards are made on a state-by-state basis and recognise the achievements of outstanding young researchers across a huge variety of scientific fields including medical research, technology, engineering and mathematics. I’m pleased to say that my name was among the list of 11 awardees for the 2013 Queensland Young Tall Poppies. It was a real thrill and surprise for me. The award ceremony was held at the Queensland University of Technology’s Science and Engineering Centre in mid-November (a really impressive place that you should check out next time you are in Brisbane City!), hosted by Queensland’s Chief Scientist, Dr Geoff Garrett, with the individual awards presented by the Queensland Minister for Science, Information Technology, Innovation and the Arts, Mr Ian Walker.

Out of the 11 awardees, one was chosen to become the Young Queensland Tall Poppy of the Year. The 2013 candidates are an incredible bunch of young scientists and include researchers working in a variety of different areas from molecular biology, public health, neuropharmacology, tissue engineering and more. I was really blown away to hear about their research- they’re doing some massively impressive things. But what surprised, and humbled me more than anything, was when I heard my name read out for the top prize! I really couldn’t believe it!

My boss, Professor Gregg Webb, was in the audience- he was super pumped, perhaps even more than I was! It’s a great opportunity, not just for me, but for my research group to really start showing off some of the cool palaeo-type things that we do. Although I tend to talk up my megafauna research much more than anything, the real crux of what I do really goes far beyond those Ice Age megabeasts. Yep, it would be awesome if we could figure out why diprotodon and co suffered extinction, but wouldn’t it be brilliant to know how the species that we still have around us today staved off extinction? How did they respond to the massive climatic changes and anthropogenic impacts that have gripped Australia since the last Ice Age? How were they able to adapt at a time when a huge variety of different creatures were dropping off the evolutionary family tree?

Receiving the 2013 Tall Poppy Award

Receiving the 2013 Tall Poppy Award from the Honorable Mr Ian Walker

So that is the ultimate research question- how have modern floras, faunas and ecosystems responded to past episodes of climate change and environmental peturbation? And critically, what can we do with that knowledge? The past is what informs that present, and it can also help us understand where we might be heading in the future. That’s an insight that can only be provided by the fossil record and is especially important at this time of widespread apprehension over the potentially devastating impacts of future anthropogenic climate change. There are a lot of lessons that we can learn about the past, with great potential for applying that to modern conservation approaches and ecosystem management.

I’m looking forward to the opportunities that the Young Tall Poppy award will bring me over 2014. It’ll be a great chance to spread the fossil-word to one and all, and hopefully attract a bit more community support for the palaeo-sciences, not just in Queensland, but across Australia more broadly.

Ice Age Queensland

In late 2011, I was invited to write a chapter for an upcoming book on the Quaternary geology of Queensland. Not being a geologist, I was initially hesitant to take on the job. I thought about it for a bit though- I work in the Quaternary (i.e, the last 2.6 million years of Earth’s history) and in Queensland, so I eventually thought to myself, “why not?!” It turns out that it was one of the most challenging things that I have ever done, but also one of the best moves that I could have made.

Ice Age Queensland

Quaternary chapter for ‘Geology of Queensland’ (2013; ed. Dr Peter Jell)

Over the course of a month or so, I read a huge number of papers. I already knew the palaeontology side of Queensland’s Quaternary pretty well so that was not a big problem, but I also had to had to get stuck into loads of papers on palaeoclimates, fluvial and aeolian deposits, speleogenesis, soil formation and weathering, and volcanism- the sorts of things that aren’t normally on my reading list. But I learnt so much.

What really struck me was that although Queensland doesn’t have too much going in the way of Quaternary economic geology, most research had a strong palaeoclimate / palaeoenvironmental theme. And what really stood out was the role of geochronology (dating) in tying all of these seemingly disparate records of Queensland’s Quaternary together. Back in the early 1960’s, the time of the first modern review of Queensland geology, there were very few methods with which to date the important deposits. However, since then numerous geochronological approaches have been developed that allow for the development of a reliable temporal framework critical for understanding how climate change has impacted upon and shaped Queensland over the past 2.6 million years.

The modern Channel Country of western Queensland in flood (photo: G. Nanson)

The modern Channel Country of western Queensland in flood (photo: G. Nanson)

By combining all of the results of the different studies, it immediately became clear that there have been some massive climate-driven environmental changes in Queensland, and more broadly through Australia, over the course of the Quaternary. The first part of the Quaternary was relatively warm and humid, and less seasonal than it is today. Up until around 300 thousand years ago, conditions were so good that extensive rainforests grew much of the way along the eastern coast. The arid interior was not even that arid at that time. In fact, it was fairly well-watered, possibly with semi-permanent La Niña conditions in place for several thousands of years (incidentally, the La Niña climate systen is what caused the terrible flooding of 2011-13 in eastern Australia; but it was even wetter 300 thousand years ago!).

After around 300 thousand years ago, long before the first humans traipsed onto Australia’s shores, the climate started to shift, so much so that the rainforests of the east started to contract northwards; the arid inland rivers began to dry up; and numerous species started disappearing from their formally well-watered environments.

Late Quaternary stalagmite that grew from 20-7.8 thousand years ago

Late Quaternary stalagmite that grew from 20-7.8 thousand years ago

The results showed that long-term shifts in climate oscillation, in line with orbital forcing, saw Queensland descend into an intense last glacial cycle or ‘Ice Age’. The late Pleistocene (beginning around 130 thousand years ago) started with a massive marine transgression of the Gulf of Carpentaria, which coincided with incredible fluvial activity both in north Queensland and the western Channel Country (flowing into Lake Eyre in central Australia). The warm, wet conditions persisted through 120-90 thousand years ago. Temperatures then plummeted, causing sea levels to fall so low that the Gulf of Carpentaria became a lake! The change is also associated with a major vegetational reorganisation in the tropics, with other records suggesting reduced monsoonal activity at that time. Through this period, you can see a progressive decline in megafaunal diversity in southeastern Queensland.

After around 47 thousand years ago, fluvial activity basically ceased in the Channel Country, and dune building became the dominant sedimentological process. This coincided with the time that saw the final ever filling of the Lake Eyre megalakes (the connection of Lake Eyre to other central Australian lakes). There is also the last direct, dated evidence for megafauna at that time (the youngest assemblage that we know about – Neds Gully – had only two or three large-bodied megaherbivores, rather than the 65+ species that are commonly regarded as having being extant at that time). The earliest record of humans in the State is around 40 ka. The intense climatic / biological events were clearly in-train before that.

One of the youngest Diprotodon skulls known (this specimen is from Neds Gully, Darling Downs)

One of the youngest Diprotodon skulls known (this specimen is from Neds Gully, Darling Downs)

The vegetation shifts after 45 ka and up to the Last Glacial Maximum (around 20 ka) were similar to previous changes from earlier glacial maxima in some ways, but was markedly more intense in terms of its aridity. The sedimentological record of Lake Carpentaria from the early penultimate last glacial maximum (just before 130 ka) saw vast rivers flowing across the lake, whereas as the period leading into the Last Glacial Maximum saw the lake transition through phases where there was almost total desiccation. The period around the Last Glacial Maximum also saw significant landscape instability (in part, a function of a change in vegetation cover from forest to open habitat). Post-Ice Age warming meant a return of the monsoon, leading to Lake Carpentaria expand to capacity size and all-time lows in salinity, then full marine transgression by around 10 thousand years ago. Speleothem (e.g., stalagmites) records suggest an enhanced monsoon after that time as well. This is of course all associated with another vegetation shift where forests returned and swallowed up the open areas.

The implications of this synopsis are massive when it comes to trying to understand the causes of megafaunal extinctions. Although it is regularly argued that climate change was not significant in the last glacial cycle and that there was no climate change when the megafauna supposedly went extinct between 40-50 thousand years ago, the data just do not support such an inference. There were incredible changes at that time and were part of a long-term shift towards increasingly arid climates. This doesn’t mean that climate alone caused the final megafaunal extinctions (the earliest humans, arriving around 50 thousand years ago could also have made a contribution), but we can no longer ignore it.

My chapter was published in the book ‘Geology of Queensland’ (edited by Dr Peter Jell) earlier this year. The rest of the book documents all other aspects of what we know about Queensland’s geology, not just the Quaternary. It’s an incredible book- I highly recommend it to one and all. It’s a huge read- over 900 pages, full colour, hardback, and retails at only around $75! Such good value and one of the most important books ever written on any aspect of Australian science. You can order it here.

Summary of major climatic and biological events for the last 350 thousand years in Queensland relative to the oxygen isotope curve

Summary of major climatic and biological events for the last 350 thousand years in Queensland relative to the oxygen isotope curve

Palaeoecology during the Ice Ages in northeastern Australia

Main study sites in northeastern Australia

One of the challenges of working in academia is the constant need and pressure to secure research project funding. The main research funding body in the country is the Australian Research Council (ARC). They offer a number of schemes for supporting research, all of which are incredibly competitive.

In 2011, I applied for funding under a new ARC scheme called the Discovery Early Career Research Award (DECRA). The DECRA’s are intended for junior researchers, generally with less than five years post-PhD research experience. There was an incredible number of applicants in the round – over 3180 – for just 277 awards (success rate of less than 9%). The outcomes were announced in mid-November, and to my surprise and delight, my application was successful! My funding will secure my research program for the next three years.

My study will focus on developing a baseline understanding of faunal responses to climate change and environmental perturbations through the Quaternary in northeasternQueensland. The region is unique for the concentration of a vast array of well-documented Quaternary palaeoclimatic archives (e.g., deep marine pollen cores, records in lacustrine sediments, rainfall archives from speleothems, offshore ostracod and foraminifer geochemical records). Such records extend back several hundred thousand years, through numerous glacial-interglacial cycles, and document how the region’s climate and environments have evolved through to the present. Strikingly, they provide key information on the timing and duration of prehistoric dry intervals, and document a long-term trend in the weakening of the Australian Monsoon: patterns of climate change that mirror those that are predicted to continue into the future.

Diprotodon skeleton at Floraville

Although there is an increasingly robust model of Quaternary climate change for the region, a lack of well-documented faunal records hampers efforts to understand prehistoric biological responses to the climate perturbations. However, that is not through want of appropriate fossil sites, but rather, lack of investigation. Areas such as Chillagoe are renowned for their unique Pleistocene faunas and contain animals such as the enigmatic Quinkana fortirostrum (extinct terrestrial crocodile) and Propleopus chillagoensis (giant carnivorous rat-kangaroo), two species that are known from nowhere else on the continent. Yet, we have little or no knowledge of their palaeoecology, palaeobiology and extinction simply owing to a lack of significant investigation in the region (the last major studies in the area ceased in the 1970’s). Other areas such as Floraville contain remarkably diverse Plio-Pleistocene faunas (including both megafauna and smaller-bodied species), but only preliminary results have ever been published. Well-documented sites, such as Wyandotte, preserve highly significant faunal assemblages previously thought to date to around the time of terminal megafaunal extinctions, but they now require re-dating because the previously established dates are no longer accepted. It is clear that northeastern Australia can yield critical data for understanding ongoing patterns of faunal change.

A major goal of my project will be to quantify the precise timing, magnitude, rates of climatic and environmental changes, and the long-term response of northeastern Australia’s terrestrial faunas to such events. For this reason, fossil deposits with long depositional sequences and well-preserved faunal remains in potentially easily datable contexts will be the focus of the research. Strategically, this includes targeting fossil assemblages that represent accumulation at different times through interglacial/glacial cycles, both before and after the arrival of humans on the continent, as well as more recent deposits within the timeframe of European colonisation (such as Carrington Cave, a site that contains the introduced house mouse, Mus musculus).

I’m currently planning fieldwork for the upcoming year. In late May, I will be heading up to the BrokenRiverarea. Several fossil deposits have already been identified from caves in the area by my friend Doug Irvin, a long-serving member of the Chillagoe Caving Club. Through June-July, I will be trekking to the Floraville area, just south of the Gulf of Carpentaria. Fossils have been collected from the region for the past 40 years by my colleagues Prof. Michael Archer and Henk Godthelp, both of the Universityof New South Walesin Sydney. We’ll be visiting the main sites, collecting new fossil specimens and hopefully some dating samples. In 2011, we excavated one of Australia’s most complete Diprotodonskeletons. I collected some dating samples at the time, but am still waiting on the results.

Waterfall in the Leichhardt River, Floraville Crossing

I’ve almost completed my first manuscript relating to the project- a direct fossil dating study. The purpose of the study is to determine the age of the specimen and to demonstrate the utility of the direct fossil dating approach of museum specimens using U-series methods. The specimen, a maxilla of the extinct marsupial ‘tapir’ (Palorchestes azael) was collected from the cave in 1977 and curated into the fossil collections of theQueenslandMuseum before being sequestered for dating. The results demonstrate that the specimen is between ~137–199 thousand years old, thus, predating the hypothesised time of final megafaunal extinctions. The result is significant in that it is the most northerly mainland dated recorded for any of the extinct Australian megafauna and represents one of the youngest reliably dated records for the species. The stratigraphic relationship of the dated specimen to other fossils from the cave is unclear. I hope to be able to submit the manuscript to a journal in the next month or so.

With the fieldwork, lab work, and paper writing, it’s bound to be a busy year!