Memoir

Understanding interconnectivity

The science of the Antarctic system

THERE’S NO EXPERIENCE on Earth like diving under the ice in Antarctica. On life support and in an uninhabited and extreme environment, it’s as close as you can get to a spacewalk while remaining on this planet. My diving work in the Antarctic’s Ross Sea was twenty years ago now, but the beauty of that experience will never leave me.

We cleared snow from the surface of the sea ice to let light through, like a giant skylight. Then we drilled a wide hole through two metres of ice.

Seawater doesn’t freeze at zero degrees Celsius – the temperature has to be closer to minus two; this means you’re essentially diving in an ice slurry. To slip through a two-­metre-­wide shaft into water of dazzling clarity is to be surrounded by swirling constellations of ice crystals glittering in the light. Right below you on the seabed incredible biodiversity is revealed.

It may seem that not much could live beneath the ice in Antarctica, but life finds a way: there are sea ‘spiders’ as big as a hand; metre-­long nemertean worms; colourful sponge gardens; soft corals waving in the current; fish with anti-­freeze in their blood.

Similar types of animals also live on reefs in southern Australia – starfish, sea urchins, kelp – but these icy species are endemic: they’re only found in Antarctica. The frozen fjords around Australia’s Davis Research Station in the Vestfold Hills hold amazing reefs that are kilometres long – instead of coral, they’re made out of shelly tubeworms.

The pristine and inaccessible nature of these environments is a lure to any adventurous scientist. But as a marine microbiologist, what first brought me to Antarctica was invisible and all-­pervasive – the microbes.

This microscopic level of life is essential for the health and survival of the marine realm that covers three-­quarters of our planet. A hidden world of microbes lives in the ocean with a complexity and diversity that rivals all other life on Earth. They include bacteria, viruses, fungi, single-­celled protozoans and micro-organisms known as archaea that can thrive in extreme environments.

If you could weigh all the living organisms in the ocean, 90 per cent of their combined weight would come from microbial cells. These clean up waste, create most of Earth’s oxygen, drive carbon and nutrient cycles, defend against disease, glow in the dark…they even help shape clouds. These microbes were the first life on the planet and they continue to live in places where nothing else can, from boiling deep-­sea volcanoes to glacial lakes under the Antarctic ice sheet. They enable other life to thrive in places where otherwise it would not be possible.

Without microbes, the world as we know it would not exist. And by understanding microbes as sentinels of environmental change, we can get insights into the shape of the world that may be yet to come. I think about this whenever I go diving, and I’ve dived to study this rich microbial life across the span of the globe, from the tropics to the poles.

 

A CORAL REEF is the perfect example of how a hidden microbial world is the foundation of an entire ecosystem. Coral reefs thrive in what is the equivalent of a marine desert because they rely on diverse communities of microbes to capture and recycle rare nutrients.

For my PhD at James Cook University, on the doorstep of the Great Barrier Reef, I wanted to understand how stable and persistent these microbial partnerships are across reef species. Does a commitment between a microbe and its host (a sponge for example) mean marriage for life, until ‘death do us part’? Or is it a more transitory dalliance, an occasional ‘friends-with-benefits’ scenario?

That’s when I started to discover how sensitive microbes were to changes in environmental conditions. They’re the first thing to be affected when an environment changes, which makes them excellent indicators – like living early warning signs or the infamous canaries in the coalmines – of change in an environment, for good or for bad.

While the lifespan of animals may be years, many microbes turn over generations in a matter of hours. As a result, it’s possible to see adaptive responses much more quickly at this microscopic level and well before declines are obvious in the broader health of a whole ecosystem. If the water gets polluted, or the ocean warms, or carbon emissions make it more acidic, microbes are on the frontline – this is what first led me to work in Antarctica.

At the end of last century, the New Zealand Antarctic program wanted to see if microbes could be a useful indicator of the impact of human activities at New Zealand’s Scott Base: in 2000, I went to Antarctica to find out. That meant a trip from days of 30-­plus degrees in the tropics to roughly minus-30 degrees in the Ross Sea to dive underneath that ice. It was both a life-­ and career-­defining experience.

Slipping beneath the ice slurry invoked a sensory overload. The sharpness of the cold was enough to momentarily take my breath away. The perpetual groan and creak of the ice above was punctuated only by the occasional forlorn ping of a Weddell seal. The colour of the marine life below the ice was astounding: bright green and yellow sponges, soft pink corals and orange anemones; so incredibly beautiful. These indelibly etched memories would inevitably lure me back to the icy continent.

But after three years studying microbial life in the Ross Sea, I went back to work on the Great Barrier Reef. I was a researcher at the Australian Institute of Marine Science for almost twenty years with a dual professorial role at the University of Queensland. The ongoing focus of my work was to research the role of microbes in all aspects of ecosystem health: trying to understand their utility as indicators of anthropogenic impact; attempting to determine their role in inducing the settlement and metamorphosis of other reef species; and identifying sensitivity thresholds for climate change, water quality and industrial contamination. The research is still embryonic, but we’re starting to explore whether microbes can help coral reef organisms adapt faster to climate change by improving their tolerance of warmer temperatures.

 

BUT THE ICE drew me back. And in 2021, I moved my attention thousands of kilometres south. I went from being an active tropical microbial ecologist to the chief scientist of the Australian Antarctic Program. The two may seem poles apart, but this was actually a fairly logical transition: the Great Barrier Reef and Antarctica are two of the fastest changing environments under climate change.

There’s one critical difference: the future of the polar regions is also intrinsically linked to the future of the entire planet and our own destiny, because Antarctica and the surrounding Southern Ocean are key drivers of Earth’s oceanic and atmospheric systems. There is still much to learn, but there is no doubt that understanding changes in Antarctica and the Southern Ocean is key to preparing Australia for different climate futures.

Sea levels are currently predicted to rise by as much as one metre by 2100, with Antarctic ice loss likely to be the largest contributor. Research that assesses the vulnerability and risks of collapse and retreat of key regions in East Antarctica has never been more urgent – we rely on this science to inform Australian policies for disaster management and develop effective resilience and adaptation measures. For urban development, the impacts from projected sea-­level rise for Australia’s coastal management and exposed infrastructure are vast. For water security, Antarctic ice core records of wet and dry phases over the past 2,000 years reveal that eastern Australia’s drought risk is greater than previously thought.

It’s exciting to head up a science program that seeks to answer these ­challenging existential big-­picture questions. How fast is Antarctica responding to climate change? What do changes in the East Antarctic Ice Sheet mean for sea-­level rise? How will shrinking Antarctic sea ice alter Southern Ocean nutrient supplies, ecosystem composition and the biological carbon pump? How can we manage or mitigate these changes?

At a time of critical questions that demand urgent answers, I became somewhat torn. While coral reef microbes had rocked my world for more than twenty years, the long and meandering path between generating research results and creating tangible net benefits was becoming increasingly frustrating – particularly in this era of very rapid environmental change.

So while my new role involves a step away from active research, taking on a role that enables me to shape the Australian Antarctic science program is immensely rewarding. I see pathways to the application of Antarctic science that are more immediate and can make a difference at scale.

Finding answers to truly global issues needs audacious science that includes big data to integrate learnings from chemistry, physics and biology. Take the role of atmospheric circulation (physics) in driving changes in sea ice. Animals such as the emperor penguin need sea ice to breed (biology). When sea ice forms, salt is pushed into the ocean water below, making it denser than the surrounding water (chemistry), which also contributes to global ocean circulation. To understand Antarctica and its interconnections we need to study the system. Indeed, most of the critical scientific uncertainties are at the boundaries of the ‘cryosphere’ between ice and atmosphere, and ice and ocean.

Critically, and like all things on the seventh continent, Antarctic science also needs collaboration, so we are all working together to be more than the sum of our parts. In the Australian Antarctic Division (AAD) alone we have more than 150 external partners – other institutions and research organisations. What’s important now is to help develop the innovative and collaborative pathways needed to improve our understanding, management and conservation of our wild and sensitive polar ecosystems by bringing together diverse disciplines such as atmospheric physics, glaciology and biogeochemistry, to name a few.

 

ONE OF MY first jobs as the AAD’s chief scientist was to seek a review of the relevance and impact of the division’s science: this landscape was explored by an independent panel led by Emeritus Professor Mary O’Kane as one of Australia’s foremost scientists and engineers. In response to the recommendations from this review, the AAD formally asserted that science is at the heart of our Antarctic program and that its decisions and resourcing would reflect this commitment.

The timing of this recommendation is critical. While Antarctic Treaty parties have declared Antarctica a natural reserve, devoted to peace and science, the continent and surrounding ocean are sensitive and increasingly vulnerable to climate change. Globally ambitious science is needed to elevate our protection of this unique continent and support risk and mitigation planning in Australia.

To achieve this, we are in the process of developing a decadal plan to establish an integrated and collaborative Australian Antarctic science program that delivers world class Antarctic and Southern Ocean science and ­reinforces our leadership in environmental stewardship. The plan, which will be overseen by the Australian Antarctic Science Council, will also identify key capabilities, including the skills, technology, data and infrastructure that are required to address the highest priority scientific questions in support of Australia’s national interests in Antarctica.

And we can dream big because we have the world’s most advanced polar research vessel, Australia’s new icebreaker RSV Nuyina, in active service – a game changer for Antarctic and Southern Ocean science. Like an International Space Station of the south, the ship sets us up to explore the deep ocean, the ice and the atmosphere for decades to come. It can position Australia as a global leader in krill and krill predator research, environmental stewardship and Antarctic climate science.

I describe Nuyina as a Disneyland for scientists because it’s a floating lab packed with technology that will extend our reach into new frontiers like never before – echosounders on movable keels to map the ocean floor; a moon pool ‘window’ to the Southern Ocean that allows us to make observations no matter the weather or ice cover; a ‘wet well’ that lets us sample delicate marine life without damage; a trawl deck that can deploy anything from deep-­sea corers to mini-­submarines.

For decades AAD and our partners have been monitoring wildlife, ­meteorology, ice-­sheet dynamics, oceanographic processes and sea ice. Now, our new East Antarctic Monitoring Program (EAMP) will build on and expand that work by supporting sustained scientific observations of essential biodiversity, climate and ocean variables in Antarctica and the Southern Ocean, underpinned by an interdisciplinary, strategically focused and prioritised monitoring plan. Such an integrated and sustained observing system will enable us to detect change at a range of scales across space and time. Equipped with that information we can more reliably forecast, under­stand and manage the Antarctic region and provide scientific advice to inform climate adaptation, resilience and mitigation policy in Australia. The EAMP will take advantage of technological developments in data science, low-­cost sensors, space-­borne instruments and autonomous vehicles such as long-­range drones to enhance mapping and charting.

This ‘polar convergence’ of technological advance and scientific imperative impels us to establish more ambitious big data science for the Antarctic continent. Our Integrated Digital East Antarctica Program will enable cutting-­edge simulation and modelling science to answer the most pressing scientific questions about future projections for ice, ocean and the atmosphere in the Antarctic region. From the frontline of future global change, our science can look ahead and provide the decision-­support tools governments need for evidence-­based policy-­making.

Our environmental research into plankton, krill, fish, whales, seals and seabirds will also expand under a new Southern Ocean Ecosystems Program that will integrate diverse multidisciplinary science, including climate-­change impacts, across all trophic levels of the Southern Ocean ecosystem to ensure we have well-­managed and sustainable Southern Ocean fisheries and to protect and conserve Antarctic wildlife. Our Environmental Stewardship Program will reinforce Australia’s leadership role and meet our legislative and treaty obligations in Antarctica by implementing conservation, management and remediation projects – such as harnessing the powers of native microbes to clean up legacy-­waste sites. And the Antarctic Climate Program will monitor the atmosphere, sea ice, glaciers and carry out deep ice coring to improve weather forecasts for Australia while undertaking future climate projections to support Australian agriculture and our Pacific neighbours.

 

THIS LAST SUMMER I joined our ice core team at Law Dome near Casey Research Station. If you think of Law Dome as a library, then drilling an ice core is like taking a book off the shelf with its tiny bubbles of air, trace chemicals and particles trapped inside. Their mission was to retrieve the latest chapter on the planet’s climate history from this Antarctic ice ‘library’. Standing on the ice sheet about 100 kilometres inland, in twenty-­five knot winds and numbing temperatures, I marvelled at the patience of the team overcoming technical issues with the drill and relished our elation to finally retrieve the last one metre of core needed to achieve an overlap in the climate record.

Science is never easy – especially in remote and extreme Antarctica. But this is where we need to be. Achieving the scientific ambitions we’ve set will be daunting, and I feel incredibly privileged to take on a role that shapes the Australian Antarctic science program.

While I miss the unmatchable joy of frontline scientific discovery – and that feeling when I first put my face under the ice in the Ross Sea more than two decades ago – I continue to live that dream vicariously through the exhilaration of others. But there’s far more to Antarctica than wonderment. On the ice, in the abyss, under the flickering aurora: in Antarctica we find a precious shared purpose of peace and science that holds the keys to the planet’s future – and our own.

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