Australasian Science: Australia's authority on science since 1938

Feature

Feature article

Microbe Genes Could Curb Livestock Burps

Ruminant methane alone accounts for 31% of New Zealand's greenhouse gas emissions.

Ruminant methane alone accounts for 31% of New Zealand's greenhouse gas emissions.

By Graeme Attwood

The DNA sequence of a microbe that produces methane in ruminants provides a target for vaccines and other drugs to reduce greenhouse gas emissions from livestock.

Since their first domestication about 10,000 years ago, cattle, sheep, deer and goats have provided meat, milk and fibre for human use. Products derived from these ruminants are more commonly used than most people realise, with proteins derived from ruminants found in thousands of items ranging from sports drinks and processed foods to products used in oriental remedies.

A Matter of Taste

Image of tongue

While food preferences vary quite substantially in different cultures, hedonic responses to pure tastes in isolation are relatively independent of culture or diet in adults.

By John Prescott

Newborn babies will smile when they first taste sucrose and wrinkle their noses at the bitter taste of quinine. What is the adaptive significance of such innate responses to taste?

Almost two centuries ago, the French gastronome Brillat-Savarin noted in his meditations on foods and eating, The Physiology of Taste, that taste can be reduced “in the last analysis, in the two expressions, agreeable or disagreeable”. Neither our everyday experiences nor more recent scientific explorations of taste preferences have contradicted Brillat-Savarin’s conclusion that the dimension underlying taste is pleasure.

John Prescott is Associate Professor of Psychology at the University of Newcastle.

It’s a Wiggly, Wiggly Universe

Image of cosmic microwave background

Figure 1. The Cosmic Microwave Background as revealed by NASA’s WMAP satellite. This is a picture of the whole sky in microwaves, and shows the fluctuations of matter in the Universe only 400,000 years after the Big Bang. The sky is covered in little hot and cold spots of size ~1°, corresponding to the distance sound can travel in the early Universe. Image: NASA / WMAP Science Team

By Karl Glazebrook

A map of the universe as it existed six billion years ago is close to completion, and may provide new insights into the physics of dark energy.

In the Beginning there was Light. But there was also Sound and Fury...

13.7 billion years ago our universe began in the Big Bang, when the whole of infinity was compressed to a singular point. While we do not yet understand the moment of singularity, cosmologists such as Stephen Hawking see that as their ultimate quest.

The Biggest Losers

An artist’s reconstruction of some extinct Australian animals (clockwise from top left): Genyornis newtoni, Diprotodon optatum, Procoptodon goliah, the thylacine (which survived in Tasmania until 1936), Thylacoleo carnifex (the biggest marsupial carnivore) and the giant lizard Megalania prisca. Image courtesy of the artist Peter Trusler and Australia Post

An artist’s reconstruction of some extinct Australian animals (clockwise from top left): Genyornis newtoni, Diprotodon optatum, Procoptodon goliah, the thylacine (which survived in Tasmania until 1936), Thylacoleo carnifex (the biggest marsupial carnivore) and the giant lizard Megalania prisca. Image courtesy of the artist Peter Trusler and Australia Post

By Richard “Bert” Roberts & Barry Brook

New evidence tightens the noose on humans as the decisive factor in the extinction of the last of the megafauna in Australia and North America.

Despite being separated by more than 11,000 km of ocean, the prehistoric heritage of Australia and North America share much in common. Both continents were once home to a diverse range of giant animals – the “megafauna” – that suffered a mass extinction some time in the geologically recent past, and the first humans to colonise both land masses were members of our species (Homo sapiens), an entirely new predator to which the megafauna had to adapt or die.

Prof Richard ‘Bert’ Roberts is an Australian Research Council Professorial Fellow in the Centre for Archaeological Science, School of Earth and Environmental Sciences at the University of Wollongong. Prof Barry Brook is the Sir Hubert Wilkins Chair of Climate Change in The Environment Institute at the University of Adelaide.

In Space No One Can Hear You Sneeze

Image of astronaut

Space is a harsh environment that presents several serious health risks to astronauts

By Elizabeth Blaber, Helder Marcal, John Foster & Brendan Burns

The altered gravity conditions of space can have serious detrimental effects on the health of astronauts. Understanding the cellular basis of this phenomenon could lead to better medical treatments on Earth.

Humans have gazed into the night sky for thousands of years and wondered what the billions of twinkling spots were that they could see. Different cultures have assigned their own meaning to the universe throughout the millennia, but rapid advances in research and technology are only just beginning to further our understanding of the nature and mysteries of the cosmos.

Fresh Water Using Geothermal Heat

By Hal GurGenci

Geothermal heat can provide cheap fresh water to homesteads and small townships in the outback by removing salt from brackish aquifers.

Water is essential for life. Living in the driest continent on Earth, Australians probably know this better than anyone else. Most of our large cities are currently subject to water restrictions. Large-scale desalination plants are already operating in Perth and Brisbane; Sydney is building one bigger than those two and Melbourne has plans to build the biggest.

These plants use reverse osmosis technology. This essentially involves pumping the salty water through membrane filters that trap the salt and pass only freshwater.

Hal Gurgenci is a Professor of Mechanical Engineering at the University of Queensland, and the Director of the Queensland Geothermal Energy Centre of Excellence, which was established last year by a $15 million grant from the Queensland government.

Freaks of the Sea

Image of freak wave

In 1978 the German cargo vessel MS München was struck by a freak wave 24–30 metres high. Image from Horizon – Freak Wave courtesy of BBC Worldwide. © BBC/Monkey Experiment

By Murray Rudman

Once the stuff of maritime legend, rogue waves up to 30 metres high have been detected by satellites, posing a significant threat to shipping and oil rigs. Now computational scientists are smashing virtual rogue waves into virtual oil and gas platforms to help design stronger, safer structures.

Rogue waves were once thought to be the folklore of mariners who had spent too much time at sea. Giant waves rising out of the blue in the open ocean, towering more than 20 metres in height, terrified sailors and damaged vessels.

Satellite and direct observations have now revealed that these freak waves really exist and pose a risk to ocean structures like oil rigs, as well as the workers on them. Fortunately, they are a risk that can be managed.

Dr Murray Rudman is Program Leader of Computational and Mathematical Modelling at CSIRO Mathematics, Informatics and Statistics in Melbourne.

Reef Emissions Affect Climate

Image of reef

Reefs produce aerosols that affect rainfall locally.

By Graham Jones & Zoran Ristovski

Coral reefs produce a natural aerosol that creates clouds over the ocean and keeps sea surface temperatures stable – with implications for both reefs and rainforests.

In the 1970s, researchers from the Australian Bureau of Meteorology found very large concentrations of aerosol particles in the air above the Great Barrier Reef. At the time they guessed that the coral of the reef was responsible, but just what the aerosols were composed of was a complete mystery.

When we first read this research paper we knew we had to start some research on the climate aerosol dimethylsulfide (DMS) in coral reefs. Previous research indicated that the coral algae contained the DMS precursor substance DMSP.

Graham Jones is an Associate Professor in climate science at Southern Cross University, Lismore. Zoran Ristovski is an Associate Professor in atmospheric science at Queensland University of Technology, Brisbane.

How Australia Dried Out

Image of ancient lake

Sediments of the ancient Lake Bungunnia near Rufus River in western NSW. The white horizon is the dust layer marking the start of arid climatic regimes. Photo: Richard Stanaway

By Sandra McLaren & Malcolm Wallace

Lake Bungunnia, a megalake that existed 1–2 million years ago in today’s Murray–Darling Basin, reveals the story and timing of the onset of arid climatic conditions in south-eastern Australia.

The modern challenge of climate change demands a sound scientific understanding of the Earth’s climatic history. Historic temperature and rainfall records are very important, but so is the geological evidence of climate recorded in sedimentary rocks that are formed on the surface of the Earth.

Dr Sandra McLaren and Dr Malcolm Wallace are from the School of Earth Sciences at the University of Melbourne. This article is based on their research published recently in the journal Global and Planetary Change.

The First Breath

Image of lungfish ribs

The cranial ribs in the Australian lungfish Neoceratodus forsteri are needed to anchor the pectoral girdle, allowing the fish to raise its head to gulp air. Image adapted from Johanson et al. 2005.

By Alice Clement

A new fossil find shows that a global decline in oxygen millions of years ago drove the evolution of air-breathing in lungfishes.

Most people enjoy a dip in the ocean at their local beach or favourite holiday spot, but if you lived during the Devonian you might think twice before taking the plunge.

The Devonian Period, 416–359 million years ago, is known as the Age of Fishes. Life in the seas was very different to what we know today. The waters teemed with a plethora of beasts, including huge armoured placoderm fishes and early sharks and bony fishes. Nautiloids floated by while trilobites (ancient arthropods) scuttled around beneath them.

Alice Clement is a PhD student at the Research School of Earth Sciences of the Australian National University and Museum Victoria, where she is studying lungfish evolution and anatomy.