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Feature article

Spitting Image

An archerfish spits a carefully aimed jet of water.

An archerfish spits a carefully aimed jet of water to knock an unsuspecting insect down to the water.

By Shelby Temple

Archerfish are known for their remarkable hunting technique of spitting water at insects above the water, and their eyes are specially adapted for seeing both above and below the water’s surface.

Archerfish have earned their name for spitting jets of water at insects to knock them down to the water’s surface where they can be eaten. However, what is most incredible is not that they can spit, but that they can spit accurately despite the distortion that occurs due to refraction as light travels from air to water. Recent research is giving us new clues as to how they achieve their astonishing accuracy.

Heat Stress in a Warming World

Global warming is, unsurprisingly, making heat waves hotter.

Global warming is, unsurprisingly, making heat waves hotter.

By Steven Sherwood, Tord Kjellstrom and Donna Green

Heat stress could be the most dangerous consequence of global warming this century.

Imagine you are working in a Vietnamese shoe factory without air conditioning. During the hot season, as temperatures soar towards 40°C inside the stifling building, your production targets remain fixed. To maintain your output you are allowed to take a little longer on your breaks to cool down. Still, the sweltering heat means that you just can’t work as efficiently, so in order to complete your work you start an hour earlier and finish later.

The Straw Men of Climatology

scarecrow

The contrarian critique of climatology in the media, popular books and blogs is based on a “straw man” version of science. Image: iStockphoto

By James Risbey

The straw man arguments of climate contrarians portray a brittle image of climatology that ignores how science produces robust knowledge by embracing and correcting errors.

The climate contrarian voice has been prominent in media discussions of climate change in Australia, New Zealand, the UK, North America and elsewhere. For example, Australian geologist Ian Plimer and Danish author Bjorn Lomborg have made numerous appearances in the media to argue that anthropogenic climate change is not an issue. Recent tours of Australia by international contrarians such as Christopher Monckton and Anthony Watts have also received broad, largely uncritical coverage in the media.

James Risbey is a senior research scientist in the Centre for Australian Weather and Climate Research at CSIRO Marine and Atmospheric Research.

Capturing Carbon with Membranes

emissions

By 2030, 80% of world energy will still be supplied by fossil fuels because the global energy demand during this period is expected to grow by 45%.

By Colin Scholes

Membrane technologies being developed in Australia hope to cut the cost of capturing industrial emissions of carbon dioxide.

It has been well-established that increasing carbon levels in the atmosphere are linked to global climate change. Therefore, to avoid the danger of catastrophic climate change there needs to be a global movement to reduce carbon emissions.

This presents a significant challenge because the world relies upon carbon-intensive industries to power the modern economy, such as electricity generation, fertiliser manufacture and metal smelting. Therefore, the scientific and engineering challenge of climate change is to develop technologies that can reduce carbon emissions cheaply.

Colin Scholes is a Research Fellow at the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), the University of Melbourne.

Double Jeopardy for Corals

Bleached coral

During the bleaching event there was a sharp contrast between corals that had C2 algae (left) and type D algae (right)

By Alison Jones

Not only are corals jeopardised by warmer waters but their growth is constrained as they change from heat-sensitive to heat-tolerant symbiotic algae in order to survive.

Until recently, scientists were hoping that coral reefs could adjust to climate change by gradually acclimatising to warmer conditions. This hope was based on the idea that most of the corals that make up tropical reefs could increase the amount of heat they can withstand by changing the type of algae within their tissue.

Dr Alison Jones is a postdoctoral researcher at the Centre for Environmental Management at Central Queensland University in Rockhampton, and has been studying the impacts of climate change on local coral communities in the southern Great Barrier Reef Keppel area since 2004.

Big Floods = Big Barras

barramundi

Study co-author Ian Halliday catches a barramundi, a popular species for anglers in rivers such as the Daly River in the Northern Territory.

By Tim Jardine, Brad Pusey and Ian Halliday

More barramundi survive to adulthood during big flood years due to increased feeding opportunities.

Floods can be devastating natural forces that wreak havoc on just about anyone and anything living in low-lying areas. We often see images of homes, other property and human lives tragically destroyed by floods.

Yet for all this devastation and destruction, surely there must be some benefit? After all, floods have come and gone on this continent for millions of years, and the plants and animals that we see today are the product of this flood–drought cycle.

Tim Jardine and Brad Pusey are Research Fellows at the Australian Rivers Institute, Griffith University. Ian Halliday is a biologist with the Queensland Department of Employment, Economic Development and Innovation.

Sinking Aristotle’s Sailing Octopus

argonaut

A female argonaut (Argonauta argo) swimming close to the sea surface in the Sea of Japan. Photo: Julian Finn, Museum Victoria

By Julian Finn

By expertly manipulating air gathered from the sea surface, argonauts are able to control their buoyancy and traverse the world’s oceans at depth.

In 300 BC, Aristotle wrote of a peculiar octopus that rises from the deep to sail on the ocean surface in a boat made of shell. Using two arms as sails and six arms as oars, it was said to have navigated the oceans of the world.

Two thousand years later, we now know that Aristotle’s fanciful octopus was in fact the pelagic octopus, named Argonauta by Linnaeus in 1758 on account of this sailing reputation. The boat, as Aristotle referred to it, is the beautiful white shell of the female argonaut. The sails are specialised webs used for secreting this shell.

Dr Julian Finn is a Curator of Marine Invertebrates at Museum Victoria. This study has been published in the Proceedings of the Royal Society of London, B: Biological Sciences.

Sleight of Memory

Finger

iStockphoto

By John Bradshaw

Our memories can easily deceive us, for good or for ill.

Not long ago I came across a box of old possessions containing a picture book entitled My Farmyard Friends. My mother had sent the material years earlier when clearing out my juvenilia, and it had long languished until the time came for another generational spring clean. The book immediately evoked vivid recall of its pictures in the finest detail. It also brought back a much darker memory, but more of that shortly.

John Bradshaw is Emeritus Professor of Neuropsychology at Monash University. This is an edited version of a script broadcast on Ockham’s Razor.

Head Modification Explains the Origin of the First Australians

skull

The Nacurie 1 cranium provides evidence that mothers intentionally modified the shape of their infants’ heads in the Murray River region of south-eastern Australia during the terminal Pleistocene. Photo: Peter Brown

By Peter Brown

Evidence of head shape modification among Pleistocene Australians helps refute claims of an evolutionary connection with Indonesian Homo erectus.

For more than a century there has been a protracted debate over the origins of Australia’s first human inhabitants and what was their biological and cultural relationship with earlier populations in the Asian region. This discussion has also been relevant to the broader debate concerning the evolution and dispersion of humans globally, including the relationship between Neandertals and modern humans in Europe.

Peter Brown holds the Chair of Palaeoanthropology at the University of New England, Armidale, NSW.

Lizards Give Birth To Cancer Clues

skink

The same protein found in pre-cancerous skin cells helps blood vessels to grow in the placenta of the three-toed skink (Saiphos equalis). Photo: Nadav Pezaro

By Bridget Murphy

A gene found in a pregnant lizard may provide important information about the origins and treatment of cancer in humans.

Cancer cells always seem to be one step ahead of medical researchers. Tumours grow and spread by piggy-backing on the molecular systems in our body that evolved to keep us healthy. This is part of why cancers are so difficult to treat – because drugs often hurt healthy cells as well as the cancerous ones.

Recent research shows that cancer cells are using the same genes that first evolved to allow pregnancy in animals. For example, embryos and cancer cells both use the same genetic systems to avoid immune rejection.

Bridget Murphy is completing a PhD in biology at the University of Sydney.