- The study is the first step towards helping researchers explain some of the strange properties of water, which prevent oceans from freezing solid and allow fish and other aquatic life survive under ice sheets.
- The Seafood Cooperative Research Centre is calling for more commercial interest in Kakadu Plum production.Research has shown native plum extract, which is high in Vitamin C and antioxidants, can be used to keep prawns fresher for longer.
- South Australians will feel the pain from the state budget in a sharp rise in the annual Emergency Services Levy.
News on Health Professional Radio. Today is the 20th June 2014. Read by Rebecca Foster.
Scientists have taken their first look at the microscopic structure of liquid water at the coldest temperatures yet.
The study is the first step towards helping researchers explain some of the strange properties of water, which prevent oceans from freezing solid and allow fish and other aquatic life survive under ice sheets.
A team reporting in today’s issue of the journal Nature successfully took X-ray pulse images of ‘supercooled’ water, which they were able to keep liquid at temperatures of minus 46°C.
Water has many unusual physical features, which become even more striking when it’s cooled below its freezing point while still remaining liquid, a state known as supercooled.
For example, while liquids usually decrease in volume when cooled, water reaches its maximum density at 4 °C.
“Upon cooling below 4°C water expands instead of contracting,” says Professor Anders Nilsson from the Stanford University National Accelerator Laboratory.
This explains why bottles of water placed in the freezer crack.
And it also explains why ice forms on the surface of lakes, rivers and oceans in cold climates, while the liquid water below remains warmer.
Researchers have long been interested in exploring the structure of supercooled water because its anomalous properties become amplified at low temperatures.
But to date, the onset of rapid ice crystallisation has prevented the exploration of the so-called ‘no-man’s land’ of temperatures below minus 41°C.
Nilsson and colleagues used a liquid jet to generate 10-micron sized water droplets in a vacuum, which cool rapidly as they evaporate.
For periods of just a millisecond, the researchers were able to keep droplets of water liquid down to temperatures of minus 46°C.
They then probed the structure of the droplets using a new X-ray laser generated by a particle accelerator, giving ultra-short 50 femtosecond pulses.
Nilsson and colleagues observed an accelerating transformation of the density and structure of the liquid water as temperatures approach no-man’s land.
“The transformation is continuous without abrupt change,” says Nilsson.
The findings will help scientists resolve debate over what happens to water at such low temperatures, and ultimately help shed light on the mysterious properties of this life-giving substance.
The Seafood Co-operative Research Centre is calling for more commercial interest in Kakadu Plum production.
Research has shown native plum extract, which is high in Vitamin C and antioxidants, can be used to keep prawns fresher for longer.
The centre’s director, Len Stephens, says the process is completely organic.
“They’re a wild fruit from Northern Australia harvested by the indigenous community,” he said.
“All we do is simply mash them up, strain them out and then dilute it and apply it to the prawns.”
Speaking at the World Aquaculture Conference in Adelaide, Dr Stephens says scientists are confident the treatment will work on other seafood as well.
“We think it could work on any seafood product that is sold fresh,” he said.
“It doesn’t impart any flavour or taste or taint to the fish.
“One of the other findings about it is that even in frozen form it works to help the product come out of the freezer looking fresher and better.”
But Dr Stephens says there aren’t enough plums for the whole seafood industry and the concept needs more interest from food manufacturing companies.
“It’s the chicken and egg scenario,” he said.
“As the market sees the usefulness, then the supply will increase.
“There are people who are establishing plantations of the Kakadu plum in Northern Australia, so we think it’s a product that can just grow slowly over the next couple of years.”
South Australians will feel the pain from the state budget in a sharp rise in the annual Emergency Services Levy.
It is to go up by about $150 for the average South Australian household from July 1, with the SA Government saying it needs to cover budget shortfalls from federal coffers.
Treasurer Tom Koutsantonis says he is delivering a budget which will offset $898 million of federal funding cuts.
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