Warming altering ocean salinity and the water cycle

A clear change in salinity has been detected in the world’s oceans, signalling shifts and an acceleration in the global rainfall and evaporation cycle.

In a paper published today in the journal Science, Australian scientists from the CSIRO and the Lawrence Livermore National Laboratory, California, reported changing patterns of salinity in the global ocean during the past 50 years, marking a clear fingerprint of climate change.

Lead author, Dr Paul Durack, said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has strengthened by four percent from 1950-2000. This is twice the response projected by current generation global climate models.

“Salinity shifts in the ocean confirm climate and the global water cycle have changed.

“These changes suggest that arid regions have become drier and high rainfall regions have become wetter in response to observed global warming,” said Dr Durack, a post-doctoral fellow at the Lawrence Livermore National Laboratory.

With a projected temperature rise of 3ºC by the end of the century, the researchers estimate a 24 per cent acceleration of the water cycle is possible.

Scientists have struggled to determine coherent estimates of water cycle changes from land-based data because surface observations of rainfall and evaporation are sparse. However, according to the team, global oceans provide a much clearer picture.

“The ocean matters to climate – it stores 97 per cent of the world’s water; receives 80 per cent of the all surface rainfall and; it has absorbed 90 per cent of the Earth’s energy increase associated with past atmospheric warming,” said co-author, Dr Richard Matear of CSIRO’s Wealth from Oceans Flagship.

“Warming of the Earth’s surface and lower atmosphere is expected to strengthen the water cycle largely driven by the ability of warmer air to hold and redistribute more moisture.”

He said the intensification is an enhancement in the patterns of exchange between evaporation and rainfall and with oceans accounting for 71 per cent of the global surface area the change is clearly represented in ocean surface salinity patterns.

In the study, the scientists combined 50-year observed global surface salinity changes with changes from global climate models and found “robust evidence of an intensified global water cycle at a rate of about eight percent per degree of surface warming,” Dr Durack said.

Dr Durack said the patterns are not uniform, with regional variations agreeing with the ‘rich get richer’ mechanism, where wet regions get wetter and dry regions drier.

He said a change in freshwater availability in response to climate change poses a more significant risk to human societies and ecosystems than warming alone.

“Changes to the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilization,” Dr Durack said.

Dr Susan Wijffels, co-Chair of the global Argo project and a co-author on the study, said maintenance of the present fleet of around 3500 profilers is critical to observing continuing changes to salinity in the upper oceans.

Resistant starch may help protect against bowel cancer

Even though Australians eat more dietary fibre than many other western countries, bowel cancer is still the second most commonly reported cancer in Australia with 30 new cases diagnosed every day.

Dr David Topping, from CSIRO’s Food Futures Flagship, said this is referred to as ‘the Australian paradox’.

“We have been trying to find out why Australians aren’t showing a reduction in bowel cancer rates and we think the answer is that we don’t eat enough resistant starch, which is one of the major components of dietary fibre,” Dr Topping said.

These findings, published in the latest issue of The Journal of Nutrition, reinforce the fact that dietary fibre is beneficial for human health, but go further to show that fibre rich in resistant starch is even better.

“It’s not just the amount of fibre that we eat that’s important, but the diversity of fibre in our diet,” Dr Topping said.

“We studied various sources of resistant starch, including corn and wheat, and the results suggest they could all protect against DNA damage in the colon, which is what can cause cancer.”

Dr Trevor Lockett, colorectal cancer researcher with CSIRO’s Preventative Health Flagship, said Australia has one of the highest incidence rates of bowel cancer in the world.

“Research suggests that improving our diets could go a long way to reducing our personal risk of developing this disease, which would also have the follow-on benefit of reducing healthcare costs associated with bowel cancer.

“These new studies suggest that increasing the amount of resistant starch in our diets may be one important step along the path to reducing the burden of bowel cancer. It takes about 15 years from the time of the first bowel cancer-initiating DNA damage to the development of full-blown bowel cancer, so the earlier we improve our diets the better,” Dr Lockett said.

The recommended intake of resistant starch is around 20 grams a day, which is almost four times greater than a typical western diet provides. Twenty grams is equivalent to eating three cups of cooked lentils.

“Currently, it is difficult for Australians to get this much from a typical diet,” Dr Topping said.

“We have already had success in developing barley with high levels of resistant starch, and now our focus is on increasing the levels of resistant starch in commonly consumed grains like wheat.  These grains could then be used in breads and cereals to make it easier for Australians to get enough resistant starch from their diet.”

Resistant starch is a component of dietary fibre that resists digestion in the small intestine and instead passes through to the bowel where it has positive effects on bowel health. Resistant starch is sometimes called the third type of dietary fibre (in addition to soluble and insoluble fibre) and is found in legumes, some wholegrain breads and cereals, firm bananas and cooked and cooled potatoes, pasta and rice.

Ironing the bugs out of insect silk

Thanks to exceptional strength and toughness, insect silk is potentially a key component in a wide range of new products and applications from composite fibres for the aviation and marine industries, to medical applications including wound repair, drug delivery, and repairing and replacing human tissues such as membranes, ligaments, blood vessels and cartilage.

Woven artificial bee silk.

Bringing the new insect silk products to the global market is the focus of a partnership between CIRO and life science industry supplier, Lonza. The agreement is to advance and market new insect silks for a broad range of medical and industrial applications.

CSIRO is bringing scientific discovery, biomedical and materials science expertise to the partnership, according to CSIRO Business Development and Commercialisation General Manager, Cameron Begley.

“CSIRO has identified a broad range of insect silks that could be produced sustainably and used for a wide range of industrial and medical applications,” Mr Begley said.

“We have found ways to convert the bee silk into a range of different forms, from micro-particles and sponges through to spun fibres that can lead to knitted and woven fabrics.”

Lonza brings its biotechnology and life-science product and service expertise to the partnership and is already providing process development for the recombinant bee silk protein.

“Lonza is excited by the potential of insect silks as a relatively untapped route to sustainable and life enhancing products for our current markets and beyond, and it is encouraging to see such strong projects resulting from our Lonza Innovation for Future Technology initiative,” Allison Haitz, Lonza’s Head of Global Innovation, said.

“Lonza has been very impressed with CSIRO’s research and development work. This is a world class combination with CSIRO’s research team developing new ways of processing silks and achieving continuous strong silk fibre production, and Lonza’s experience and capability in manufacturing to take that research to the marketplace and support the successful commercialisation.”

Lighting up to take down bacteria

By Merrin Fabre

Whilst some bacteria can provide health benefits there are others that can do annoying things – like kill you. So in order to save ourselves we should probably kill them first.

So, stand aside bacterial wipes, hand sanitisers and antiseptic sprays there is a new bug zapper in town.

Bring in the plasma flashlight – a torch that emits a plasma jet that kills bacteria on the skin in an instant. Developed by a group of Chinese and Australian scientists, including CSIRO, the flashlight is completely mobile, light, efficient, and works at room temperature.

The plasma bacteria zapper.

Due to its mobility it could be used in ambulance emergency calls, natural disaster sites, military combat operations and many other instances where treatment is required in remote locations.

Kostya Ostrikov from CSIRO was one of the researchers working on the flashlight.

“‘The plasma flashlight is an exciting development in potential health treatments,” Kostya said. “It not only inactivates individual bacterial cells but also bacterial biofilms.”

Biofilms are multilayered bacterial colonies which can give the bacterium addition resistance. The plasma flashlight effectively inactivated a thick biofilm of one of the most antibiotic and heat-resistant bacteria, Enterococcus faecalis – a bacterium which often infects the root canals during dental treatments.

“We used an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature,” Kostya said. ” For individual bacteria, the inactivation time could be just tens of seconds.”

“There is potential for this device to be used to kill pathogens, such as bacteria, viruses, spores or fungi.

“It can then be used to clean and sterilise medical equipment and wounds. It could also be used for plasma-assisted coagulation to help heal wounds, plus it could be used to treat cancers such as skin cancer.”

But it doesn’t have to be restricted to medical use.

“This device could be miniaturised and used in hygiene treatments such as toothbrushes or chopping boards in the kitchen,” Kostya said.

One day you could be zapping your bacteria away with your very own plasma toothbrush.

MEDIA: Merrin Fabre. Ph: 03 9545 8362 E: merrin.fabre@csiro.au Mb: 0402 764 573