Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Brief bites of science news.

Whale Sharks Don’t Mind Tourists

Whale sharks that have interacted with large numbers of tourists off Ningaloo Reef in Western Australia have the same rate of return to the popular tourist spot as those that had few human encounters, according to Mr Rob Sanzogni of the Australian Institute of Marine Science.

The finding is important because whale sharks have become increasing tourist drawcards in recent years, and opportunities to swim with whale sharks have been promoted as an alternative to fishing the vulnerable species.

“Our research shows that the code of conduct used by the Department of Environment and Conservation to protect whale sharks is very effective, with no detectable impacts of tourists on their aggregation behaviour at Ningaloo across years,” said Sanzogni.

Dumb Apps for Smartphones

Tobacco companies are circumventing laws regarding the promotion of cigarettes by producing smartphone apps to encourage people to smoke. Nasser Bin Dihm of the University of Sydney’s School of Public Health was able to identify 107 pro-smoking apps for Apple and Android. “The regulation of these apps is lagging behind the legislation in Australia and many other countries which ban tobacco advertising, including through the internet and virtual stores,” said Dihm.

The apps include smoking simulations that allow users to smoke virtual cigarettes, and games where users share cigarettes between characters. Pro-smoking apps were found under categories such as “Entertainment”, “Games”, “Lifestyle” and even “Health and Fitness”.

“Independent studies have shown that such virtual images of cigarettes are more likely to trigger smoking-craving behaviour than to help users quit,” said Dihm.

Flavourings from Waste

Australian chemical company the Circa Group has opened a plant that turns waste cellulose into levoglucosenone (LGN), a platform chemical used to make pharmaceuticals, food flavourings and fragrances.

LGN manufacturing is currently a cottage industry, with the largest producer in the world manufacturing 2 kg/month.

Circa is now selling the LGN it is producing to universities and other research labs. “Our next step is to scale up the system to produce about 20 tonnes of LGN per year at a capital cost around $5 million,” said CIRCA CEO Tony Duncan.

Besides replacing petroleum-based LGN with a renewable product, Circa’s technique produces phosphate-rich charcoal that may prove effective as a fertiliser and as a method of sequestering carbon in soil.

Circa is also developing technology to turn cellulose to biofuel at an efficiency more than twice that of ethanol production (AS, May 2008, p.8).

Climate’s Real False Consensus

Critics of climate science may object to the idea of consensus among scientists, but it seems the consensus problem is their own. A study in Nature Climate Change has found that those who reject evidence for global warming are inclined to overestimate the proportion of the community that shares their views, something psychologists call a false consensus.

Curtin University PhD student Zoe Leviston conducted two surveys asking more than 5000 Australians their beliefs on global warming and their estimates of what proportion of Australians would take each position. On average just 6.4% denied that climate change is occurring, but the sample thought 22.3% held that position. Likewise, very few said they did not know, but the average estimate was that more than 20% were unsure.

While everyone overestimated the number of people who denied climate change, and underestimated the proportion who said it was happening and human-induced, the discrepancy was much larger among those in the denial camp, while those who see the changing climate as human-induced were most accurate in their estimates of the national mood.

Bottle Wine in Green

There is a reason the 10 bottles on the wall were green – until they fell off they were doing a better job of protecting their contents than clear equivalents.

Dr Andrew Clark of the National Wine and Grape Industry Centre noted that white wine contains “tartaric acid, which is a major organic acid in wine, and iron, a metal ion found at low concentrations in all wines. These same agents were in fact used as photographic emulsions by the pioneers of photography in the mid-1800s.”

Clark found that the iron and tartaric acid consume preservatives and turn brown when exposed to light. Coloured glass helped protect the wine from sunlight, and “darker green and amber coloured bottles were particularly useful to absorb the active wavelengths of incident light”.

Arsenic Affects Lung Development

Arsenic-contaminated water affects lung development of mice in the womb, a study in Environmental Health Perspectives has found, explaining the appalling rates of lung disease among people who drink water from wells with similar concentrations of arsenic.

“We found abnormal lung development and structural damage to an extent that is likely to cause problems later in life. We also found that arsenic increased the amount of mucous produced by the lungs, which may reduce the ability to clear respiratory pathogens,” said Ms Kathryn Ramsey of the Telethon Institute for Child Health Research.

“These findings are significant because whilst arsenic is well-known for its cancer-causing properties, its impact on lung health is less known.”

Toads Need Water

Cane toads are dependent on artificial water bodies installed by graziers to spread, a paper in the Journal of Applied Ecology claims. “By removing these water bodies in key locations it is possible to halt the spread of toads,” said Dr Ben Phillips of James Cook University.

Phillips says that attempts to remove individual toads are doomed to failure as a result of their extraordinary fecundity. However, by removing around 100 artificial water bodies, toads can be prevented from occupying 268,000 square kilometres of their potential range in Western Australia, which is an area larger than Great Britain.

Phillips says the community must be brought on-side if toad spread is to be prevented. This would mean “serious financial compensation” for graziers who have to remove their stock-watering infrastructure.

Apples Fight Inflammation

The old saying about daily apple consumption appears true, with evidence that certain apple cultivars can control inflammatory bowel disease (IBD).

Scientists at New Zealand’s Plant and Food Research compared concentrations from 109 apple cultivars to choose five with contrasting chemical profiles. Extracts from the flesh and skin of these five types were applied to cell lines.

The Journal of Agricultural and Food Chemistry reported the observation that apples with high concentrations of procyanidin and triterpene compounds inhibited two molecules, NF-kB and TNFα, which are important in IBD.

“Apple is one of the most highly consumed fruits worldwide,” says Dr William Laing. “Understanding which compounds in apple influence pathways in disease, such as IBD, allows us to breed new varieties of apple with more of these compounds that can then be used as ingredients in foods specifically designed to control the disease symptoms.”

Breast Cancer Type in Transcription

A type of breast cancer that does not respond to major chemical treatments is triggered by a transcription factor that inhibits sensitivity to oestrogen. Further work indicates it may be possible to transform the most aggressive forms of breast cancer into varieties that are more responsive to treatment.

ELF5 turns off genes that make breast tissue cells sensitive to oestrogen. A/Prof Chris Ormandy of the Garvan Institute has shown that ELF5 can also turn ordinary breast cancers to oestrogen-insensitive forms that do not respond to Tamoxifen or aromatase inhibitors.

“This raises the therapeutic option of manipulating ELF5 levels to treat breast cancer,” said Ormandy. “There is also the possibility of testing ELF5 levels in tumours to predict response to treatment and therefore guide treatment decisions.”

Jellyfish Numbers Stable

Fears that jellyfish numbers are rising ignore older data, an international study has concluded.

Early in 2012 Prof Carlos Duarte of the University of Western Australia cast doubt on the idea that jellyfish are increasingly common, saying: “After examining the evidence, we believe that claims of a big rise in jellyfish numbers is very much a case of misreporting of qualified data” (AS, April 2012, p. 15).

Duarte has now backed up this theory with a paper in the Proceedings of the National Academy of Sciences tracking long-term fluctuations in jellyfish numbers. He found a largely unnoticed surge in the 1970s, followed by an 80s decline before the more recent increase that has attracted attention.

“There are major consequences for getting the answer correct for tourism, fisheries and management decisions as they relate to climate change and changing ocean environments,” said Duarte. “The more we know, the better we can manage oceanic ecosystems or respond accurately to future effects of climate change.”