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	Issue 32

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Hydrogen – fuel of the future? Today's space vehicles propel themselves into orbit using the energy of hydrogen. Because of expected shortages in petroleum by early next century, cars of the future may also be running on that remarkable fuel. Download Article

The southern bluefin tuna may be in trouble Researchers from CSIRO suspect that the southern bluefin tuna, the fish landed in greatest quantity by the Australian fishing industry, is being over-exploited. They fear that, unless the annual catch is reduced, a population crash similar to those experienced by a succession of whale species is likely. Download Article

A weevil to control salvinia
It has become a truism that, because of Australia's long isolation from the rest of the world, newly introduced plants and animals often have dramatic impacts on our environment. Free from the parasites and predators of their homelands, the new migrants can increase unchecked, and often the only way to control them is to import some of those old enemies.
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High cost of fuel from sappy plants The milky sap that flows from the broken stems of some thistles and other weeds and shrubs is reputed to cure warts; according to recent speculation, it may also provide a remedy for dwindling petroleum reserves. Download Article

The ups and downs of chimney plumes Fortunately, a parcel of material issuing from a chimney tends to disperse rather than hanging together. In this way, pollutants can become so diluted in the atmosphere that they become essentially harmless. Download Article

The Australian National Wildlife Collection To an ecologist, a museum resembles a library. These skeletons and skins — they are works of reference.' Download Article

Why CSIRO has stopped cloud-seeding After nearly 30 years of experiments, CSIRO has closed down its cloud-seeding operations. The decision was taken after research findings showed that clouds suitable for seeding are less common than previously thought. Download Article

Improvements in solar collector technology Three new CSIRO developments offer significant improvements in the heat-collecting efficiency of flat-plate solar collectors. Download Article

One foot in warm water, the other in cold Mariners sometimes report ocean fronts in waters off New South Wales, which can be followed across the continental shelf and towards the coast. Download Article

A structural wood composite from short-rotation plantations Australia has about 15 million hectares of native forests managed for sustained yields of sawn hardwood and some 800 000 ha of pine plantations for softwood production. Yet, despite the relatively small size of its population, it is a fairly heavy importer of forest products. Download Article

Wetter since World War II It's been getting wetter back of Bourke. Figures compiled by Dr Barrie Pittock of the CSIRO Division of Atmospheric Physics show that average summer (November to April) rainfall between 1946 and 1979 at Dubbo, Bourke, and points west in New South Wales was up 30% and more on the figures for 1913–45. Download Article

Butterflies can leave a bad taste
Not all butterflies are as innocent as they appear. For instance, those in the danaid family, which includes the familiar orange and black wanderer and the black-and-white common crow, thrive on the juices of poisonous plants such as ragwort, heliotrope, and crotolaria. They use the poisons — pyrrolizidine alkaloids — both as aphrodisiacs and to make their enemies sick.
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