More than 50 kilogrammes of fossil leaves were found by David Harwood
of the University of Nebraska at a site on Beardmore Glacier, part of the
Transantarctic mountain range.

¿ìè¶ÌÊÓƵs from Tasmania and Nebraska who are studying the leaves are
elated by the find. Species of southern beech are a good indicator of the
environment. Because they evolve slowly, they do not adapt easily to changes
in climate: if the temperature changes significantly, they disappear.

Bob Hill, from the University of Tasmania, believes that the leaves
may be related to a species of Nothofagus found today in South America.

The leaves were mostly undamaged and the detail in the fossils is very
fine. This suggests that they were not blown about but fell quickly during
autumn to form a mat beneath a tree.

Hill will examine the pores and veins of leaves and look for evidence
of leaf fungus. These should provide clues to the range of temperatures,
rainfall, humidity and the rate of photosynthesis (an indication of how
much carbon dioxide is in the atmosphere) in Antarctica three million years
ago. Hill believes that in summer temperatures rose to at least 5 °C,
about 15 °C warmer than today. In winter, the temperature would have
dropped to about -20 °C.

The world’s most advanced research ship for the southern oceans is making its maiden voyage to Antartica. The Aurora Australis is due at the Australian base of Mawson next Monday. This leg of its six-week journey to Antartica will be the first real test of its ice breaking capabilities.

If the ship lives up to expectations, scientists will have an extra month each year to carry out research in Antarctic waters. The ship will be able to reach Antarctica earlier in the summer and stay for longer periods as winter approaches about six months later.

But extending the season will depend on the ship’s performance in the ice. The Aurora Australis has been designed to slice through ice 1.2 metres thick at a speed of 2.5 knots. ¿ìè¶ÌÊÓƵs also want to use the ship to study the abundance of krill in pack ice – a study that has been limited in the past. There are fears that the amount of krill, a vital part of the food chain in Antarctic waters, is declining.

The Aurora Australis arrived at the base of Casey on 18 October, about two weeks earlier than any previous ship after the long Antarctic winter. But the ship did not strike any thick ice on this leg of the journey. This voyage – the first of three this summer – is being used to supply the bases of Casey, Mawson and Davis after the winter.

The Aurora Australis, designed by the Finnish company Wartsila Marine, is the first icebreaker built in Australia. The Australian government is chartering the ship for 180 days a year from its owners, P&O Polar, for use by the Australian Antarctic Division. It has been leased for the next 10 seasons. The 8,500 tonne vessel can take up to 100 scientists to Antarctica.

The ship has been plagued with a problem that could jeopardise one of its main research projects – using echo sounders to return signals are picked up by transducers situated in the hull.

During trials earlier this month off Tasmania, the problem was solved when the tranducers were moved to new positions. ¿ìè¶ÌÊÓƵs will not know if this adjustment solves the problem in Antarctic waters until the ship undertakes its cruise next year from 4 January to 19 March. Cruising speeds may also be reduced during hydro-acoustic surveys to reduce the build up of bubbles.

¿ìè¶ÌÊÓƵs from the British Antarctic Survey are keen to find out what happens to the Aurora Australis because a similar ship, the James Clark Ross, will be launched in December for use by the BAS.

The echo sounders on board the Aurora Australis operate at frequencies of 38, 120 and 200 kilohertz – these frequencies are need to detect animals of different sizes and at varying depths. The lower frequencies – bouncing signals off the air bladers – will detect larger fish near the ocean floor. The higher frequencies, which have lower water penetration but higher resolution, will be used for the krill resarch. Krill inhabit the top 200 metres of the sea.

Krill do not have an air sack but the reflected sound off the swarms of krill wil be picked up by the acoustic system. A device with echo sounding equipment will be towed to measure krill in the top 10 metres, where the acoustic system does not work.

A robot vehicle with lights, camera and echo sounder will be lowered over the side to do research under sea ice where scientists suspect that large nubers of krill graze on algae. Also, an instrument to determine the density and temperature of water can be lowered to depths of 6.5 kilomertres.

The Aurora Australis has a trawling capability to match commercial trawlers. This will be used to estimate the rates of catch by the fishing industry. ¿ìè¶ÌÊÓƵs are concerned about depletion of fishing stocks in southern waters.

The ship will also take in sea water for oceanographic experiments. Measurements of chlorophyll will be made to indicate the abundance of phytoplankton, a plant at the bottom of the food chain. In one experiment this summer, atmospheric scientists from the CSIRO, Australia’s national research centre, will measure the pH of the water to determine levels of carbon dioxide, the main greenhouse gas.

AUSTRALIAN seismologists said last week that they were not surprised
by the magnitude of the earthquake that rocked the New South Wales city
of Newcastle three days after Christmas. They added that the possibility
of earthquake activity in a populated area such as Newcastle was also expected.

Both conclusions run contrary to the views held by many Australians,
who were taught at school that since their continent is one of the oldest,
it is not subject to damaging earthquakes, and only experiences the occasional
tremor. In the past, there has been damage to buildings and services, but
never any loss of life.

On 28 December, at 10.28 am, an 11-second earthquake measuring 5.5 on
the Richter scale rocked the steel-manufacturing city of Newcastle. Twelve
people were killed, nearly 200 injured, and widespread and severe damage
was caused to buildings. The Newcastle Workers Club collapsed, killing nine
people. Train services were suspended in case the vibrations they produced
caused nearby damaged multi-storey buildings to collapse.

¿ìè¶ÌÊÓƵs from the Australian Seismological Centre in Canberra rushed
to the area and installed 10 seismological machines to measure the aftershock,
to calculate the locations of the epicentre and the hypocentre, and to gather
data about the cause of the quake.

Only one aftershock has been recorded, registering 1.5 on the Richter
scale. The epicentre appears to have been located in the middle of the city’s
central business district, with the hypocentre about 5 kilometres underground.
Shock waves were felt as far away as Queensland.

The quake is now considered to have been a ‘shallow’ one. As a result,
it gave the district a severe shaking, causing greater damage that might
have been expected from a ‘deeper’ quake. The large amount of masonry that
was not reinforced contributed to the widespread damage to buildings.

Analysis of the data collected could shed light on the cause of the
earthquake, but will probably confirm existing knowledge of earthquakes
on the east coast of Australia. The coast does not contain a distinctive
and continuous fault line, such as the San Andreas fault running through
San Francisco. The southeast of Australia, from Melbourne to Newcastle,
is a well-known ‘intra-plate’ zone.

The stresses that build up in this portion of the Australian plate are
thought to be the result of plate movement outside Australia, along a line
stretching roughly from Papua New Guinea to New Zealand and the Antarctic
region. What is unusual is that the Newcastle quake occurred at the northern
edge of the plate, in what is considered a low-risk area.

Dr Kevin McCue of the Australian Seismological Centre said that he was
also puzzled by the fact that so few aftershocks were recorded. ‘Our first
seismograph was installed within 12 hours of the quake, and the remaining
nine machines were in place by the next morning,’ he said.

The only aftershock that was registered took place at 10 pm the following
day. ‘Normally for an earthquake measuring 3-4 on the Richter scale you
would expect up to 20 aftershocks,’ McCue added.

The Australian Seismological Centre is currently analysing the data
it has collected, and will shortly be issuing a revised risk map to assist
the Standards Association of Australia to update its design and structural
engineering codes.

Mike Gladwin, from the University of Queensland, Australia, has developed
this instrument, which indicates subtle ground distortions by measuring
shear strain and changes in the volume of rocks.

The borehole strainmeter is very sensitive, measuring up to one part
in 10 000 million, has adequate long-term stability, and can operate continuously.

The geophysicists have recorded defor-mation, but, says Gladwin: ‘We
don’t know enough about earthquakes to know if the signals are useful for
prediction.’ The geophysicists found no obvious short-term precursors for
the earthquake; this is typical of previous earthquakes. The scientists
will now follow up the long-term signals, to find out more about this quake.

CHEMISTS IN Australia have developed a monitor that can measure the main components of photochemical smog and track the pollutants back to their source. The device, called Airtrak, can also predict the build-up of smog and its likely path, and give early warning of dangerously high levels.

The chemists, from Australia’s national research organisation, the CSIRO, believe that Airtrak could revolutionise the management of smog. They claim that until now, it has only been possible to measure smog as it accumulates. ¿ìè¶ÌÊÓƵs could not trace back the source of the smog nor predict how it might develop.

Photochemical smog is produced by a chemical cycle in which light reacts with various components in the air, particularly certain hydrocarbons, to produce ozone, nitrogen oxides and nitrogen-based chemicals.

Central to this device is a computer program that models the formation of smog. Graham Johnson, who led the CSIRO team, ignored the theoretical approaches commonly used in the US. Over 10 years of studying smogs, he worked out a two-stage model that he calls the Integrated Empirical Rate Model.

Johnson’s model takes account of concentrations of the main constituents of smog – nitrogen oxides and reactive carbon compounds – and describes how it forms. In the first stage, the concentration of smog is directly related to the amount of sunlight and the composition and concentration of the hydrocarbons. In the second phase, the concentration of the smog remains nearly constant depending on the initial concentration of nitrogen oxides in the air.

Airtrak includes a two-stage chemical reactor and analyser in which air samples undergo a number of tests. In the first stage, Airtrak measures the extent of smog. In the second stage, a bank of sunlamps generates further smog in the sample as sunlight does in the atmosphere. A computer receives the data from the two stages. Using Johnson’s program, it calculates the concentration of ozone and the maximum that could be generated in the sample. Using meteorological information such as temperature, helps the computer to pinpoint the source of the pollution.

Johnson’s model suggests a way that environmental authorities could control the formation of ozone. Depending on weather conditions and estimates of exhaust fumes, they could limit the emissions of either hydrocarbons or nitrogen oxides from industry. Common practice in the US is to limit both. But it is conceivable that because Johnson’s model separates the effects of hydrocarbons and nitrogen oxides, release of effluents from individual factories could be permitted at certain times during the day.

The team also developed a new chemical procedure to measure the concentrations of reactive carbon compounds in the air, ozone and nitrogen oxides. Existing monitoring devices can measure ozone and nitrogen oxides, and a broad range of hydrocarbons in the atmosphere but not all the important carbon or organic compounds that are photochemically sensitive. These reactive organic compounds are important because, together with temperature and sunlight, they play a major part in the rate of smog formation.

The CSIRO has formed a partnership with a South Australian company, Mineral Control Instrumentation. Airtrak was unveiled recently in the US and Europe and is expected to cost around Dollars A75 000 (Pounds sterling 36 000).

Airtrak can also assist town planners decide where to locate new industries. In Sydney the construction of an Dollars A85 million plant by Pilkington-ACI will go ahead, after a study by the CSIRO showed that the expected release of nitrogen oxides by the plant of 1200 tonnes a year, would not add to the city’s photochemical smog problem. Johnson gave evidence to the commission investigating the proposed plant. The site for the plant, in the southwest of Sydney, has the city’s highest smog levels.

Johnson discovered that the smog in that area was mainly due to the amount of sunlight, not the amount of nitrogen oxide emitted and that the level of oxides of nitrogen would be below the National Health and Medical Research Council’s maximum ground-level concentration of 16 parts per 100 million.

Because Airtrak can trace the origins of the smog, the situation could arise where one country will claim compensation from another. This is already a sensitive issue for several countries within Europe, and between the US and Canada. Central to any legal battle will be the validity of Airtrak’s results, particularly the mathematical model developed by Johnson. The CSIRO is sure that Airtrak will stand up to close scientific and legal scrutiny.

Airtrak may also be used to screen motor fuels for the amount of effluents they produce. In the US there is controversy over the effectiveness of reducing hydrocarbon emissions from exhausts by substituting methanol for petrol. A modified version of Airtrak should be able to show whether this will be an effective method of smog control or whether changing the hydrocarbon mix in petrol would be more effective.

The CSIRO has kept the development of the reactor a secret over the
past year and is now marketing a commercial version, called MicroLab, at
around A$15 000, in the hope that the reactor will become a basic research
tool in chemical laboratories.

The idea for this design of microwave reactor occurred to Chris Strauss
at the CSIRO after reading an article in ¿ìè¶ÌÊÓƵ (‘The chemist’s quick
cookbook’, 12 November 1988). As the article said, it was only that year
that Richard Gedye demonstrated the possibilities of using microwave ovens
for accelerating organic reactions. Before 1988, chemists had used them
mainly for drying compounds.

Since then, researchers have discovered that microwaves can speed up
some reactions by a thousand times or more and new areas of chemical synthesis
are opening up as a result. Strauss sees many applications for the reactor:
the development of new polymers and pharmaceuticals, sewage and water treatment,
pesticides and even bath heaters for saltwater spas.

MicroLab can operate over many hours, with materials flowing through
it at a rate of 20 millilitres per minute at temperatures of up to 200 Degree
C and pressures around 1200 kilopascals – conditions that are not readily
achieved with conventional equipment. For example, conventional electric
ovens would take 18 hours to produce isopropyl acetate, yielding about 47
per cent of the materials as product. In MicroLab, the job will take 2.3
minutes with a product yield of 98 per cent. This is 470 times as fast,
and more than twice the yield, of the conventional reactor.

The CSIRO has formed a partnership with Industrial Microwave Applications,
a company in Australia, to produce a reactor with 200 times the capacity
of MicroLab, to be called MacroLab. This reactor can process 4 litres of
material per minute.

Strauss’s experience in the distillation and continuous processing of
spirits helped him to see some ways of improving the developments of Gedye
and his other Canadian collaborators, Frank Smith and Kenneth Westaway.

The Canadians placed a sealed Teflon vessel that contained the reaction
mixture inside a microwave oven. They found that increasing the volume of
reaction mixture in the sealed container reduced the rates of heating and
reaction, making large-scale processing of compounds difficult and limiting
the chemists to processing small batches. Furthermore, the containers occasionally
exploded.

This indicated to Strauss that sealed flasks were not the answer. He
also felt that the process described in the article needed better monitoring
and more accurate control. Strauss says he realised that the best way to
do this is to pump material through the oven and have all the monitoring
devices immediately outside.

With guidance from Strauss, a team at the CSIRO produced a prototype
reactor using a domestic microwave oven. They connected a pump to one end
of the Teflon tube, drilled two holes in the oven and fed the free end of
the tube through the oven, coiling the tube on the way. They added the heat
exchanger and a special valve and found that they could accurately monitor
and control reactions.

When Strauss first suggested his microwave reactor to his colleagues,
they thought it was a joke. But it did not take long for them to realise
the advantages of his simple idea. The new reactor offers great scope for
controlling reactions, particularly pressure. Another advantage is that
the Teflon tubing is transparent, so chemists can now observe reactions
in progress, allowing better control. As the reactor operates on a continuous-flow
basis, the CSIRO is certain that it can scale up the process to industrial
requirements easily.