The researchers calculated the beast’s size by looking at the proportions of
smaller, related species. “As only remnants were available for analysis, we had
to extrapolate its dimensions,” says Jörg Schneider, a palaeontologist at
Freiberg University. It belongs to the genus Arthropleura, but the
creature has not yet been given a species name.

The largest modern arthropods are marine spider crabs, which have spindly
legs up to 1.5 metres long. However, their bodies have a diameter of around 50
centimetres, so their bulk is much less than that of the mammoth
Arthropleura.

Schneider says the creature inhabited estuarine marshes, probably feeding on
amphibians and smaller invertebrates. Why it became extinct is unclear, but a
drying of its habitats and the rise of reptiles—which would have competed
for prey or even preyed on it—could have been to blame.

A hydrogen fuel cell is a way of burning a gas that generates electricity
directly, instead of heat. Rather than allowing hydrogen to react with oxygen
directly, the gas is first split into protons and electrons by a catalyst. The
electrons flow through a circuit—providing electrical power—before
combining with oxygen molecules to form negative ions, which then react with the
protons, producing water.

But fuel cells require a constant supply of hydrogen, and it is not safe to
store hydrogen in sufficient quantities. So Thomas Rampe of the Fraunhofer
Institute for Solar Energy Systems in Freiburg looked for new ways to make it in
close proximity to the fuel cell. His team devised what it calls an autothermal
reactor, in which the crucial temperature for splitting propane—900
°C—is reached by burning some of the hydrocarbon itself. Besides
allowing campers to run fridges, Rampe says the new technology could also power
remote equipment, such as TV and radio transmitters. He sees no reason why such
fuel cells could not one day supply power to housing estates. The generator will
be shown in prototype form at May’s Hanover Fair.

Meanwhile, DaimlerChrysler and Ford both plan to launch cars powered by
hydrogen fuel cells in 2004, which will, like the Fraunhofer system, give off
only water in their exhaust. The firms say the cell will extract 80 per cent of
the fuel’s energy, more than twice the efficiency of a petrol engine. Both cars
will travel 450 kilometres between fuelling stops at up to 145 kilometres per
hour.

“The bacterium is a real novelty in two ways,” says Werner Liesack, a team
member from the Max Planck Institute for Terrestrial Microbiology in Marburg. It
is unrelated to other methane-eating bacteria, and it thrives in acidic
conditions.

Although most of the bacteria that produce methane live in acidic wetlands in
the northern hemisphere, these environments were thought to be unsuitable for
bacteria that digest the gas. But the scientists noticed that some wetlands in
Europe were only producing about half as much methane as expected—and this
led them to the bacterium.

“It plays a vital role in protecting the atmosphere,” says Liesack. Almost
half the world’s methane emissions come from wetlands in the northern
hemisphere.

The bacterium is under threat, however. Nikolai Panikov and Svetlana Dedysh
of Moscow University found that it is especially sensitive to nitrate and
sulphate pollution from industry and traffic. They say that the methane output
of acidic wetlands is now higher than it was before the industrial revolution,
because of the decline in this methane-eating bacterium. The team, whose
research has yet to be published, is still deciding what to call it.

The recent avalanches were inevitable, says Blyth Wright of the Scottish
Avalanche Information Service. “In each case, the area had got a metre or more
of snow within a day or two, and there were high winds.” Deep “wind slabs” of
new snow pile on top of existing snow. The bonding between the old and new
layers is often weak, especially if there was an icy crust on the old snow. The
weight of the new snow can exert enough force on the weak junction between the
layers to tear the top snow away.

Even though avalanches are unavoidable and there are more people in their way
than ever before, the Alps have never been safer. Nearly five times more people
pour into the Alps now than in 1980, as the popularity of winter sports,
especially skiing, has snowballed. In 1980, more than 13 million visitors spent
at least one night in the Alps. By 1990, it was 35 million, and in 1995, the
latest year for which figures are available, there were 60 million. And the
number of skiing complexes has also multiplied to cater for this demand.

Over the years the frequency of avalanches has remained roughly the same. And
although there has been a rise in off-piste fatalities in Switzerland—the
country with the best records—deaths per skier have fallen while deaths
caused by avalanches sweeping into buildings or ploughing into traffic have fallen sharply
(see Diagram).
Much of the credit goes to avalanche science.

Information about past avalanches, the routes they took and the punch they
packed allows buildings to be strengthened or only built in areas that are not
avalanche-prone, while tunnels protect roads and railways. And understanding
what triggers avalanches enables scientists to make detailed forecasts of
avalanche risks. That, at least, is the theory.

The planners in the Alps, for example, use the scientists’ forecasts to zone
land for building. Building is banned in zones that the scientists say are
avalanche-prone and only allowed in places that are beyond the reach of the
snow. The researchers start with data on the extent of past avalanches, how fast
they travelled and how far they went, and from this they can calculate their
mass and density, says Paul Föhn at the Swiss Federal Institute for Snow
and Avalanche Research in Davos.

The models they use are similar to those used to predict the flow of rivers.
But the models are far from perfect. They are accurate only to within 50 metres,
for example. And reliable historical data only go back 50 years—so the
models cannot take account of events that occur less frequently than this. One
of the victims this year was a farmer in Switzerland, who died when snow
demolished a house built in 1678.

However, this year’s abundant snow did do some good—it allowed
François Dufour and his colleagues, also at Davos, to unleash their first
experimental avalanche in February. Their work is part of a project funded by
the European Union to improve models used to zone land for building.

A small dynamite charge sent hundreds of thousands of cubic metres of snow
crashing down towards a small bunker where the scientists huddled. They pointed
a radar at the avalanche to measure its speed, as well as monitoring the
maelstrom’s pressure and temperature. At the last minute, they slammed the door
of the bunker shut, says Dufour, but even so some scientists were flung to the
ground, and all had sore ears from the pressure wave that precedes an avalanche.
This can be strong enough to knock a bus off a bridge.

Bizarre as the experiment sounds, it did yield precise statistics about the
avalanche. “We were able to get the total mass balance of the avalanche,” says
Föhn. This enables the scientists to calculate how far the snow is likely
to travel and how destructive it will be. Combining a more precise understanding
of the physics with the historical records , he says, should enable the planners
to be more accurate when they zone an area for building.

Several holiday homes were hit this year, in the avalanches at Evolène
in Switzerland, where two died, at Chamonix in France, where 13 died, as well as
at GaltĂĽr. Local inquiries into the deaths are considering if the zones
were defined correctly.

Where buildings do lie in the path of avalanches, the key to improving safety
is better forecasting, which can be used to warn people to stay off the slopes,
shelter in avalanche-proof buildings or leave the area. Since 1992, the French
meteorological service’s Centre for Snow Studies at Grenoble has been issuing
forecasts for the Alps and Pyrenees using a chain of three models to predict the
changing structure of the snow pack throughout the winter.

The model is based solely on meteorological data. Snow and rainfall,
temperature, humidity and satellite observations of clouds are combined in a
model called SAFRAN, which calculates average weather conditions for 23 zones in
the Alps. The weather map is then passed to a model called CROCUS, which
forecasts the way that the weather influences the crystal structure and other
properties of snow, and calculates the changes in the snow pack.

The model does have its limits. Any errors tend to accumulate over the
winter, says Eric Martin, head of the snow centre. But it did “a pretty good
job” when tested against the real evolution of the snow pack, says Föhn.
Finally, the results from CROCUS are handed to another model, MEPRA, which
analyses snow structure to look for weak points and calculates the risk of snow
slipping on particular slopes.

Swiss researchers who have been closely involved with the development work of
these models are trying to improve the modelling by sampling the snow pack
during the winter and feeding these real observations into the models. This
February, the French models worked well. “We predicted the danger, and everyone
who should not have been out on the slopes stayed in,” says Martin—except
for three climbers, who went out during a brief lull in the storm and had to be
rescued.

But good models are useless if people are not warned of the risks. The growth
in skiing has slowed, leaving hotels with empty beds, according to the
International Commission for the Protection of the Alps in Liechtenstein. And
Alpine regions dependent on tourism are reluctant to issue evacuation orders.
“We issue the warnings,” shrugs Eric Martin. “We can’t make people heed them.”

The surgeons’ little helper is Acetobacter xylinum, a bacterium that
makes cellulose out of sugars. Bacteria have already been put to work making
cellulose sheets, such as those used in the manufacture of loudspeaker
diaphragms. Now Dieter Klemm of the University of Jena has found a way to make
the bacteria produce narrow cellulose tubes that make good substitutes for blood
vessels.

Previous attempts to use cellulose to build artificial blood vessels relied
on the clumsy drilling of a duct from a frozen block of cellulose, a “brute
force” method that has not taken off (Patents, 27 July 1991, p 25). Klemm has
developed a culturing technique that allows the bacteria to produce cellulose in
the narrow space between a ceramic tube and a core, forming almost ideal
artificial blood vessels as little as 1 millimetre in diameter and up to 1.5
centimetres long. The Jena team have found that by using different-sized tubes
they can produce vessels tailor-made for particular parts of the body.

“Patients will benefit greatly from them,” says Dieter Schumann, a surgeon
who is also a director at Jena University Hospital. Artificial vessels are used
to replace arteries or veins damaged in accidents or destroyed—perhaps as
a side effect of radiotherapy.

Artificial blood vessels made of Teflon are unsuitable for microsurgery
because they increase the risk of blood clotting. Instead, vessels have to be
taken from some other place in the body.

In tests on rats, the cellulose vessels did not increase the risk of clots
and were not rejected. “From both ends, endothelial cells grow in and completely
cover the inside wall within a couple of weeks,” says Schumann, who did the
tests. The epithelial cells prevent blood cells from sticking to the wall and
causing clots. Local tissue then grows over the outside wall of the cellulose
vessel, integrating it almost entirely into the body.

But researchers in Germany have found a way of diagnosing abnormalities by
isolating fetal cells in the mother’s blood. This carries no risks for the
unborn child. They claim the technique could one day replace invasive methods of
diagnosis.

Fetal diagnosis is generally carried out only on women over 35, who have a
higher risk of carrying children with chromosomal defects. Cells are removed
either from the amniotic fluid or from the chorion, the outer membrane around
the placenta. A doctor inserts a needle through the mother’s abdominal wall to
extract the cells, which runs the risk of introducing infection or disrupting
the development of the fetus and placenta.

Removing cells from the amniotic fluid—known as
amniocentesis—carries a miscarriage risk of between 0.5 per cent and 2 per
cent. In Germany, 400 pregnancies fail every year after amniocentesis. Removing
cells from the chorion—chorionic villus sampling, which can be done 12
weeks after conception compared with 18 weeks for amniocentesis—is riskier
still.

Fetal cells are extremely rare in the maternal blood stream—one in a
million on average. To identify the cells Ferdinand von Eggling and his
colleagues at the University of Jena used antibodies that bind to proteins found
only on the surface of young red blood cells. They then used the polymerase
chain reaction to amplify the genetic material, and checked the DNA of the fetal
cells for defects.

The researchers point out that the technique has its drawbacks. Not only are
fetal cells scarce, they are hard to distinguish from the mother’s cells,
especially as maternal blood also contains immature red blood cells that, like
young fetal blood cells, still contain DNA.

The team distinguished the cells of a male fetus from his mother’s by the Y
chromosome. But those from a female fetus were harder to spot because there is
no reliable way of telling them apart, and the researchers were unsure in almost
half the cases. “If you don’t find anything, you still don’t know,” says von
Eggling. If a chromosomal defect is found, however, it is certain to be in a
fetal cell.

Another drawback is that blood samples rarely contain enough fetal cells to
test for more than 70 per cent of chromosomal abnormalities. There is no way of
culturing fetal blood cells, and gynaecologists would simply run out of cells
before completing all the tests. Invasive techniques, on the other hand, produce
enough cells for full testing.

Opponents of the use of amalgam—which contains mercury and another
metal such as silver—claim it leaks mercury into the body. Mercury is a
toxic metal that can affect the nervous system even at low levels. Children born
to mothers who had low levels of the metal in their blood during pregnancy had
deficiencies in learning, memory and attention
(see This Week, 22 November 1997, p 4).
German health minister Andrea Fischer announced last month that she is
planning to look again at the concerns surrounding the alloy and will ban it if
doubts over its safety emerge.

Anton Rudolf and Josef Bailer, psychologists at the University of Heidelberg
at Mannheim, and others looked at 40 patients who were complaining of health
problems connected with their amalgam fillings, such as headaches, anxiety and
lack of concentration. They compared them with 40 others who had a similar
number of fillings but no complaints. When they measured mercury concentrations
in the saliva, blood and urine of the subjects, they found very low levels in
all of them and no difference between the two groups.

However, the researchers found that a high proportion of the complainants had
histories of psychological problems, compared with few of the others. These
people tended to be emotionally unstable, showed depressive symptoms and a
slightly obsessive attitude towards their body and health, says Rudolf. He
believes that while they were not imagining their symptoms, if they had not
heard in the media that amalgam may be harmful, they would have looked for other
causes to blame for their symptoms.

Concern over the effects of amalgam are apparently widespread. When the
researchers asked 1000 people in the Frankfurt area about their attitudes
towards it, 23 per cent said they thought the alloy posed a considerable hazard
to their health.

Christof Schumacher, spokesman for the German Dentists’ Institute in Cologne,
says that amalgam is not without its risks. But he points out that other
materials used for filling have drawbacks too.

So when rumours started a couple of years ago that wolves had returned to the Swiss Alps from Italy for the first time in over a century, local people were very concerned. Since then the remote Wallis Canton, close to the borders of France and Italy, has become famous for wolf sightings. Telltale footprints in the snow and the loss of several dozen sheep persuaded local newspapers to launch a hunt for the “Wallis beast”.

Late last year, the Swiss government confirmed that European wolves (Canis lupus) were indeed living in the region. It appears that they have returned to other parts of central Europe too. They have been seen near the Mercantour national park in the French Alps, and two weeks ago one crossed the Odra River from Poland and was reported near the German Baltic coast.

Wolves have been living in the north of Spain and Portugal and in parts of Italy for some time, and they have been steadily moving out from their over-populated strongholds in Eastern Europe and Russia since the lifting of the Iron Curtain. But their arrival in the heart of Europe has kindled a debate that is more commonly associated with rural Africa.

Just how should we deal with wild animals that are endangered and protected but can cause extensive damage to people’s livelihoods? While reports of wolves attacking humans are rare, Austria has recently celebrated the reintroduction of brown bears, and several bears have crossed into Italy from what used to be Yugoslavia. Hunters, farmers, shepherds and conservationists in the Alps are at odds over how to deal with these animals. “Up to now, we have been telling the people in Africa or India whether they were allowed to shoot elephants or tigers when they were a hazard,” says Eric Zimen, who is based in Bavaria and is one of Europe’s foremost experts on wolves. “Now we face the same kind of problem here.”

Conservationists concerned with mammals in Africa, where wildlife management is focused on a system of protected areas, are split roughly into two camps: those who oppose any killing, and those who would allow local people to profit from animals-by selling hunting licences, for example-as an incentive to preserve them.

But many experts say techniques used successfully in Africa, or in Asia or North America, could never work in central Europe. For a start, there is not enough unpopulated land to establish protected areas. And the practice in North America-where wolves have been reintroduced in some areas-of allowing animals to roam freely and shooting them only when they stray too close to built-up areas would not work for the same reason. There is just too little wilderness left.

Zimen says that the only way forward is for people to learn how to coexist with wolves again. Historically, this is precisely what happened. Before the 16th century, wolves survived on wild populations of alpine ibex and deer, says Jean-Marc Landry of KORA, a wildlife think-tank in Berne that is advising the Swiss government. Only when the alpine forests were heavily used for grazing and exploited for wood, and wolves’s natural prey started to disappear, did they begin to harass domestic animals. By the mid-19th century, alpine ibex and red deer had become extinct in Switzerland, and roe deer were becoming scarce. “Wolves were almost forced to feed on sheep,” says Landry.

With the fast improving accuracy of rifles and the development of strychnine, an effective poison, the wolf was wiped out in central Europe by about 1880. It retreated to the eastern fringes of Europe and Russia, where it has survived in large numbers away from civilisation. Now it is moving back, and there are several thousand living west of the former Soviet republics. Luigi Boitiani, an animal behaviourist at the University of Rome who has studied wolves in Italy, says the animals have been living harmoniously with people in the mountainous Abruzze region and even in the heavily populated plains in the north.

But despite suggestions that humans and wolves can live happily together, many farmers would prefer to shoot them to protect their already fragile livelihoods. They cannot legally do this, for the European wolf is protected by the 1979 Berne Convention, which aims to conserve threatened species in their natural habitats. And Boitiani believes killing is unnecessary: sheep can be managed in ways that protect them from wolves.

One way to reduce deaths is to use breeds of sheep that tend to disperse rather than flock together-flocking sheep are easy prey to a wolf, which will often kill more than it can eat in one attack. Another is to use sheepdogs that have been bred to protect sheep from predators. Few farmers in Italy lose sheep that are guarded by dogs. If they do, compensation payments from the government help to calm their anger, and culling wolves is tolerated by the government if a lot of damage is done.

When wolves colonise a new area, farmers soon adapt to protect their flocks, Zimen says. “It is always the same. When they show up in a new area, there is much fuss about them. But later, everything calms down.” For example, when some wolves first reached the Mercantour national park in France in 1992, there were heavy losses of livestock. But this stopped when farmers started using sheepdogs.

Switzerland is planning a similar approach, with compensation for farmers who lose sheep. “We want to live with the wolves,” stresses Philippe Roche, director of the BUWAL, the federal environmental agency. Farmers will need to take the presence of wolves into account when they tend livestock, he says.

Because wild ungulates are relatively numerous in the Alps, wildlife experts expect the wolves to turn to wild prey as soon as the sheep are protected. In Italy, where Boitiani and Zimen successfully reintroduced red deer more than a decade ago, wolves feed primarily on wild animals. Indeed, humans and wolves rarely come into contact. “We’ve seen wolves roaming at two o’clock in the morning on a piazza,” says Zimen. “But the inhabitants didn’t ever notice them. By dawn, they had withdrawn to the mountains.”

So the future for wild mammals in Europe would seem to lie in coexisting with humans rather than in the hunting licences and protected areas used in Africa and Asia. But not all farmers are keen to change the way they manage their animals, and many of them have the backing of local politicians. Indeed, the changes involved are often dramatic. In summer, many flocks roam freely on the alpine slopes. It can take two days to gather a flock and this would be impossible to do every time a wolf is reported, says Jean-René Fornier, Wallis’s minister for security and institutions. But shooting wolves, even if the locals are in favour, is unlikely to get the backing of central government. As Roche points out: “Forty dead sheep are not yet a reason to open fire.”

Bacteria break down pollutants with enzymes. But these enzymes remain within
the cell, so bacteria are ineffective against chemicals that cannot enter the
cell, such as those with molecules too large to pass through the cell
membrane.

When white rot fungi (Trametes versicolor) are starved of food, however, they
release enzymes outside their bodies. These enzymes are usually less specific
than bacterial ones, so they could be used to tackle a wider range of
pollutants. Erich Leidig of Karlsruhe University in Germany found that white rot
fungus broke down 90 per cent of a dye, poly-R-4-78, commonly used to test
decontamination techniques.

One reason fungi have not been used in this way before is that in an open
environment they lose out to bacteria, which feed on them. Leidig, however, has
found that he can protect the fungus from bacteria by encapsulating it in
hydrogel—permeable to water and the fungus’s enzymes, but not to
bacteria.

Leidig says it would probably be most useful for cleaning waste water from
the paper industry, which contains high levels of cellulose, a nutrient that is
not decomposed by bacteria.

Christian Wolter of the Institute of Freshwater Ecology and Inland Fisheries
in Berlin and his team have been monitoring fish in the river Oder on the border
between Germany and Poland since it broke its banks last year, in its biggest
flood this century. They found that while no fish populations were permanently
damaged, the number of young fish of some species decreased dramatically.

Between 80 and 90 per cent of the roach and common bream that hatched last
year were washed out to sea or died of starvation in the flood, compared with a
natural mortality rate over a year of about 50 per cent. “Both species are well
adapted to a wide range of water speeds, but the current in the mainstream Oder
was too much for them,” says Wolter.

The fish could not find enough food as they fought the currents. The flood
washed away sediments that hold invertebrates on which several species depend.
In addition, some young fish that had hatched in streams failed to find their
way up the river because the flood gates were shut.

But some fish benefited from the flood. Chub, dace and pikeperch, which live
in parts of the river where the current is stronger, thrived because the high
water removed other species with which they compete for food. “[Food shortage]
affected all species, but those that tolerate higher water velocity were also
able to forage a wider range of habitats in the flooding river,” says Wolter.
“Their [feeding] and reproductive behaviour is adapted to flooding.”

The researchers even found a species not seen in the lower Oder
before—the whitefin gudgeon. They believe the flood created new habitats
for it.

The team concludes that the regular flooding of lowlands helps a number of
fish species to survive. Spring floodings create shallow waters that provide
ideal breeding conditions for several species. Most river fish are adapted to
spring floods and reproduce early in the season, relying on currents to wash the
fry out to flooded areas, says Wolter.

He suggests that instead of repairing the dykes in the Oder National Park,
where people were not at risk, the area should have been allowed to flood
naturally. This, he argues, is what a national park devoted to the protection of
a river ecosystem is all about.