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PERESTROIKA has reached the bottom of the planet’s deepest, oldest and
most remarkable lake, Baikal. Thanks to President Gorbachov’s policies,
scientists from all over the world are joining their Soviet counterparts
in an ambitious research programme to unlock the secrets of Eurasia’s biggest
lake.

To the local native people, the traditionally Buddhist and shamanist
Buryats, Baikal is literally a holy sea and a spiritual entity. To Russians
and particularly to Siberians, who have long sung of ‘sacred Baikal, the
glorious sea’, the lake is famous and venerated as no other part of their
huge land for its unspoilt beauty, made even more dramatic by the forests
and mountains around its rim. And, until the disasters at Chernobyl and
the catastrophic shrinking of the Aral Sea, Baikal’s environmental problems
– largely from industrial effluent – were by far the most emotive in the
Soviet Union.

Unquestionably, this rift valley crescent, nearly 650 kilometres long,
is the planet’s most interesting lake: it is the oldest at between 20 and
25 million – possibly even 50 million – years old. Excluding only Lake Tanganyika,
which is around 2 million years old, all other lakes are less than 20,000
years old. Baikal is also the deepest of lakes, at 1637 metres. Although
only the seventh largest in the world at 34,000 square kilometres, it is
still bigger than Belgium. Because of its combination of surface and depth,
however, Lake Baikal contains the world’s largest volume of surface freshwater
– more than that of North America’s five Great Lakes.

Some 300 tributaries, large and small (and underground), add continuously
to Baikal’s waters, but the lake has only one outlet, the Angara River.
Not surprisingly, the enormous power of the Angara is harnessed by a chain
of hydroelectric stations. Ecologically, Baikal is the Soviet Union’s most
interesting – and unique – ecosystem, with the richest lake life in terms
of both biomass and the number of recorded species – 1550 species and variants
of animals and 1085 of plants – of which more than 1000 are found nowhere
else. At the bottom of the lake is an extraordinarily deep layer of sediment.
In some places the depth from surface to bedrock is more than 7 kilometres,
almost seven times as deep as the Grand Canyon and by far the planet’s greatest
depression on land. This depression is the central section of a rift zone
1000 kilometres long. The movements of the Earth’s crust here are widening
Baikal by around 2 centimetres a year.

Although research into the lake began in the 18th century, modern scientific
studies really started in 1918, when a permanent scientific station was
set up near the Angara outflow. That station has since evolved into the
Limnological Institute of the Siberian Branch of the Academy of Sciences.
In the decades since then, more than 1400 scientific papers on Baikal have
been published. Mikhail Grachev, a chemist who specialises in nucleic acids,
became the director of the institute in 1986 and last year moved the research
and staff to a still incomplete new building in the city of Irkutsk.

Last October, with the backing of Valentin Koptyug, then President of
the Siberian Department of the Academy of Sciences, Grachev organised a
conference that laid the foundations for a new research centre, the Baikal
International Centre for Ecological Research (BICER). The centre will be
as remarkable as the subject of its research for it will have an international
board of directors and will open up an area of study to foreign scientists
in a way that would have been inconceivable 10 years ago. The venture is
ambitious and innovative with Grachev thinking big in true Soviet scientific
style: he has envisaged not only a large new laboratory and aquaria but
also an international telecommunications centre, a computer centre linked
to world databases, a new port and accommodation for 1000 staff.

The Siberian Department of the Academy has already given 5 million roubles
(around Pounds sterling 5 million) and has promised to match foreign contributions
with roubles. Initially the idea was that foreign scientific institutions
would contribute $500,000 to become founding members of the centre; ordinary
members would contribute $100,000. But Western science institutions have
failed to find that much money.

The only realistic alternative is to attract funds from foreign governments
rather than individual institutions. So, in April, Grachev arranged a fourth
international meeting, in Irkutsk, this time backed and chaired by the Soviet
Ministry of Foreign Affairs. France, Belgium, the Netherlands, Switzerland,
China, Japan, the US and Britain sent scientific and governmental representatives.

Britain’s Royal Society has played an active role in the venture from
the start, sending representatives to all the meetings, supporting visits
by British scientists and forming an ad hoc committee especially concerned
with Baikal. The society’s president, Sir George Porter, visited Baikal
in December and signed an agreement with the Academy of Sciences for scientific
collaboration on the lake.

The Royal Society now has many links with scientists in the Soviet Union
and is involved in some 30 or 40 projects, most of them in Moscow and Leningrad.
But the society attaches special importance to the Baikal link, which involves
both fundamental science and environmental issues. ‘Baikal is a wonderful
opportunity,’ says Stephen Cox, the society’s assistant secretary for international
affairs. This year at least four British scientists will be working at Baikal.
In 5 years’ time, Cox expects to see 20 or more.

This summer, Patrick Denny and two of his colleagues at the Centre for
Research in Aquatic Biology (CRAB), part of the University of London’s Queen
Mary and Westfield College, will begin work at Baikal. Denny, a specialist
in water plants, and Jim Green, a freshwater ecologist, who have both worked
on lakes in Africa’s Rift Valley, will begin two projects: the first is
an analysis of the interface of Baikal’s open water with its deltas, inflows
and bays. The physics and chemistry of these waters differ considerably
from those of the open lake. The plants and animals are different, too,
having more in common with species in the surrounding region than with those
characteristic of Baikal itself.

Denny’s second project involves measuring the production of orangey-red
pigments (carotenoids) by Baikal’s planktonic plants and following their
progress through the food chain. For this Baikal offers a simple community
of planktonic organisms in which to measure production of the pigments,
and a complex web of organisms on the lake floor in which to follow the
fate of the pigments. These bottom-dwelling animals include endemic sponges
and a range of amphipods, some bright red with carotenoids, some pale and
almost free of any pigment.

Baikal, it seems, has everything to offer the scientist. But its interest
lies in different areas depending on which scientist you talk to. ‘It is
without question the most scientifically interesting lake of all, with so
many unique features – a list as long as your arm,’ says Green. ‘But the
really unique thing about it is its circulation right down to that tremendous
depth.’ The only other comparable lakes, Tanganyika and Malawi, are not
as deep and are virtually lifeless below 200 to 300 metres. In contrast,
the circulation in Lake Baikal carries oxygen to the very bottom, where
even at a depth of more than 1600 metres, there is a flourishing community
of animals.

According to Green, the most interesting question about Baikal is what
drives this enormously deep circulation. ‘The answer may be partly its large
size, long wind fetch and deep stir to incredible depth, plus the ice dynamics
when the melting ice sinks, but they don’t explain all the mixing.’

The other really absorbing factor for many scientists is Baikal’s enormous
range of endemic species. An average European lake might have three species
of shrimp-like amphipods and eight of flatworms; Baikal has 255 amphipods
and 80 flatworms. (One flatworm, a giant at 40 centimetres, is the world’s
largest and eats fish.) It would be exceptional for any lake to have more
than a few species of cottoid fish (bullheads); Baikal, remarkably, has
22.

To David Hunt, the third member of the team from CRAB, the most unique
thing about Baikal is the evolutionary radiation of some of its species.
‘Now that science can look at evolution at a molecular level, Baikal’s 200-odd
endemic species of freshwater shrimps provide a wonderful chance of looking
at a species radiation never studied in this way before.’

Evolution within lakes is a long-established interest of the Natural
History Museum in London. Geoffrey Boxshall, an invertebrate zoologist at
the museum, will study the tiny planktonic copepod crustaceans at Baikal
this summer. ‘The lake presents a superb opportunity to look at the mechanism
of evolution and the origin of species over many millions of years,’ he
enthuses. In many great lakes a fraction of the animals have undergone an
explosive speciation – the cichlid fishes in Lake Victoria, for instance.
‘But in Baikal nearly everything’s undergone an evolutionary explosion .
. . including the copepods.’

From the US, the National Geographic Society is sponsoring a long-term
research programme and has funded four projects for this summer involving
some 20 scientists in joint Soviet-American teams. Geochemists and microbiologists,
for instance, will try to find out what controls the cycling of nutrients
in the delta of the Selenga River, Baikal’s largest tributary. One investigation
concerns the possibility that there are hot water vents on the lake bed
similar to the hydrothermal vents of the deep ocean.

Last year, Soviet scientists did find localised, uneven heat entering
the lake. Such geothermal heating, escaping from hot rocks, could help to
explain Baikal’s deep circulation. If this year’s investigators can locate
hot water vents, there is also a chance that they will find whole communities
of animals new to science as has been the case with vents in the deep sea.

One American expert on lakes, Charles Goldman, of the University of
California at Davis, proposes an intensive survey of Baikal. With four colleagues
he aims to apply experimental approaches developed over 30 years at California’s
Lake Tahoe to evaluate which chemical and physical factors control Baikal’s
productivity, what effects the inputs from various watersheds around the
lake have, and to what extent human activity is affecting the ecosystem.

Changing focus to the very specific, Goldman’s team has picked on a
small shrimp-like creature, the amphipod Macrohectopus branickii, which
plays a prominent part in the food web of the open lake. This amphipod bears
a remarkable resemblance to the predatory opossum shrimp Mysis relicta,
introduced to Lake Tahoe in the 1960s in an attempt to improve the fishery
for trout and salmon. Unfortunately, the opposum shrimp destroyed the population
of two of the lake’s native species of zooplankton – ‘a good example,’ said
Goldman, ‘of trying to enhance the food chain and producing just the opposite
effect’. Goldman and his colleagues want to compare the relationship between
the opossum shrimp and its prey in Lake Tahoe, where the predator is a new
invader, with that of the amphipod in Lake Baikal, where predator and prey
have evolved together.

Perhaps the most important of all the joint programmes at the lake is
the ‘Baikal drilling project’ (BDP), which involves scientists from seven
countries: the Soviet Union, the US, Britain, West Germany, the Netherlands,
China and Japan. The project has two main objectives: to understand the
evolution of the lake’s ecosystem, and to chart the climatic history of
north-central Asia from Baikal’s sedimentary record. For at the bottom of
the lake, under more than 1.5 kilometres of water, lies an accumulation
of sediment more than 5 kilometres deep. This layer of sediment was deposited
over tens of millions of years and has never been disrupted by glaciation.
In theory, it should record the changes in geology, climate and biology
over that span of time. The mineral and geochemical composition of cores
of sediment will mirror the geological evolution of the Baikal region and
its tectonic history. Fossil remains of microscopic plants and pollen –
and perhaps molluscs – will provide a history of the ecosystem and how it
has responded to changes in the climate of northern Asia.

Last summer, Soviet geophysicists obtained 15 profiles of the lake’s
bed and bedrock, covering about 1500 kilometres using the technique of seismic
profiling. Another group of researchers from the University of Hamburg collected
a further 1300 kilometres of profile. These profiles will provide a view
of how the deep depressions that make up Lake Baikal developed. The rift
valley here is formed by tectonic movements: the part of Asia, northwest
of Baikal, known as the Siberian platform, is literally being forced apart
from the other parts of Asia, southeast of Baikal, by huge forces in the
Earth’s mantle. Seismic profiling can provide fundamental information on
the process before any attempts are made at deep drilling.

This year, too, scientists from the US Geological Survey and from American
universities will join Soviet researchers in collecting sediment cores.
Already, scientists know that the rate at which sediment is laid down in
the lake varies dramatically from year to year and from place to place;
in one area a five-metre core can represent 30 000 years, in another perhaps
as much as a million. These studies will also involve the most advanced
dating techniques to measure precisely the rate at which the sediment was
laid down in different parts of the lake.

The geologists will move out of the water and onto land in an attempt
to plot the course of Baikal’s early history. Next year, scientists at the
Soviet Ministry of Geology and the Academy of Sciences plan to drill into
the sediment of the adjoining Tunka river valley, once part of the Tunkin
lake basin. After analysing this second and longer climate record, which
extends through 3 kilometres of sediment, the team will turn to the ‘deep
water history’ of Baikal – drilling through 5 kilometres of sediment in
the present lake.

Ocean drilling ships with the technology to do this already exist, but
not at Baikal, so a drilling platform is being designed for use in three
years’ time. These cores should provide evidence of climatic changes over
some 30 million years, making a massive contribution to the record of climatic
change both on the continent and globally.

Despite the lake’s depth and age, some Western scientists believe that
its sediment will be disappointingly uninformative. They say the sediment
contains very little organic material, which is essential for understanding
the biological evolution of the lake, or calcium carbonate, which is an
important indicator of past temperature. Organic material trapped in sediments
has a molecular ‘fingerprint’ that identifies the type of organism it came
from. Carbonate laid down by living organisms such as molluscs or ostracods
(seed shrimps) contains in its matrix a ratio of stable isotopes of oxygen
that varies depending on the temperature of the water.

Douglas Williams, of the University of South Carolina, and a guiding
light of the drilling project scotches these pessimistic beliefs. He has
found calcium carbonate, in the form of calcite, in almost every core sample
from the north of the lake. The origin of this calcite is unclear. According
to Williams it does not seem to have been produced biologically, but it
might be the result of weathering of biological carbonate deposited in the
lake much earlier.

Williams has also found as much as 4 per cent of organic carbon in core
samples, an extremely high figure, either for lakes or for the oceans. The
amount of carbonate and organic material in the sediment fluctuates dramatically.
Williams believes that these fluctuations correspond to changes in the climate.
High concentrations of organic material correspond to times when the productivity
of plankton was high – when the climate was warm and there was also plenty
of light.

Last summer, Williams was shown sedimentary outcrops up to 8 million
years old which were originally underwater. Some layers contained large
amounts of organic carbon, showing that productivity was higher when these
sediments were laid down than it is today. Along with many foreign scientists,
Williams has ambitions to go to the bottom of Lake Baikal this summer in
one of two submersibles lent by the Institute of Oceanology, in Moscow.
Observations made during these dives, and photographs taken from the submersibles,
will provide direct evidence for processes at the bottom of the lake. In
5 or 10 years’ time, scientists may be able to build a picture of Baikal’s
long history, and at the same time supply some of the missing pieces in
the jigsaw puzzles of the Earth’s evolution and geology.

John Massey Stewart is a freelance writer specialising in Siberia. He
is working on a book on Siberian natural history, geography and environmental
problems.

Next week John Massey Stewart discusses environmental problems at Baikal.