The Word Lake Baikal

New Scientist vol 175 issue 2358 - 31 August 2002, page 47

"If you are stopped suddenly by a penetrating blue and your heart stops, as sometimes happened only in childhood, from astonishment and delight... it means, this is Baikal." The words of poet Mark Sergeev capture Russian feelings about their great lake. It b a wonder in statistics too: it is the deepest (1637 metres) and oldest (about 20 million years) lake in the world, containing a fifth of the fresh surface water on the planet (23 thousand billion cubk metres) and lull of creatures more than 2000 of them found nowhere else.

Why get excited about it now? Because, astoundingly, Baikal is growing even bigger. Usually, lakes gradually fill with sediment. But Russian scientists based in Irkutsk have found that Baikal is growing at four times the rate at which it is being silted up, which makes it very unusual.

What is making Baikal grow? First, the lake is growing wider. It sits in a huge rift valley and its sides are gradually moving apart Although it is widening by only five millimetres a year, multiply that by rts depth and 636-kilometre length and you get an extra 20 million cubk metres of water a year. The lake is also growing deeper. The area is seismkally active and monitoring stations around and within the lake pick up more than 2000 earthquakes each year. Some of these can have drastic effects on the lake floor: in 1959 it dropped by 20 metres, at a stroke increasing the volume of the basin by 200 million cubic metres.

What about all those unique species? Lake Baikal is known as the "Galapagos of Russia" and is probably the most biologically diverse lake in the world: more than 1000 species of aquatic plants, 56 types of fish, 300 protozoans - and entire groups that haven't yet been studied.

The highlights? We are especially fond of the Baikal turbellaria, multicoloured worms that grow up to 30 centimetres long and live on the lake floor. They feed by paralysing their victims, enveloping them in mucus and slowly swallowing them.

Perhaps the most extraordinary fish is the golomyanka, which looks rather like a high-speed train with its long sloping head. It can endure the immense pressures at the very bottom of the lake, swimming freely where - according to local scientists - you'd have trouble firing a cannon ball.

Then there's the Baikal seal, or nerpa, which can dive to 300 metres and go for 70 minutes between breaths. The nerpa's nearest relatives are several thousand kilometres away, which raises the question, how did it get to Baikal?

Luckily, Baikal is not only growing bigger but remains mostly free of pollution. You can even buy bottled Baikal water. Let's raise our glasses and wish the lake a long and healthy future.

New Scientist

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