Over The Horizon

Studying Lakes in Siberia

A Lincoln University soil scientist recently took part in an international interdisciplinary study of the depths of Lake Baikal, the world's oldest lake, in Siberia. Bob Leonard joined US and Russian scientists in examining the lake's water, aquatic life, ecosystems and physical structure.

"Lake Baikal, the jewel of Siberia, is a remarkable rift lake", says Leonard. "It is estimated to be 20 million years old -- the world's oldest -- and it is also the deepest lake, at 1,637 metres."

Within the huge 23,000 cubic kilometre volume of the lake's fresh waters are found over 1,500 endemic aquatic species of plants and animals, including sponges and seals. The summer expedition conducted studies of sponge physiology and influence on phytoplankton, lake water quality and physical properties, and wetland influence on tributary water quality.

The influence of Baikal's sponges on phytoplankton and water chemistry in the littoral zone -- the shallow area around a lake shore where the light penetrates to the bottom --  was investigated. The studies used on-site incubation chambers developed for marine studies at the Virgina Institute of Marine Sciences.

"This was the first opportunity for the Virginia scientists to deploy their chambers in a fresh water sponge community," says Leonard. A remotely operated vehicle (ROV) with television cameras was brought to Baikal by a US scientist specifically to complement the sponge studies. The ROV was used to conduct surveys of sponge coverage of the littoral zone in several areas of the lake. Species, density and depth distribution could be determined where scuba diving was not possible.

A team from the University of California at Davis focussed on water quality studies. Vertical profiles, some to depths of 500 metres, were monitored at eleven open water stations. These covered the entire 636-kilometre length of the lake, and provided data on temperature, conductivity, dissolved oxygen, pH, and chlorophyll fluorescence. Water samples were taken for chemical and phytoplankton analysis.

Optical properties of the lake waters were measured along with temperature and depth using a custom-built instrument called the "Tow Yo", provided by the Stanford Research Institute International. The Tow Yo contains an array of different light sensors and was towed at variable depths through regions of the lake of particular interest in water circulation studies. Data was monitored in real-time and recorded by ship-board computer.

Siberia is a region of vast wetlands. A tributary of Lake Baikal, the Barguzin River, drains a large wetland measuring some 30 kilometres by 200 km, which was once a rift lake itself.

The natural resources of Siberia include minerals, timber, soil, wildlife, and water. Lake Baikal alone is the repository of 80% of Russia's fresh water.

The Baikal International Centre for Ecological Research (BICER), founded in 1990, is a non-governmental interdisciplinary institute open to scientists of all nations interested in cooperation with Russian scientists in research on Lake Baikal. Leonard is assessing scientific interest in BICER membership for New Zealand, hoping that local scientists can become involved at Lake Baikal and the greater Siberian region.

"International ecological research, cooperation and funding can help the Russians to protect their environment as pressures for exploitation of natural resources increase," he says.