Plant seeds can remain viable in a cold and dry environment for long periods. There are currently a number of long-term seed storage facilities around the world which use refrigeration equipment or natural cold with further artificial cooling to maintain desired temperatures. Their disadvantages are high power demands and the risk of collection loss due to power failure. An alternative strategy is to rely solely on the natural cold without using any machines or mechanisms.
A 30-year experimental study carried out by the Institute of Biological Problems of the Cryolithozone (IBPC) and the Melnikov Permafrost Institute (MPI) with the long-term seed storage in permafrost under a wide range of subzero temperatures suggests that temperatures of -6° to -8°C are optimal for maintaining the viability and genetic integrity of seeds. Such low ground temperatures are only found in the northern areas, and additional cooling to reduce permafrost temperatures is required elsewhere. Ambient air is a readily available source of natural cold when its temperature in winter becomes colder than that of the ground.
In November 2012, the Melnikov Permafrost Institute completed the construction of a seed repository in permafrost. The facility, situated in the grounds of MPI at Yakutsk, consists of a storage room, two vertical shafts and surface buildings. The storage room, 32 m in length and 4 m in width, is located at a depth of 9.15 m. Shelving racks for seed storage containers total 90 sq. m in area. The vertical shafts are equipped with stairs and a service lift. The enclosing frozen ground has a natural temperature of -2.5°C; therefore a self-powered cooling system is used to achieve the required temperatures. The system based on natural air convection consists of two loops operating independently in summer and winter. During the summer period, temperature in the repository is controlled by an innovative method of accumulating the winter cold in near-surface frozen ground.
After ground temperature stabilization, the repository will start accepting seeds for long-term storage. Initially it will store the IBPC’s collection of Yakutian native seeds, but in the future it is expected to grow to a national seed bank.
The project is supported by the Yakutia/Sakha Government and the Siberian Branch of the Russian Academy of Sciences.