22-04-2025
The Svalbard Global Seed Vault is humanity's safety net for food security
Deep in the Arctic Circle, approximately 800km from the North Pole, lies Svalbard, a Norwegian archipelago. Here, one finds Earth's northernmost permanent human settlements.
It is also the location of the Svalbard Global Seed Vault (SGSV), a natural freezer, and home to a growing number — more than 1.3 million — of seed samples from around the world.
These seeds have been carefully selected to ensure humanity's food security in the face of a rapidly changing climate and global conflicts. The loss of a food species and the genes associated with millennia of selective breeding is irreversible.
The destruction caused by climate change and conflicts has made it more urgent for us to preserve valuable seeds for our survival in an unpredictable world.
A selection of seeds of almost every important crop variety is found in the SGSV, with donations made from seed banks around the world. Given its location and temperature, seeds deposited at the SGSV are treated and maintained in conditions that ensure they remain viable for long periods.
Last year was a particularly active year for the SGSV. In May 2024, just over 20,000 samples from 15 gene banks across the world were received by the vault for storage. And in October 2024, another 30,000 samples were received from 23 gene banks. The list of contributing countries and institutions is impressive.
There has also been a move to store seeds from regions that are destabilised by conflict. For example, seeds of at least 21 species of legumes, vegetables and herbs from Israeli-occupied Palestinian territories were deposited at the SGSV, given the widespread destruction over the last year.
The seed vault also expects submissions from Sudan, where civil war has placed an almost unprecedented risk on food security and a further loss of crop security.
During the escalation of bombing in Aleppo in 2012, for example, the gene bank in the region was unable to operate. It then turned to the SGSV, where important seeds of the region had already been stored.
Withdrawing this valuable resource from the SGSV allowed for the re-establishment of seed banks in other areas (such as Morocco) with similar climatic conditions and the seeds' subsequent reintroduction to markets. This ensures that the valuable genes preserved in the seeds are not lost forever.
Freezing conditions
Storing seeds in the SGSV under freezing conditions is no simple matter. Not all seeds can be frozen, and not all frozen seeds remain viable after thawing.
Only those seeds that are referred to as 'orthodox' are minimally affected by freezing. These can be frozen for extended periods without losing their viability. Once thawed, these seeds readily germinate. There is a highly complicated and sophisticated physiological system that allows such seeds to withstand freezing.
On the other hand, however, there are numerous seeds that cannot be frozen. The problem is that seeds contain varying, but significant amounts of water. Unless seeds can manage this water and dehydrate without damage, they cannot be stored by freezing.
When water freezes, it expands and forms ice crystals. This is very destructive to seeds, and one can imagine the ice crystals piercing cellular structures, expanding and bursting the cells that make up the seeds, killing the seed or damaging them irreparably. For these seeds, storing in the SGSV is not a simple option.
This is where our research comes in. We are plant biotechnologists, and a part of our work seeks to understand the physiology and biochemistry that controls freezing, stress, water management and storage of seeds.
We have focused on developing methods to store seeds under varying conditions, including freezing. Among the species that have dominated our work have been those that are highly nutritious but underutilised for food security in South Africa, like Amaranthus dubius (locally referred to as imfino).
Little was known about the storage behaviour of this species until our work. The species is widely available and grows readily, making it ideal as a crop to hedge against food insecurity. It is therefore critical that such local species form part of the collection at the SGSV.
By understanding the mechanisms that allow Amaranthus seeds to be frozen and remain viable, we hope to be able to extend this knowledge to a variety of other indigenous, high-value, but underutilised crops.
Through a series of experiments and steps, we have been able to support Amaranthus seeds to prepare for long-term cold storage by managing dehydration, slowing down seed metabolism, and surviving freezing in liquid nitrogen.
Once thawed, these seeds can germinate into fully functional plants.
Throughout this process, we carefully monitored the genes that code for seed survival under such stressful conditions, and are now in a position to identify and monitor similar genes across many other species.
With this growing body of knowledge, we aim to form a collection of indigenous seeds that can form part of a local collection for deposit at the SGSV.
In resource-constrained settings, it is practical to store some seeds for the medium term in a refrigerator, or even at room temperature. This strategy is viable, cost-effective and can support smallholder farmers in conserving seeds for local food production.
However, if longer-term storage is required for security against climate change or unforeseen disruptions, cryogenic (frozen) storage is necessary, and the SGSV is the most feasible and cost-effective option for global conservation.
This will not only contribute to protecting biodiversity but will also ensure that future generations have access to a resilient and nutritionally rich food supply, no matter what uncertainties lie ahead. DM
Prof Muhammad Nakhooda is an associate professor of biotechnology at the Cape Peninsula University of Technology (CPUT).
Dr Shakira Shaik is a plant biotechnologist at the University of KwaZulu-Natal's School of Life Sciences. Her specialised expertise lies in bioreactor technology and cryopreservation techniques, with particular emphasis on underutilised crops, medicinal plants and species facing vulnerability or endangerment.
