From their genomes, you can identify evolutionary adaptations used by haloarchaea to colonise their environment. For the Deep Lake community, life proceeds in slow motion. In laboratory conditions at -1°C (the temperature at the surface of the lake), the haloarchaea divide only six times per year, a glacial pace compared to E. coli, which divides every 20 minutes.

However, in the close quarters of Deep Lake, a very distinctive evolutionary element is at play. The Antarctic haloarchaea are quite promiscuous, engaging in a high rate of gene swapping across the lake’s species. This bartering of genetic information between distinct species is an infrequent occurrence in other environments. However, despite this genetic exchange, the microbial community does not homogenise; haloarchaeal species still retain their unique genetic identity.

The reason may lie in their environment. In a habitat that offers very limited options, each species co-exists in their respective ecological niches. Each haloarchaea is partitioned off by what seem to be evolutionary barriers, such as their optimal temperatures and their metabolic pathways.

As isolated as Deep Lake is, Prof Cavicchioli emphasises that it is a microcosm that represents the importance of maintaining and preserving microbial diversity on a much larger scale, especially their contribution to the nutrient cycle. “The world is largely microbial, and they perform critical roles,” he said. “Environmental microorganisms perform roles in life that no other organism can do.”

Cold environments below 5ºC, including the ocean, represent a vast bulk of the planet, around 85%, and from an anthropocentric viewpoint it is far too cold for us to colonise. However, these environments are dominated by microbes. In fact, 95% of the ocean’s biomass is microbial.

To ask ecologically relevant questions about extremophiles, we need to remember that the word ‘extreme’ is used from an anthropocentric standpoint. Extremophiles were named by humans and thus defined by what are considered extreme conditions from our perspective. Transplant an extremophile usually content in the heat of the hydrothermal vent to room temperature, and the sheer shock would probably kill it. The terms ‘extreme’ and ‘stress’ are relative; extremophiles are in their natural state and thrive within their own specialties and ecological niches.

Recent attention has turned to cellular components of extremophilic archaeal cells that might be appropriated for biotechnology or industrial purposes. Extremophile enzymes that can withstand high temperature processes have an indispensable presence in laboratories. Taq polymerase and Pfu DNA polymerase, two essential enzymes in polymerase chain reaction, a technique that revolutionised forensic science and hereditary testing, have their origins in heat-loving extremophiles.