Scientists brave the Namib elements to find the secret to life on other planets
It is 7am and the merciless desert sun is already baking overhead. The mercury will climb up to 40°C, and yet Don Cowan, a professor of genetics at the University of Pretoria, dressed in a golf shirt, shorts and sun hat, has a huge grin on his face, as though there is nowhere in the world he would rather be.
This is one of the most extreme environments on Earth, with very little water and temperatures that would kill most animals. It is the first day of his team’s annual expedition in the Namib desert, and by searching for and analysing tiny organisms such as bacteria and viruses they will piece together the microscopic story of this world heritage site. It continues to keep secrets from the international and local researchers who have spent decades studying its mysteries, some of which may help us to find life on other planets.
Smelling of suntan lotion, people are getting into four 4x4s to go to different projects: taking samples from the mysterious fairy circles where nothing will grow; collecting soil in a desert transect to investigate both what organisms live in it and the water content; others to the salt pans; or to look for hypoliths – communities of photosynthetic bacteria that live under rocks.
One thread of the Namib’s story begins in the Lesotho mountains, from which soil travels more than 2 000km down the Orange River into the sea on the west coast.
The sand is pulled north by the irresistible Benguela Current and blown back inland, forming the famous dunes of Namibia under the escarpment. The Gobabeb Research Centre, 120km from Walvis Bay, is in a unique location. It is the meeting place of the dune seas to the south, the hyper-arid plains to the north, and the ephemeral Kuiseb River whose dry bed lies behind the centre. Formerly home to a Topnaar community and called !Nomabeb, which means “place of the fig tree”, Gobabeb is now a hotbed of, inter alia, biological, geological and environmental research.
Chris McKay, a senior scientist at Nasa’s Ames Exploration Centre in California, has been going to Gobabeb for a number of years, and invited Cowan. McKay tells the Mail & Guardian that he is not interested in the desert ecology, but rather in its role “as a guide to life in desert worlds like Mars”. The hypoliths – found under many of the quartz rocks in the hyper-arid plains, often just a line of green coated on its base – could hold the secret to life on other planets. They are technically called “extremophiles”, organisms that thrive in extreme environments that would kill most other life forms.
“We’re interested in extremophiles … because of their implications for astrobiology,” says McKay, whose work focuses on desert systems, including the Namib and the Atacama Desert in Chile.
“For life, there must be an organism at the base of the food chain, a primary producer. In the deserts, we focused on photosynthesis [a process whereby sunlight is converted into chemical energy in plants] … the ability [of organisms] to produce biomass in the desert. Not importing it, but producing it locally,” he says.
On Mars, there is nowhere to “import” these base organisms from, so that is why scientists are looking at how they survive on Earth in these extreme environments.
Wits University’s Professor Duncan Mitchell, a conservation physiologist, has been going to Gobabeb for more than 30 years, and he believes that Nasa’s programme is sensible. “If you’re going to find life on Mars,” he says, “it’s not going to be a zebra.” They are asking “what type of life would survive in harsh environments … that means you don’t waste your time on Mars looking for things that are completely out of line with what is possible”.
As the sun moves higher into the sky, it is a wonder that anything can live in the desert – heat haze shimmers on the horizon, turning it into an undulating line. But the researchers in Cowan’s team – some international tenured professors, others master’s students – are out in the field, collecting drums filled with sand, measuring soil temperatures and placing sensors to measure water content in different parts of the Namib.
Vincent Scola, one of Cowan’s master’s students, has undertaken a transect of the desert – taking soil samples at regular intervals across 120km from the coast to the mountains, Cowan says, wiping beads of sweat from his forehead. “We’re getting huge changes in the microbial community structure as we go through the salty coast to the hyper-arid zone to the grassy arid areas to the wet mountains ... It’s going to be a story we can tell, as good scientists tell stories, in a really good article, in a good journal.”
He says the word “story” means something different to scientists: “It’s a narrative, where we have asked questions, formed hypotheses, tested those hypotheses that have still worked and come up with answers.”
If you ask questions of any researcher who has worked at Gobabeb in the past 40 years, they will say: “Have you spoken to Mary?”
American scientist Mary Seely, who first came to the centre as a postdoctoral student in 1967, is acknowledged as one of the world’s leading desert ecologists.
Although technically retired, 75-year-old Seely remains actively involved in research at Gobabeb, and her interest at the moment is the fog system. “The Namib desert is a unique coastal fog desert, with the largest sand dunes influenced by fog. There are coastal fog deserts on all continents, but they don’t have the same dune extent nor are they isolated below a large escarpment [like the Namib].”
But is climate change affecting the desert’s fog and all of the organisms and creatures that rely on it? “That’s a good question,” says Seely in her characteristic no-nonsense tone. “We don’t know.” She is involved in the German-funded FogNet project, which aims to understand how the fog system operates in the Namib.
She has also been instrumental in setting up FogLife, with funding from the joint South Africa-Namibia project.
“We intend to revisit the more than 1 000 publications from Gobabeb and see which ones could be profitably revisited to see if there are changes through time and against climate change,” says Seely. “With the change in fog, what is going to happen to this fog-dependent ecosystem? Because everything we’re talking about here is dependent on the fog to some degree or another.”
Sitting on the veranda of one of Gobabeb’s buildings, Seely talks with a distinctive American drawl, even though she has been living at the centre, or in Windhoek, for decades. This acknowledged Gobabeb expert originally wanted to be a forester. “I could have studied the four-year forestry course, but I wouldn’t have been able to become a forester because I couldn’t go on the third-year summer holiday, because I’m female.” She smiles wryly: “I was born in the pre-Jane Goodall era.”
When she was appointed director of the centre in 1970, similar sentiments from men in nearby towns made her job difficult. “It was crazy,” Seely says. “Because we had a gender balance [among researchers] like we do now, the rumour got out that Mary was running a brothel.”
She chuckles: “Men from the towns actually came down here [to Gobabeb] and stayed down at the camping site and would come to the research centre, one at a time,” enquiring about sexual services.
Asked why she stayed, Seely, originally trained as a biochemist, says: “If I’d gone back to the [United] States, what would I have done? Worked on the back hind leg of a lizard? Here, I get to do all sorts of things. I’ve worked with all sorts of incredible people. Don is just one example of the many, many people who come here from all over the globe to do interesting things.”
Mitchell, who is collaborating with Seely on FogLife, says that he first came to the Namib to study lizards, but “got addicted”. He visits the centre two or three times a year. “The Namib is unique,” he says. The animals here “swim” in the sand, something that is not found in any other desert in the world.
The sand in the dunes is so clean and “polished” by the wind that it sits in dunes like marbles, allowing animals to breathe in the air between the sand grains, Mitchell says. “Animals wouldn’t sand swim in any other desert.” He likens research in the Namib to being a doctor in a hospital’s emergency room: “The lessons you learn there in that cauldron, you can take anywhere. From a conservation physiologist’s perspective, if you understand the Namib desert, you can understand arid regions everywhere.”
Cars start returning to the centre, and red-faced and strangely elated scientists spill out into the cooling evening air.
Tomorrow, they will go back on to the arid plains, the sand seas and the salt plains, and find more evidence to tell the story of this desert.
As the sun crawls into the western horizon, the vast plains in front of Gobabeb, the centre’s iconic water tower, and the majestic towering dunes behind it glow red, making it easy to believe that the research centre is in fact on a different planet.
From the ‘ground zero’ of Africa’s ecological researchRaw nature: The Namib desert is a hotbed of biological, geological and environmental research by scientists from all over the world. Dr Eoin Gunnigle (right) is taking notes, while Dr Jean-Bapiste Ramond buries sensors on the periphery of a fairy circle. Photos: Don Cowan and Sarah Wild