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    Threatened Mexican oasis loses its main researcher and protector — will it survive?

    On a warm day in March, ecologist Valeria Souza went into a temazcal, or sweat lodge, in Texcoco, Mexico, to pray for the wetlands that she had been studying in the Chihuahuan Desert for the past quarter of a century. She had been performing this shamanic ceremony for years, asking for guidance to help save the scientifically treasured basin in the northern reaches of the country — known as Cuatro Ciénegas — from human exploitation. But this time was different.
    Mexico is seeding clouds to make rain — scientists aren’t sure it works
    Souza, the region’s lead scientist, based at the National Autonomous University of Mexico in Mexico City, instead asked for permission to step away and forgiveness that she couldn’t do more. Despite the fight she’d put up, farmers and other local residents have been slowly draining water from the area for their crops and other sustenance. This has led to many of the basin’s pools drying up, turtles and plants dying, and prized microbes receding into the ground beyond researchers’ grasp. With climate change pushing the landscape’s temperatures ever higher, it has been an uphill struggle.Souza loves Cuatro Ciénegas. Researchers think that the isolated landscape has preserved microorganisms for hundreds of millions of years. “It’s a unique window into the past,” she says. But she is also tired, and says that it’s time to leave the task of protecting the basin to a new generation of scientists and advocates.A lost worldCuatro Ciénegas, which translates to ‘four marshes’, has long fascinated scientists. Although its name was inspired by springs located at the four cardinal points shaping the valley, in total, it contains more than 300 blue-green pools, or pozas, filled with microbes, bacterial mats and ancient microbial reefs called stromatolites. “It’s perhaps the most diverse place on the planet in terms of bacteria and archaea,” Souza says.

    Valeria Souza, during a visit to Cuatro Ciénegas.Credit: Esteban Gonzalez de Leon

    The wetland is fed by “an ancient sea” beneath the nearby Sierra de San Marcos y Pinos mountain, Souza adds. Rain on the mountain feeds the aquifer, which is heated by magma deep underground. The water then seeps upward, through ancient marine sediments, to form the pools.The region’s stromatolites have especially intrigued scientists. In other parts of the world, researchers usually come upon stromatolites as fossils — dried-out layers of ancient cyanobacteria containing trapped sedimentary grains. But those in Cuatro Ciénegas are alive, allowing scientists to study what early life on Earth must have been like. One way they do this is by extracting stromatolite DNA and analysing how it might have evolved.Drawn to the area in 1998, researchers funded by NASA’s Astrobiology Institute in Mountain View, California, went there to study the origins of life — with an eye towards understanding whether life could have once existed on Mars’s arid surface. James Elser, a limnologist who was one of the lead scientists on the project and who was at Arizona State University in Tempe, invited Souza to collaborate.Emptied oasisSouza confesses that the fight to save the place has been like a rock on her back.Because it is one of the most abundant sources of water in the Chihuahuan Desert, Cuatro Ciénegas has been tapped extensively by local residents. Three main canal systems — La Becerra, Santa Tecla and Saca Salada — siphon water from the wetlands, especially to grow alfalfa (Medicago sativa), a crop mainly used to feed cows.To halt this drainage, Souza brought in Mexican business magnate Carlos Slim, who partnered with the global wildlife charity WWF in 2009 to buy the land around the region’s largest lagoon, El Churince, and make it a protected area. She also successfully lobbied the dairy company Grupo LaLa, based in Gómez Palacio, to stop buying alfalfa from the region. But demand for water continues to soar, and the wetlands have steadily dried up.

    This set of time-lapse aerial images shows El Churince, once the largest lagoon in Cuatro Ciénegas, dry up and disappear (images run from 1997 to 2022).Credit: Landsat data courtesy of the U.S. Geological Survey

    By 2017, El Churince — which held the vast majority of fish species found in Cuatro Ciénegas and housed more than 5,000 species of bacteria, most of them only found in the region — was gone. Souza says that, after seeing the “graveyard of turtles and fishes” left behind, she mourned for years.Others have tried to protect the region. For instance, in 2000, the civil association Pronatura Noreste in Monterrey acquired the Pozas Azules ranch, whose roughly 2,700 hectares hold 100 of Cuatro Ciénegas’ pools. But the organization has similarly struggled to make headway. The land is protected, but the aquifer beneath it is not, says the association’s director, Rosario Alvarez.Souza would like to see Mexico’s National Water Commission (Conagua) take more stringent steps to protect the aquifer. The agency doesn’t keep a record of all the water that’s extracted from it, or the permissions for its use. This leads to over-extraction, which is collapsing the wetland, she says. “There is no inventory, and it’s urgent that [Conagua keep one] because the system cannot last five more years,” Souza adds.Conagua did not respond to Nature’s requests for comment.Saving an ancient worldSouza’s one hope is the generation of scientists and advocates she trained.When she became interested in Cuatro Ciénegas, she spent time educating children from the local school, CBTA 22, as well as the surrounding community, about the importance of preserving the wetland. Among the people she taught is Héctor Arocha, now a biotechnologist who is taking over research in the basin. Arocha works for 2040 Plan, a foundation in Cuatro Ciénegas that seeks to support the development of the community over the next 25 years.
    The world faces a water crisis — 4 powerful charts show how
    As part of that effort, on 4 April, Arocha opened Genesis 4C, the first scientific museum in the region, with the mission of creating a culture of conservation. “We gathered all the research that has been done in the valley in collaboration with Valeria and the whole team of researchers who have come over the years,” Arocha says. The museum has a research centre and plans to continue microbial-ecology projects on the origins of life, as well as to find uses for the wetland’s microorganisms in agriculture and medicine.Souza also sees ecotourism efforts in the area as promising. “Hoteliers and non-governmental organizations own the largest areas of Cuatro Ciénegas,” she says. One of the hotels, the María Elena, is donating to the 2040 Plan. There’s also an ecotourism park, called Las Playitas, that educates visitors about the marshes and donates money to the foundation.It’s hard to know whether the pools of Cuatro Ciénegas will survive, but Souza takes solace in the longevity of the bacteria that she loves. “Time is very relative” to the microbes living under the mountain, she says. The water in the pools might completely dry up, but the microorganisms are capable of patiently waiting millions of years underground before rising back up to the surface if the aquifer ever refills. Humans might never see that — “we will be extinct by then”, she predicts — but the microbes could endure. More

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    Water pollution ‘timebomb’ threatens global health

    Up to 5.5 billion people worldwide could be exposed to polluted water by 2100, a modelling study has found.Researchers mapped surface water quality under three different visions of future climate and socio-economic development.In every case, sub-Saharan Africa was shown to be among the worst-affected areas.The predictions, published in Nature Water on 17 July1, offer “a temporal and spatial analysis of what has been, until now, anecdotal evidence regarding water quality in sub-Saharan Africa”, says Tafadzwa Mabhaudhi, who studies climate change and food security at the University of KwaZulu-Natal in Durban, South Africa.Without adequate investment in water infrastructure or treatment, “we are definitely sitting on a time bomb”, adds Joshua Edokpayi, a researcher in water-quality management at the University of Venda in Thohoyandou, South Africa.

    Source: Ref 1.

    According to United Nations estimates, two billion people worldwide already struggle to access safe drinking water. In the past few decades, East Asia and the Pacific region have had the most surface water pollution, owing to booms in industrialization and population that have led to increasing demand for water in areas that do not have the infrastructure to support it.Water forecastTo investigate the future effects of similar trends, researchers modelled water quality in 20-year chunks from 2005 to 2100, using existing models of global water quality.They considered three future climate scenarios used by the Intergovernmental Panel on Climate Change, known as SSP1-RCP2.6, SSP5-RCP8.5 and SSP3-RCP7.0. SSP stands for ‘shared socio-economic pathways’, and considers various societal factors, whereas RCP describes ‘representative concentration pathways’, referring to trajectories of greenhouse-gas concentrations. For example, SSP5-RCP8.5 denotes a ‘business-as-usual’ trajectory defined by continued strong technological progress with limited concern for global warming. SSP1-RCP2.6 defines an optimistic ‘green’ future where sustainability becomes globally prioritized.
    The water crisis is worsening. Researchers must tackle it together
    The team found that under all of the scenarios, water quality got worse in countries in South America and sub-Saharan Africa with emerging economies. By contrast, in many wealthy countries, levels of organic pollutants and substances that can cause disease tended to decrease, owing to improved water treatment.The SSP3-RCP7.0 projection, which describes an upcoming ‘bumpy road’ of increasing national rivalries coupled with slow economic and environmental progress, stood out as the worst-case scenario (see ‘Pollution predictions’). In this model, organic water pollution in sub-Saharan Africa more than quadruples by 2100, leaving 1.5 billion people exposed to unsafe water. Deterioration in water quality in South Asia, the Middle East and North Africa also leads to increased pollution exposure in those regions.This came as a surprise, says study co-author Edward Jones, a geoscientist at Utrecht University in the Netherlands. He adds that although a ‘business-as-usual’ scenario would involve unsustainable dependence on fossil fuels, it could also lead to improved water infrastructure and thus water quality, as has already been seen in some countries. The SSP3-RCP7.0 scenario is characterized by poor economic growth, severe climate change and population expansion, which leads to much worse water-quality management.Global effortBoth Edokpayi and Mabhaudhi say that the research highlights the need for better implementation of regional water-quality policies. Under the UN’s Sustainable Development Goals, everyone worldwide should have access to safe drinking water by 2030. However, Mabhaudhi says there is a disconnect between global policies and the reality on a smaller scale, and that the world needs joined-up approaches that “place people and planet outcomes at the core”.Pollution defies national boundaries, says Edokpayi, and cross-boundary collaborations will be crucial to keep the worst predictions from coming true. More

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    Preparedness for drought is more than a climate-change fix

    Pollution of surface waters and overexploitation of aquifers are making it harder for annual precipitation to fulfil most of the world’s water requirements. Drought preparedness therefore depends largely on local water management and foresighted governance.
    Competing Interests
    The authors declare no competing interests. More

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    Women in engineering: using hydrology to manage Jordan’s scarce water

    International Women in Engineering Day

    Nature is marking International Women in Engineering Day on 23 June by profiling two female engineers who are role models for the Liverpool Women in Science & Engineering (LiVWiSE) initiative, based at the University of Liverpool, UK. The accompanying profile of automotive engineer Imogen Howarth can be found here.

    Esraa Tarawneh, a water resercher in the Civil and Environmental Engineering Department at Mutah University, Jordan, describes how growing up in Jordan made her passionate about research into hydrological extremes, flash floods and the impacts of climate change on water resources.How did your love of engineering begin?As a child, I liked to solve things. With a problem you make a plan, break the problem down into different aspects and try to solve each part on its own. Then you assemble the parts back together. This is what I enjoyed. Everyone around me said, “She’s an engineer.”The environment in our home was all ‘study, study, study’. I am the second of ten siblings and all of us are either medical doctors, engineers, pharmacists or computer specialists, bar one, a judge. Three of the six daughters are engineers — two civil engineers and an electrical power engineer.What does your research involve?I work on hydrological and analytical modelling, providing and developing scenarios of what can happen, and I predict change in water patterns. I also study how we can improve ways of harvesting water and managing floods.I went into hydrology to provide tangible solutions. Jordan is one of the most water-poor countries; there is a huge shortage. The severe water scarcity threshold, as defined by the United Nations children’s charity UNICEF, is 500 cubic metres of renewable water resources per person per year, but in Jordan we have less than 100 cubic metres per person per year. And it can actually be way below that — it varies from place to place. Often, we have just 2 cubic metres a week, sometimes over 2 weeks, per family.How did your career in engineering begin?In 1999, I started my undergraduate degree in civil engineering at Mutah University. It covered highway engineering, roads, bridges, construction, everything.But I always wanted to specialize in water, so after graduating I registered for a new master’s degree there, in water and environmental engineering. My thesis was on water and sediment yield for the Wala Dam catchment area located just to the south of Amman.I then spent four years at the Jordanian Ministry of Public Works and Housing before gaining a scholarship, in 2012, from Mutah University. It was to study at the University of Liverpool, UK, for a PhD in water and environmental engineering.I used modelling for various scenarios, including the feasibility of increasing the height of the Wala Dam for sustainable land and water management in an environment for which we do not have abundant data. I am very grateful for that chance to come to a world-class university such as Liverpool, which would never have happened without Mutah’s support.When I returned to Mutah University in 2018, I was the only woman with a PhD in a department of around 20; the only other woman was an architect. Now there are seven women with PhDs. That’s a positive move.As a woman, were you unusual among your peers in Jordan, in wanting to be an engineer?In Jordan, we do not distinguish between girls and boys doing engineering, unlike in the United Kingdom, where in my experience women do not want to do engineering as much as men do. But my youngest sister, the power engineer, has had difficulty in getting a job since she completed her studies at Mutah — the companies in Jordan seem to want men.What have been the main challenges or barriers in your career?Throughout my time as a university professor, I have faced a range of challenges including balancing the heavy teaching load while also striving to devote decent time to research. This requires some innovative solutions to maximize productivity and manage priorities.And I have faced the same challenges that affect women generally: stereotypes, a lack of female role models and unconscious biases. You have to find your own way and support yourself, which I have taken as an opportunity to improve, to find wider networks and collaborate with people from around the world. Studying in the United Kingdom gave me the confidence to seek professional development opportunities in countries including the United States, Germany, Belgium and the Netherlands, with financial support from international funding schemes.What does successful collaboration look like for you?When I came back to Jordan in 2018, I collaborated with my PhD supervisor on a joint project to link UK experts with peers in Jordan to work on sustainable catchment management and water security, which was implemented the following year. It was supported by the Newton Fund, which is managed by the UK government’s Department for Business, Energy and Industrial Strategy, and which builds research and innovation partnerships with countries in Africa, Asia and Latin America.We were able to use those links after a tragic, fatal event in October 2018, when a school bus was washed away in a flash flood near the Dead Sea. It was thought that in these very arid or semi-arid regions and with a tough environment and harsh topography, nothing could be done to prevent such incidents. But we can’t just stand there and say that nothing can be done.
    Are you a postdoc working in academia or industry? Share your career experiences with Nature
    I wanted to predict the floods and propose scenarios for how to manage or mitigate them, using hydrological modelling. I started looking into that, trying to collect resources to reconstruct these floods and make data available to other researchers as well, to learn lessons. At one point we were stuck, so we called for a collaboration with Sheffield Hallam and Aberystwyth universities in the United Kingdom, to secure funds to continue. This led to an 18-month project with UK representatives carrying out fieldwork in Jordan, which contributed to developing greater awareness of and improved resilience to flood events in the region.How would you encourage women to study engineering?Look at the problems around us, for instance, climate change. It’s not the role of only men to work in these fields and contribute to mitigating the impact. We all have this responsibility, so, we must all share our knowledge and contribute.Women are powerful enough to stand shoulder to shoulder with men — they are not limited to humanitarian work, they can be astronauts or anything. We don’t want to be left behind while men are working on artificial intelligence in engineering, science and mathematics, and solving problems in the world.What advice would you give to your younger self?Believe in yourself and look for opportunities. Also, this might sound weird, but stop looking for perfection — 100% perfect things do not exist in life. Perfectionism can make you get stuck at some point and cause you to underestimate your work. My PhD supervisor, Jonathan Bridge, gave me this advice, saying that you can contribute to solving a problem if you do the best you can.What’s been the best advice you have had?My PhD was tough, owing to the lack of data and the fact that the project was in a remote place in Jordan. At one point I was really suffering, and Jonathan said, “As long as you succeed in this, you will be really strong-boned and nothing in life can break you easily.” That was really inspiring. I thought that I was the only one struggling and he told me, “A PhD is not meant to be easy because you’re contributing to knowledge and doing something that no one else has done before.” I feel I’m really strong-boned, and I really would like to thank him for that. I appreciate what he’s done for me.What does being a role model for the LivWiSE programme involve, and why did you agree to be one?Liverpool was a very supportive environment that sparked many of my current achievements, and I want to give back. My LivWiSE programme role is to actively engage with students and aspiring prospective engineers to share my experiences, knowledge and insights, and participate in mentoring programmes.If I’m experienced and skilful, but everyone around me is not having similar opportunities, then I cannot do much with my skills. So I try my best to contribute to building their capacity. More

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    Uruguay’s water crisis: prepare for future events

    Last month, an extended drought in Uruguay forced the water-treatment plant that supplies 60% of the population to start processing and distributing brackish, non-potable water. Even though the authorities are used to highly variable precipitation and are aware of the social and political consequences of water shortages, they were completely unprepared for the crisis.
    Competing Interests
    The author declares no competing interests. More

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    Water: a commons beyond economic value

    I contend that calls to govern ‘green’ water (in air, biomass and soils) on a global scale through markets are unrealistic (see J. Rockström et al. Nature 615, 794–797; 2023). They could also distract from addressing the everyday challenges of ensuring that access to ‘blue’ water from rivers, lakes and reservoirs is sustainable and equitable.
    Competing Interests
    The author declares no competing interests. More

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    Rampant groundwater pumping has changed the tilt of Earth’s axis

    Children collect drinking water from a well in Murkata, India.Credit: Biju Boro/AFP via Getty

    The Earth has lost enough groundwater to thirsty humans to measurably tilt the planet’s axis of rotation1.The net water lost from underground reservoirs between 1993 and 2010 is estimated to be more than 2 trillion tons. That has caused the geographic North Pole to shift at a speed of 4.36 centimetres per year, researchers have calculated. The results appeared on 15 June in Geophysical Research Letters.A wobbling of the EarthThe tilt of the axis on which any celestial object spins tends to be stable. But small changes can occur when large masses shift location inside a planet and on its surface. “Every mass moving around on the surface of the Earth can change the rotation axis,” says Ki-Weon Seo, a geophysicist at Seoul National University.Astronomers can track such motions in the Earth’s axis by observing quasars, the bright centres of distant galaxies that constitute practically immobile points of reference. The largest axis change is seasonal and is triggered by the motion of atmospheric masses as the weather and seasons change. This effect causes the Earth’s geographic poles to wobble by up to several metres every year.
    The world faces a water crisis — 4 powerful charts show how
    Shifts in water masses can cause smaller but still measurable changes in the tilt of Earth’s axis. Until recently, researchers thought that these water-driven effects would be caused mainly by the melting of glaciers and ice caps. But when Seo and his collaborators tried to model the Earth’s water content to account for how much the axis has tilted, they could not fully explain the data. Adding the effects of changes in surface reservoirs did not help, says Seo, “so I just scratched my head and said, ‘probably one effect is groundwater’”.Gravitational surveys have measured the depletion of underground reservoirs, which is caused in large part by irrigation, especially in northwestern India and western North America. These surveys show that groundwater pumping shifted enough mass into the oceans to cause 6.24 millimetres of global sea-level rise between 1993 and 2010.By including these changes in their model, the authors calculated that they should have a substantial impact on the Earth’s rotation axis. They predicted that the displacement of groundwater alone causes a shift in the North Pole of 4.36 centimetres per year, roughly in the direction of Russia’s Novaya Zemlya islands. More

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    Chile: lithium mining versus flamingos and aquifers

    The Chilean government plans to nationalize 20 salt lakes in the unique Altiplano ecosystem and exploit them for lithium extraction. As well as creating a huge and long-lasting trail of environmental damage, intensive mining activity will disrupt the region’s delicate ecological and hydrological balance.
    Competing Interests
    The author declares no competing interests. More