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A Better Solar Evaporator | Earth Wise

May 21, 2021 By EarthWise Leave a Comment

Water security is a serious global problem. Nearly 1.5 billion people – including almost half a billion children – live in areas of high or extremely high water vulnerability. Less than 3% of the world’s water is fresh and demand for it is rising with increasing population growth, urbanization, and growing water needs from a range of sectors.

Researchers at the University of South Australia have developed a promising new technique that could help reduce or eliminate water stress for millions of people. The technique uses highly efficient solar evaporation to obtain fresh water from seawater, brackish water, or even contaminated water. According to the researchers, their technique can deliver enough daily fresh drinking water for a family of four from just one square meter of source water.

Solar evaporation has been the focus of a great deal of effort in recent years, but it has generally been found to be too inefficient to be practically useful. The new technique overcomes those inefficiencies and can deliver fresh water at a fraction of the cost of existing technologies like reverse osmosis.

The system utilizes a highly efficient photothermal structure that sits on the surface of a water source and converts sunlight to heat, focusing energy precisely on the surface to rapidly evaporate the uppermost portion of the liquid. The technique prevents any loss of solar energy and even draws additional energy from the bulk water and surrounding environment.

The system is built entirely from simple, everyday materials that are low cost, sustainable, and easily obtainable.

The technology has the potential to provide a long-term clean water solution to people who can’t afford other systems, and these are the places where such solutions are most needed.

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Sunlight to solve the world’s clean water crisis

Photo, posted November 13, 2016, courtesy of Steve Austin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

American Robins And Climate Change | Earth Wise

April 30, 2020 By EarthWise Leave a Comment

American robins are migratory songbirds that can be found throughout much of North America. Named after European robins because of their reddish-orange breast, American robins are often found hopping across lawns and nesting on porches. Their rich caroling is among the first pre-dawn bird songs heard in spring and summer.

While some overwinter in northern parts of the United States and southern Canada, most American robins migrate south to overwinter in places like Florida and the Gulf Coast, as well as central Mexico and the Pacific Coast. They typically head south by the end of August and return north sometime between February and March to their breeding grounds in Canada and Alaska. They spend their short time there trying to find a mate, build a nest, raise a family, and consume enough food to sustain themselves on their long return journey south.

But climate change is making these seasonal rhythms less predictable. According to a new study recently published in the journal Environmental Research Letters, American robin migration is kicking off earlier by about five days each decade. The birds now migrate 12 days earlier than they did in 1994.

For 25 years, researchers at Canada’s Slave Lake have been recording the timing of American robin spring migration. They attached GPS devices to 55 robins, tracking their movements from April through June. The researchers linked the birds’ movement with weather data, including air temperature, snow depth, wind speed, and precipitation. The results showed that robins start migrating north earlier when winters are warm and dry.

Understanding the influence over the timing of migratory events is important because the timing of migration can influence reproductive success.

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A Migration Mystery

American robins now migrate 12 days earlier than in 1994

Photo, posted January 1, 2020, courtesy of Becky Matsubara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

DNA Analysis of River Water

April 17, 2017 By EarthWise

DNA analysis has become commonplace and inexpensive. Millions of people have their DNA tested to learn about their origins and family connections. And the technology has spread to biological research in the form of Environmental DNA or eDNA, which is such a powerful tool that it is transforming the field of wildlife biology.