July 13, 2020
Enjoy these interesting stories from the scientific community.
*-- New technology combines wood, bacteria, sunlight to purify water --*
Engineers have developed a new wood-based steam generator that can purify water using bacteria-produced nanomaterials and the sun's energy.
Solar steam generators, which use the sun's energy to separate water molecules from contaminants via evaporation, aren't new, but the quest to make the technology as efficient as possible is never-ending.
When working to improve upon solar steam generators, scientists can focus one or more sources of inefficiencies: light absorption, heat management, water transport or evaporation.
Researchers at the University of Science and Technology of China developed a water purification device that improves on all four processes.
The team of scientists selected wood for its sustainability, and because its porosity allows for rapid water transport. To bind the device's wood layers, researchers relied on long cellulose nanofibers, which are produced by bacteria.
After sterilizing the wood, scientists applied the bacteria strain Gluconacetobacter xylinus and allowed it to ferment on the back of a block of wood. Next, researchers sprayed on a layer of aerosolized glass bubbles, an excellent insulator.
"The glass bubbles became embedded in the cellulose nanofibers produced by the bacteria, forming a hydrogel," researchers explained in a news release.
The cellulose nanofibers formed by the bacteria worked to bind together layers of the device together. To complete the device's light absorbing top layer, researchers applied carbon nanotubes, which became intertwined with the cellulose nanofibers.
The device -- detailed Wednesday in the journal Nano Letters -- works by pulling and filtering water up throw the wood layers to the light absorbing top layer, which is heated by the sun. The purified water evaporates and is collected and condensed above and funneled to a holding tank.
The carbon nanotubes and cellulose nanofibers lower the energy required for water vaporization, while the layer of glass bubbles ensure the sun's energy doesn't dissipate down through the wood layers.
In addition to being constructed using relatively cheap and sustainable materials, the device boasts a higher evaporation rate and greater efficiency than most current solar steam generators.
The simple technology could be used to purify seawater, as well as contaminated lake and river water, in remote locations and in parts of the developing world.
*-- Scientists move to create single, comprehensive list of Earth's living species --*
 An international group of scientists hope to convince biologists, taxonomists, conservationists and policy makers the world over to use a single, comprehensive list of the world's species -- from mammals and birds to plants, fungi and microbes.
On Tuesday, the team of scientists, organized by the International Union of Biological Sciences, published a series of principles in the journal PLOS Biology that they hope will serve as a roadmap for compiling such a list.
It's not the first time scientists have called for a big list of all the planet's living things.
"There have been attempts to do this, and even very good ones, such as the Catalogue of Life," IUBS team member Frank Zachos told UPI.
"But it is a relatively small group of people that decide which species end up in the list, and there is no agreed upon process for deciding on how to deal with discrepancies," said Zachos, an evolutionary biologist with the Natural History Museum Vienna in Austria.
Deciding taxonomic questions about whether a seemingly unique group of organisms is a subspecies, or whether a subspecies is actually a species, may seem like a purely academic endeavor. Researchers say, however, that such decisions have serious implications -- for conservation, trade development, local economies and scientific research.
In 2014, the different opinions of taxonomists underpinned a petition brought forth by a group of builders associations in California. The petition alleged that the coastal California gnatcatcher, Polioptila californica californica, wasn't a subspecies of the California Gnatcatcher.
"If it is a subspecies, the U.S. Endangered Species Act says it needs protection," Zachos said. "When it's endangered, not only is the species protected, but its potential habitat is too."
"If it is a subspecies, multi-billion dollar real estate investments cannot be realized," he said. "The name can make people rich or not."
Such disputes are not uncommon, he said.
According to Zachos and his colleagues, consistency, openness and inclusiveness are the keys to settling disputes and compiling a single, comprehensive species list.
"We have suggested a framework within which a transparent and as democratic a process as possible can be started to get as much authority and legitimacy as we can to a project such as this," Zachos said. "We are spreading the word and getting participation from people in more and more taxonomic groups."
The new paper, co-authored by Zachos, features ten principles for the compilation of a comprehensive species list.
According to the group of IUBS scientists, the list should be dictated exclusively by science. It should be compiled in a way that promotes community support and use, they said, and its composition should be transparent.
"The governance of validated lists of species is separate from the governance of the names of taxa," according to the authors. "[And the] governance of lists of accepted species must not constrain academic freedom."
The authors suggest species boundaries should be as consistent as possible across different plant and animal groups. Additionally, the list should be archived, accessible and properly recognize contributors.
Finally, the authors suggest the list compilation process should be governed by a principle of diversity -- to include taxonomists and the local knowledge of scientists from outside Europe and North America.
"Most of biodiversity occurs in countries that are in the tropics, in Africa, in South America, in Southeast Asia," Zachos said. "We can only benefit from including more scientists and stakeholders from these parts of the world. We don't want to perpetuate academic neocolonialism, we want to include people."
Zachos said that he and his partners with the IUBS group are currently working on a series of papers that address in greater detail the process of democratically and transparently settling taxonomic disputes.
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