Astronomy
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Mars Has Features That Look Very Similar To Life Bearing Hot Springs On Earth
A type of rock formation found on Mars may be some of the best evidence yet for life on that planet, according to a new study at Nature.com. The formations in question are in the Gusev Crater. When Spirit examined the spectra of the formations, scientists found that they closely match those of formations at El Tatio in Northern Chile.
The significance of that match? The El Tatio formations were produced by a combination of living and non-living processes.
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Biomediated Structures?
The rock structures at El Tatio are typically covered with very shallow water that supports bio-films and mats comprised of different diatoms and cyanobacteria. The size and shape of the structures varies, probably according to the variable depth, flow velocity, and flow direction of the water. The same variations are present at Gusev on Mars. This begs the question, “Could the structures at Gusev also have a biological cause?”
Luckily, we have a rover on Mars that can probe the Gusev formations more deeply. Spirit used its Miniature Thermal Emission Spectrometer (Mini-TES) to obtain spectra of the Gusev formations. These spectra confirmed the similarity to the terrestrial formations at El Tatio.
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Unfortunately, Spirit lacks the instrumentation to look deeply into the internal microscale features of the Martian rocks. If Spirit could do that, we would be much more certain that the Martian rocks were partly biogenic in origin. All of the surrounding factors suggest that they do, but that’s not enough to come to that conclusion.
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Pluto's Wandering Heart Hints At Subsurface Ocean
Pluto's famous heart-shaped feature caused the dwarf planet to roll over the eons, and this reorientation probably wouldn't have been possible without a subsurface ocean, new research suggests.
The left lobe of Pluto's "heart" is a 600-mile-wide (1,000 kilometers) plain called Sputnik Planitia (formerly known as Sputnik Planum), which astronomers think is an enormous impact crater. This basin has been filling with nitrogen ice over the years and now contains huge amounts of the stuff. Indeed, observations by NASA's New Horizons spacecraft, which flew by Pluto last year, suggest that Sputnik Planitia's ice may be up to 6 miles (10 km) thick.
Sputnik Planitia is aligned nicely with Pluto's "tidal axis" — the line along which the gravitational pull from the dwarf planet's largest moon, Charon, is the strongest.
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The researchers suggested that the impact that created the basin weakened the crust overlying a buried ocean, causing some of the water to rise close to the surface. This action, along with the deposition of nitrogen ice in Sputnik Planitia, would have created enough of a "positive mass anomaly" to roll the dwarf planet, Nimmo and his colleagues wrote.
It's hard to imagine Pluto reorienting in this way if it didn't have an ocean, Nimmo said. For example, the team's calculations suggest that Sputnik Planitia's ice layer would have to be 25 miles (40 km) thick if no ocean existed.
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Biology
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Life In Earth's Soils May Be Older Than Believed
Way before trees or lichens evolved, soils on Earth were alive, as revealed by a close examination of microfossils in the desert of northwestern Australia, reports a team of University of Oregon researchers.
These tiny fossils require a microscope to see and probably represent whole organisms. The 3,000 million-year-old Australian rocks have long been thought to be of marine origin. However, "a closer look at the dusty salt minerals of the rocks suggests they had to have experienced evaporation on land," said UO paleontologist Gregory Retallack, lead author on a study in the December issue of the international journal Gondwana Research.
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The study outlines a microbiome of at least five different kinds of microfossils recognized from their size, shape and isotopic compositions. The largest and most distinctive microfossils are spindle-shaped hollow structures of mold-like actinobacteria, still a mainly terrestrial group of decomposers that are responsible for the characteristic earthy smell of garden soil.
Other sphere-shaped fossils are similar to purple sulfur bacteria, which photosynthesize organic compounds in the absence of oxygen while leaving abundant sulfate minerals in the soil.
"With cell densities of over 1,000 per square millimeter and a diversity of producers and consumers, these microfossils represent a functioning terrestrial ecosystem, not just a few stray cells," said Retallack, a professor in the Department of Earth Sciences and director of paleontology collections at the Museum of Natural and Cultural History. "They are evidence that life in soils was critical to the cycles of carbon, phosphorus, sulfur and nitrogen very early in the history of the planet."
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There’s Something Cool About Arctic Bird Poop
Seabird poop helps the Arctic keep its cool, new research suggests.
The droppings release ammonia into the atmosphere, where it reacts with other chemicals in the air to form small airborne particles. Those particles form the heart of cloud droplets that reflect sunlight back into space[.]
Even though the poop’s presence provides only modest cooling, understanding the effect could help scientists better predict how the region will fare under future climate change, says study coauthor Greg Wentworth. “The humor is not lost on me,” says Wentworth, an atmospheric chemist at Alberta Environment and Parks in Canada. “It’s a crucial connection, albeit somewhat comical.”
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Earlier this year, Wentworth and colleagues reported finding surprisingly abundant ammonia in Arctic air. They linked the chemical to the guano of the tens of millions of seabirds that flock to the frigid north each summer. Bacteria in the Arctic dine on the feces and release about 40,000 metric tons of ammonia annually. (The smell, Wentworth says, is awful.)
Once in the atmosphere, that ammonia reacts with sulfuric acid and water to form small particles that increase the number of cloud droplets, the researchers now propose. A cloud made up of a lot of smaller droplets will have more surface area and reflect more sunlight than a cloud made up of fewer but larger droplets.
This effect causes on average about 0.5 watts of summertime cooling per square meter in the Arctic, with more than a watt of cooling per square meter in some areas, the researchers estimate using a simulation of the Arctic’s atmospheric chemistry. For comparison, the natural greenhouse effect causes about 150 watts of warming per square meter worldwide. On top of that, carbon dioxide from human activities currently contributes about 1.6 watts per square meter of warming on average.
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Chemistry
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Nanocars Gear Up For First Race Of Its Kind After Warm-Up Lap
Have you heard of the 24 Hours of Le Mans? The gruelling day-long endurance race held every year in the south of France? Just down the road in Toulouse, scientists are gearing up for an even longer, totally unprecedented race. It won’t take place on a classic track, but on the world’s smallest purpose built gold racing circuit. It’s the first ever nanocar race or, simply, nanorace. Fun as it may seem, the race has a serious scientific purpose: testing a unique scanning tunnelling microscope (STM) recently installed in the south of France. The race will also provide new insights into how nanocars cope in extreme conditions.
Christian Joachim, a researcher at France’s National Centre for Scientific Research (CNRS) and organiser of the nanorace, says that ‘thanks to the progress on STM systems, it’s now possible to manipulate single atoms, or even molecules’. ‘With the new four tip microscope, different people can work on the same surface simultaneously. This technique will ultimately increase the operational speed of an otherwise slow instrument,’ he adds. This means that four nanocars can be ‘driven’ independently, with each tip powering a machine. The electrons flowing from each tip will in effect be the nanocar’s fuel – propelling it along – and the winning machine will be the one that travels the furthest.
Around a month ago, three of the six participating teams took part in a ‘warm-up’ lap in Toulouse. Éric Masson, one of the team leaders of the American Ohio Bobcat Nano-Wagon team and a researcher at the University of Ohio in the US, is excited about ‘getting to use this pretty amazing four tip STM’. He had never worked in nanocars before, but had synthesised other supramolecules. He decided to combine some of those and design a nanocar for the first time. ‘Our design merges aesthetics and practicality. I had previously worked on macrocycles that could easily be envisioned as the wheels, and pseudorotaxanes with a rigid axle component.’ The Ohio team built its nanocar in an elegant manner: ‘We suspend the frame in water,’ explains Masson. ‘Then, we add the wheels, and the car self-assembles step by step. When we add the last wheel, the car suddenly becomes water soluble, and the precipitate disappears.’ The complexity of the nanocar’s structure suggests that it would have a highly complex NMR spectrum. But Masson says this isn’t the case at all and, thanks to the symmetry of the nanocar, ‘the NMR is pristine, there’s no doubt on where the wheels end up’.
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We-Hyo Soe, one of the ‘drivers’ for the Japanese team and the holder of the 2012 Guinness World Record for the world’s smallest working gear, explains to Chemistry World why the race will take 38 hours. ‘Because we have to keep the track at cryogenic temperatures of around 5K (–268°C), we are limited by the capacity of our helium tank.’ For Soe, ‘winning the race is not important’ as it’s all about expanding understanding of the behaviour of molecular machines.
However, Gwénaël Rapenne, leader of the French Toulouse Nanomobile Club team and chemistry professor at the University of Toulouse , says: ‘The goal of this race is to win! Kidding apart, the real goal is to use the new four tip STM microscope, which is quite unique in the world.’ Rapenne also sees the nanorace as a wonderful opportunity to find new sources of funding. ‘We cannot use public money to finance events like the race, and it’s also complicated to get private companies to fund fundamental research, because applications are too far away.’ The nanorace has been sponsored by companies like Toyota, Peugeot or Michelin. Rapenne says that support from the car companies will help them to develop their new STM microscope. The French team features two cars: their original, techno-mimetic, covalently-bonded nanocar and their newly designed curved nanocar – dubbed ‘the green buggy’ as the molecule is actually green – which minimises interactions with the track. Rapenne says that ‘molecular assemblies with covalent bonds are much more stable, rigid and accurate than the self-assembled nanocars’. According to Rapenne, ‘similar molecules can last up to six months within the STM. They are insanely stable!’
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What Molecules You Leave On Your Phone Reveal About Your Lifestyle
"You can imagine a scenario where a crime scene investigator comes across a personal object -- like a phone, pen or key -- without fingerprints or DNA, or with prints or DNA not found in the database. They would have nothing to go on to determine who that belongs to," said senior author Pieter Dorrestein, PhD, professor in UC San Diego School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences. "So we thought -- what if we take advantage of left-behind skin chemistry to tell us what kind of lifestyle this person has?"
In a 2015 study, Dorrestein's team constructed 3D models to illustrate the molecules and microbes found at hundreds of locations on the bodies of two healthy adult volunteers. Despite a three-day moratorium on personal hygiene products before the samples were collected, the researchers were surprised to find that the most abundant molecular features in the skin swabs still came from hygiene and beauty products, such as sunscreen.
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Thirty-nine healthy adult volunteers participated in Dorrestein's latest study. The team swabbed four spots on each person's cell phone -- an object we tend to spend a lot of time touching -- and eight spots on each person's right hand, for a total of nearly 500 samples. Then they used a technique called mass spectrometry to detect molecules from the samples. They identified as many molecules as possible by comparing them to reference structures in the GNPS database, a crowdsourced mass spectrometry knowledge repository and annotation website developed by Dorrestein and co-author Nuno Bandeira, PhD, associate professor at the Jacobs School of Engineering and Skaggs School of Pharmacy and Pharmaceutical Sciences at UC San Diego.
With this information, the researchers developed a personalized lifestyle "read-out" from each phone. Some of the medications they detected on phones included anti-inflammatory and anti-fungal skin creams, hair loss treatments, anti-depressants and eye drops. Food molecules included citrus, caffeine, herbs and spices. Sunscreen ingredients and DEET mosquito repellant were detected on phones even months after they had last been used by the phone owners, suggesting these objects can provide long-term composite lifestyle sketches.
"By analyzing the molecules they've left behind on their phones, we could tell if a person is likely female, uses high-end cosmetics, dyes her hair, drinks coffee, prefers beer over wine, likes spicy food, is being treated for depression, wears sunscreen and bug spray -- and therefore likely spends a lot of time outdoors -- all kinds of things," said first author Amina Bouslimani, PhD, an assistant project scientist in Dorrestein's lab. "This is the kind of information that could help an investigator narrow down the search for an object's owner."
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Ecology
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Biodiversity Needs Citizen Scientists
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“Citizen scientists are already contributing enormously to environmental science,” says IIASA researcher Linda See. “For example, a huge amount of species occurrence data is provided by members of the interested public. The question we addressed was, where are citizens contributing and where are they not, and how can we draw on this phenomenon to help fill the gaps in science?”
The new article looks at international conventions on biodiversity and endangered species, and the indicators that are needed to track biodiversity on a global scale, known as Essential Biodiversity Variables (EBVs). It examines the areas where citizen scientists already contribute, those where they do not, and what areas could benefit from expansion of citizen science efforts.
“Biodiversity is essential to our well-being on planet Earth, providing core ecosystem services such as pollination, pest control, and buffering of extreme events. With many continuing pressures on land, biodiversity is constantly threatened so there is a need to better monitor this valuable resource globally. But there are many big data gaps in biodiversity, often in those places where the need is greatest. Citizen scientists can help to fill some of these gaps, both geographically and taxonomically,” says Mark Chandler, Director of Research Initiatives at the Earthwatch Institute, who led the study.
The study represents the most comprehensive survey to date of citizen science, including community-based monitoring. It finds that citizen scientists are one of the main sources of data on species occurrence, in particular for birds and especially in North America and Europe. The researchers argue that such programs could be strategically expanded in order to provide more data on other indicators and from countries outside North America and Europe.
The researchers also found that while a lot of citizen-generated data already exists, less than 10% finds its way into global biodiversity monitoring. This bottleneck comes from a lack of resources, issues of interoperability, and a need for data repositories. Although the Global Biodiversity Information Facility has been a great success for curating global species occurrence data, this represents only 1 out of 22 EBVs. The researchers say that it is important to establish similar repositories for other EBVs.
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Corals Survived Caribbean Climate Change
Half of all coral species in the Caribbean went extinct between 1 and 2 million years ago, probably due to drastic environmental changes. Which ones survived? Scientists working at the Smithsonian Tropical Research Institute (STRI) think one group of survivors, corals in the genus Orbicella, will continue to adapt to future climate changes because of their high genetic diversity.
“Having a lot of genetic variants is like buying a lot of lottery tickets,” said Carlos Prada, lead author of the study and Earl S. Tupper Post-doctoral Fellow at STRI. “We discovered that even small numbers of individuals in three different species of the reef-building coral genus Orbicella have quite a bit of genetic variation, and therefore, are likely to adapt to big changes in their environment.”
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To look back in time, the team of researchers working at the Smithsonian’s Bocas del Toro Research Station and Naos Molecular and Marine Laboratories collected fossils from ancient coral reefs and used high-resolution geologic dating methods to determine their ages. They compared the numbers of fossilized coral species at different time points. One of the best-represented groups in the fossil collections were species in the genus Orbicella. In addition to the fossil collections, they also used whole genome sequencing to estimate current and past numbers of several Orbicella species.
Within a single individual there are two copies of their genetic material, and in some instances, one copy is different than the other and is called a genetic variant. The authors first assembled the full genomic sequence of an individual from Florida and then, using it as an anchor, reconstructed the genetic variation contained within single individuals. Depending on the amount of the genetic variation at certain intervals across the genome, the authors were able to recover the population sizes of each species at different times in the past.
Between 3.5 to 2.5 million years ago, numbers of all coral species increased in the Caribbean. But from 2 to 1.5 million years ago, a time when glaciers moved down to cover much of the northern hemisphere and sea surface temperatures plunged, the number of coral species in the Caribbean also took a nosedive. Sea levels fell, eliminating much of the original shallow, near-shore habitat.
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Physics
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Breakthrough Offers Greater Understanding Of Safe Radioactive Waste Disposal
A group of scientists from The University of Manchester, the National Nuclear Laboratory (NNL) and the UK's synchrotron science facility, Diamond Light Source, has completed research into radioactively contaminated material to gain further understanding around the issue, crucial for the safe and more efficient completion of future decommissioning projects.
Safely decommissioning the legacy of radioactively contaminated facilities from nuclear energy and weapons production is one of the greatest challenges of the 21st Century. Current estimates suggest clean-up of the UK's nuclear legacy will cost around £117bn and take decades to complete.
The team identified a concrete core taken from the structure of a nuclear fuel cooling pond contaminated with radioactive isotopes of caesium and strontium, located at the former Hunterston A, Magnox nuclear power station in Ayrshire. The core, which was coated and painted, was taken to the Diamond synchrotron for further analysis.
Strontium is a high yield nuclear fission product in nuclear reactors and tests showed that it was bonded to the titanium oxide found in the white pigment of the paint on the concrete core's coating. By identifying the specific location of the radioactive isotopes, the research makes future investigation easier and could potentially leads to more efficient decontamination, saving millions of pounds by reducing the volume of our radioactive waste.
The work also found that the painted and rubberised under layers were intact and the paint had acted as a sealant for 60 years. However, experiments were conducted to examine what would happen if the contaminated pond water had breached the coating. It showed that the strontium would be bound strongly to the materials in the cement but the caesium was absorbed by clays and iron oxides forming part of the rock fragments in the concrete.