Archives de catégorie : sciences-general

The world’s deepest freshwater cave just got a whole lot deeper

by C. Hartley, August 31, 2020 in ScienceAAAS


For decades, spelunkers have flocked to the flooded caverns of the Czech Republic’s Hranice Abyss, which stretches farther below ground than any other freshwater cave system. Now, a scientific campaign to the cave has revealed it is 1 kilometer deep, more than twice as deep as previously thought. The researchers also say the abyss formed as groundwater seeped down from the surface, not as water percolated up, as previously believed—a finding that could call into question the origin of other deep caves.

The abyss sits in karst, a Swiss cheese–like terrain formed when soluble rock such as limestone is slowly dissolved by water. Most caves form from the surface downward, when water from rain or melted snow—slightly acidic from dissolved carbon dioxide—makes its way underground, eating into rock and creating cracks that widen over time. However, deep caves can also form from the bottom up, when acidic groundwater heated by Earth’s mantle burbles up. Researchers believed the Hranice Abyss was in this second category because its waters contain carbon and helium isotopes that come from deep inside Earth.

The Hranice Abyss is the world’s deepest freshwater cave. But it is not the deepest overall. That honor belongs to Georgia’s Veryovkina Cave, a 2.2-kilometer-deep incursion formed when sea levels in the neighboring Black Sea dropped dramatically millions of years ago. In 2016, researchers using a remotely operated vehicle estimated the Hranice Abyss to be 473.5 meters deep. However, the vehicle’s fiber optic communication cable kept it from going deeper, and the true extent of the cave system remained a mystery.

In this photo taken Sept. 27, 2016 in the flooded Hranicka Propast, or Hranice Abyss, in the Czech Republic Polish explorer Krzysztof Starnawski, left, and Bartlomiej Grynda, right, are reading images from a remotely-operated underwater robot, or ROV, that went to the record depth of 404 meters ,1,325 feet, revealing the limestone abyss to be the world’s deepest flooded cave, during the ‘Hranicka Propast – step beyond 400m’ expedition led by Starnawski and partly funded by the National Geographic. (AP Photo/ Marcin Jamkowski)

 

 

Giant waves of sand are moving on Mars

by K. Kornei, July 23, 2020 in ScienceAAAS


Researchers have spotted large waves of martian sand migrating for the first time. The discovery dispels the long-held belief that these “megaripples” haven’t moved since they formed hundreds of thousands of years ago. They’re also evidence of stronger-than-expected winds on the Red Planet.

It’s pretty staggering that humans can detect these changes on Mars, says Ralph Lorenz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory who was not involved in the research. “We can now measure processes on the surface of another planet that are just a couple times faster than our hair grows.”

Megaripples are found in deserts on Earth, often between dunes. Waves in the sand spaced up to tens of meters apart, they’re a larger version of ripples that undulate every 10 centimeters or so on many sand dunes.

The researchers focused on two sites near the equator of Mars. They analyzed roughly 1100 megaripples in McLaughlin crater and 300 in the Nili Fossae region. They looked for signs of movement by comparing time-lapse images of each site—taken 7.6 and 9.4 years apart, respectively. Megaripples in both regions advanced by about 10 centimeters per year, the team reports in the Journal of Geophysical Research: Planets. That’s about how fast megaripples move in the Lut Desert of Iran.

It’s a surprise that megaripples move at all on Mars, says Jim Zimbelman, a planetary geologist at the Smithsonian Institution’s Air and Space Museum. Just a few decades ago, there was no evidence that sands on Mars were mobile, he says. “None of us thought that the winds were strong enough.”

Megaripples near a sand dune on Mars.

NASA/JPL/UNIVERSITY OF ARIZONA

Mass spectrometry and climate science. Part I: Determining past climates

by Judith Curry, June 16, 2020 in ChRotter_WUWT


Mass spectrometry is essential for research in climate science.

Understanding climate requires having sufficient knowledge about past climate and about the important factors that are influencing climate today, so that reliable models can be developed to predict future climate.

Analytical chemistry enables measurement of the chemical composition of materials, from the amounts of elements and their isotopes in a sample to the identity and concentrations of substances in the most complex biological organisms.

This two-part series covers the application of a powerful analytical chemistry technology — mass spectrometry — to two important areas in climate science:

  • Obtaining reliable information about past climate
  • Understanding composition and behavior of aerosols, which have a large impact on climate

The examples that are included for each topic were selected out of many published papers on the study of climate using mass spectrometry, partly because they feature a very wide range of types of these instruments. The authors were very helpful in providing me with information on their work.[1]

The technology described in this essay may at times be quite complicated! However, I hope that the results of each study will be understandable.

Part 1: Determining past climate

Figure 1: Age of samples taken at indicated depth below surface of ice core

Impact-induced amino acid formation on Hadean Earth and Noachian Mars

by Takeuchi et al., June8, 2020 in SciReports Open Access


Abstract

Abiotic synthesis of biomolecules is an essential step for the chemical origin of life. Many attempts have succeeded in synthesizing biomolecules, including amino acids and nucleobases (e.g., via spark discharge, impact shock, and hydrothermal heating), from reduced compounds that may have been limited in their availabilities on Hadean Earth and Noachian Mars. On the other hand, formation of amino-acids and nucleobases from CO2 and N2 (i.e., the most abundant C and N sources on Earth during the Hadean) has been limited via spark discharge. Here, we demonstrate the synthesis of amino acids by laboratory impact-induced reactions among simple inorganic mixtures: Fe, Ni, Mg2SiO4, H2O, CO2, and N2, by coupling the reduction of CO2, N2, and H2O with the oxidation of metallic Fe and Ni. These chemical processes simulated the possible reactions at impacts of Fe-bearing meteorites/asteroids on oceans with a CO2 and N2 atmosphere. The results indicate that hypervelocity impact was a source of amino acids on the Earth during the Hadean and potentially on Mars during the Noachian. Amino acids formed during such events could more readily polymerize in the next step of the chemical evolution, as impact events locally form amino acids at the impact sites.

Supercomputer model simulations reveal cause of Neanderthal extinction

by Insitute for basic science, May 20, 2020 in PhsyOrg


Climate scientists from the IBS Center for Climate Physics discover that, contrary to previously held beliefs, Neanderthal extinction was neither caused by abrupt glacial climate shifts, nor by interbreeding with Homo sapiens. According to new supercomputer model simulations, only competition between Neanderthals and Homo sapiens can explain the rapid demise of Neanderthals around 43 to 38 thousand years ago.

Neanderthals lived in Eurasia for at least 300,000 years. Then, around 43 to 38 thousand years ago they quickly disappeared off the face of the earth, leaving only weak genetic traces in present-day Homo sapiens populations. It is well established that their extinction coincided with a period of rapidly fluctuating climatic conditions, as well as with the arrival of Homo sapiens in Europe. However, determining which of these factors was the dominant cause, has remained one of the biggest challenges of evolutionary anthropology.

 

Figure 1: Computer simulations of population density of Neanderthals (left) and Homo sapiens (right)

Ancient Bones Found in Bulgarian Cave Are Oldest Evidence of Modern Humans in Europe

by P. Dockrill, May 12, 2020 in ScienceAlert


The oldest bones of Homo sapiens ever found in Europe have been discovered in a Bulgarian cave, providing the earliest known evidence of our species’ emergence in the European continent, according to new research.

The appearance and spread of modern humans in Europe is a difficult timeline for researchers to reconstruct, owing to a scarcity of sufficiently ancient remains that have been identified in the fossil record.

When modern humans did show up, though, our arrival ultimately sealed the fate of the indigenous Neanderthals who called Europe home before us, as we then proceeded to swiftly replace them over the course of the next several thousand years.

 

ESO telescope observes exoplanet where it rains iron

by C. Rotter, March 13, 2020 in WUWT


Researchers using ESO’s Very Large Telescope (VLT) have observed an extreme planet where they suspect it rains iron. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where it condenses into iron droplets.

“One could say that this planet gets rainy in the evening, except it rains iron,” says David Ehrenreich, a professor at the University of Geneva in Switzerland. He led a study, published today in the journal Nature, of this exotic exoplanet. Known as WASP-76b, it is located some 640 light-years away in the constellation of Pisces.

This strange phenomenon happens because the ‘iron rain’ planet only ever shows one face, its day side, to its parent star, its cooler night side remaining in perpetual darkness. Like the Moon on its orbit around the Earth, WASP-76b is ‘tidally locked‘: it takes as long to rotate around its axis as it does to go around the star.

Breakthrough gives insight into early complex life on Earth

by H. Devlin, January 15, 2020 in TheGuardian


For the first 2 billion years, life on Earth comprised two microbial kingdoms – bacteria and archaea. They featured an innumerable and diverse variety of species, but, ultimately, life on Earth was not that exciting judged by today’s standards.

Then, the theory goes, a rogue archaeon gobbled up a bacterium to create an entirely new type of cell that would go on to form the basis of all complex life on Earth, from plants to humans.

Now, for the first time, scientists have succeeded in culturing an elusive species of archaea believed to be similar to the ancestor that gave rise to the first sophisticated cells, known as eukaryotes. The work has been described as a “monumental” advance that sheds new light on this evolutionary milestone.

Nick Lane, professor of evolutionary biochemistry at UCL, described the work as “magnificent”, while a commentary by two other experts in the field said it marked a “huge breakthrough for microbiology”.

Like bacteria, archaea continue to thrive on Earth today. But despite the pivotal role they are thought to have played in the emergence of complex life there has been relatively little research on them. Many species are found in inhospitable environments and are incredibly difficult to grow in the lab.

The Japanese team behind the latest advance has dedicated 12 years to the effort, overcoming a series of setbacks along the way.

The archaeon which was cultured and characterised from deep marine sediment. Photograph: Nature

 

Simulations explain giant exoplanets with eccentric, close-in orbits

by University of California – Santa Cruz, Oct 30, 2019 in ScienceDaily


As planetary systems evolve, gravitational interactions between planets can fling some of them into eccentric elliptical orbits around the host star, or even out of the system altogether. Smaller planets should be more susceptible to this gravitational scattering, yet many gas giant exoplanets have been observed with eccentric orbits very different from the roughly circular orbits of the planets in our own solar system.

Surprisingly, the planets with the highest masses tend to be those with the highest eccentricities, even though the inertia of a larger mass should make it harder to budge from its initial orbit. This counter-intuitive observation prompted astronomers at UC Santa Cruz to explore the evolution of planetary systems using computer simulations. Their results, reported in a paper published in Astrophysical Journal Letters, suggest a crucial role for a giant-impacts phase in the evolution of high-mass planetary systems, leading to collisional growth of multiple giant planets with close-in orbits.

Deducing the scale of tsunamis from the ’roundness’ of deposited gravel

by Tokyo Metropolitan University, August 25, 2019 in ScienceDaily


Scientists from Tokyo Metropolitan University and Ritsumeikan University have found a link between the “roundness” distribution of tsunami deposits and how far tsunamis reach inland. They sampled the “roundness” of gravel from different tsunamis in Koyadori, Japan, and found a common, abrupt change in composition approximately 40% of the “inundation distance” from the shoreline, regardless of tsunami magnitude. Estimates of ancient tsunami size from geological deposits may help inform effective disaster mitigation.

Journal Reference: Daisuke Ishimura, Keitaro Yamada. Palaeo-tsunami inundation distances deduced from roundness of gravel particles in tsunami deposits. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-46584-z

The Sun’s Weather Cycle May Start in ‘Tsunamis,’ End with ‘Terminators’

by Passant Rabbie, July 31, 2019 in Space


A tsunami of plasma rushes through the sun before a new sunspot cycle begins.

Astronomers may have finally figured out what causes the sun’s 11-year cycle of activity, and it involves a “tsunami” of magnetic fields.

The sun, like other stars, goes through a cycle marked by a change in magnetic activity, levels of radiation, and the number and size of sunspots. While our sun’s 11-year cycle was discovered more than a century ago, predicting exactly when one cycle ends and a new one begins has been an ongoing challenge.

A pair of related studies have mapped out the sun’s activity over the course of 140 years, looking for clues about the solar cycle that are visible on the surface. By looking at the way bright flashes of ultraviolet light migrate across the sun’s surface, the researchers discovered that the sun’s mysterious 11-year cycle may be marked by a “terminator” event that ends one cycle and a “tsunami” of magnetic fields that initiates a new one. Those bright flickers of ultraviolet light and the sun’s magnetic fields appear to drive the cycle itself, and monitoring those flashes could help scientists predict when a new cycle will begin.

LE PEER-REVIEW, IRREPROCHABLE ?

by Jo Moreau, 17 juillet 2019 in Belgotopia


Quel est le principe de fonctionnement du « peer review », ou révision par les pairs 

Nous avons déjà pu apprécier à quel point la publication d’un article dans une revue scientifique pratiquant le « peer review » constitue pour certains le sommet, et même la condition sine qua non pour se voir accorder l’autorisation d’émettre un avis sur un sujet donné (dans notre cas : le réchauffement, pardon, les changements climatiques).

L’exemple le plus récent est illustré par la position d’un réseau social bien connu qui émet un avis à la limite calomnieux à l’égard d’un physicien par ailleurs professeur d’université, qui a fait l’objet de mon article précédent : https://belgotopia.com/2019/07/15/menaces-ouvertes-sur-les-ecrits-giecosceptiques/

Comment cela fonctionne-t-il ? Le scientifique (ou le groupe de scientifiques) soumet son étude à l’éditeur de la revue qu‘il aura choisie (ou à plusieurs d‘entre eux). Il s’agit souvent du premier filtre, l’éditeur jugeant si l’étude est ou non conforme à la ligne éditoriale de la revue. Le physicien Edwin BERRY vient encore d’en faire l’expérience. Son étude « Le CO2 d’origine humaine a peu d’effet sur le CO2 présent dans l’atmosphère » a été refusée par l’American Journal of Climate Change sous le seul et unique motif que « La conclusion de cet article est complètement opposée au consensus de la communauté universitaire ». Evidemment, le fait que Ed BERRY soit un GIECosceptique affirmé n’aura pas favorisé sa démarche …

Super salty, subzero Arctic water provides peek at possible life on other planets

by University of Washington, July 12, 2019 in ScienceDaily


On Earth, scientists are studying the most extreme environments to learn how life might exist under completely different settings, like on other planets. A University of Washington team has been studying the microbes found in “cryopegs,” trapped layers of sediment with water so salty that it remains liquid at below-freezing temperatures, which may be similar to environments on Mars or other planetary bodies farther from the sun.

At the recent AbSciCon meeting in Bellevue, Washington, researchers presented DNA sequencing and related results to show that brine samples from an Alaskan cryopeg isolated for tens of thousands of years contain thriving bacterial communities. The lifeforms are similar to those found in floating sea ice and in saltwater that flows from glaciers, but display some unique patterns.

“We study really old seawater trapped inside of permafrost for up to 50,000 years, to see how those bacterial communities have evolved over time,” said lead author Zachary Cooper, a UW doctoral student in oceanography.

Low oxygen levels could temporarily blind marine invertebrates

by Scripps Institution of Oceanography at the University of California San Diego, May 8, 2019 in ScienceDaily


These results, published recently in the Journal of Experimental Biology, are the first demonstration that vision in marine invertebrates is highly sensitive to the amount of available oxygen in the water.

Oxygen levels in the ocean are changing globally from natural and human-induced processes. Many marine invertebrates depend on vision to find food, shelter, and avoid predators, particularly in their early life stages when many are planktonic. This is especially true for crustaceans and cephalopods, which are common prey items for other animals and whose larvae are highly migratory in the water column.

Research on terrestrial animals has shown that low oxygen levels can affect vision. In fact, humans can lose visual function in low oxygen conditions. Pilots flying at high altitude, for instance, have been shown to experience vision impairment if aircraft fail to supplement cockpits with additional oxygen. Additionally, health problems such as high blood pressure and strokes, both associated with oxygen loss, can damage vision.

What would happen to Earth’s Climate and Weather if we had no Moon?

by A. Watts, February 15, 2019 in WUWT


A provocative hypothetical question: What if the Moon was not there? Video follows.

This giant rock lights up the night and can even change colors. So what would we do without it? Would we all need night vision goggles? How would it affect the ocean tides? Our seasons? Or our sleep cycles? Or would the consequences be far more drastic?

As the closest celestial body to our planet, the moon exerts a gravitational pull that governs much of what happens here on Earth Take the sea, for example. If you like surfing, you can thank the moon when the moon’s gravitational pull tugs on our spinning Earth, the oceans respond, giving us high tides in some parts of the world, and low tides elsewhere.

New islands, happy feet: Study reveals island formation a key driver of penguin speciation

by Molecular Biology and Evolution (Oxford University Press), February 5, 201 in ScienceDaily


Ever since Darwin first set foot on the Galapagos, evolutionary biologists have long known that the geographic isolation of archipelogos has helped spur the formation of new species.

Now, an international research team led by Theresa Cole at the University of Otago, New Zealand, has found the same holds true for penguins. They have found the first compelling evidence that modern penguin diversity is driven by islands, despite spending the majority of their lives at sea.

“We propose that this diversification pulse was tied to the emergence of islands, which created new opportunities for isolation and speciation,” said Cole.

Over the last 5 million years, during the Miocene period, (particularly within the last 2 million years), island emergence in the Southern Hemisphere has driven several branches on the penguin evolutionary tree, and also drove the more recent influence of human-caused extinctions of two recently extinct penguin species from New Zealand’s Chatham Islands.

German Scientists To More Closely Investigate Cloud Formation, A Vital Component In Climate

by P. Gosselin, January 27, 2019 in NoTricksZone


Leipzig, 20 December 2018

Researchers from Leipzig cooperate with scientists from Punta Arenas (Chile) to learn more about the relationship between air pollution, clouds and precipitation.

Leipzig/Punta Arenas. How do airborne particles, so-called aerosols, affect the formation and life cycle of clouds and precipitation? In order to come one step closer to solving this question, atmospheric scientists from the Leibniz Institute for Tropospheric Research (TROPOS) and the Leipzig Institute for Meteorology (LIM) at Leipzig University will observe the atmosphere at one of the cleanest places in the world for at least a year. The choice fell on Punta Arenas because the city is located on a comparable geographical latitude as Germany and will thus enable comparisons between the northern and southern hemispheres. The measurement campaign is part of the International Year of Polar Prediction (YOPP), which aims to improve weather and climate forecasts for the polar regions through intensive measurements.

Meteoroid Hits the Moon During Recent Lunar Eclipse

by Anthony Watts, January 22, 2019 in WUWT


This is a treat. On Jan. 21st, a meteoroid slammed into the Moon. We know this because many amateur astronomers witnessed the explosion and recorded video and photos. The fireball was visible against the shadowy backdrop of a total lunar eclipse. Video of the event follows.

We know this because many amateur astronomers witnessed or photographed the explosion. Petr Horálek was one of them; he captured the fireball from Boa Vista, one of the islands of Cape Verde …

Scientists identify two new species of fungi in retreating Arctic glacier

by Research Organization of Information and Systems, January 15, 2019 in ScienceDaily


Two new species of fungi have made an appearance in a rapidly melting glacier on Ellesmere Island in the Canadian Arctic, just west of Greenland. A collaborative team of researchers from Japan’s National Institute of Polar Research, The Graduate University for Advanced Studies in Tokyo, Japan, and Laval University in Québec, Canada made the discovery.

The scientists published their results on DATE in two separate papers, one for each new species, in the International Journal of Systematic and Evolutionary Microbiology.

“The knowledge of fungi inhabiting the Arctic is still fragmentary. We set out to survey the fungal diversity in the Canadian High Arctic,” said Masaharu Tsuji, a project researcher at the National Institute of Polar Research in Japan and first author on both papers. “We found two new fungal species in the same investigation on Ellesmere Island.”

Bacterial origin of the red pigmentation of Phanerozoic carbonate rocks: an integrated study of geology-biology-chemistry

by A. Préat et  al., December 2018 in GeologicaBelgica (with .pdf)


Abstract

Explaining the color of rocks is still a complex problem. This question was raised long ago in the community of geologists, particularly for the pigmentation of the ‘red marbles’ of the Frasnian of Belgium at the beginning of the last century, with many unsatisfactory hypotheses. Our recent analysis of different red carbonate rocks in Europe and North Africa (Morocco) may provide an alternative explanation for the color of these rocks. For this it was necessary to bring together diverse and complementary skills involving geologists, microbiologists and chemists. We present here a synthesis of these works. It is suggested that the red pigmentation of our studied Phanerozoic carbonate rocks, encompassing a time range from Pragian to Oxfordian, may be related to the activity of iron bacteria living in microaerophilic environments. A major conclusion is that this red color is only related to particular microenvironments and has no paleogeographic or climatic significance. All red carbonates have not necessarily acquired their pigmentation through the process established in this review. Each geological series must be analyzed in the light of a possible contribution of iron bacteria and Fungi.

Mars: Oxygen-rich, life-supporting liquid water?

by California Institute of Technology, October 22, 2018 in ScienceDaily


A team led by scientists at Caltech and the Jet Propulsion Laboratory (JPL), which Caltech manages for NASA, has calculated that if liquid water exists on Mars, it could — under specific conditions — contain more oxygen than previously thought possible. According to the model, the levels could even theoretically exceed the threshold needed to support simple aerobic life.

That finding runs contrary to the current, accepted view of Mars and its potential for hosting habitable environments. The existence of liquid water on Mars is not a given. Even if it is there, researchers have long dismissed the idea that it might be oxygenated, given that Mars’s atmosphere is about 160 times thinner than that of Earth and is mostly carbon dioxide.

Ancient Mars had right conditions for underground life, new research suggests

by Brown University, September 24, 2018 in ScienceDaily/EPSL


A new study shows evidence that ancient Mars probably had an ample supply of chemical energy for microbes to thrive underground.

“We showed, based on basic physics and chemistry calculations, that the ancient Martian subsurface likely had enough dissolved hydrogen to power a global subsurface biosphere,” said Jesse Tarnas, a graduate student at Brown University and lead author of a study published in Earth and Planetary Science Letters. “Conditions in this habitable zone would have been similar to places on Earth where underground life exists.”

New research shows that ancient Mars likely had ample chemical energy to support the kinds of underground microbial colonies that exist on Earth.
Credit: NASA / JPL

BBC tells journalists that IPCC is God, can not be wrong –”No debate allowed”

by JoNova, September 8, 2018


Lets all bow to the IPCC — a modern God that shalt not be questioned. The Holy Sacred Climate Cow!

The IPCC is an unaudited and unaccountable foreign committee. Not only are no scientists paid to check its findings, now the publicly mandated BBC is making sure none of their journalists will check its findings either.

Carbonbrief has a copy of the BBC new internal guidance on how to report climate change.

In April, the UK regulator, Ofcom, found the BBC was guilty of not sufficiently challenging Lord Lawson, a skeptic. So in response the BBC now promises they will never sufficiently challenge the IPCC. That’s “false balance” for you.

Direct evidence of surface exposed water ice in the lunar polar regions

by Shaui Li et al., August 20, 2018 PNAS


We found direct and definitive evidence for surface-exposed water ice in the lunar polar regions. The abundance and distribution of ice on the Moon are distinct from those on other airless bodies in the inner solar system such as Mercury and Ceres, which may be associated with the unique formation and evolution process of our Moon. These ice deposits might be utilized as an in situ resource in future exploration of the Moon.

Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin

by Holly C. Betts et al., August 20, 2018 in NatureEcology&Evolution


We derive a timescale of life, combining a reappraisal of the fossil material with new molecular clock analyses. We find the last universal common ancestor of cellular life to have predated the end of late heavy bombardment (>3.9 billion years ago (Ga)). The crown clades of the two primary divisions of life, Eubacteria and Archaebacteria, emerged much later (<3.4 Ga), relegating the oldest fossil evidence for life to their stem lineages. The Great Oxidation Event significantly predates the origin of modern Cyanobacteria, indicating that oxygenic photosynthesis evolved within the cyanobacterial stem lineage. Modern eukaryotes do not constitute a primary lineage of life and emerged late in Earth’s history (<1.84 Ga), falsifying the hypothesis that the Great Oxidation Event facilitated their radiation…