Biologist warn of early stages of Earth"s sixth mass extinction event

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The planet’s current biodiversity, the product of 3.5 billion years of evolutionary trial and error, is the highest in the history of life. But it may be reaching a tipping point.In a new review of scientific literature and analysis of data published in Science, an international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the early days of the planet’s sixth mass biological extinction event.Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.And while previous extinctions have been driven by natural planetary transformations or catastrophic asteroid strikes, the current die-off can be associated to human activity, a situation that the lead author Rodolfo Dirzo, a professor of biology at Stanford, designates an era of “Anthropocene defaunation.”Across vertebrates, 16 to 33 percent of all species are estimated to be globally threatened or endangered. Large animals — described as megafauna and including elephants, rhinoceroses, polar bears and countless other species worldwide — face the highest rate of decline, a trend that matches previous extinction events.Larger animals tend to have lower population growth rates and produce fewer offspring. They need larger habitat areas to maintain viable populations. Their size and meat mass make them easier and more attractive hunting targets for humans.Although these species represent a relatively low percentage of the animals at risk, their loss would have trickle-down effects that could shake the stability of other species and, in some cases, even human health.For instance, previous experiments conducted in Kenya have isolated patches of land from megafauna such as zebras, giraffes and elephants, and observed how an ecosystem reacts to the removal of its largest species. Rather quickly, these areas become overwhelmed with rodents. Grass and shrubs increase and the rate of soil compaction decreases. Seeds and shelter become more easily available, and the risk of predation drops.Consequently, the number of rodents doubles — and so does the abundance of the disease-carrying ectoparasites that they harbor.”Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” said Dirzo, who is also a senior fellow at the Stanford Woods Institute for the Environment. …


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Planet-sized space weather explosions at Venus

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Researchers recently discovered that a common space weather phenomenon on the outskirts of Earth’s magnetic bubble, the magnetosphere, has much larger repercussions for Venus. The giant explosions, called hot flow anomalies, can be so large at Venus that they’re bigger than the entire planet and they can happen multiple times a day.”Not only are they gigantic,” said Glyn Collinson, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “But as Venus doesn’t have a magnetic field to protect itself, the hot flow anomalies happen right on top of the planet. They could swallow the planet whole.”Collinson is the first author of a paper on these results that appeared online in the Journal of Geophysical Research in February 2014. The work is based on observations from the European Space Agency’s Venus Express. The results show just how large and how frequent this kind of space weather is at Venus.Earth is protected from the constant streaming solar wind of radiation by its magnetosphere. Venus, however, has no such luck. A barren, inhospitable planet, with an atmosphere so dense that spacecraft landing there are crushed within hours, Venus has no magnetic protection.Scientists like to compare the two: What happened differently at Earth to make it into the life-supporting planet it is today? What would Earth be like without its magnetic field?At Earth, hot flow anomalies do not make it inside the magnetosphere, but they release so much energy just outside that the solar wind is deflected, and can be forced to move back toward the sun. Without a magnetosphere, what happens at Venus is very different.Venus’s only protection from the solar wind is the charged outer layer of its atmosphere called the ionosphere. …


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The ups and downs of early atmospheric oxygen

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UC Riverside research team challenges conventional view of a simple two-step rise in early oxygen on Earth; study suggests instead dynamic oxygen concentrations that rose and fell over billions of years.A team of biogeochemists at the University of California, Riverside, give us a nontraditional way of thinking about the earliest accumulation of oxygen in the atmosphere, arguably the most important biological event in Earth history.A general consensus asserts that appreciable oxygen first accumulated in Earth’s atmosphere around 2.3 billion years ago during the so-called Great Oxidation Event (GOE). However, a new picture is emerging: Oxygen production by photosynthetic cyanobacteria may have initiated as early as 3 billion years ago, with oxygen concentrations in the atmosphere potentially rising and falling episodically over many hundreds of millions of years, reflecting the balance between its varying photosynthetic production and its consumption through reaction with reduced compounds such as hydrogen gas.”There is a growing body of data that points to oxygen production and accumulation in the ocean and atmosphere long before the GOE,” said Timothy W. Lyons, a professor of biogeochemistry in the Department of Earth Sciences and the lead author of the comprehensive synthesis of more than a decade’s worth of study within and outside his research group.Lyons and his coauthors, Christopher T. Reinhard and Noah J. Planavsky, both former UCR graduate students, note that once oxygen finally established a strong foothold in the atmosphere starting about 2.3 billion years ago it likely rose to high concentrations, potentially even levels like those seen today. Then, for reasons not well understood, the bottom fell out, oxygen plummeted to a tiny fraction of today’s level, and the ocean remained mostly oxygen free for more than a billion years.The paper appears in Nature on Feb. 19.”This period of extended low oxygen spanning from roughly 2 to less than 1 billion years ago was a time of remarkable chemical stability in the ocean and atmosphere,” Lyons said.His research team envisions a series of interacting processes, or feedbacks, that maintained oxygen at very low levels principally by modulating the availability of life-sustaining nutrients in the ocean and thus oxygen-producing photosynthetic activity.”We suggest that oxygen was much lower than previously thought during this important middle chapter in Earth history, which likely explains the low abundances and diversity of eukaryotic organisms and the absence of animals,” Lyons said.The late Proterozoic — the time period beginning less than a billion years ago following this remarkable chapter of sustained low levels of oxygen — was strikingly different, marked by extreme climatic events manifest in global-scale glaciation, indications of at least intervals of modern-like oxygen abundances, and the emergence and diversification of the earliest animals. Lyons notes that the factors controlling the rise of animals are under close scrutiny, including challenges to the long-held view that a major rise in atmospheric oxygen concentrations triggered the event.”Despite the new ideas about animal origins, we suspect that oxygen played a major if not dominant role in the timing of that rise and, in particular, in the subsequent emergence of complex ecologies for animal life on and within the sediment, predator-prey relationships, and large bodies” said Lyons. “But, again, feedbacks always rule the day. Environmental change drives evolution, and steps in the progression of life change the environment.”No single factor is likely to be the whole story, and there is much more to be written in the tale. …


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Theory on origin of animals challenged: Some animals need extremely little oxygen

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One of science’s strongest dogmas is that complex life on Earth could only evolve when oxygen levels in the atmosphere rose to close to modern levels. But now studies of a small sea sponge fished out of a Danish fjord shows that complex life does not need high levels of oxygen in order to live and grow.The origin of complex life is one of science’s greatest mysteries. How could the first small primitive cells evolve into the diversity of advanced life forms that exists on Earth today? The explanation in all textbooks is: Oxygen. Complex life evolved because the atmospheric levels of oxygen began to rise app. 630 — 635 million years ago.However new studies of a common sea sponge from Kerteminde Fjord in Denmark shows that this explanation needs to be reconsidered. The sponge studies show that animals can live and grow even with very limited oxygen supplies.In fact animals can live and grow when the atmosphere contains only 0.5 per cent of the oxygen levels in today’s atmosphere.”Our studies suggest that the origin of animals was not prevented by low oxygen levels,” says Daniel Mills, PhD at the Nordic Center for Earth Evolution at the University of Southern Denmark.Together with Lewis M. Ward from the California Institute of Technology he is the lead author of a research paper about the work in the journal PNAS.A little over half a billion years ago, the first forms of complex life — animals — evolved on Earth. Billions of years before that life had only consisted of simple single-celled life forms. The emergence of animals coincided with a significant rise in atmospheric oxygen, and therefore it seemed obvious to link the two events and conclude that the increased oxygen levels had led to the evolution of animals.”But nobody has ever tested how much oxygen animals need — at least not to my knowledge. …


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#Earth, #Ecology, #Institute, #Marine, #Mills, #Oxygen, #Science, #Technology

Four unknown galaxy clusters containing thousands of galaxies discovered 10 billion light years from Earth

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Four unknown galaxy clusters each potentially containing thousands of individual galaxies have been discovered some 10 billion light years from Earth.An international team of astronomers, led by Imperial College London, used a new way of combining data from the two European Space Agency satellites, Planck and Herschel, to identify more distant galaxy clusters than has previously been possible. The researchers believe up to 2000 further clusters could be identified using this technique, helping to build a more detailed timeline of how clusters are formed.Galaxy clusters are the most massive objects in the universe, containing hundreds to thousands of galaxies, bound together by gravity. While astronomers have identified many nearby clusters, they need to go further back in time to understand how these structures are formed. This means finding clusters at greater distances from Earth.The light from the most distant of the four new clusters identified by the team has taken over 10 billion years to reach us. This means the researchers are seeing what the cluster looked like when the universe was just three billion years old.Lead researcher Dr David Clements, from the Department of Physics at Imperial College London, explains: “Although we’re able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old. This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further.”The clusters can be identified at such distances because they contain galaxies in which huge amounts of dust and gas are being formed into stars. This process emits light that can be picked up by the satellite surveys.Galaxies are divided into two types: elliptical galaxies that have many stars, but little dust and gas; and spiral galaxies like our own, the Milky Way, which contain lots of dust and gas. Most clusters in the universe today are dominated by giant elliptical galaxies in which the dust and gas has already been formed into stars.”What we believe we are seeing in these distant clusters are giant elliptical galaxies in the process of being formed,” says Dr Clements.Observations were recorded by the Spectral and Photometric Imaging Receiver (SPIRE) instrument as part of Herschel Multi-tiered Extragalactic Survey (HerMES). Seb Oliver, Head of the HerMES survey said: “The fantastic thing about Herschel-SPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things. …


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Christian Olsen and Michael Bradley - 2 young guys battling mesothelioma

Both Christian and Michael are brave mesothelioma warriors who both live in the USA. Michael is 29 years of age and Christian has just celebrated his 34th birthday with his wife Lisa and their 2 small children.Michael is at home after a few days in hospital to get his pain under control. He is doing it tough at the moment – however he know has his own wheelchair and is getting out during the day to his favourite places with family and friends – there is no tying Michael to his bed!(This link below is for Michael’s facebook page)https://www.facebook.com/groups/315461631836891/?fref=tsChristian is due to start chemotherapy tomorrow morning cisplatin/alimta. I have been speaking with him today and he has been asking relevant questions that I …


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Is an earthquake behind the Shroud of Turin image? Radiation from earthquake could have led to "wrong" 1988 dating

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Neutron radiation caused by 33 A.D. earthquake could have led to “wrong” 1988 radiocarbon dating of Shroud, suggest researchersAn earthquake in Old Jerusalem might be behind the famous image of the Shroud of Turin, says a group of researchers led by Alberto Carpinteri of the Politecnico di Torino in Italy in an article published in Springer’s journal Meccanica. They believe that neutron radiation caused by an earthquake could have induced the image of a crucified man — which many people believe to be that of Jesus — onto the length of linen cloth, and caused carbon-14 dating done on it in 1988 to be wrong.The Shroud has attracted widespread interest ever since Secondo Pia took the first photograph of it in 1898: about whether it is Jesus’ purported burial cloth, how old it might be, and how the image was created. According to radiocarbon dating done in 1988, the cloth was only 728 years old at the time. Other researchers have since suggested that the shroud is much older and that the dating process was incorrect because of neutron radiation — a process which is the result of nuclear fusion or nuclear fission during which free neutrons are released from atoms — and its interaction with the nuclei of other atoms to form new carbon isotopes.However, no plausible physical reason has yet been proposed to explain the origin of this neutron radiation. Now Carpinteri’s team, through mechanical and chemical experimentation, hypothesizes that high-frequency pressure waves generated in Earth’s crust during earthquakes are the source of such neutron emissions. This is based on their research into piezonuclear fission reactions, which are triggered when very brittle rock specimens are crushed under a press machine. In the process, neutrons are produced without gamma emissions. Analogously, the researchers theorize further that neutron flux increments, in correspondence to seismic activity, should be a result of the same reactions.The researchers therefore believe that neutron emission from a historical earthquake in 33 A.D. in Old Jerusalem, which measured 8.2 on the Richter Scale, could have been strong enough to cause neutron imaging through its interaction with nitrogen nuclei. …


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