Cretaceous Atmosphere Was 35% O2?

Ages of ice samples found on the Earth cover a span approaching 200,000 years. Gas bubbles trapped in that ice can be used to learn about the composition of Earth's atmosphere at the time they were trapped in the ice. But how can we tell what the Earth's atmosphere was like before that?

Recently, USGS scientists have used a gas QMS to determine the oxygen level of ancient samples of Earth's atmosphere from a most unlikely place - amber. The fossilized resin of conifer trees, amber is interesting to scientists as a medium that traps insects, small animals, and plants, preserving them through geologic time for future study.

The recent extraction by scientists, of ancient DNA from organisms entombed in amber much like in the science-fiction novel and movie, Jurassic Park is an example of why scientists are intensely interested in amber. Minute bubbles of ancient air trapped by successive flows of tree resin during the life of the tree are preserved in the amber.

Analyses of the gases in these bubbles show that the Earth's atmosphere, 67 million years ago, contained nearly 35 percent oxygen compared to present levels of 21 percent. Results are based upon more than 300 analyses by USGS scientists of Cretaceous, Tertiary, and recent-age amber from 16 world sites.* The oldest amber in this study is about 130 million years old.

Whoa.

I wonder how well this will stand up.

They SOOOOO need to find samples from the Jurassic.

C4 Grasses Evolution Timing Now Divorced From CO2 Drop

A new analysis of fossilized grass-pollen grains deposited on ancient European lake and sea bottoms 16-35 million years ago reveals that C4 grasses evolved earlier than previously thought. This new evidence casts doubt on the widely-held belief that the rise of this incredibly productive group of plants was driven by a large drop in atmospheric carbon dioxide concentrations during the Oligocene epoch.

The research team, led by University of Maryland Center for Environmental Science Appalachian Laboratory researcher Dr. David Nelson and University of Illinois Professor Feng Sheng Hu, examined the carbon isotope signatures of hundreds of grass-pollen grains and found that C4 grasses were already present on the landscape during the early part of the Oligocene, some 14 million years earlier than previously thought from geological evidence. Their findings are now published online in the journal Geology and will shortly appear in the print edition.

"The idea that C4 grasses originated prior to global decreases in carbon dioxide levels requires us to reevaluate the way we think about the evolution of C4 photosynthesis," said Dr. Nelson. "This new information should encourage the examination of alternate evolutionary selection pressures, such as warm temperatures or dry climates."

C4 plants compose only 3 percent of flowering plant species, yet account for about 25 percent global terrestrial productivity. About 60% of C4 species are grasses, and they dominate the world's grassland and savanna biomes, particularly those in warmer, lower latitude areas. Their ecological success results from the way these species concentrate and then fix carbon dioxide in order to power photosynthesis. While the most well known C4 plants are maize and sugar cane, both of which are critical to human consumption, there is a growing interest in their use as biofuels in order to capture carbon from the atmosphere to mitigate increasing global carbon dioxide levels.

The team used an innovative technique pioneered by Dr. Nelson earlier in his career - the Single Pollen Isotope Ratio Analysis or SPIRAL – to analyze the samples. The scientists first extracted grains of grass pollen from sedimentary rocks using a micromanipulator; then analyzed the tiny samples using a microcombustion device interfaced with an isotope ratio mass spectrometer in Ann Pearson's laboratory at Harvard University, which houses one of only a handful of these devices in the world. Through this analysis, they were able to detect the signature of C4 species from their more common C3 counterparts, because C4 and C3 plants take up different ratios of carbon isotopes during photosynthesis.

"SPIRAL enables us to detect C4 grasses at much lower abundances in geological records than previous approaches, which is helping to revolutionize our ability to study their ecology and evolution," said Dr. Hu. University of Illinois graduate student Michael Urban, lead author of the paper, continues to analyze samples from other parts of the world to look at variation in C4-grass abundance in relation to past changes in atmospheric CO2 and climate.

Not very Medean. ;)

New Top 500 Supercomputers List (11/10)

From the top 10% (50) systems:

China holds #1, #3, #28, #35
America holds #2, #5, #7, #8, #10 - 16, #18, #21, #26, #30-32, 40, 41, #43-46, and #48-50.
Japan holds #4, #33, and #42.
France holds #6, #27, #36, and #37.
Germany holds #9, #22, and #23.
Russia holds #17.
South Korea holds #18, #19, #24, and #25.
Brazil holds #29.
Saudi Arabia holds #34.
Switzerland holds #38.
Canada holds #39.
India holds #47.

The list by country is here and pie chart is here. Over all the US holds 54.8 % of all HPC systems on the Top 500 list. China has 8.2%. Japan has 5.2%. France has 5.2% and Germany has 5.2%. UK has 5%.

A personal note: the day job holds #5! And #26 in the top 50.

Antihydrogen Trapped for the First Time

Physicists working at the European Organization for Nuclear Research (CERN) in Geneva, Switzerland, have succeeded in trapping antihydrogen – the antimatter equivalent of the hydrogen atom – a milestone that could soon lead to experiments on a form of matter that disappeared mysteriously shortly after the birth of the universe 14 billion years ago.

The first artificially produced low energy antihydrogen atoms – consisting of a positron, or antimatter electron, orbiting an antiproton nucleus – were created at CERN in 2002, but until now the atoms have struck normal matter and annihilated in a flash of gamma-rays within microseconds of creation.

The ALPHA (Antihydrogen Laser PHysics Apparatus) experiment, an international collaboration that includes physicists from the University of California, Berkeley, and Lawrence Berkeley National Laboratory (LBNL), has now trapped 38 antihydrogen atoms, each for more than one-tenth of a second.

While the number and lifetime are insufficient to threaten the Vatican – in the 2000 novel and 2009 movie "Angels & Demons," a hidden vat of potentially explosive antihydrogen was buried under St. Peter's Basilica in Rome – it is a starting point for learning new physics, the researchers said.

"We are getting close to the point at which we can do some classes of experiments on the properties of antihydrogen," said Joel Fajans, UC Berkeley professor of physics, LBNL faculty scientist and ALPHA team member. "Initially, these will be crude experiments to test CPT symmetry, but since no one has been able to make these types of measurements on antimatter atoms at all, it's a good start."

CPT (charge-parity-time) symmetry is the hypothesis that physical interactions look the same if you flip the charge of all particles, change their parity – that is, invert their coordinates in space – and reverse time. Any differences between antihydrogen and hydrogen, such as differences in their atomic spectrum, automatically violate CPT, overthrow today's "standard model" of particles and their interactions, and may explain why antimatter, created in equal amounts during the universe's birth, is largely absent today.

The team's results will be published online Nov. 17 in advance of its print appearance in the British journal Nature.

AWESOME!

Climate Change Can Crunch China's Agriculture

Climate change could trigger a 10 percent drop in China's grain harvest over the next 20 years, threatening the country's food security, a leading agriculture expert warned in comments published Friday.

Tang Huajun, deputy dean of the Chinese Academy of Agricultural Sciences, warned crop production could fall by five to 10 percent by 2030 if climate change continues unchecked, in an interview with the official China Daily.

"The output of the country's three main foods -- rice, wheat and corn -- may suffer a 37 percent decline in the latter part of this century if the government fails to take effective measures to address the impact of climate change," Tang was quoted as saying.

[...]

Tang is the chief scientist for a government project launched in September to study the impact of climate change on China's grain production over the past 20 years at 11 research stations in the north and south of the country.

"Agriculture has been the worst hit by climate change and some negative effects have become more obvious due to rising temperatures and water shortages over the past 10 years," Tang said.

Drought is the biggest threat to China's grain harvest, causing an annual average loss of 15 to 25 million tonnes from 1995 to 2005, or four to eight percent of the country's annual output, Tang said.

Noel. I am going to get to that 'How Bad Can It Get' post relatively soon. Maybe over Tday weekend. That said, I suspect 10% may be a little too conservative. Reason being that precipitation change is poorly predicted at this point, but is wildly different depending on the temperature range in models and almost always more negative for Australia, Central Asia and Africa.

The Proposed Unmanned NASA Unmanned Probes for the Next Decade

The total proposed tab without cost overruns is $40.2 bilion FY15 $. Given the issues of plutonium production alone there is going to be a massive pruning of this list. Nevermind regular funding...

First European Farmers: The Out of Turkey Hypothesis?

A team of international researchers led by ancient DNA experts from the University of Adelaide has resolved the longstanding issue of the origins of the people who introduced farming to Europe some 8000 years ago.

A detailed genetic study of one of the first farming communities in Europe, from central Germany, reveals marked similarities with populations living in the Ancient Near East (modern-day Turkey, Iraq and other countries) rather than those from Europe.

Project leader Professor Alan Cooper, Director of the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, says: "This overturns current thinking, which accepts that the first European farming populations were constructed largely from existing populations of hunter-gatherers, who had either rapidly learned to farm or interbred with the invaders."

The results of the study have been published today in the online peer-reviewed science journal PLoS Biology.

"We have finally resolved the question of who the first farmers in Europe were – invaders with revolutionary new ideas, rather than populations of Stone Age hunter-gatherers who already existed in the area," says lead author Dr Wolfgang Haak, Senior Research Associate with ACAD at the University of Adelaide.

"We've been able to apply new, high-precision ancient DNA methods to create a detailed genetic picture of this ancient farming population, and reveal that it was radically different to the nomadic populations already present in Europe.

"We have also been able to use genetic signatures to identify a potential route from the Near East and Anatolia, where farming evolved around 11,000 years ago, via south-eastern Europe and the Carpathian Basin (today's Hungary) into Central Europe," Dr Haak says.

[...]

The ancient DNA used in this study comes from a complete graveyard of Early Neolithic farmers unearthed at the town of Derenburg in Saxony-Anhalt, central Germany.

No time. Seriously no time. Just trying to get back to doing this some.

Baby Apatosaurus Run Bipedally?

A baby dinosaur approximately the size of a pug dog scurried alongside what may have been its mom or dad some 148 million years ago in what is now foothills near Denver, scientists reported today (Nov. 1) at the annual meeting of the Geological Society of America in Denver.

They caught the paleo-action in the footprints left behind there near the town of Morrison, Colo. The scientists think the dinosaur prints, a set of infant prints next to partial prints from an adult, belonged to Apatosaurus, a sauropod - giant, long-necked dinosaurs that preferred veggies - and once known as Brontosaurus.

As an adult, Apatosaurus is the largest dinosaur found in the Denver metro area, the researchers say, spanning a length of three school buses and weighing as much as eight Asian elephants.

The prints likely made by the infant Apatosaurus were tiny - if you were to place a mug over one, it would completely eclipse the print, according to one of the discoverers, Matthew Mossbrucker, director of the Morrison Natural History Museum in Boulder, Colo.

"The distance between each step is two times wider than what we observe in walking tracks, indicating the animal was at a low-speed run," Mossbrucker said. "I am not aware of any running sauropod tracks anywhere."

The trackway of running prints show only the hind paws, suggesting either that while the baby dinosaur was running, its hind paws eclipsed and removed the front paw track, or that the animal was running only on its hind paws. The tracks made by the adult in a walking mode did show a front paw print.

"We've been arguing for more than a century as to whether or not sauropods could stand up on their back paws," Mossbrucker told LiveScience. "Apparently they can, and the young can even run."

Mossbrucker notes that under the scientific definition of running, this little guy may not have met the criteria. But "if you were to see this animal scurry and scamper in front of you, you would say it's running," he said.

"In the end, we might have a baby sauropod that is running like a Basilisk lizard, a modern lizard that is mostly a quadroped, but when spooked it runs on its hindlegs," Mossbrucker said.

no time.

That Chinese Supercomputer, Tianhe-1A (Milky Way)

China has officially built the world's faster computer. This is impressive. Most people have been saying that its all built from US parts. There is some truth to that. The CPUs and whatnot are nvidia GPUs and CPUs (AMD?) are US $tech.

However, the ever important interconnect is NOT American. This is homegrown and that is really impressive. Interconnects are hard. its also rumored to be twice as fast as QDR infiniband and laid out as a fat tree. its also rumored to use around 14 MW. That's excellent.

This has been compared to what the Japanese did with the Earth Simulator. That claimed the top spot for some time because it was around 4x+ faster than the US counterparts. The difference here between Tinhe-1A and the US counterparts is not that much, in comparison: 50%. I would expect this machine to be overtaken in a year at most. Possibly by June.

Congratulations to the Chinese. I wish I were going to SC10 now. Its sure to be an exciting event now. we'll see if the US can pull out any surprise benchmarks now. Never know. I doubt it though.

Raising Insects in Multiple Atmosperhic Oxygen Levels

The giant dragonflies of ancient Earth with wingspans of up to 70 centimeters (28 inches) are generally attributed to higher oxygen atmospheric levels in the atmosphere in the past. New experiments in raising modern insects in various oxygen-enriched atmospheres have confirmed that dragonflies grow bigger with more oxygen, or hyperoxia.

However, not all insects were larger when oxygen was higher in the past. For instance, the largest cockroaches ever are skittering around today. The question becomes how and why do different groups respond to changes in atmospheric oxygen.

The secrets to why these changes happened may be in the hollow tracheal tubes insects use to breathe. Getting a better handle on those changes in modern insects could make it possible to use fossilized insects as proxies for ancient oxygen levels.

"Our main interest is in how paleo-oxygen levels would have influenced the evolution of insects," said John VandenBrooks of Arizona State University in Tempe. To do that they decided to look at the plasticity of modern insects raised in different oxygen concentrations. The team raised cockroaches, dragonflies, grasshoppers, meal worms, beetles and other insects in atmospheres containing different amounts of oxygen to see if there were any effects.

One result was that dragonflies grew faster into bigger adults in hyperoxia. However, cockroaches grew slower and did not become larger adults. In all, ten out of twelve kinds of insects studied decreased in size in lower oxygen atmospheres. But there were varied responses when they were placed into an enriched oxygen atmosphere. VandenBrooks will be presenting the results of the work on Monday, Nov. 1 at the annual meeting of the Geological Society of America in Denver.

"The dragonflies were the most challenging of the insects to raise," said VandenBrooks because, among other things, there is no such thing as dragonfly chow. As juveniles they need to hunt live prey and in fact undergraduate students Elyse Muñoz and Michael Weed working with Dr. VandenBrooks had to resort to hand feeding the dragonflies daily.

"Dragonflies are notoriously difficult to rear," said VandenBrooks. "We are one of the only groups to successfully rear them to adulthood under laboratory conditions."

Once they had worked that out, however, they raised three sets of 75 dragonflies in atmospheres containing 12 percent (the lowest oxygen has been in the past), 21 percent (like modern Earth's atmosphere) and 31 percent oxygen (the highest oxygen has been).

Cockroaches, as anyone who has fought them at home knows, are much easier to rear. That enabled the researchers to raise seven groups of 100 roaches in seven different atmospheres ranging from 12 percent to 40 percent oxygen mimicking the range of paleo-oxygen levels. Cockroaches took about twice as long to develop in high oxygen levels.

"It is the exact opposite of what we expected," said VandenBrooks. One possibility is that the hyperoxic reared roaches stayed in their larval stage longer, perhaps waiting for their environment to change to a lower, maybe less stressful oxygen level.

This surprising result prompted the researchers to take a closer look at the breathing apparatus of roaches – their tracheal tubes. These are essentially hollow tubes in an insect's body that allow gaseous oxygen to enter directly into the insect tissues.

VandenBrooks and his team took their hyperoxic reared roaches to Argonne National Lab's x-ray synchrontron imaging facility to get a closer look at the tracheal tubes. The x-ray synchrontron is particularly good at resolving the edges where things of different phases meet – like solids on liquids or gas on solids. That's just what the inside of a tracheal tube is.

What they found was that the tracheal tubes of hyperoxic reared roaches were smaller than those in lower oxygen atmospheres. That decrease in tube size with no increase in the overall body size would allow the roaches to possibly invest more in tissues used for other vital functions other than breathing – like eating or reproducing. The roaches reared in hypoxia (lower oxygen) would have to trade off their investment in these other tissues in order to breathe.

The next step, said VandenBrooks, will be to look closely at the tracheal tubes of insects fossilized in amber to see what they might say about oxygen levels at various times in the past. These might possibly serve as a proxy for paleo-oxygen levels.

Abstract: ATMOSPHERIC OXYGEN AND THE EVOLUTION OF INSECT GIGANTISM.

How much bigger were the hyperoxic raised dragonflies?

Cell Phone in 1928 Chaplin Film?

Good for a giggle. There's a youtube video on the UT site too.

I have to wonder if this was a case of someone with TEH AWESOME photoshop powers striking.

Did Cyanobacteria Produce Oxygen Oceanic Oases?

More than two and a half billion years ago, Earth differed greatly from our modern environment, specifically in respect to the composition of gases in the atmosphere and the nature of the life forms inhabiting its surface. While today's atmosphere consists of about 21 percent oxygen, the ancient atmosphere contained almost no oxygen. Life was limited to unicellular organisms. The complex eukaryotic life we are familiar with – animals, including humans – was not possible in an environment devoid of oxygen.

The life-supporting atmosphere Earth's inhabitants currently enjoy did not develop overnight. On the most basic level, biological activity in the ocean has shaped the oxygen concentrations in the atmosphere over the last few billion years. In a paper published today by Nature Geoscience online, Arizona State University researchers Brian Kendall and Ariel Anbar, together with colleagues at other institutions, show that "oxygen oases" in the surface ocean were sites of significant oxygen production long before the breathing gas began to accumulate in the atmosphere.

By the close of this period, Earth witnessed the emergence of microbes known as cyanobacteria. These organisms captured sunlight to produce energy. In the process, they altered Earth's atmosphere through the production of oxygen – a waste product to them, but essential to later life. This oxygen entered into the seawater, and from there some of it escaped into the atmosphere.

"Our research shows that oxygen accumulation on Earth first began to occur in surface ocean regions near the continents where the nutrient supply would have been the highest," explains Kendall, a postdoctoral research associate at the School of Earth and Space Exploration in ASU's College of Liberal Arts and Sciences. "The evidence suggests that oxygen production in the oceans was vigorous in some locations at least 100 million years before it accumulated in the atmosphere. Photosynthetic production of oxygen by cyanobacteria is the simplest explanation."

The idea of "oxygen oases," or regions of initial oxygen accumulation in the surface ocean, was hypothesized decades ago. However, it is only in the past few years that compelling geochemical evidence has been presented for the presence of dissolved oxygen in the surface ocean 2.5 billion years ago, prior to the first major accumulation of oxygen in the atmosphere (known as the Great Oxidation Event).

Kendall's work is the latest in a series of recent studies by a collaborative team of researchers from ASU; University of California, Riverside; and University of Maryland that point to the early rise of oxygen in the oceans. Together with colleagues from University of Washington and University of Alberta, this team first presented evidence for the presence of dissolved oxygen in these oceans in a series of four Science papers over the past few years. These papers focused on a geologic formation called the Mt. McRae Shale from Western Australia. One of these papers, led by the ASU team, presented geochemical profiles that showed an abundance of two redox-sensitive elements – rhenium (Re) and molybdenum (Mo) – implying that small amounts of oxygen mobilized these metals from the crust on land or in the ocean, and transport them through an oxic surface ocean to deeper anoxic waters where the metals were hidden into organic-rich sediments. Kendall participated in this research while a postdoctoral student at the University of Alberta.

Kendall's goal in the new project was to look for evidence of dissolved oxygen in another location. He wanted to see if the geochemical evidence from the Mt. McRae Shale in Western Australia would be found in similarly-aged rocks from South Africa. Those rocks were obtained in a project supported by the Agouron Institute. Kendall's research was supported by grants from NASA and the National Science Foundation.

What Kendall discovered was a unique relationship of high rhenium and low molybdenum enrichments in the samples from South Africa, pointing to the presence of dissolved oxygen on the seafloor itself.

"In South Africa, samples from the continental slope beneath the shallower platform were thought to be deposited at water depths too deep for photosynthesis. So it was a big surprise that we found evidence of dissolved oxygen on the seafloor at these depths. This discovery suggests that oxygen was produced at the surface in large enough quantities that some oxygen survived as it was mixed to greater depths. That implies a significantly larger amount of oxygen production and accumulation in 'oxygen oases' than was previously realized."

A key contribution to this study came from Christopher Reinhard and Timothy Lyons, collaborators at the University of California, Riverside, and Simon Poulton at Newcastle University, who found that the chemistry of iron (Fe) in the same shales is also consistent with the presence of dissolved oxygen.

"It was especially satisfying to see two different geochemical methods – rhenium and molybdenum abundances and Fe chemistry – independently tell the same story," Kendall noted.

Evidence that the atmosphere contained at most minute amounts of oxygen came from measurements of the relative abundances of sulfur (S) isotopes. These measurements were performed by Alan Kaufman, a collaborator at the University of Maryland.

no time.

Autism: An X Chromosome Linked Trait?

New research from the Centre for Addiction and Mental Health (CAMH) and The Hospital for Sick Children (SickKids), both in Toronto, Canada provides further clues as to why Autism Spectrum Disorder (ASD) affects four times more males than females. The scientists discovered that males who carry specific alterations of DNA on the sole X-chromosome they carry are at high risk of developing ASD. The research is published in the September 15 issue of Science Translational Medicine.

ASD is a neurological disorder that affects brain functioning, resulting in challenges with communication and social interaction, unusual patterns of behaviour, and often, intellectual deficits. ASD affects one in every 120 children and a startling one in 70 boys. Though all of the causes of ASD are not yet known, research has increasingly pointed towards genetic factors,. In recent years, several genes involved in ASD have successfully been identified.

The research team was led by Dr. John B. Vincent, Senior Scientist and head of CAMH's Molecular Neuropsychiatry and Development Laboratory and Dr. Stephen Scherer, Senior Scientist and Director of The Centre for Applied Genomics at SickKids, and Director of the McLaughlin Centre at the University of Toronto. The scientists analyzed the gene sequences of 2,000 individuals with ASD, along with others with an intellectual disability, and compared the results to thousands of population controls. They found that about one per cent of boys with ASD had mutations in the PTCHD1 gene on the X-chromosome. Similar mutations were not found in thousands of male controls. Also, sisters carrying the same mutation are seemingly unaffected.

"We believe that the PTCHD1 gene has a role in a neurobiological pathway that delivers information to cells during brain development – this specific mutation may disrupt crucial developmental processes, contributing to the onset of autism." said Dr. Vincent. "Our discovery will facilitate early detection, which will, in turn, increase the likelihood of successful interventions."

"The male gender bias in autism has intrigued us for years and now we have an indicator that starts to explain why this may be," says Dr. Scherer. "Boys are boys because they inherit one X-chromosome from their mother and one Y-chromosome from their father. If a boy's X-chromosome is missing the PTCHD1 gene or other nearby DNA sequences, they will be at high risk of developing ASD or intellectual disability. Girls are different in that, even if they are missing one PTCHD1 gene, by nature they always carry a second X-chromosome, shielding them from ASD." Scherer adds, "While these women are protected, autism could appear in future generations of boys in their families."

There was a relatively recent study that found that autism was more common in affluent caucasian families with older parents. It went rather contrary to the environmental causes hypothesis. If I have time (HA!) I'll find and put a link to that one.

It makes me wonder if this can be directly linked to postponing having kids: we already know of increased rates of other issues such as down's and whatnot. Perhaps the damage is being caused by meiosis potentially going slightly off tracks in (some) older women. As more women postpone their fertility, the number of autistic children rises and will continue to do for generations afterwards because their daughters might be carriers of the damaged regions on their inherited X chromosomes.

I can't imagine that this will be a popular study result or my hypothesis either.

Habitability of the Gliese 581 System

High Marine Phosphorus Followed Snowball Earth Episodes

A team of scientists, led by biogeochemists at the University of California, Riverside, has found new evidence linking "Snowball Earth" glacial events to the rise of early animals.

The controversial Snowball Earth hypothesis posits that the Earth was covered from pole to pole by a thick sheet of ice lasting, on several occasions, for millions of years. These glaciations, the most severe in Earth history, occurred from 750 to 580 million years ago. The researchers argue that the oceans in the aftermath of these events were rich in phosphorus, a nutrient that controls the abundance of life in the oceans.

The UC Riverside team and colleagues tracked phosphorus concentrations through Earth's history by analyzing the composition of iron-rich chemical precipitates that accumulated on the seafloor and scavenged phosphorus from seawater. Their analyses revealed that there was a pronounced spike in marine phosphorus levels in the mid-Neoproterozoic (from ~750 to ~635 million years ago).

To explain these anomalously high concentrations, the researchers argue that the increase in erosion and chemical weathering on land that accompanied Snowball Earth glacial events led to the high amounts phosphorus in the ocean. The abundance of this nutrient, which is essential for life, in turn, led to a spike in oxygen production via photosynthesis and its accumulation in the atmosphere, facilitating the emergence of complex life on Earth.

Study results appear in the Oct. 28 issue of Nature.

"In the geological record, we found a signature for high marine phosphorus concentrations appearing in the immediate aftermath of the Snowball Earth glacial events," said Noah Planavsky, the first author of the research paper and a graduate student in the Department of Earth Sciences. "Phosphorus ultimately limits net primary productivity on geological timescales. Therefore, high marine phosphorus levels would have facilitated a shift to a more oxygen-rich ocean-atmosphere system. This shift could have paved the way for the rise of animals and their ecological diversification. Our work provides a mechanistic link between extensive Neoproterozoic glaciations and early animal evolution."

Planavsky explained the link between marine phosphorus concentrations and the levels of oxygen in the atmosphere.

"High phosphorus levels would have increased biological productivity in the ocean and the associated production of oxygen by photosynthesis," he said. "Much of this organic matter is consumed, in turn, as a result of respiration reactions that also consume oxygen. However, the burial of some proportion of the organic matter results in a net increase of oxygen levels in the atmosphere."

Until now, scientists believed that geochemical conditions in the iron-rich ocean would have led to low phosphorus concentrations. The UC Riverside researchers found no evidence of a phosphorus crisis after Snowball Earth glacial events, however, finding instead indications of an abundance of phosphorus.

no time.

Complete Remains of an Early Jurassic/Late Triassic Sauropod

Scientists have discovered in China the first complete skeleton of a pivotal ancestor of Earth's largest land animals – the sauropod dinosaurs. The new species, tentatively dubbed Yizhousaurus sunae, lived on the flood plains around Lufeng in the Yunnan Province of South China about 200 million years ago. The species helps explain how the iconic four-footed, long-necked sauropod dinosaurs evolved.

Unlike the 120-foot-long, 100-ton sauropod giants that came later, Yizhousaurus was about 30 feet in length, but it shows all of the hallmarks of later sauropods: the beginning of a long neck, a robust skeleton and four-legged posture. It also comes with an intact fossilized skull – which is very rare and crucial for understanding its place in the evolution of sauropods.

"Sauropods have these big bones but their skulls are very lightly constructed and also very small," said paleontologist Sankar Chatterjee of Texas Tech University. Chatterjee presents the discovery on Sunday, Oct. 31 at the annual meeting of the Geological Society of America in Denver.

Yizhousaurus's skull is broad, high and domed, less than a foot long with a short snout, eye sockets on the sides for scanning enemies. It has an unusually wide and U-shaped jaw, in top view, like that seen in later Camarasaurus, said Chatterjee. Numerous serrated and spoon-shaped teeth of the upper and lower jaws would shear and slide past each other for cutting plant material during feeding. The sturdy teeth and raised neck let the animal very easily nip small branches from treetops and then chew the plant material.

Abstract here.

So is this Hettangian or Rhaetian/Norian?

Dinosaurs Ancestors Evolved Right After the Permian Extinction

The oldest evidence of the dinosaur lineage—fossilized tracks—is described this week in Proceedings of the Royal Society B. Just one or two million years after the massive Permian-Triassic extinction, an animal smaller than a house cat walked across fine mud in what is now Poland. This fossilized trackway places the very closest relatives of dinosaurs on Earth about 250 million years ago—5 to 9 million years earlier than previously described fossilized skeletal material has indicated. The paper also described the 246-million-year-old Sphingopus footprints, the oldest evidence of a bipedal and large-bodied dinosaur.

"We see the closest dinosaur cousins immediately after the worst mass extinction," says Stephen Brusatte, a graduate student affiliated with the Division of Paleontology at the American Museum of Natural History. "The biggest crisis in the history of life also created one of the greatest opportunities in the history of life by emptying the landscape and making it possible for dinosaurs to evolve."

The new paper analyzes three sets of footprints from three different sites in the Holy Cross Mountains of central Poland. The sites, all quarries within a 25-mile radius of each other, are windows into three ecosystems because they represent different times periods. The Stryczowice trackway is the oldest at 250 million years. The Baranów trackway is the most recent at 246 million years of age while the Wióry trackway is sandwiched in time between the others.

Because footprints are only an imprint of a small part of the skeleton, identification of trackmakers is often tricky. Luckily, dinosaurs have a very distinctive gait, especially when compared to their diapsid relatives (the evolutionary group that includes birds, reptiles, and extinct lineages) like crocodiles and lizards. While lizards and crocodiles have a splayed walking style, dinosaurs place their two feet closer together. The footprints at all three Polish sites show this feature as well as indisputable dinosaur-like features, including three prominent central toes and reduced outer two toes, a parallel alignment of these three digits (a bunched foot), and a straight back edge of footprints, additional evidence of a dinosaur-like simple hinged ankle.

Because all of these features are seen in footprints at the oldest site, Brusatte and colleagues conclude that the Stryczowice prints—which are only a few centimeters in length—are the oldest evidence of the dinosaur lineage. These dinosaurs, though, are considered "stem dinosaurs," or the immediate relatives of dinosaurs not part of the slightly more derived clade that technically defines dinosaurs. Also, this animal did walk on all four limbs, an abnormal posture for early dinosaurs and their close relatives, although it appears that its forelimbs were already being reduced to more dinosaur-like proportions since the footprints overstep handprints.

The Baranów and Wióry trackways show changes early in the evolutionary history of dinosaurs. Wióry at 248 million years ago shows slight diversification in the types of tracks, but all tracks remain quadrupedal. Footprints from Baranów at 246 million years ago, however, may be the earliest evidence of moderately large-bodied and bipedal true dinosaurs. These tracks, which are called Sphingopus, are 15 centimeters long.

Less than no time.

Things on My Mind

James did that. Glad he's able to with all the crap going down for me. oy.

Something Very Depressing

Ceratopsian Year Continues

See Zach. Or the original paper.