Geosciences posts
- February 10, 2012
- 05:33 PM
- 42 views
The Terrible, Prehistoric Frog That Wasn’t
Over 300 million years ago, long before the time of the dinosaurs, giant amphibians hopped along the sandy shores of Pennsylvania. At least, that was what Pittsburgh Post-Gazette reporter James Ross explained to readers of the newspaper’s November 28th, 1948 issue. The inspiration for the report was a set of strange tracks found in the [...]... Read more »
Niedźwiedzki, G., Szrek, P., Narkiewicz, K., Narkiewicz, M., & Ahlberg, P. (2010) Tetrapod trackways from the early Middle Devonian period of Poland. Nature, 463(7277), 43-48. DOI: 10.1038/nature08623
- February 9, 2012
- 02:39 PM
- 61 views
Supercontinents: A method to their madness
by Brooke N in Smaller Questions
In 50-200 million years all of Earth’s continents will meet again to form a single massive supercontinent around the North Pole. Move over Pangaea, meet our next supercontinent: Amasia.
There are currently two hypotheses for the organizing pattern of supercontinents...... Read more »
Mitchell, R., Kilian, T., & Evans, D. (2012) Supercontinent cycles and the calculation of absolute palaeolongitude in deep time. Nature, 482(7384), 208-211. DOI: 10.1038/nature10800
- February 8, 2012
- 04:40 PM
- 83 views
Melting Ice and Sea Level Rise
by Greg Laden in Greg Laden's Blog
If all the water currently trapped in all the glaciers across the entire world, the sea level would rise far more than most people imagine. Almost everyone living anywhere in the world at an elevation of below about 500 feet with a direct drainage to the sea would be directly affected; The sea level rise itself might be a bit over 300 feet, but oceans tend to migrate horizontally when they rise onto previously uninnundated land surfaces. So if you lived at 500 feet above sea level in most of Maine, you'd have a much shorter walk to the rocky shoreline, but if you lived at 500 feet across much of the Gulf Coast it would only be a matter of time until the eroding sea cliff reached you incorporated you into the offshore sediments.
Having said that, Anthropogenic Global Warming has resulted in only modest sea level rise to date, and it is at this point probably true that warming of the ocean causing thermal expansion has been at the same level of magnitude (or greater) than seas rising because of the influx of melted glacial water.
The problem is, it is very difficult to measure either sea level rise or ice loss very accurately, for a number of reasons. But there is a saving grace. Or should I say, GRACE. GRACE is a NASA project; Twin satellites measure changes in the Earth's gravity field in such a way that it is possible to identify changes in the distribution of water. From the GRACE overview statement:
Read the rest of this post... | Read the comments on this post...... Read more »
Jacob, T., Wahr, J., Pfeffer, W., & Swenson, S. (2012) Recent contributions of glaciers and ice caps to sea level rise. Nature. DOI: 10.1038/nature10847
- February 6, 2012
- 12:45 PM
- 61 views
Mosasaurs: Masters of the Bronx Cheer
[Author's Note: After months of fieldwork, museum visits, and other research, A Date With a Dinosaur is finally coming together. And not a moment too soon - my deadline is rapidly approaching. New essays will continue to surface here, but I'm also going to dredge up some favorite posts from years past to help keep [...]... Read more »
Schulp, A.; Mulder, E.; Schwenk, K. (2002) Did mosasaurs have forked tongues?. Netherlands Journal of Geosciences, 84(3), 359-371. info:/
- February 3, 2012
- 04:34 PM
- 86 views
SPSP 2012: Political Polarization
by Melanie Tannenbaum in PsySociety
What’s that? This is some sort of big year for American politics? Ah, yes – it’s 2012. We’re in the middle of the Republican primaries, there’s a presidential election in 9 months, and political psychology was all over this year’s … Continue reading →... Read more »
Krosnick, J. A., Holbrook, A. L., & Visser, P. S. (2000) The impact of the Fall 1997 debate about global warming on American public opinion. Public Understanding of Science. info:/
- January 30, 2012
- 01:31 PM
- 27 views
Preening the History of Primates
When viewed within the broader context of our evolutionary history, we are anthropoid primates. That’s the group which contains monkeys and apes (with our species being a specialized variety of ape, and apes being a particular subset of monkeys, and monkeys representing the major group of anthropoids). But how anthropoid primates originated has been a [...]... Read more »
Maiolino, S., Boyer, D., & Rosenberger, A. (2011) Morphological Correlates of the Grooming Claw in Distal Phalanges of Platyrrhines and Other Primates: A Preliminary Study. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 294(12), 1975-1990. DOI: 10.1002/ar.21498
Maiolino, S., Boyer, D., Bloch, J., Gilbert, C., & Groenke, J. (2012) Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins. PLoS ONE, 7(1). DOI: 10.1371/journal.pone.0029135
Williams, B., Kay, R., & Kirk, E. (2010) New perspectives on anthropoid origins. Proceedings of the National Academy of Sciences, 107(11), 4797-4804. DOI: 10.1073/pnas.0908320107
- January 26, 2012
- 01:26 PM
- 81 views
New Jersey’s Turnpike Croc
Two years ago, when I was still stuck in the middle of the garden state, New Jersey State Museum assistant curator of natural history Jason Schein took me on a brief tour of his institution’s collections. There were crocodyliforms everywhere. Shelf after shelf contained the teeth, armor, and bones of a variety of prehistoric crocs [...]... Read more »
Brochu, C., Parris, D., Grandstaff, B., Denton, R., & Gallagher, W. (2012) A new species of (Crocodyliformes, Eusuchia) from the Late Cretaceous–early Paleogene of New Jersey . Journal of Vertebrate Paleontology, 32(1), 105-116. DOI: 10.1080/02724634.2012.633585
- January 25, 2012
- 02:10 PM
- 92 views
Real-Life DinoCrocs Crushed the Competition
Giant "DinoCrocs" of the Cretaceous didn't just hang out in the background while predatory dinosaurs stole the spotlight. Laelaps blogger Brian Switek explains how new fossils show they competed as a top predator.... Read more »
RIFF, D., & KELLNER, A. (2011) Baurusuchid crocodyliforms as theropod mimics: clues from the skull and appendicular morphology of Stratiotosuchus maxhechti (Upper Cretaceous of Brazil). Zoological Journal of the Linnean Society. DOI: 10.1111/j.1096-3642.2011.00713.x
- January 24, 2012
- 02:08 AM
- 100 views
temperature aNOMalies
by csoeder in Topologic Oceans
If you are new to climate science, you might be wondering what, exactly, this ‘temperature anomaly’ thing is that you keep hearing about. I know I was a bit confused at first! This post explains the concept, using a real-world example. Cities tend to be warmer than their surrounding countrysides, a fact known as the [...]... Read more »
Jones, P., Lister, D., & Li, Q. (2008) Urbanization effects in large-scale temperature records, with an emphasis on China. Journal of Geophysical Research, 113(D16). DOI: 10.1029/2008JD009916
- January 20, 2012
- 09:19 PM
- 175 views
Lead Poisoning in Rome - The Skeletal Evidence
by Kristina Killgrove in Powered By Osteons
A friend alerted me to today's IO9 post, "The First Artificial Sweetener Poisoned Lots of Romans." It's a (very) brief look at some of the uses of lead (Pb) in the Roman world, including the hoary hypothesis that rampant lead poisoning led to the downfall of Rome - you know, along with gonorrhea, Christianity, slavery, and the kitchen sink.
Roman Lead Artifacts (clockwise from top left) -
curse tablet, shot, pipe, ingots, jewelry
The fact the Romans loved their lead isn't in question. We have plenty of textual and archaeological sources that inform us of the use of lead - as cosmetics, ballistics, sarcophagi, pipes, jewelry, curse tablets, utensils and cooking pots, and, of course sapa and defrutum (wine boiled down in lead pots) - but what almost all stories about the use of lead in ancient Rome miss is the osteological evidence.
But let's start with some contemporary medical knowledge. Metabolic disorders can be caused by a lack of nutrients - a lack of vitamin C gives you scurvy, and a lack of vitamin D gives you rickets - but they can also be caused by an abundance of something, like too much fluoride, too much mercury, too much arsenic, or too much lead.
Lead is a heavy metal, one that isn't needed by the human body, unlike vitamins C or D. This element is found in the environment naturally, so we do expect to find some amount of lead in the skeleton of every person, ancient or modern. But, because of the physical properties of lead - it can be made into hard, sharp things - people have been using it for millennia and thus have been exposed to heavy metal toxicity for millennia as well. The dangers of lead actually weren't well known until the second half of the 20th century, which was when lead was taken out of things like paint and gasoline.
The main problem with lead - the reason that it's toxic - is that it interferes with normal enzyme reactions within the human body. Lead can actually mimic other metals that are essential to biological functioning. But since lead doesn't work the same way as those metals, the enzymatic reactions that depend on things like calcium, iron, and zinc are disrupted. The most damaging enzymatic reaction that lead affects is the production of hemoglobin, or red blood cell production, which can cause anemia. So doctors in modern times often find anemia in a person with lead poisoning. Lead is also particularly problematic because it stays in the body for a very long time once it's absorbed, inhaled, or ingested. Most of it gets deposited in the bones and teeth. Lead can be removed from the body, excreted through the kidneys and urine, but it's a very slow process without modern chelation therapy.
Map of Imperial Rome and Suburbs
In modern society, lead poisoning is diagnosed through a blood test to determine the level of lead in the body. We don't have blood in ancient remains, of course, so we have to investigate lead through the levels we can measure in bone and enamel. As far as I know, the first and only study to actually measure levels of lead in skeletons from Rome is the one that involved my samples from the two cemeteries of Casal Bertone and Castellaccio Europarco (1st-3rd c AD).* The analysis was led by Janet Montgomery, now at Durham University, and also involved around 200 samples from Britain from the Neolithic to the Late Medieval periods (see below, Montgomery et al. 2010).
One of the charts from that article is below. The Romans are there in the middle. What you can see is that there are fairly low levels of lead in the earlier periods in Britain (Neolithic to Iron Age) and in the post-fall of the Roman Empire (5th-7th c AD). So what do those numbers mean on a scale of Normal to Lead Poisoned? Well, the modern recommendation by the World Health Organization and the Centers for Disease Control is that children should not have more than 1 mg/kg of lead in their bones (or 10 ug/dL measured in blood). Back to the chart, and no one in the Neolithic is getting poisoned. By the Iron Age, some people are above that level. The Imperial period is pretty special - we've got people with lead levels up to 30 mg/kg, which is 30 times higher than modern recommendations! In fact, this level is three times higher than the level the WHO considers "very severe lead poisoning."
Lead Concentrations from Britain and Rome
(Montgomery et al. 2010, Figure 11.2)
The chart below shows my Roman samples separate from the British samples. These are all median human lead concentrations. You can see a spike in the British samples during the Roman period, but the Romans themselves are so much higher, at least until the Medieval period, when people started working with lead again.
Median Lead Concentrations in Britain and Rome
(Montgomery et al. 2010, Figure 11.3)
It's not yet clear what the data mean, though, other than that some people likely had lead poisoning and others didn't. The sample size is fairly small, and more importantly, I don't know where people were living. That is, if the people buried at Casal Bertone and Castellaccio Europarco were living in an industrial area or were metalworkers, then they were more at risk for high levels of lead than were people not living in those areas a... Read more »
Aufderheide, A., Rapp, G., Wittmers, L., Wallgren, J., Macchiarelli, R., Fornaciari, G., Mallegni, F., & Corruccini, R. (1992) Lead exposure in italy: 800 BC-700 AD. International Journal of Anthropology, 7(2), 9-15. DOI: 10.1007/BF02444992
J. Montgomery, J. Evans, S. Chenery, V. Pashley, & K. Killgrove. (2010) 'Gleaming, white, and deadly': using lead to track human exposure and geographic origins in the Roman period in Britain. Roman Diasporas, Journal of Roman Archaeology, 199-226. info:/
- January 17, 2012
- 12:07 PM
- 111 views
How the “Terrible Heads” Became World Travelers
Earlier this week, paleontologists described another of our distant, ancient cousins. This was no hominin, early primate, or even archaic mammal, but a much, much older variety of creature that would superficially seem to have more in common with terrible primeval reptiles than with us. Named Pampaphoneus biccai, this knobby-headed, 260 million year old predator [...]... Read more »
Modesto, S., Smith, R., Campione, N., & Reisz, R. (2011) The last “pelycosaur”: a varanopid synapsid from the Pristerognathus Assemblage Zone, Middle Permian of South Africa. Naturwissenschaften, 98(12), 1027-1034. DOI: 10.1007/s00114-011-0856-2
- January 16, 2012
- 09:51 AM
- 233 views
Is this journal for real?
by Neurobonkers in Neurobonkers
This year 134 suspect new journals have appeared from the abyss, all published by the same clandestine company “Scientific & Academic Publishing, USA“. Scientists have been quick to raise the alarm and ruthless in their response.... Read more »
Morrison, Heather. (2012) Scholarly Communication in Crisis. Freedom for scholarship in the internet age. Simon Fraser University School of Communication. info:/
- January 15, 2012
- 01:06 PM
- 93 views
The Jurassic’s Housecat Croc
At long last, Fruitachampsa lives. Sort of. This strange crocodyliform has been extinct for around 150 million years. But, after three decades of waiting, this short-snouted croc has finally been officially named.
The new paper that describes Fruitachampsa callisoni calls the animal “A new shartegosuchid crocodyliform from the Upper Jurassic Morrison Formation of western Colorado.” That’s [...]... Read more »
CLARK, J. (2011) A new shartegosuchid crocodyliform from the Upper Jurassic Morrison Formation of western Colorado. Zoological Journal of the Linnean Society. DOI: 10.1111/j.1096-3642.2011.00719.x
- January 13, 2012
- 08:46 AM
- 203 views
New Study Explains How to Battle Climate Change with Simple, Attainable Measures
by Jaime Menchen in United Academics
There is, more than ever, the need of comprehensive, practical studies that present immediately possible actions against climate change. That’s exactly what a new research published today in Science has taken into account.... Read more »
Drew Shindell1,*, Johan C. I. Kuylenstierna2, Elisabetta Vignati3, Rita van Dingenen3, Markus Amann4, Zbigniew Klimont4, Susan C. Anenberg5, Nicholas Muller6, Greet Janssens-Maenhout3, Frank Raes3, Joel Schwartz7, Greg Faluvegi1, Luca Pozzoli3,†, Kaarle, Lisa Emberson, David Streets, V. Ramanathan, Kevin Hicks, N. T. Kim Oanh, George Milly, Martin Williams, Volodymyr Demkine, & David Fowler. (2012) Simultaneously Mitigating Near-Term Climate Change and Improving Human Health and Food Security. Science. info:/10.1126/science.1210026
- January 12, 2012
- 10:00 AM
- 68 views
Cold snaps curtail invasions
Climate change not only causes shifts in the distributions of native species, but also allow invasive species to establish new populations. For example, many Caribbean species are taking advantages of warming temperatures, expanding polewards and invading into the south-eastern United States. Having established themselves, however, it’s not unknown for the invaders to come to pain. [...]... Read more »
Canning-Clode, J., Fowler, A., Byers, J., Carlton, J., & Ruiz, G. (2011) ‘Caribbean Creep’ Chills Out: Climate Change and Marine Invasive Species. PLoS ONE, 6(12). DOI: 10.1371/journal.pone.0029657
- January 9, 2012
- 09:53 AM
- 149 views
Human CO2 emissions thwart next Ice Age
by Carian Thus in United Academics
A new Ice Age would begin within the next 1,500 years, but it might not, due to human emissions of carbon dioxide - says a new study of Cambridge University. ... Read more »
Jaccard, S., & Galbraith, E. (2011) Large climate-driven changes of oceanic oxygen concentrations during the last deglaciation. Nature Geoscience. DOI: 10.1038/ngeo1352
- January 4, 2012
- 09:39 PM
- 187 views
A Walkthrough To Find Credible Souces and Answers to the Controversies of Vaccines, Evolution, Holocaust, and Global Warming
by DJ Busby in Astronasty
Where do you get your facts?
Hopefully, a reliable source.
So what's an online reliable source, and how can a regular Joe get a hold of this information?
A very easy way to be confident is to make sure that you're reading from an .edu or .gov page. One of the easiest (and quickest) ways to find your topic is through the citations on Wikipedia. Some people doubt the validity of Wikipedia in fear of hecklers. The nature or self-maintaining issue of Wikipedia aside, the citations at the bottom are a real treasure trove.
... Read more »
Bonhoeffer J, & Heininger U. (2007) Adverse events following immunization: perception and evidence. Current opinion in infectious diseases, 20(3), 237-46. PMID: 17471032
Demicheli V, Jefferson T, Rivetti A, & Price D. (2005) Vaccines for measles, mumps and rubella in children. Cochrane database of systematic reviews (Online). PMID: 16235361
Committee on Revising Science and Creationism: A View from the National Academy of Sciences, National Academy of Sciences and Institute of Medicine of the National Academies. (2008) Science, Evolution, and Creationism. The National Academies Press. info:/9780309105866
Boykoff, M., & Boykoff, J. (2004) Balance as bias: global warming and the US prestige press. Global Environmental Change, 14(2), 125-136. DOI: 10.1016/j.gloenvcha.2003.10.001
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- January 4, 2012
- 03:57 PM
- 177 views
Russian Rivers and Arctic Salinity: Climate Variation Better Understood
by Greg Laden in Greg Laden's Blog
The sun heats the earth, but unevenly. The excess heat around the equator moves towards the poles, via a number of different mechanisms, the most noticeable for us humans being via air masses. That's what much of our weather is about. Heat also moves towards the poles, in the ongoing evening-out of energy distribution on the planet's surface, via ocean currents.
One of the interesting things that happens with ocean currents is this: Warm water tends to move from equator towards polar regions across the surface, then cools down and drops to the deep sea, where it moves back south again, often in a kind of loop that we call a "conveyor." Becuase of some quirky historical stuff, the continents on this planet are mostly in the norther hemisphere, so the loops of ocean water that mariners have long called "currents" are extra strange in the north, and as it happens, there is a big loop of warm water or two that go way farther north (as warm water) than usual, where increased evaporation and cooling cause the water to a) loose it's heat to the air and b) sink rather dramatically to the bottom of the sea. The sinking helps direct the north-moving surface currents, maintaining the loop. The release of heat keeps England from looking like Canada and Norway from looking like Greenland, as much of this heat leaves the North Atlantic and traverses Europe first. By the time that energy gets around the world all the way back to Greenland, well, it isn't helping to melt glaciers very much, bit it does in fact have an effect. Without this warming, there would probably be continental glacial masses on Europe and Canada, rather than scattered and small mountain glaciers. In other words, there would be an ice age.
Did I mention the evaporation as a driving force in the conveyor? Yes, of course I did. And the reason this works is that when the warm surface water evaporates, it becomes more saline relative to the rest of the ocean, and sinks, because salty water is denser than fresh water. We believe that there have been times in the past when fresh water being added to the northern seas has mixed with a conveyor, caused the water to be less salty, turned off the flow of warm water to the northerly latitudes, and ushered in a mini-ice age, or perhaps a maxi-ice age. Indeed, there are some theories about paleoclimate that suggest, very strongly, that this is exactly the mechanism that triggers an ice age. Read the rest of this post... | Read the comments on this post...... Read more »
Morison, J., Kwok, R., Peralta-Ferriz, C., Alkire, M., Rigor, I., Andersen, R., & Steele, M. (2012) Changing Arctic Ocean freshwater pathways. Nature, 481(7379), 66-70. DOI: 10.1038/nature10705
- January 3, 2012
- 07:41 PM
- 137 views
The Sloth’s Evolutionary Secret
On the surface of things, a two-toed sloth doesn’t look much like its closest fossil kin. The tubby, pug-nosed mammal is not quite as imposing or majestic as Megalonyx – the “great claw” Thomas Jefferson discovered and mistakenly identified as an enormous lion over two centuries ago. But the two are relatively close relatives. In [...]... Read more »
Nyakatura, J. (2011) The Convergent Evolution of Suspensory Posture and Locomotion in Tree Sloths. Journal of Mammalian Evolution. DOI: 10.1007/s10914-011-9174-x
- January 1, 2012
- 09:41 AM
- 250 views
Copyright vs Medicine: If this topic isn’t covered in your newspaper this weekend, get a new newspaper
by Neurobonkers in Neurobonkers
According to the New England Journal of Medicine, after thirty years of silence, authors of a standard clinical psychiatric bedside test have issued take down orders of new medical research.... Read more »
Newman, J., & Feldman, R. (2011) Copyright and Open Access at the Bedside. New England Journal of Medicine, 365(26), 2447-2449. DOI: 10.1056/NEJMp1110652
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