News Article | April 19, 2017
Biologist Leo Smith held an unusual job while an undergraduate student in San Diego. Twice a year, he tagged along on a chartered boat with elderly passengers. The group needed him to identify two particular species of rockfish, the chilipepper rockfish and the California shortspine thornyhead. Once he’d found the red-orange creatures, the passengers would stab themselves in the arms with the fishes’ spines. Doing so, the seniors believed, would relieve their aching arthritic joints. Smith, now at the University of Kansas in Lawrence, didn’t think much of the practice at the time, but now he wonders if those passengers were on to something. Though there’s no evidence that anything in rockfish venom can alleviate pain — most fish stings are, in fact, quite painful themselves — some scientists suspect fish venom is worth a look. Studying the way venom molecules from diverse fishes inflict pain might help researchers understand how nerve cells sense pain and lead to novel ways to dull the sensation. Smith is one of a handful of scientists who are studying fish venoms, and there’s plenty to investigate. An estimated 7 to 9 percent of fishes, close to 3,000 species, are venomous, Smith’s work suggests. Venomous fishes are found in freshwater and saltwater, including some stingrays, catfishes and stonefishes. Some, such as certain fang blennies, are favorites in home aquariums. Yet stinging fishes haven’t gotten the same attention from scientists as snakes and other venomous creatures. But thanks to Smith’s recent work, scientists can now see how venomous fishes fit within a tree of all fishkind. The tree shows that venom arose multiple times throughout history. Understanding which fishes are venomous is the crucial first step to working out the nature of the venoms, Smith says. Researchers are exploring how different fish venoms affect their victims and are discovering extraordinary diversity among fishes’ chemical weaponry. The scientists hope the powerful molecules in the venoms might yield insights that could be turned into medicines. One newly described venom appears to act on opioid receptors, perhaps to stupefy its victims. And venom molecules that stall cell division and others that calm inflammation are inspiring new treatment ideas that go beyond pain relief. While fish-venom studies are rare, fish stings are not. An old estimate says about 40,000 to 50,000 people are stung by fish each year. But the number is probably much higher, Smith says, since many people don’t bother to report their experiences. The most noticeable effect of a venomous fish sting is immediate pain, ranging from the mild sting of those rockfish from Smith’s scouting days to a feeling much more excruciating. “The most pain that I’ve ever been in was my first stingray envenomation,” says venom researcher Bryan Fry of the University of Queensland in Brisbane, Australia. He was trying to collect a sample from a roughly 1½-meter-wide smooth stingray when it stabbed him in the thigh. “The pain is immediate and blinding.” Smith’s first painful run-in was with a fuzzy dwarf lionfish at a pet store where he worked in his late teens. Later, at the library, he found no reports of that species having venom. In fact, medical records of fish stings documented only about 200 fish species as venomous. The experience helped set his career. As his research progressed, Smith began building fish family trees to get a better handle on which fish spew venom. He presumed that fish related to known venomous ones could also be venomous. So he checked their anatomy for venom-delivery structures, like grooved spines. He reported a partial tree in 2006 and published a more complete version last year in Integrative and Comparative Biology. To assemble the latest tree, Smith and colleagues examined eight locations in the genetic instruction books, or genomes, of 388 species of fish, then used a computer program to work out, based on differences and similarities in those genomes, how the animals are probably related. He also examined museum samples of 90 types of fish for spines or fangs and venom glands. Based on what’s known about fish diversity, Smith’s lowball estimate is that, of about 35,000 fish species, 2,386 to 2,962 are venomous. Based on his new tree, Smith estimates that there were 18 distinct instances in which nonvenomous fish evolved a venom apparatus — give or take a few, since venom might have been lost from some groups, or evolved multiple times in others, he says. Jeremy Wright, curator of ichthyology at the New York State Museum in Albany, who has studied venom in catfish family trees, says Smith’s methods were sound and the data support the tree. However, Wright’s research suggests venom arose separately two or more times in the catfish lineage, while Smith’s tree says all stinging catfishes share a single common, venomous ancestor. Whether fish venom arose 18 times, or 15, or 20, that’s a big contrast to other animals that use venom: In snakes, venom appears to have evolved only once. The same is true for the venom in bees and ants. “To have venom evolve multiple times within a group is extraordinary,” says Fry, who’s studied a range of venomous critters. Fish experts say the distinct origins of fish venoms make sense because, unlike snakes, which always use their teeth, fish deliver venom in diverse ways. Spines with venom glands are most commonly found in fins atop the fish’s back, but not always. In many venomous catfishes, the pectoral fins contain the barbs and venom glands. Weever fish spines sit on the operculum, a bony flap that protects the gills on the fish’s cheeks. In stingrays, the flattened spine protrudes just above the tail. And in fang blennies, the venom glands sit at the base of enlarged lower canines, calling to mind tiny vampires of the sea. Even within one fish genus, the venom-delivery apparatus can vary. Ichthyologists Jacob Egge, now at Pacific Lutheran University in Tacoma, Wash., and Andrew Simon of the University of Minnesota analyzed pectoral stingers of 26 species of madtom catfish, found in eastern North American freshwater. Some had smooth spines with a venom gland in the shaft, the two reported in 2011. Others had serrated spines, the better to cause injury, with a gland at the shaft and glands spread along the serrations. One species had no venom gland at all. The effects of venom — from fishes and other creatures — vary widely, but in fishes, the goal is usually the same: to stop an attack. For most fish venoms, pain is key, but some cause numbness, too. All affect the cardiovascular system in some way, by lowering blood pressure, for example, which would probably startle and debilitate a predator, Smith says. In people who have been stung, skin reddening, swelling, itching or temporary localized paralysis might also occur. In some cases, the venom can kill the tissues near the sting site. In rare cases, a combination of low blood pressure, failure of circulation or weak breathing can lead to death. Just within the catfishes, venom effects differ between species. Wright injected venom from nine different species of catfish into largemouth bass, which are typical predators. “It was clear that it was an uncomfortable experience for them,” Wright says of his unlucky subjects. Many venoms caused loss of color and bleeding, some induced jerky muscle contractions or loss of balance, and one simply killed the bass outright, he reported in BMC Evolutionary Biology in 2009. Why did such diverse venoms and delivery apparatuses evolve so many times in fish? With Smith’s comprehensive map of fish venom evolution, scientists can now address that sort of question, says Meg Daly, who studies sea anemone venom at Ohio State University in Columbus. For instance, since most fish use venom for defense, Daly wonders if the evolutionary origins of venoms coincided with times when new predators arrived on the scene. Venom seems to have arisen often in slow-moving bottom dwellers, which would certainly be vulnerable to predation. “If you’re a catfish sitting there sucking on some mud, you need to have some spines,” Fry says. Consider the reef stonefish. It loafs on the floor of the Indian and Pacific oceans, often covered in camouflaging algae, hoping to snatch a passing fish or crustacean. When distressed, the fish raises the 13 spines on its back that are adjacent to venom glands, which hold toxins powerful enough to kill a person. Though venoms have evolved multiple times across fish species, the toxic blends often converge chemically on a set of similar ways to cause damage. For example, the proteins in many fish venoms act by assembling into large rings that then insert themselves into the membranes of cells. This opens a hole where a cell’s innards leak out. When this happens to pain-sensing nerve cells, the body interprets the signal as excruciating discomfort — a good way to distract a predator from chowing down, Fry says. Other fish venoms share their modes of action with certain venoms from other animals. For example, the venoms of stonefishes, snakes and some other organisms contain hyaluronidase, an enzyme that dissolves some of the matrix that supports cells. In that way, the enzyme helps the other venom molecules speed through the victim’s tissues. But still, the multiple evolutions of fish venoms mean that each group of venomous fish probably makes venom components that attack their victims differently. Scientists are just beginning to delve into the specific molecules and actions of different venoms. Fry and collaborators took a stab in a study published February 16 in Toxins, extracting and analyzing venom from six types of fishes — dusky flathead, Luderick, mullet, yellowback seabream and two types of stingrays. “It was incredibly variable,” says study coauthor Nicholas Casewell, a venom biologist at the Liverpool School of Tropical Medicine in England. Injected into a rat, the mullet and seabream toxins caused heart rate to drop slightly, while the other venoms had no effect. All venoms resulted in an initial drop in blood pressure — as is common in human envenomations by fish — but the stingray, mullet and seabream venoms then caused blood pressure to rise. In nerves and muscles growing in a dish, the venoms of stingrays and dusky flatheads blocked muscle twitching, which could potentially mean some moderate level of partial paralysis for a predator, Casewell says. Indeed, paralysis and weakness can occur in people stung by fish. The other fishes’ venoms, in contrast, boosted twitching a bit. Even though the venoms all cause pain, Fry says, these results show that the underlying effects of each venom are a bit different. It’s a classic case of evolutionary convergence, in which different evolutionary pathways lead to the same end result — in this case, the pain that makes the predator skedaddle. In a separate study published online March 30 in Current Biology, Casewell, Fry and colleagues examined fang blennies. Certain species, found in shallow reefs of the Indian and Pacific oceans, use venomous fangs to defend against predators. The researchers were puzzled that fang blenny venom didn’t seem to cause pain when injected into a mouse’s paw. The venom, it turns out, acts on opioid receptors, where it might work like a sedative. It also lowers blood pressure, probably leaving the victim disoriented or dizzy. The victim is essentially “stoned,” Fry says. A predator won’t be able to swim away properly, he surmises, or it’ll die of something akin to a heroin overdose. Another group, at the University of Tübingen in Germany, is investigating the venom of the lesser weever fish of the Mediterranean. Graduate student Myriam Fezai was inspired to study the fish by its ability to induce swelling and paralysis in fishermen and tourists in her homeland, Tunisia. The venom also blackens and kills tissues, so she and collaborators wanted to know how it killed cells. The researchers tested the venom on red blood cells in the lab, where it caused the cells to shrink in a form of programmed cell death, Fezai and colleagues reported in Scientific Reports in 2016. The team tested the weever fish venom on cancer cells, too. The cells stopped growin g and their mitochondria stopped working properly, triggering apoptosis, a classic mechanism by which cells kick the bucket. Even cells that survived tended to stop dividing regularly. Next, the researchers hope to identify the individual components of the venom involved in the cell killing. The hope is that something in weever fish venom can be turned into an anticancer drug. Medicines based on venoms from other animals already exist, including the blood pressure drug captopril (Capoten) from a pit viper. There’s even a painkiller, ziconotide (Prialt), developed from the potent venom of a marine cone snail. Sometimes, the same molecules that cause pain can, if applied correctly, also relieve it. Capsaicin, the spicy tongue-burning stuff in peppers, is used in a cream to relieve the pain of shingles and other conditions. The molecule desensitizes the pain sensors in nerve cells. Venoms provide a rich source of potentially useful molecules, says Mandë Holford, a snail venom expert at Hunter College and the American Museum of Natural History in New York City. Evolution has already honed the venoms to precisely interact with their targets. “Every time I read about a new venomous organism, like the fish in Leo [Smith’s] work, I get excited becaus e our pot is getting bigger,” she says. Several venoms, examples below, have been repurposed as medicines for human use, most for their effect on blood. Scientists around the world are in the early stages of investigating fish venoms that might combat cancer, control blood pressure or clot blood. In Brazil, researchers studying the venom of the lagoon-dwelling toadfish Thalassophryne nattereri found a small protein they named TnP, which has anti-inflammatory abilities. They hope to develop a medicine for multiple sclerosis, a disease in which immune cells cause inflammation and attack the nervous system. In February, the team reported in PLOS ONE that in mice with a form of multiple sclerosis, a synthetic version of TnP dampened inflammation, protected and promoted repair of nerves and improved muscle coordination. Isolating the specific venom ingredient that causes the desired effects, as the Brazilian researchers did with TnP, is the direction several scientists are going in their studies of fish venom. Some are analyzing which genes are uniquely turned on in a fish’s venom glands and not activated in nearby fin tissue. Modern mass spectrometry also helps, Holford says, because it allows scientists to analyze the components of even the tiny amount of venom they can extract from a snail or fish. Unlike snakes, which are easily milked for their venom, collection from fish typically involves clipping the spine off wild specimens and scraping a small bit of venom into a test tube. (The involuntary donor, sent on its way, can typically regrow the spine, like a fingernail, Fry says.) Then things get difficult. “Fish venom is just horrible … it has this snotlike consistency,” Fry says. “It’s easily the most challenging venom that I’ve had the misfortune to work with.” In contrast to venom from other creatures, which often consists of fairly small, stable proteins, fish venom tends to be made of large proteins that fall apart easily once out of the fish. Freeze it, heat it or expose it to certain chemicals, and the proteins fall apart. That’s a major disadvantage in the lab, and for medicines, too, Casewell notes. Therefore, he doubts a fish venom could yield the next blockbuster pharmaceutical. Fry acknowledges that successes such as captopril or ziconotide, in which venom directly leads to a medicine, are quite rare. However, he believes scientists can learn about pain from fish venoms and apply that knowledge to invent novel painkillers. Similarly, Fezai, who started the weever fish project, doesn’t think the venom ingredients themselves would be the drug, but some molecule that mimics their actions might be. The upside of the fragility of fish venoms, though, is that treatment for a fish sting is quite straightforward: running hot water over the affected body part. That’s what Smith did when he was stung by a blue tang — think Dory from Finding Nemo — while cleaning his tank at home. About a half an hour under the hot tap stopped the pain by destroying the venom in his finger. But some damage had already been done. About 10 days later, a pea-sized chunk of his finger fell off, dead. The rockfish, so desired by Smith’s copassengers on the San Diego fishing trips, has a milder sting. Those arthritis sufferers weren’t risking much. But whether they were really relieving joint pain with a fish venom is an open question. They certainly seemed to think so, Smith says, though as of yet no data support this particular fishy treatment. But, he notes, the venom of scorpion fish — cousin to rockfish — affects the nervous system, immune system and blood pressure, all of which could, in theory, have some “real” effect on the arthritis. “There’s reason to believe that’s possible,” he speculates. This article appears in the April 29, 2017, issue of Science News with the headline, "A Sea of Hurt: Venomous swimmers have evolved many ways to sting."
Li Z.,University of Illinois at Urbana - Champaign |
Ding B.,University of Illinois at Urbana - Champaign |
Han J.,University of Illinois at Urbana - Champaign |
Kays R.,New York State Museum
Proceedings of the VLDB Endowment | Year: 2010
Recent improvements in positioning technology make massive moving object data widely available. One important analysis is to find the moving objects that travel together. Existing methods put a strong constraint in defining moving object cluster, that they require the moving objects to stick together for consecutive timestamps. Our key observation is that the moving objects in a cluster may actually diverge temporarily and congregate at certain timestamps. Motivated by this, we propose the concept of swarm which captures themoving objects that move within arbitrary shape of clusters for certain timestamps that are possibly nonconsecutive. The goal of our paper is to find all discriminative swarms, namely closed swarm. While the search space for closed swarms is prohibitively huge, we design a method, ObjectGrowth, to efficiently retrieve the answer. In ObjectGrowth, two effective pruning strategies are proposed to greatly reduce the search space and a novel closure checking rule is developed to report closed swarms on-thefly. Empirical studies on the real data as well as large synthetic data demonstrate the effectiveness and efficiency of our methods. © 2010 VLDB Endowment.
Landing E.,New York State Museum |
English A.,Chevron |
Keppie J.D.,University National Automona Of Mexico
Geology | Year: 2010
Exquisite Pywackia baileyi Landing n. gen. and sp. specimens from the lower Tiñu Formation, southern Mexico, extend the bryozoan record into the Upper Cambrian. They are ~8 m.y. older than the purported oldest bryozoans from South China, and show that all skeletalized metazoan phyla appeared in the Cambrian. The new form differs from similar, twig-like cryptostomes by its shallow autozooecia and an elongate axial zooid, which may be homologous to the stolon in nonmineralized ctenostomes. It may morphologically resemble mineralized stem group bryozoans that retained a stolon-like individual, although an ability to bud was acquired by the feeding individuals (autozooids). The latest Cambrian origin of bryozoans, several mollusk classes (polyplacophorans, cephalopods), and euconodonts was a major evolutionary development and can be considered the onset of the Ordovician radiation of more complex marine communities. © 2010 Geological Society of America.
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 306.01K | Year: 2012
The co-evolution and geographical spread of trees and deep-rooting systems is widely proposed to represent the Devonian engine of global change that drove the weathering of soil minerals and biogeochemical cycling of elements to exert a major influence on the Earths atmospheric CO2 history. If correct, this paradigm suggests the evolutionary appearance of forested ecosystems through the Devonian (418-360 Myr ago) constitutes the single most important biotic feedback on the geochemical carbon cycle to emerge during the entire 540 Myr duration of the Phanaerozoic. Crucially, no link has yet been established between the evolutionary advance of trees and their geochemical impacts on palaeosols. Direct evidence that one has affected the other is still awaited, largely because of the lack of cross-disciplinary investigations to date. Our proposal addresses this high level earth system science challenge. The overarching objective is to provide a mechanistic understanding of how the evolutionary rise of deep-rotting forests intensified weathering and pedogenesis that constitute the primary biotic feedbacks on the long-term C-cycle. Our central hypothesis is that the evolutionary advance of trees left geochemical effects detectable in palaeosols as forested ecosystems increased the quantity and depth of chemical energy transported into the soil through roots, mycorrhizal fungi and litter. This intensified soil acidification, increased the strength of isotopic and elemental enrichment in surface soil horizons, enhanced the weathering of Ca-Si and Ca-P minerals, and the formation of pedogenic clays, leading to long-term sequestration of atmospheric CO2 through the formation of marine carbonates with the liberated terrestrial Ca. We will investigate this research hypothesis by obtaining and analysing well-preserved palaeosol profiles from a time sequence of localities in the eastern North America through the critical Silurian-Devonian interval that represents Earths transition to a forested planet. These palaeosol sequences will then be subjected to targeted geochemical, clay mineralogical and palaeontological analyses. This will allow, for the first time, the rooting structures of mixed and monospecific Mid-Devonian forests to be directly linked to palaeosol weathering profiles obtained by drilling replicate unweathered profiles. Weathering by these forests will be compared with the control case - weathering by pre-forest, early vascular land plants with diminutive/shallow rooting systems from Silurian and lower Devonian localities. These sites afford us the previously unexploited ability to characterize the evolution of plant-root-soil relationships during the critical Silurian-Devonian interval, whilst at the same time controlling for the effects of palaeogeography and provenance on palaeosol development. Applying geochemical analyses targeted at elements and isotopes that are strongly concentrated by trees at the surface of contemporary soils, and which show major changes in abundance through mineral weathering under forests, provides a powerful new strategy to resolve and reconstruct the intensity and depth of weathering and pedogenesis at different stages in the evolution of forested ecosystems. The project is tightly focused on improving current knowledge of the interaction between the evolution of life and the Earth, which represents one of the three high level challenges within NERCs Earth System Science Theme.
Landing E.,New York State Museum |
MacGabhann B.A.,National University of Ireland
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010
The first evidence for Cambrian glaciation is provided by two successions on the Avalon microcontinent. The middle lowest Cambrian (middle Terreneuvian Series and Fortunian Stage-Stage 2 boundary interval) has an incised sequence boundary overlain by a fluvial lowstand facies and higher, olive green, marine mudstone on Hanford Brook, southern New Brunswick. This succession in the lower Mystery Lake Member of the Chapel Island Formation may be related to melting of an ice sheet in Avalon. The evidence for this interpretation is a muddy diamictite with outsized (up to 10 cm in diameter), Proterozoic marble and basalt clasts that penetrated overlying laminae in the marine mudstone. That eustatic rise was associated with the mudstone deposition is suggested by an approximately coeval rise that deposited sediments with Watsonella crosbyi Zone fossils 650 km away in Avalonian eastern Newfoundland. A sea-level rise within the Watsonella crosbyi Chron, at ca. 535 Ma, may correspond to a unnamed negative 13C excursion younger than the basal Cambrian excursion (BACE) and the ZHUCE excursion in Stage 2 of the upper Terreneuvian Series. Cambrian dropstones are now also recognized on the northern (Gander) margin of Avalon in continental slope-rise sedimentary rocks in southeast Ireland. Although their age (Early-Middle Cambrian) is poorly constrained, dropstones in the Booley Bay Formation provide additional evidence for Cambrian glaciation on the Avalon microcontinent. Besides providing the first evidence of Cambrian glaciation, these dropstone deposits emphasize that Avalon was not part of or even latitudinally close to the terminal Ediacaran-Cambrian, tropical carbonate platform successions of West Gondwana. © 2009 Elsevier B.V. All rights reserved.
Kroger B.,Humboldt University of Berlin |
Landing E.,New York State Museum
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2010
The Beekmantown Group records the important early interval of the Ordovician Radiation. This Upper Cambrian-Middle Ordovician, carbonate-dominated, tropical succession was deposited near the eastern passive margin of the Laurentian platform. This depositional setting remained remarkably stable although the craton was flooded repeatedly with eustatic rises and unconformity-bound, macroscale sedimentary cycles were deposited as successive geological formations. The individual depositional cycles (i.e., formations) show a nearly identical vertical succession with a type 1 sequence boundary, a basal conglomerate, transgressive sandstones, locally a subtidal shale-dominated unit that marks the deepest facies, and a highstand carbonate facies with thrombolite buildups in its middle part. The thrombolitic buildups of each depositional cycle contain a mollusc-dominated macrofauna that changed remarkably from cycle to cycle. In the limestones of the Upper Cambrian Ritchie and Rathbunville School members, the macrofauna is very rare and of low diversity. By comparison, the absolute abundance of macrofossils is high throughout the Lower Ordovician thrombolitic limestones. The genus-level diversity of brachiopods, trilobites, gastropods, and cephalopods increased moderately during the three Lower Ordovician depositional sequences. Dramatic changes in cephalopod disparity, body size, and biomass indicate significant paleoecological changes at the top of the ecosystem food chains, and are an indication of community evolution and intrinsic evolutionary processes. Increased coiling and ornamentation in cephalopods and an increasing number of large gastropod genera with thick shells indicate an escalation among predators. We interpret these changes as evidence for a rise in competition within ecological guilds by a continuing increase in internal differentiation of the food web. Increased organismal interaction and the differentiation of the food web (i.e., community evolution) are regarded as a major driving mechanism early in the Ordovician Radiation. © 2009 Elsevier B.V.
Landing E.,New York State Museum |
Geyer G.,University of Würzburg |
Geyer G.,Uppsala University |
Brasier M.D.,University of Oxford |
Bowring S.A.,Massachusetts Institute of Technology
Earth-Science Reviews | Year: 2013
Use of the first appearance datum (FAD) of a fossil to define a global chronostratigraphic unit's base can lead to intractable correlation and stability problems. FADs are diachronous-they reflect species' evolutionary history, dispersal, biofacies, preservation, collection, and taxonomy. The Cambrian Evolutionary Radiation is characterised by diachronous FADs, biofacies controls, and provincialism of taxa and ecological communities that confound a stable Lower Cambrian chronostratigraphy. Cambrian series and stage definitions require greater attention to assemblage zone successions and non-biostratigraphic, particularly carbon isotope, correlation techniques such as those that define the Ediacaran System base. A redefined, basal Cambrian Trichophycus pedum Assemblage Zone lies above the highest Ediacaran-type biotas (vendobionts, putative metazoans, and calcareous problematica such as Cloudina) and the basal Asteridium tornatum-Comasphaeridium velvetum Zone (acritarchs). This definition and the likely close correspondence of evolutionary origin and local FAD of T. pedum preserves the Fortune Head, Newfoundland, GSSP of the Cambrian base and allows the presence of sub-Cambrian, branched ichnofossils. The sub-Tommotian-equivalent base of Stage 2 (a suggested "Laolinian Stage") should be defined by the I'/L4/ZHUCE δ13C positive peak, bracketed by the lower ranges of Watsonella crosbyi and Aldanella attleborensis (molluscs) and the Skiagia ornata-Fimbrioglomerella membranacea Zone (acritarchs). The W. crosbyi and A. attleborensis FADs cannot define a Stage 2 base as they are diachronous even in the Newfoundland "type" W. crosbyi Zone. The Series 2 base cannot be based on a species' FAD owing to the provincialism of skeletalised metazoans in the Terreneuvian-Series 2 boundary interval and global heterochrony of the oldest trilobites. A Series 2 and Stage 3 (a suggested "Lenaldanian Series" and "Zhurinskyan Stage," new) GSSP base is proposed at the Siberian lower Atdabanian δ13C IV peak-which correlates into South China, Avalonia, and Morocco and assigns the oldest trilobites to the terminal Terreneuvian Series. © 2013 Elsevier B.V.
Landing E.,New York State Museum
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2012
The Early Paleozoic featured nine intervals of strong expansion of an upper slope, dysoxic/anoxic (d/a) water mass with eustatic rise or epeirogenic transgression. Strong expansion of this d/a water mass led to deposition of time-specific, macroscale alternations of dark grey-black mudstone within oxic, green to red mudstone on the middle-lower slope. This d/a facies even onlapped warm- (carbonate) and cool-water (siliciclastic) shelves. As in the Mesozoic, d/a muds were deposited in shallow water, perhaps tens of metres deep, with sea-level rise. These nine d/a macroscale alternations correspond to intervals of "global hyperwarming"-times of very intense greenhouse conditions that resulted from a feedback initiated by higher insolation and heat storage as shallow seas onlap tropical palaeocontinents. Warm epeiric seas heated the ocean, and thermal expansion accelerated eustatic rise. Ever more extensive epeiric seas heightened oceanic and global temperature as heat storage capacity increased. Deep ocean circulation intensity fell below that of a greenhouse interval and lead to d/a deposition low on the slope and on the platforms to provide the signature of global hyperwarming. Global hyperwarming differs from a hothouse interval as it does not require CO2 input from large igneous provinces to produce high temperatures and never shows deep-sea anoxia. Late Ordovician and Late Devonian black mudstones that cover much of Laurentia record epeirogenic transgressions that led to global hyperwarming, and suggest that cold water upwelling or plant terrestrialisation had nothing to do with epeiric sea anoxia. Global hyperwarming reduced oxygen solubility in these seas, and erosion of orogens produced muddy water that limited light penetration and promoted shallow-water anoxia. The global hyperwarming hypothesis means that relative eustatic and epeirogenic sea levels complement the effect of global pCO2 on climate, and sea level must also be regarded as a primary driver of Phanerozoic climate. © 2011 Elsevier B.V.
News Article | November 20, 2016
Large hairy elephants got me into paleoanthropology, eventually. I had a strong interest in science, and it was nurtured and expanded by my frequent visits to the New York State Museum, and there was never a doubt in anyone’s mind, anywhere, that the coolest exhibit at that museum was the Cohoes Mastodon exhibit. Barbarians eventually came along and tore that exhibit down, along with all the other fantastic and traditional museum displays, when they made the new, slick, produced for consumption and not intense engagement with materials knowledge building museum. My friend John McKay also got into paleo studies as a young child because of a hairy elephant, but in his case, it was diminutive and green, unlike the large hairy Cohoes elephant. But John persevered in the large elephant area, while I went in somewhat different directions (though I did get to help dig up an extinct four tusker in Africa once). Eventually, John became the Go To Guy in all matters Mammoth and related things. John is an historian, so his focus has been the emerging understanding of the past (and present) as western (and other) civilization(s) repeatedly encountered and grappled with the remains of ancient and unbelievable beasts. The reason I mention any of this at all is because John wrote a book, Discovering the Mammoth: A Tale of Giants, Unicorns, Ivory, and the Birth of a New Science , that is now available for pre-order, and that you must read. I’ve not seen the book yet, but I’ve read some of the stuff that is going into it. Think Stephen Jay Gould meets Don Prothero. Rich, engagingly written, context-rich, carefully done description and analyses of the afore mentioned process. This book promises to be an interesting and important, and very readable, exploration of the development of natural history and modern science. I know John, this is what I expect of him, and this is what I’m confident he is going to give us. The book will be available in hardcover or kindle . Of course, I’ll write a review as soon as I can. The book is slated for publication in June 2017.
News Article | June 19, 2016
Ticked Off! Here's What You Need To Know About Lyme Disease The fossil of an extinct giant beaver species — unearthed 170 years ago in New York — offers new insights into paleoproteomics, the study of ancient proteins. Ancient proteins are potentially useful in positioning animals on the evolutionary tree as well as in understanding the evolution of life and the planet over time. Researchers who study ancient proteins would depend on fossils dug up for the specific purpose. In the new study, the team used a fossilized giant beaver skull obtained in 1845 from Central New York and has been housed since then at New York State Museum. "In paleoproteomics we've generally looked at specimens collected recently and carefully stored in climate-controlled conditions,” explained study author and postdoc researcher Timothy Cleland from the University of Texas-Austin, adding that in their study they dealt with a specimen long sitting on a museum shelf. That is the challenge when using existing fossils for paleoproteomics, a young discipline: will the long gathered specimens offer the needed protein information? For this study, the team extracted proteins coming from the Castoroides ohioensis skull, the first ever found, and used a technique called mass spectrometry analysis to seek for proteins, which are amino acid chains obtained from instructions in DNA that assume a number of roles in living organisms. They detected plenty of specimens of collagen 1, the most prevalent bone protein, along with post-translational modifications or chemical changes found on the protein surface that are not DNA-defined. Discovering these modifications is considered valuable since it has little precedent in the emerging field. Cleland said, for instance, that post-translational modifications of some proteins can shed light on how certain organisms manipulate or process the protein, such as collagen, for better functioning. What has been done so far is just “scratching the surface,” noted the authors. A database containing post-translational modifications to ancient creatures, as well as a database of primary protein sequences, is hoped to be used for better tackling evolutionary changes. Protein engineering, too, can see how an ancient protein function compares to the same in modern living animals. The research also emphasized the significance of museum collections in further research and scientific exploration. “Without maintaining collections rich in diversity of specimens, both ancient and modern, similar research that examines these windows into our past would not be possible,” said vertebrate paleontology curator Robert Feranec of New York State Museum. The findings were detailed in the journal Proceedings of the Royal Society B. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.