Research Blogging - Geosciences - English

Hot rocks, big rivers and the world’s tallest mountain face

2012-05-16T16:24:51Z

In areas of active mountain-building the middle crust can get hot and weak, like a soft jam/jelly filling in a sandwich. These squishy rocks are hidden from us by the cold rigid upper crust, so we wouldn’t expect to see … Continue reading →...

Peter K. Zeitler, Anne S. Meltzer, Peter O. Koons, David Craw, Bernard Hallet, C. Page Chamberlain, William S.F. Kidd, Stephen K. Park, Leonardo Seeber, Michael Bishop.... (2001) Erosion, Himalayan Geodynamics, and the Geomorphology of Metamorphism. GSA Today. info:/

Cómo reconocer la buena geociencia

2012-05-14T19:47:47Z

[Versión extendida del artículo para Amazings]La ciencia avanza A Hombros de Gigantes, decía Chartres ya en el siglo XII. La frase se refierea que nuestra pequeña contribución al conocimientose basa y se suma a lo que nos transmitierongeneraciones anteriores, y sólo gracias a ellaspodemos ver más allá. [Fuente]. ¡Hay tantos estudios que se arrogan el estatus de científico sin serlo! Los Magufos están incluídos en ese grupo, pero en la prensa se citan infinidad de trabajos cuya acientificidad es más sutil. La geociencia es especialmente vulnerable a este tema (por motivos históricos, p.e., Alvarez y Leitao, 2012, Geology). Recordad si no el grito de "Geology is not a true science!" de Sheldon en Big Bang Theory (vídeo). Así que me arremango para recordar los ingredientes más comunes de los estudios científicos y cómo reconocerlos cuando navegamos por la web:Pregunta científica:La cuestión que aborda un trabajo científico debe estar bien definida y ser precisa. Puede no ser nueva e incluso puede tener ya una respuesta bien consolidada entre los especialistas, pero hay que dejar clara su relación con estudios anteriores que han abordado los mismos unknowns. En investigación, como en otras formas de vida, uno pasa más tiempo buscando las preguntas correctas que buscando respuestas (inevitable evocar aquí las infames palabras de Rumsfeld).Referencias, trabajos previos:La ciencia es un método de recopilación y extensión sistemática del conocimiento y portanto cualquier nuevo estudio debe partir de resultados anteriores. Por eso el extracto de sauce blanco usado medicinalmente en la América precolombina pudo ser un conocimiento extraordinariamente útil, pero no científico: sus propiedades no habían sido relacionadas cuantitativa ni sistemáticamente con otros conocimientos de la época. En cambio el descubrimiento de su principio activo y el aislamiento del ácido acetilsalicílico (aspirina) sí lo son. Cualquier estudio científico tiene que partir de lo que ya se ha descrito antes, debe anclarse en el conocimiento científico existente. Eso es una pesadez, pero demostrar que conoces lo que ya se ha hecho en tu campo es el primer paso para que tu estudio sea tomado en serio. En la web, los magufos se delatan por carecer de enlaces a fuentes fiables e independientes que apoyen lo que dicen; de forma parecida, la clave de un buen artículo en Wikipedia es la calidad de sus referencias.Hipótesis y predicciones validables o falseablesLos antecedentes permiten formular una hipótesis, la idea que se quiere poner a prueba. De nuevo, son los antecedentes los que dan solidez a esa hipótesis y los que te permiten distinguir una curiosidad legítima de una chorrada. Luego, el estudio podrá validar o refutar esa hipótesis y en función de ello postular una nueva. Pero vuelvo a ese punto más tarde.Observación objetiva, repetida, sistemática, cuantitativaPara mejorar el conocimiento hay que contar con experiencias nuevas. En geociencia pueden ser experiencias de laboratorio (experimentos), de campo (visita y muestreo de una zona) o de cálculo (simulaciones, modelos). Si un experimento de cristalografía (pienso en los infames cristales de hielo de Emoto) no está bien descrito, ni es repetible, ni está cuantificado, entonces puede que sea divertido, pero no es científico. No siempre es sencillo juzgar cuando las observaciones son objetivas y sistemáticas, y no siempre pueden ser cuantitativas, pero es importante recordar que la aspiración natural del científico es el mayor grado de cuantificación posible. El motivo es que, antes o después, el proceso de comprensión pasa por (o aspira a) formular matemáticamente aquello que se estudia. Vuelvo a esto luego.Experimentos y análisis reproduciblesLa reproducibilidad es tambien esencial, aunque a menudo olvidada. Un ejemplo claro de trabajo no científico es el que se basa en muestras de roca cuya localización no está publicada, porque no se puede contrastar los análisis con otras muestras del mismo lugar. O estudios basados en experimentos numéricos (simulaciones informáticas) que usan un modelo (un programa) muy complejo cuyo código fuente no está disponible. En este caso no se pueden reproducir los cálculos ni comprobar la unicidad de su ajuste de las observaciones. Ambos trabajos pueden ser excelentes, pero no son ciencia porque nadie puede reproducirlos ni poner a prueba sus resultados. Y ambos casos abundan en las Ciencias de la Tierra.Pero no siempre está tan claro, y para muestra invito a leer este artículo sobre lo que no se suele compartir entre científicos (interesantes los comentarios de lectores al pie). Otro ejemplo: las rocas de una perforación deberían estar disponibles para su estudio crítico por otros grupos, permitiendo la reproducción de su análisis. Pero si cuando pides una muestra no hay nadie que la empaquete y te la envíe, o si una compañía que financió la perforación impide el acceso a las muestras ¿el estudio original sigue siendo científico?Formulación matemáticaLa formulación matemática es la expresión mássólida de un concepto y permite ponerlo a pruebasin ambigüedad en escenarios distintos. En este casose trata del principio de isostasia, que relaciona la elevaciónde una región (h1) con el engrosamiento de lacorteza terrestre (b1) y con las densidades de lacorteza y el manto.Describir un proceso natural con una ecuación tiene algo de trascendental. La matemática es la máxima expresión de lo que mencionaba: objetividad, cuantificación, reproducibilidad. Un ejemplo: una buena parte de la tectonofísica se basa en la formulación de...

Alvarez, W., & Leitao, H. (2011) The neglected early history of Geology: The Copernican Revolution as a major advance in understanding the Earth: REPLY. Geology, 39(9). DOI: 10.1130/G32501Y.1

How to dig a submarine canyon with no net erosion

2012-05-08T14:01:43Z

[This just appeared in Geology (link to abstract)]Survival of a submarine canyon during long-term outbuilding of a continental marginDavid Amblas et al., Universitat de Barcelona, E-08028 Barcelona, Spain. Geology, doi: 10.1130/G33178.1. The resemblance between subaerial and submarine canyons has led to the long-standing view of submarine canyons as purely erosive landforms. Yet submarine canyons forming at continental slopes that grow from long-term accumulation of sediment are observed both at the present sea floor and further beneath, buried under sediment. This suggests that the canyon is prograding together with the margin. David Amblas and colleagues document the Pleistocene coevolution of a submarine canyon and adjacent slope along the Ebro Margin (NW Mediterranean) using a 3-D seismic image of the seafloor and subsurface. Seismic reflectors beneath the present-day canyon and adjacent slope show that net accumulation has occurred in both areas over the last 500,000 years. Seismic mapping reveals a mid-Pleistocene canyon beneath the modern canyon that is morphologically similar in planform but exhibits a different long profile shape. An explanation for the change in long-profile shape is proposed in terms of the dominant sedimentation processes in the canyon. This study aims to broaden thinking about canyon evolution and the processes that govern it during outbuilding of a continental margin. From this perspective, canyons are submarine landscape features that prograde at rates comparable to those of the margin, mostly undergoing net deposition while they serve as the outlet channel for the continental sediment supply towards the abissal plains. Pleistocene and present submarine canyon, and conceptual model of the depositional control of its evolutionAmblas, D., Gerber, T., De Mol, B., Urgeles, R., Garcia-Castellanos, D., Canals, M., Pratson, L., Robb, N., & Canning, J. (2012). Survival of a submarine canyon during long-term outbuilding of a continental margin Geology DOI: 10.1130/G33178.1...

Amblas, D., Gerber, T., De Mol, B., Urgeles, R., Garcia-Castellanos, D., Canals, M., Pratson, L., Robb, N., & Canning, J. (2012) Survival of a submarine canyon during long-term outbuilding of a continental margin. Geology. DOI: 10.1130/G33178.1

Were dinosaurs undergoing long-term decline before mass extinction? |video| @GrrlScientist

2012-05-03T04:00:08Z

A new scientific paper uses a unique methodology to addresses this timeless question I ran across an interesting little video by the American Museum of Natural History (AMNH) describing a newly-published piece of research into the extinction of non-avian dinosaurs. This paper reports on their findings whether the non-avian dinosaurs were experiencing a long-term population decline before the asteroid strike at the end of the Cretaceous 65 million years ago. The answer? Yes -- and no. The international research team includes the paper's lead author, Steve Brusatte, a Columbia University graduate student affiliated with the Museum's Division of Paleontology; Mark Norell, chair of AMNH's Division of Paleontology; and scientists Richard Butler of Ludwig Maximilian University of Munich in Germany and Albert Prieto-Márquez from the Bavarian State Collection for Palaeontology, also in Germany."Few issues in the history of paleontology have fueled as much research and popular fascination as the extinction of non-avian dinosaurs," remarked Mr Brusatte. "Did sudden volcanic eruptions or an asteroid impact strike down dinosaurs during their prime? We found that it was probably much more complex than that, and maybe not the sudden catastrophe that is often portrayed."Although this question has been asked many times before, the method that the research team used is unique, thus providing another perspective. The research team examined "morphological disparity" -- the variability of body structure within seven major groups of dinosaurs -- at both global and regional scales. Measuring morphological disparity of a group captures a snapshot of its anatomical variation, which can be viewed as a reflection of the breadth of that lineage's functional and ecological behaviours. In short, morphological disparity is a measure of the spectrum of body plans, behaviours, and ecological niches exploited by a group. Such measures can reveal the long-term trajectory of a particular group regardless of whether they had high or low species richness or abundance. The team's findings reveal clade-specific disparity patterns, painting a more subtle picture than previously thought. On one hand, both geographic and clade-specific morphological variability declined in large-bodied herbivores, the ceratopsids and hadrosauroids, but on the other hand, no decline in morphological variability was detected in carnivorous dinosaurs, mid-sized herbivores, and some Asian taxa. The authors propose that the decrease of morphological disparity in the ceratopsids and hadrosauroids could be due to their more specialised chewing abilities. Further, "[e]ven if the disparity of some dinosaur clades or regional faunas were in decline during the terminal Cretaceous, this does not automatically mean that dinosaurs were doomed to extinction", the authors caution in their paper. In fact, dinosaur disparity and diversity fluctuated throughout time so small increases or decreases between two or three time intervals may not be noteworthy within the overarching historical context of these animals."These disparity calculations paint a more nuanced picture of the final 12 million years of dinosaur history," says Mr Brusatte. "Contrary to how things are often perceived, the Late Cretaceous wasn't a static 'lost world' that was violently interrupted by an asteroid impact. Some dinosaurs were undergoing dramatic changes during this time, and the large herbivores seem to have been mired in a long-term decline, at least in North America." This is a video interview with two of the paper's authors, Mr Brusatte and Dr Norell:[video link]If you would like to discuss this paper's findings with the AMNH scientists, you are invited to join Mr Brusatte and Dr Norell at 1 p.m. ET on Thursday, 10 May, in the Museum's Linder Theater. If you cannot attend in person, this event will also be streamed live. Source: Brusatte, S., Butler, R., Prieto-Márquez, A., & Norell, M. (2012). Dinosaur morphological diversity and the end-Cretaceous extinction. Nature Communications, 3 doi:10.1038/ncomms1815 .. .. .. .. .. .. .. .. .. .. .. .. The American Museum of Natural History is on facebook and can also be found on twitter @AMNHMany thanks to several of my precious twitter followers for sending me this paper on such short notice this morning. (I don't know whether I can name you here, but you know who you are!) .. .. .. .. .. .. .. .. .. .. .. twitter: @GrrlScientist facebook: grrlscientist Pinterest: grrlscientistemail: grrlscientist@gmail.comGrrlScientistguardian.co.uk © 2012 Guardian News and Media Limited or its affiliated companies. All rights reserved. | Use of this content is subject to our Terms & Conditions | More Feeds...

Brusatte, S., Butler, R., Prieto-Márquez, A., & Norell, M. (2012) Dinosaur morphological diversity and the end-Cretaceous extinction. Nature Communications, 804. DOI: 10.1038/ncomms1815

Effects of the expanding agriculture frontier in the Bolivian Amazon

2012-04-30T10:00:17Z

Last week, a paper published in Nature spurred a lot of debates on the internet about the future of agriculture and our ability to feed the 9 billion people that the world will have in 2050. One important aspect related to this debate is the availability of agricultural land. However, people do not always have a clear idea of what expanding the agriculture land means. Here an example of what is happening in one of the most biodiversily rich places of the world: the Bolivan Amazon. Let’s just have a look at a few Google earth’s images of the Lake Peroto in the Llanos de Moxos (dep. of Beni in the Bolivian Amazon).Image taken the 17 of May 2003. Land use is extensive cattle ranching. Typical floating vegetation (locally called “yomomo”) is growing along the shores of Lake Peroto.Image taken the 20th of Nov 2004. Land use is extensive cattle ranching. It is the end of the dry season, and the water level is extremely low. In the greenish areas inside the lakes water is almost completely evaporated. This is normal in the Llanos de Moxos, where seasonality can be extremeImage taken the 2nd of July 2009. Land use is extensive cattle ranching. We are at the beginning of the dry season, water level is quite high, the water is clearly visible.Image taken the 8th of August 2011. Land use is extensive cattle ranching plus industrial agriculture. 70 hectares of land in the surroundings of the lake have been used to produce rice.What happened to the lake in 2011? Now the lake is almost completely covered with vegetation... Is it dry? Or is it the first effect of land use change: eutrophication? Based on my personal experience of having been working in the Llanos de Moxos for more than 10 years now and based on the fact that the nearby Lake Suarez is full of water (photo below) on the 15 of August 2011, I would conclude that Lake Peroto is in process of eutrophication.Lake Suarez. Image taken the 15th of August 2011. The lake is full.Industrial agriculture in the Beni is already causing deforestation and threatening archaeological sites (see this). Now it is also affecting lake ecology. Is industrial agriculture what people in the Beni really need? Does this kind of agriculture make any sense in a place with a density population of 1 person per square kilometre? Here, a very important part of the population lives in indigenous communities whose subsistence depends on local natural resources. What will happen to them in ten years’ time if these resources are depleted?Ref:Seufert V, Ramankutty N, & Foley JA (2012). Comparing the yields of organic and conventional agriculture. Nature PMID: 22535250...

Seufert V, Ramankutty N, & Foley JA. (2012) Comparing the yields of organic and conventional agriculture. Nature. PMID: 22535250

Graphing Out Loud: ups and downs

2012-04-28T03:05:20Z

A while back, we started looking at a poorly thought-out article from the website C3Headlines. C3 is starting to make a name for itself as a goldmine of climate comedy- their claims have recently been addressed at Tamino and SkepticalScience. We’re going to keep digging into C3‘s claim that carbon dioxide concentrations have been increasing linearly over [...]...

Long, S., Elizabeth A. Ainsworth, Andrew D. B. Leakey, Josef Nosberger, & Donald R. Ort. (2006) Food for Thought: Lower-Than-Expected Crop Yield Stimulation with Rising CO2 Concentrations. Science, 312(5782), 1918-1921. DOI: 10.1126/science.1114722

Baby Corn Plants Recruit Helpful Bacteria Posse

2012-04-27T11:35:02Z

When you're a newly sprouted corn seedling, all alone in the dirt, you need any advantage you can get. After all, you can't pick up your roots and travel to find resources or avoid pests. That's why corn plants emit toxic chemicals that keep away hungry insects aboveground and harmful microbes below. But to at least one kind of bacteria, this poison is more of a beacon. They follow the toxic trail back to the corn plant, set up camp in its roots, and help the vulnerable seedling grow. A plant's roots are the center of a miniature ecosystem called the rhizosphere. Local bacteria feed on sugars and proteins that trickle out of the roots, like antelopes at a watering hole. Symbiotic fungi enmesh themselves in the plant's roots. Helpless as it may appear, the plant can even release chemicals that encourage certain microbes to live there and discourage others, or prevent competing plant species from growing nearby. Researchers in the United Kingdom studied one of the toxic chemicals released by the roots of corn plants. The compound is a benzoxazinoid, mercifully abbreviated as BX. Seedlings of corn and other grasses secrete BX molecules to protect themselves from pests and harmful microbes. But the team, led by Andrew Neal at Rothamsted Research, suspected that certain bacteria weren't bothered by the toxin at all. Neal says this was a bit of a "leap of faith." Many bacteria that are used to clean pollutants from soil are closely related to bacteria that colonize plant roots. And some of the toxins that plant roots produce are similar to these pollutants. So the team asked whether Pseudomonas putida--"one of the best root colonizers we know of," Neal says--might be resistant to plant toxins. The researchers first took both the plants and bacteria out of the soil to see what was going on. They found that corn seedlings produce the most poison at one week old, protecting themselves at their most vulnerable stage of growth. Over the next couple of weeks, production drops off. Testing P. putida bacteria, they saw that the concentration of BX molecules around a seedling's roots didn't hurt the bacteria at all. But another common soil bacterium had serious trouble growing, even at a much lower concentration of the toxin. The chemical also broke down more quickly in the presence of P. putida, suggesting that the bacteria might not only tolerate the poison, but eat it. Next Neal and his coauthors turned to the genes of P. putida to see which ones are most active when the toxic chemical is around. A few dozen genes popped up. Some of these had to do with "chemotaxis," a trick in which bacteria use their wiggly arms to travel toward a high concentration of a chemical they like. Were P. putida bacteria actively seeking out the toxin and the corn roots that released it? Further experiments showed that the bacteria do, in fact, travel toward areas with more BX molecules. And in the soil, corn seedlings making the toxin attract more P. putida to their roots. (Genetic mutants that can't make BX molecules attract fewer bacteria.) The effect fades by the time the plant is three weeks old. This is the first time scientists have seen an otherwise toxic root chemical attracting helpful bacteria. A corn plant that has successfully recruited P. putida has a leg up--or a root up--in its development. These bacteria and other friendly microbes keep harmful bacteria away by crowding them out and producing antibiotics against them. They also help the plant reach nutrients such as iron and phosphorous in the soil. The bacteria, too, have an advantage over other microorganisms in the area because they can tolerate the plant's toxin and may even eat it. Neal says that through breeding, some crops have lost their ability to generate this chemical. "Modern varieties of cereals such as corn, wheat, barley, etc., now produce widely varying amounts of the benzoxazinones we studied," he writes. "Some produce quite a lot, others produce none." Neal hopes this research has shown why BX production is a helpful trait for plants to have. Today's breeders, better informed about what goes on beneath the soil than their predecessors, may want to create new crop varieties that can once again make their own toxins. Plants that generate BX molecules can inhibit pests and diseases--and call friendly bacteria to their aid. We might be able to use fewer pesticides and fertilizers if we let our crops' bacterial helpers help us, too. Neal, A., Ahmad, S., Gordon-Weeks, R., & Ton, J. (2012). Benzoxazinoids in Root Exudates of Maize Attract Pseudomonas putida to the Rhizosphere PLoS ONE, 7 (4) DOI: 10.1371/journal.pone.0035498 Image: Noël Zia Lee/Flickr...

Neal, A., Ahmad, S., Gordon-Weeks, R., & Ton, J. (2012) Benzoxazinoids in Root Exudates of Maize Attract Pseudomonas putida to the Rhizosphere. PLoS ONE, 7(4). DOI: 10.1371/journal.pone.0035498

Food and Energy Security – Read the Editorial by Martin Parry

2012-04-13T11:56:00Z

Read about Food and Energy Security, a new Wiley Open Access Journal, in an editorial by Martin Parry....

Parry, M. (2012) Food and energy security: exploring the challenges of attaining secure and sustainable supplies of food and energy. Food and Energy Security. DOI: 10.1002/fes3.1

A White Roof: So Simple It's Insane So Insane It Just Might Work

2012-04-13T01:39:00Z

Reflectivity might work better at mitigating global warming than focus on CO2...

Millstein, D., & Menon, S. (2011) Regional climate consequences of large-scale cool roof and photovoltaic array deployment. Environmental Research Letters, 6(3), 34001. DOI: 10.1088/1748-9326/6/3/034001

Graphing Out Loud: curves and lines

2012-04-04T16:26:18Z

I love graphs – my eyes quickly glaze over at a table of numeric data, but a graph, used correctly, can quickly and easily tell the whole story. ‘Used correctly’ is the key phrase – for all their power, graphs are infamously easy to bungle, and when used incorrectly they can misinform – or lie [...]...

Andreas D. Hüsler, & Didier Sornette. (2011) Evidence for super-exponentially accelerating atmospheric carbon dioxide growth. arXiv. arXiv: 1101.2832v3