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  • richardmitnick 11:46 am on January 19, 2021 Permalink | Reply
    Tags: "A New Archaeology for the Anthropocene Era", Addressing such thoroughly modern challenges as biodiversity; conservation; food security and climate change., , , , Archaeology today has a great deal to contribute to addressing the challenges of the modern era., Humans in the present era have become one of the great forces shaping nature., Max Planck Institute for the Science of Human History (MPI-SHH) [Max-Planck-Institut für Menschheitsgeschichte] (DE), Palaeoecology   

    From Max Planck Institute for the Science of Human History (MPI-SHH) [Max-Planck-Institut für Menschheitsgeschichte] (DE): “A New Archaeology for the Anthropocene Era” 

    Max Planck Gesellschaft

    From Max Planck Institute for the Science of Human History (MPI-SHH) [Max-Planck-Institut für Menschheitsgeschichte] (DE)

    January 18, 2021
    Prof. Nicole Boivin
    Director
    officeboivin@shh.mpg.de
    boivin@shh.mpg.de

    Scantily clad tomb raiders and cloistered scholars piecing together old pots – these are the kinds of stereotypes of archaeology that dominate public perception. Yet archaeology in the new millennium is a world away from these images. In a major new report, researchers from the Max Planck Institute for the Science of Human History probe a thoroughly modern and scientific discipline to understand how it is helping to address the considerable challenges of the Anthropocene.

    1
    Information from disciplines like archaeology, history, historical ecology and palaeoecology has an important role to play in shaping sustainable solutions to the challenges of the Anthropocene. Credit: Michelle O’Reilly, MPI-SHH.

    Indiana Jones and Lara Croft have a lot to answer for. Public perceptions of archaeology are often thoroughly outdated, and these characterisations do little to help.

    Yet archaeology as practiced today bears virtually no resemblance to the tomb raiding portrayed in movies and video games. Indeed, it bears little resemblance to even more scholarly depictions of the discipline in the entertainment sphere.

    A paper published today in Nature Ecology and Evolution aims to give pause to an audience that has been largely prepared to take such out-of-touch depictions at face value. It reveals an archaeology practiced by scientists in white lab coats, using multi-million-euro instrumentation and state of the art computers.

    It also reveals an archaeology poised to contribute in major ways to addressing such thoroughly modern challenges as biodiversity conservation, food security and climate change.

    “Archaeology today is a dramatically different discipline to what it was a century ago,” observes Nicole Boivin, lead author of the study and Director of the Institute’s Department of Archaeology. “While the tomb raiding we see portrayed in movies is over the top, the archaeology of the past was probably closer to this than to present-day archaeology. Much archaeology today is in contrast highly scientific in orientation, and aimed at addressing modern-day issues.”

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    Around the world today, we can find many examples of how past cultural and technological practices and solutions are being revived to address pressing environmental and land management challenges. Examples include (left to right) mobilization of ancient terra preta (anthropogenic dark earth) technology, revitalization of landesque capital (long-term landscape investments) and adoption of traditional fire management regimes. Credit: Michelle O’Reilly, MPI-SHH.

    Examining the research contributions of the field over the past few decades, the authors reach a clear conclusion – archaeology today has a great deal to contribute to addressing the challenges of the modern era.

    “Humans in the present era have become one of the great forces shaping nature,” emphasizes Alison Crowther, coauthor and researcher at both the University of Queensland and the MPI Science of Human History. “When we say we have entered a new, human-dominated geological era, the Anthropocene, we acknowledge that role.”

    How can archaeology, a discipline focused on the past, hope to address the challenges we face in the Anthropocene?

    “It is clear that the past offers a vast repertoire of cultural knowledge that we cannot ignore,” highlights Professor Boivin.

    The two researchers show the many ways that data about the past can serve the future. By analysing what worked and didn’t work in the past – effectively offering long-term experiments in human society – archaeologists gain insight into the factors that support sustainability and resilience, and the factors that work against them. They also highlight ancient solutions to modern problems.

    “We show how researchers have improved the modern world by drawing upon information about the ways people in the past enriched soils, prevented destructive fires, created greener cities and transported water without fossil fuels,” notes Dr. Crowther.

    People also continue to use, and adapt, ancient technologies and infrastructure, including terrace and irrigation systems that are in some cases centuries or even millennia old.

    But the researchers are keen to highlight the continued importance of technological and social solutions to climate change and the other challenges of the Anthropocene.

    “It’s not about glorifying the past, or vilifying progress,” emphasizes Professor Boivin. “Instead, it’s about bringing together the best of the past, present and future to steer a responsible and constructive course for humanity.”

    See the full article here.

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Max Planck Institute for the Science of Human History (MPI-SHH)[Max-Planck-Institut für Menschheitsgeschichte] (DE) in Jena was founded in 2014 to target fundamental questions of human history and evolution since the Paleolithic. It currently consists of three interdisciplinary research departments that integrate methods and research questions from the natural sciences and the humanities: the Department of Archaeology, the Department of Archaeogenetics, and the Department of Linguistic and Cultural Evolution.

    The MPI-SHH assembles experts, and large datasets, from research areas as diverse as archaeological science, anthropology, bioinformatics, proteomics, ancient genetics, quantitative linguistics, and others, to explore big questions of the human past:

    the settlement history of the world through past human migrations and genetic admixture events
    the impact of climatic and environmental change on human subsistence in different world regions
    human modification of ecosystems
    past human nutrition
    the spread and diversification of human-associated microbes and infectious diseases
    the spread and diversification of languages, cultures, and social practices
    the co-evolution of genes and culture

     
  • richardmitnick 12:23 pm on December 19, 2019 Permalink | Reply
    Tags: "What Lies Beneath Is Important for Ice Sheets", , , , Palaeoecology, , , The topography under Antarctic ice, Thwaites Glacier, Topography Matters   

    From Durham University via Eos: “What Lies Beneath Is Important for Ice Sheets” 

    Durham U bloc

    From Durham University

    via

    AGU
    Eos news bloc

    Eos

    12.19.19
    Sarah Derouin

    1
    The topography beneath Thwaites Glacier, above, is largely below sea level and slopes inland. Credit: NASA/James Yungel

    Ice sheets blanket continents, obscuring nooks, crannies, and even mountains below. The lay of the land underneath ice sheets is not just a side note—the topography is crucially important to how the overlying ice might behave.

    For years, researchers have been reconstructing the topography under Antarctic ice, essentially “peering” through the ice sheets with technology like ice-penetrating radar surveys.

    A team of scientists wanted to better understand how the topography changed under these continental-sized glaciers, so they worked backward, reconstructing the under-ice topography of Antarctica over the past 34 million years.

    They found that over time, Antarctic topography has become progressively lower. The researchers noted that their reconstructions can provide important boundary conditions for modelers who are trying to estimate ice volumes and sea levels during past climatic changes.

    Topography Matters

    The ice sheets of Antarctica are big players in global sea level rise. Researchers are interested in how the East Antarctic and West Antarctic Ice Sheets behaved in the past, and they rely on modeling to reconstruct ice flows.

    “Bed topography is a really important boundary condition in ice sheet models,” said Guy Paxman, a geophysicist at Durham University in the United Kingdom and lead author of the new study, published in Palaeogeography, Palaeoclimatology, Palaeoecology.

    “If researchers are modeling ice sheets in deep geological time, they need to have a more realistic version of the topography than just using the present-day topography,” he added.

    Two big factors control how ice sheets behave: the extent of land below sea level and the slope of the bed. Both characteristics can contribute to seawater seeping under the ice, a situation that encourages the glacier to start floating, become unstable, and break up. As ice sheets become unstable, they can retreat and contribute to sea level rise.

    Contemporary topographic maps show that most of the bed in West Antarctica is below sea level and slopes inland. Because of that, West Antarctic glaciers such as Thwaites are of particular interest to researchers, said Dustin Schroeder, a radio glaciologist at Stanford University who was not involved with the study.

    “One of the reasons we’re studying Thwaites Glacier is because of its shape,” said Schroeder, who added that like the Antarctic ice sheets themselves, the massive glacier could have been a big contributor to sea level rise in the past.

    Bedrock Changes over Time

    To better understand paleotopographic evolution in Antarctica, the team looked at four time slices in which significant climatic changes were preserved in the geologic record: 34 million years ago (when ice started to accumulate), 23 million years ago, 14 million years ago, and 3.5 million years ago.

    Paxman said their study is the first attempt to reconstruct Antarctic topography for multiple time periods beginning when ice first started to accumulate. To do that, the team had to piece together an immense amount of data on erosion, volcanism, and land subsidence from both crustal rifting and the weight of the overlying ice.

    To reconstruct erosion over the past 34 million years, the team examined sediment accumulation around the continent. Offshore seismic data helped them reconstruct how much land was lost through erosion, and deep-sea drilling cores helped build a more complete picture of the rate of sediment accumulation.

    The team found that glacial erosion rates in East Antarctica appeared to be higher during the Oligocene, the first 10–15 million years of Antarctic glaciation. Paxman noted that erosion started to slow down after the middle Miocene (about 14 million years ago).

    “This is the opposite situation [than] in West Antarctica, where erosion has picked up since the mid-Miocene,” he said.

    In addition to erosion rates, the team looked at ice loading and the effects of rifting in West Antarctica, including thermal subsidence. Overall, the researchers determined that Antarctica’s topography has gotten progressively lower over time: 34 million years ago, there was about 25% more land above sea level than there is today.

    3
    These simplified maps compare Antarctic topography 34 million years ago with the continent’s present-day subglacial topography. Gray represents topography above modern sea level, and blue is topography below modern sea level. Credit: Guy Paxman

    “The most significant changes we tend to find are in the [West] Antarctic rift system,” said Paxman, but he added that there were also large changes in East Antarctica, especially in basins around margins of the continent.

    Paleotopography in Practice

    The new research shows that West Antarctica has changed a lot over time. “This paper said [that] in the past, the shape [of West Antarctica] was different—and really different,” said Schroeder. “That is where it is provocative and interesting.”

    “When we do long-timescale modeling studies on these different topographies, I’m looking forward to seeing if that gives us insights into how things changed in the past,” said Schroeder. He added that this work might give additional insights into how uplift and erosion could affect glaciology and ice vulnerability. “I think it really gives us a tool to ask some important questions that were much harder to ask before.”

    The team hopes that researchers will find the work useful for future studies. “These topographies are freely available to download,” said Paxman. “We’re really encouraging people [to download them.] If they want to model ice sheets in the past, these topographies are there as a boundary condition for whoever wants to look at some of these questions about past Antarctic ice sheets.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Durham U campus

    Durham University is distinctive – a residential collegiate university with long traditions and modern values. We seek the highest distinction in research and scholarship and are committed to excellence in all aspects of education and transmission of knowledge. Our research and scholarship affect every continent. We are proud to be an international scholarly community which reflects the ambitions of cultures from around the world. We promote individual participation, providing a rounded education in which students, staff and alumni gain both the academic and the personal skills required to flourish.

     
  • richardmitnick 10:39 am on September 4, 2015 Permalink | Reply
    Tags: , , Palaeoecology,   

    From Vanderbilt: “Evidence that Earth’s first mass extinction was caused by critters, not catastrophe” 

    Vanderbilt U Bloc

    Vanderbilt University

    Sep. 2, 2015
    David Salisbury

    1
    Fossil of frond-like Ediacaran species found in Namibia. (Sarah Tweedt, Smithsonian Institution)

    In the popular mind, mass extinctions are associated with catastrophic events, like giant meteorite impacts and volcanic super-eruptions.

    But the world’s first known mass extinction, which took place about 540 million years ago, now appears to have had a more subtle cause: evolution itself.

    “People have been slow to recognize that biological organisms can also drive mass extinction,” said Simon Darroch, assistant professor of earth and environmental sciences at Vanderbilt University. “But our comparative study of several communities of Ediacarans, the world’s first multicellular organisms, strongly supports the hypothesis that it was the appearance of complex animals capable of altering their environments, which we define as ‘ecosystem engineers,’ that resulted in the Ediacaran’s disappearance.”

    The study is described in the paper Biotic replacement and mass extinction of the Ediacara biota published Sept. 2 in the journal Proceedings of the Royal Society B.

    “There is a powerful analogy between the Earth’s first mass extinction and what is happening today,” Darroch observed. “The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and we are the most powerful ‘ecosystem engineers’ ever known.”

    The earliest life on Earth consisted of microbes – various types of single-celled microorganisms. They ruled the Earth for more than 3 billion years. Then some of these microorganisms [cyanobacteria] discovered how to capture the energy in sunlight.

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    Cyanobacteria

    The photosynthetic process that they developed had a toxic byproduct: oxygen. Oxygen was poisonous to most microbes that had evolved in an oxygen-free environment, making it the world’s first pollutant.

    But for the microorganisms that developed methods for protecting themselves, oxygen served as a powerful new energy source. Among a number of other things, it gave them the added energy they needed to adopt multicellular forms. Thus, the Ediacarans arose about 600 million years ago during a warm period following a long interval of extensive glaciation.

    “We don’t know very much about the Ediacarans because they did not produce shells or skeletons. As a result, almost all we know about them comes from imprints of their shapes preserved in sand or ash,” said Darroch.

    2
    Simon Darroch (Steve Green / Vanderbilt)

    What scientists do know is that, in their heyday, Ediacarans spread throughout the planet. They were a largely immobile form of marine life shaped like discs and tubes, fronds and quilted mattresses. The majority were extremely passive, remaining attached in one spot for their entire lives. Many fed by absorbing chemicals from the water through their outer membranes, rather than actively gathering nutrients.

    Paleontologists have coined the term “Garden of Ediacara” to convey the peace and tranquility that must have prevailed during this period. But there was a lot of churning going on beneath that apparently serene surface.

    After 60 million years, evolution gave birth to another major innovation: animals. All animals share the characteristics that they can move spontaneously and independently, at least during some point in their lives, and sustain themselves by eating other organisms or what they produce. Animals burst onto the scene in a frenzy of diversification that paleontologists have labeled the Cambrian explosion, a 25-million-year period when most of the modern animal families – vertebrates, molluscs, arthropods, annelids, sponges and jellyfish – came into being.

    “These new species were ‘ecological engineers’ who changed the environment in ways that made it more and more difficult for the Ediacarans to survive,” said Darroch.

    3
    Ediacaran fossil found in the Swartput Farm site. (Sarah Tweedt / Smithsonian Institution)

    He and his colleagues performed an extensive paleoecological and geochemical analysis of the youngest known Ediacaran community exposed in hillside strata in southern Namibia. The site, called Farm Swartpunt, is dated at 545 million years ago, in the waning one to two million years of the Ediacaran reign.

    “We found that the diversity of species at this site was much lower, and there was evidence of greater ecological stress, than at comparable sites that are 10 million to 15 million years older,” Darroch reported. Rocks of this age also preserve an increasing diversity of burrows and tracks made by the earliest complex animals, presenting a plausible link between their evolution and extinction of the Ediacarans.

    The older sites were Mistaken Point in Newfoundland, dating from 579 to 565 million years ago; Nilpena in South Australia, dating from 555 to 550 million years ago; and the White Sea in Russia, dating also from 555 to 550 million years ago million years ago.

    Darroch and his colleagues made extensive efforts to ensure that the differences they recorded were not due to some external factor.

    For example, they ruled out the possibility that the Swartpunt site might have been lacking in some vital nutrients by closely comparing the geochemistry of the sites.

    It is a basic maxim in paleontology that the more effort that is made in investigating a given site, the greater the diversity of fossils that will be found there. So the researchers used statistical methods to compensate for the variation in the differences in the amount of effort that had been spent studying the different sites.

    4
    Simon Darroch in Namibia searching for fossils. (Sarah Tweedt, Smithsonian Institution)

    Having ruled out any extraneous factors, Darroch and his collaborators concluded that “this study provides the first quantitative palaeoecological evidence to suggest that evolutionary innovation, ecosystem engineering and biological interactions may have ultimately caused the first mass extinction of complex life.”

    Marc Laflamme, Thomas Boag and Sara Mason from the University of Toronto; Douglas Erwin and Sarah Tweedt from the Smithsonian Institution, Erik Sperling from Stanford University, Alex Morgan and Donald Johnston from Harvard University; Rachel Racicot from Yale University; and Paul Myrow from Colorado College collaborated in the study.

    The project was supported by grants from the Connaught Foundation, National Science and Engineering Research Council of Canada, NASA Astrobiology Institute, National Geographic Society and National Science Foundation grant EAR 1324095.

    See the full article here .

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