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News Article | May 25, 2017
Site: www.sciencedaily.com

An international team of scientists has found evidence suggesting the dehydration of minerals deep below the ocean floor influenced the severity of the Sumatra earthquake, which took place on December 26, 2004. The earthquake, measuring magnitude 9.2, and the subsequent tsunami, devastated coastal communities of the Indian Ocean, killing over 250,000 people. Research into the earthquake was conducted during a scientific ocean drilling expedition to the region in 2016, as part of the International Ocean Discovery Program (IODP), led by scientists from the University of Southampton and Colorado School of Mines. During the expedition on board the research vessel JOIDES Resolution, the researchers sampled, for the first time, sediments and rocks from the oceanic tectonic plate which feeds the Sumatra subduction zone. A subduction zone is an area where two of the Earth's tectonic plates converge, one sliding beneath the other, generating the largest earthquakes on Earth, many with destructive tsunamis. Findings of a study on sediment samples found far below the seabed are now detailed in a new paper led by Dr Andre Hüpers of the MARUM-Center for Marine Environmental Sciences at University of Bremen - published in the journal Science. Expedition co-leader Professor Lisa McNeill, of the University of Southampton, says: "The 2004 Indian Ocean tsunami was triggered by an unusually strong earthquake with an extensive rupture area. We wanted to find out what caused such a large earthquake and tsunami and what this might mean for other regions with similar geological properties." The scientists concentrated their research on a process of dehydration of sedimentary minerals deep below the ground, which usually occurs within the subduction zone. It is believed this dehydration process, which is influenced by the temperature and composition of the sediments, normally controls the location and extent of slip between the plates, and therefore the severity of an earthquake. In Sumatra, the team used the latest advances in ocean drilling to extract samples from 1.5 km below the seabed. They then took measurements of sediment composition and chemical, thermal, and physical properties and ran simulations to calculate how the sediments and rock would behave once they had travelled 250 km to the east towards the subduction zone, and been buried significantly deeper, reaching higher temperatures. The researchers found that the sediments on the ocean floor, eroded from the Himalayan mountain range and Tibetan Plateau and transported thousands of kilometres by rivers on land and in the ocean, are thick enough to reach high temperatures and to drive the dehydration process to completion before the sediments reach the subduction zone. This creates unusually strong material, allowing earthquake slip at the subduction fault surface to shallower depths and over a larger fault area - causing the exceptionally strong earthquake seen in 2004. Dr Andre Hüpers of the University of Bremen says: "Our findings explain the extent of the large rupture area, which was a feature of the 2004 earthquake, and suggest that other subduction zones with thick and hotter sediment and rocks, could also experience this phenomenon. "This will be particularly important for subduction zones with limited or no historic subduction earthquakes, where the hazard potential is not well known. Subduction zone earthquakes typically have a return time of a few hundred to a thousand years. Therefore our knowledge of previous earthquakes in some subduction zones can be very limited." Similar subduction zones exist in the Caribbean (Lesser Antilles), off Iran and Pakistan (Makran), and off western USA and Canada (Cascadia). The team will continue research on the samples and data obtained from the Sumatra drilling expedition over the next few years, including laboratory experiments and further numerical simulations, and they will use their results to assess the potential future hazards both in Sumatra and at these comparable subduction zones.


News Article | May 26, 2017
Site: www.chromatographytechniques.com

An international team of scientists has found evidence suggesting the dehydration of minerals deep below the ocean floor influenced the severity of the Sumatra earthquake, which took place on December 26, 2004. The earthquake, measuring magnitude 9.2, and the subsequent tsunami, devastated coastal communities of the Indian Ocean, killing over 250,000 people. Research into the earthquake was conducted during a scientific ocean drilling expedition to the region in 2016, as part of the International Ocean Discovery Program (IODP), led by scientists from the University of Southampton and Colorado School of Mines. During the expedition on board the research vessel JOIDES Resolution, the researchers sampled, for the first time, sediments and rocks from the oceanic tectonic plate which feeds the Sumatra subduction zone. A subduction zone is an area where two of the Earth’s tectonic plates converge, one sliding beneath the other, generating the largest earthquakes on Earth, many with destructive tsunamis. Findings of a study on sediment samples found far below the seabed are now detailed in a new paper led by Andre Hüpers of the MARUM-Center for Marine Environmental Sciences at University of Bremen – published in the journal Science. “The 2004 Indian Ocean tsunami was triggered by an unusually strong earthquake with an extensive rupture area. We wanted to find out what caused such a large earthquake and tsunami and what this might mean for other regions with similar geological properties,” said expedition co-leader Lisa McNeill, of the University of Southampton. The scientists concentrated their research on a process of dehydration of sedimentary minerals deep below the ground, which usually occurs within the subduction zone. It is believed this dehydration process, which is influenced by the temperature and composition of the sediments, normally controls the location and extent of slip between the plates, and therefore the severity of an earthquake. In Sumatra, the team used the latest advances in ocean drilling to extract samples from 1.5 km below the seabed. They then took measurements of sediment composition and chemical, thermal, and physical properties and ran simulations to calculate how the sediments and rock would behave once they had traveled 250 km to the east towards the subduction zone, and been buried significantly deeper, reaching higher temperatures. The researchers found that the sediments on the ocean floor, eroded from the Himalayan mountain range and Tibetan Plateau and transported thousands of kilometers by rivers on land and in the ocean, are thick enough to reach high temperatures and to drive the dehydration process to completion before the sediments reach the subduction zone. This creates unusually strong material, allowing earthquake slip at the subduction fault surface to shallower depths and over a larger fault area – causing the exceptionally strong earthquake seen in 2004. “Our findings explain the extent of the large rupture area, which was a feature of the 2004 earthquake, and suggest that other subduction zones with thick and hotter sediment and rocks, could also experience this phenomenon," said Andre Hüpers, of the University of Bremen. “This will be particularly important for subduction zones with limited or no historic subduction earthquakes, where the hazard potential is not well known. Subduction zone earthquakes typically have a return time of a few hundred to a thousand years. Therefore our knowledge of previous earthquakes in some subduction zones can be very limited.” Similar subduction zones exist in the Caribbean (Lesser Antilles), off Iran and Pakistan (Makran), and off western USA and Canada (Cascadia). The team will continue research on the samples and data obtained from the Sumatra drilling expedition over the next few years, including laboratory experiments and further numerical simulations, and they will use their results to assess the potential future hazards both in Sumatra and at these comparable subduction zones.


News Article | May 25, 2017
Site: www.eurekalert.org

An international team of scientists has found evidence suggesting the dehydration of minerals deep below the ocean floor influenced the severity of the Sumatra earthquake, which took place on December 26, 2004. The earthquake, measuring magnitude 9.2, and the subsequent tsunami, devastated coastal communities of the Indian Ocean, killing over 250,000 people. Research into the earthquake was conducted during a scientific ocean drilling expedition to the region in 2016, as part of the International Ocean Discovery Program (IODP), led by scientists from the University of Southampton and Colorado School of Mines. During the expedition on board the research vessel JOIDES Resolution, the researchers sampled, for the first time, sediments and rocks from the oceanic tectonic plate which feeds the Sumatra subduction zone. A subduction zone is an area where two of the Earth's tectonic plates converge, one sliding beneath the other, generating the largest earthquakes on Earth, many with destructive tsunamis. Findings of a study on sediment samples found far below the seabed are now detailed in a new paper led by Dr Andre Hüpers of the MARUM-Center for Marine Environmental Sciences at University of Bremen - published in the journal Science. Expedition co-leader Professor Lisa McNeill, of the University of Southampton, says: "The 2004 Indian Ocean tsunami was triggered by an unusually strong earthquake with an extensive rupture area. We wanted to find out what caused such a large earthquake and tsunami and what this might mean for other regions with similar geological properties." The scientists concentrated their research on a process of dehydration of sedimentary minerals deep below the ground, which usually occurs within the subduction zone. It is believed this dehydration process, which is influenced by the temperature and composition of the sediments, normally controls the location and extent of slip between the plates, and therefore the severity of an earthquake. In Sumatra, the team used the latest advances in ocean drilling to extract samples from 1.5 km below the seabed. They then took measurements of sediment composition and chemical, thermal, and physical properties and ran simulations to calculate how the sediments and rock would behave once they had travelled 250 km to the east towards the subduction zone, and been buried significantly deeper, reaching higher temperatures. The researchers found that the sediments on the ocean floor, eroded from the Himalayan mountain range and Tibetan Plateau and transported thousands of kilometres by rivers on land and in the ocean, are thick enough to reach high temperatures and to drive the dehydration process to completion before the sediments reach the subduction zone. This creates unusually strong material, allowing earthquake slip at the subduction fault surface to shallower depths and over a larger fault area - causing the exceptionally strong earthquake seen in 2004. Dr Andre Hüpers of the University of Bremen says: "Our findings explain the extent of the large rupture area, which was a feature of the 2004 earthquake, and suggest that other subduction zones with thick and hotter sediment and rocks, could also experience this phenomenon. "This will be particularly important for subduction zones with limited or no historic subduction earthquakes, where the hazard potential is not well known. Subduction zone earthquakes typically have a return time of a few hundred to a thousand years. Therefore our knowledge of previous earthquakes in some subduction zones can be very limited." Similar subduction zones exist in the Caribbean (Lesser Antilles), off Iran and Pakistan (Makran), and off western USA and Canada (Cascadia). The team will continue research on the samples and data obtained from the Sumatra drilling expedition over the next few years, including laboratory experiments and further numerical simulations, and they will use their results to assess the potential future hazards both in Sumatra and at these comparable subduction zones. 1) For images of the research expedition and interviews with Professor Lisa McNeill, please contact Peter Franklin, Media Relations, University of Southampton. Tel ++44 23 8059 5457 Email: p.franklin@southampton.ac.uk 2) Copies of the embargoed Science paper Release of mineral-bound water prior to subduction tied to shallow seismogenic slip off Sumatra may be obtained from AAAS Office of Public Programson: Tel +1-202-326-6440 Email scipak@aaas.org. 3) The expedition to Sumatra was led by led by Professor Lisa McNeill (University of Southampton), Associate Professor Brandon Dugan (Colorado School of Mines), and Dr Katerina Petronotis (IODP JRSO). 4) For more on partner institutions and organisations visit: 5) IODP is an international scientific drilling program funded by the National Science Foundation (USA), Ministry of Education, Culture, Sports, Science and Technology (Japan), European Consortium for Ocean Research Drilling, Ministry of Science and Technology (People's Republic of China), Korea Institute of Geoscience and Mineral Resources (South Korea), Australian/New Zealand Consortium, Ministry of Earth Sciences (India), and Coordination for Improvement of Higher Education Personnel (Brazil). The research vessel JOIDES Resolution (JR) is operated on behalf of NSF by the JR Science Operator based at Texas A&M University (USA). https:/ 6) The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world's challenges. We are among the top one per cent of institutions globally. Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 24,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 200,000 alumni. http://www. 7) Ocean and Earth Science at the University of Southampton has a well-established reputation for outstanding research and teaching. Our unique waterfront campus at the National Oceanography Centre Southampton (NOCS) attracts prominent researchers and educators from around the world, who join us to work within the areas of geochemistry, geology and geophysics, marine biogeochemistry, marine biology and ecology, palaeoceanography and palaeoclimate and physical oceanography. Following publication of the national Research Excellence Framework 2014 (REF2014), OES was ranked second in the UK, for proportion of research recognised as world-leading (4*) in the Earth Systems and Environmental Sciences Unit of Assessment. http://www.


News Article | May 26, 2017
Site: www.chromatographytechniques.com

An international team of scientists has found evidence suggesting the dehydration of minerals deep below the ocean floor influenced the severity of the Sumatra earthquake, which took place on December 26, 2004. The earthquake, measuring magnitude 9.2, and the subsequent tsunami, devastated coastal communities of the Indian Ocean, killing over 250,000 people. Research into the earthquake was conducted during a scientific ocean drilling expedition to the region in 2016, as part of the International Ocean Discovery Program (IODP), led by scientists from the University of Southampton and Colorado School of Mines. During the expedition on board the research vessel JOIDES Resolution, the researchers sampled, for the first time, sediments and rocks from the oceanic tectonic plate which feeds the Sumatra subduction zone. A subduction zone is an area where two of the Earth’s tectonic plates converge, one sliding beneath the other, generating the largest earthquakes on Earth, many with destructive tsunamis. Findings of a study on sediment samples found far below the seabed are now detailed in a new paper led by Andre Hüpers of the MARUM-Center for Marine Environmental Sciences at University of Bremen – published in the journal Science. “The 2004 Indian Ocean tsunami was triggered by an unusually strong earthquake with an extensive rupture area. We wanted to find out what caused such a large earthquake and tsunami and what this might mean for other regions with similar geological properties,” said expedition co-leader Lisa McNeill, of the University of Southampton. The scientists concentrated their research on a process of dehydration of sedimentary minerals deep below the ground, which usually occurs within the subduction zone. It is believed this dehydration process, which is influenced by the temperature and composition of the sediments, normally controls the location and extent of slip between the plates, and therefore the severity of an earthquake. In Sumatra, the team used the latest advances in ocean drilling to extract samples from 1.5 km below the seabed. They then took measurements of sediment composition and chemical, thermal, and physical properties and ran simulations to calculate how the sediments and rock would behave once they had traveled 250 km to the east towards the subduction zone, and been buried significantly deeper, reaching higher temperatures. The researchers found that the sediments on the ocean floor, eroded from the Himalayan mountain range and Tibetan Plateau and transported thousands of kilometers by rivers on land and in the ocean, are thick enough to reach high temperatures and to drive the dehydration process to completion before the sediments reach the subduction zone. This creates unusually strong material, allowing earthquake slip at the subduction fault surface to shallower depths and over a larger fault area – causing the exceptionally strong earthquake seen in 2004. “Our findings explain the extent of the large rupture area, which was a feature of the 2004 earthquake, and suggest that other subduction zones with thick and hotter sediment and rocks, could also experience this phenomenon," said Andre Hüpers, of the University of Bremen. “This will be particularly important for subduction zones with limited or no historic subduction earthquakes, where the hazard potential is not well known. Subduction zone earthquakes typically have a return time of a few hundred to a thousand years. Therefore our knowledge of previous earthquakes in some subduction zones can be very limited.” Similar subduction zones exist in the Caribbean (Lesser Antilles), off Iran and Pakistan (Makran), and off western USA and Canada (Cascadia). The team will continue research on the samples and data obtained from the Sumatra drilling expedition over the next few years, including laboratory experiments and further numerical simulations, and they will use their results to assess the potential future hazards both in Sumatra and at these comparable subduction zones.


News Article | December 12, 2016
Site: www.eurekalert.org

CORVALLIS, Ore. - Scientists have known for decades that small changes in climate can have significant impacts on the massive Antarctic Ice Sheet. Now a new study suggests the opposite also is true. An international team of researchers has concluded that the Antarctic Ice Sheet actually plays a major role in regional and global climate variability - a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth. Results of the study are being published this week in the journal Nature. Global climate models that look at the last several thousand years have failed to account for the amount of climate variability captured in the paleoclimate record, according to lead author Pepijn Bakker, a former post-doctoral researcher at Oregon State University now with the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany. The research team's hypothesis was that climate modelers were overlooking one crucial element in the overall climate system - an aspect of the ocean, atmosphere, biosphere or ice sheets - that might affect all parts of the system. "One thing we determined right off the bat was that virtually all of the climate models had the Antarctic Ice Sheet as a constant entity," Bakker said. "It was a static blob of ice, just sitting there. What we discovered, however, is that the ice sheet has undergone numerous pulses of variability that have had a cascading effect on the entire climate system." The Antarctic Ice Sheet, in fact, has demonstrated dynamic behavior over the past 8,000 years, according to Andreas Schmittner, a climate scientist in Oregon State's College of Earth, Ocean, and Atmospheric Sciences and co-author on the study. "There is a natural variability in the deeper part of the ocean adjacent to the Antarctic Ice Sheet - similar to the Pacific Decadal Oscillation, or El Niño/La Niña but on a time scale of centuries - that causes small but significant changes in temperatures," Schmittner said. "When the ocean temperatures warm, it causes more direct melting of the ice sheet below the surface, and it increases the number of icebergs that calve off the ice sheet." Those two factors combine to provide an influx of fresh water into the Southern Ocean during these warm regimes, according to Peter Clark, a paleoclimatologist in OSU's College of Earth, Ocean, and Atmospheric Sciences and co-author on the study. "The introduction of that cold, fresh water lessens the salinity and cools the surface temperatures, at the same time, stratifying the layers of water," Clark said. "The cold, fresh water freezes more easily, creating additional sea ice despite warmer temperatures that are down hundreds of meters below the surface." The discovery may help explain why sea ice has expanded in the Southern Ocean despite global warming, the researchers say. The same phenomenon doesn't occur in the Northern Hemisphere with the Greenland Ice Sheet because it is more landlocked and not subject to the same current shifts that affect the Antarctic Ice Sheet. "One message that comes out of this study is that the Antarctic Ice Sheet is very sensitive to small changes in ocean temperatures, and humans are making the Earth a lot warmer than it has been," Bakker said. Sediment cores from the sea floor around Antarctica contain sand grains delivered there by icebergs calving off the ice sheet. The researchers analyzed sediments from the last 8,000 years, which showed evidence that many more icebergs calved off the ice sheet in some centuries than in others. Using sophisticated computer modeling, the researchers traced the variability in iceberg calving to small changes in ocean temperatures. The Antarctic Ice Sheet covers an area of more than 5 million square miles and is estimated to hold some 60 percent of all the fresh water on Earth. The east part of the ice sheet rests on a major land mass, but in West Antarctica, the ice sheet rests on bedrock that extends into the ocean at depths of more than 2,500 meters, or more than 8,000 feet, making it vulnerable to disintegration. Scientists estimate that if the entire Antarctic Ice Sheet were to melt, global sea levels would rise some 200 feet. Other authors on the study include Nicholas Golledge of Victoria University of Wellington in New Zealand and Michael Weber of the University of Bonn in Germany.


News Article | December 12, 2016
Site: www.eurekalert.org

An international team of researchers has found that the Antarctic Ice Sheet plays a major role in regional and global climate variability - a discovery that may also help explain why sea ice in the Southern Hemisphere has been increasing despite the warming of the rest of the Earth. Results of the study, co-authored by Michael Weber, a paleoclimatologist and visiting scientist at the University of Cambridge, along with colleagues from the USA, New Zealand and Germany, are published this week in the journal Nature. Global climate models that look at the last several thousand years have failed to account for the amount of climate variability captured in the paleoclimate record, according to lead author Pepijn Bakker, a climate modeller from the MARUM Center for Marine Environmental Studies at the University of Bremen in Germany. The researchers first turned their attention to the Scotia Sea. "Most icebergs calving off the Antarctic Ice Sheet travel through this region because of the atmospheric and oceanic circulation," explained Weber. "The icebergs contain gravel that drop into the sediment on the ocean floor - and analysis and dating of such deposits shows that for the last 8,000 years, there were centuries with more gravel and those with less." The research team's hypothesis is that climate modellers have historically overlooked one crucial element in the overall climate system. They discovered that the centuries-long phases of enhanced and reduced Antarctic ice mass loss documented over the past 8,000 years have had a cascading effect on the entire climate system. Using sophisticated computer modelling, the researchers traced the variability in iceberg calving (ice that breaks away from glaciers) to small changes in ocean temperatures. "There is a natural variability in the deeper part of the ocean adjacent to the Antarctic Ice Sheet that causes small but significant changes in temperatures," said co-author Andreas Schmittner, a climate modeller from Oregon State University. "When the ocean temperatures warm, it causes more direct melting of the ice sheet below the surface, and it increases the number of icebergs that calve off the ice sheet." Those two factors combine to provide an influx of fresh water into the Southern Ocean during these warm regimes, according to Peter Clark, a paleoclimatologist from Oregon State University, and co-author on the study. "The introduction of that cold, fresh water lessens the salinity and cools the surface temperatures, at the same time, stratifying the layers of water," he said. "The cold, fresh water freezes more easily, creating additional sea ice despite warmer temperatures that are down hundreds of meters below the surface." The discovery may help explain why sea ice is currently expanding in the Southern Ocean despite global warming, the researchers say. "This response is well-known, but what is less-known is that the input of fresh water also leads to changes far away in the northern hemisphere, because it disrupts part of the global ocean circulation," explained Nick Golledge from the University of Wellington, New Zealand, an ice-sheet modeller and study co-author. "Meltwater from the Antarctic won't just raise global sea level, but might also amplify climate changes around the world. Some parts of the North Atlantic may end up with warmer temperatures as a consequence of part of Antarctica melting." Golledge used a computer model to simulate how the Antarctic Ice Sheet changed as it came out of the last ice age and into the present, warm period. "The integration of data and models provides further evidence that the Antarctic Ice Sheet has experienced much greater natural variability in the past than previously anticipated," added Weber. "We should therefore be concerned that it will possibly act very dynamically in the future, too, specifically when it comes to projecting future sea-level rise." Two years ago Weber led another study, also published in Nature, which found that the Antarctic Ice Sheet collapsed repeatedly and abruptly at the end of the Last Ice Age to 19,000 to 9,000 years ago.


News Article | October 26, 2016
Site: www.bbc.co.uk

Scientists have obtained remarkable new insights into the asteroid impact that wiped out the dinosaurs. They have been examining rocks from the crater that the 15km-wide space object dug out of what is now the Gulf of Mexico some 66 million years ago. The team says it can see evidence in these materials for how life returned to the scene soon after the calamity. Descendants of these small organisms are likely thriving today in amongst the crater's smashed up materials. The international project has shipped the hundreds of metres it drilled from beneath the Gulf floor earlier this year to the MARUM Center for Marine Environmental Sciences, at the University of Bremen, Germany. It is here that the cores are being catalogued, analysed and archived. Chicxulub Crater - The impact that changed life on Earth Prof Sean Gulick, from the University of Texas, US, is one of the two chief scientists involved. He cautioned that the rock investigation was a long-term endeavour, but then shared some early observations. "We've been able to examine that first 10,000 years after the impact, which is dominated by what we call 'disaster species' - dominated by the organisms that love stressed environments. And then we can see evolution coming back in [during] the next few hundred thousands years after that," he told BBC News. The "disaster species" that left their fossil traces in the rocks are tiny plankton-type organisms, such as particular forms of dinoflagellates. But of considerable delight for the research team is evidence in the cores for what may be current biology. These deep-living cells would be the descendants of organisms that invaded pore spaces and cracks through which hot fluids flowed. Similar life-sustaining hydrothermal systems are seen at volcanic vents at mid-ocean ridges. "We've got some cell counts and some DNA, but it's all very early days; we're very concerned about contamination," explained Prof Jo Morgan. "But the signs are that, yes, this crater was occupied soon after the impact." These are moments to treasure for the Imperial College London scientist. She had lobbied for 16 years to get the drill project approved and funded. It was conducted just off the Mexican coast from April to June. The drill mechanism got to 1,335m below the modern sea floor. For its first 600m, it had to push through typical ocean sediments that have built up since the impact. But then, in the lower part of the hole, it hit the true rocks that make up the Chicxulub Crater, as it has become known. "They're very strange rocks," said Prof Morgan. "The rocks have formed this feature: it's called a 'peak ring'. They're very, very highly… what we call 'shocked'. Shock pressures of many tens of gigapascals have deformed the rocks. They're also highly fractured, and have moved long distances. So, even though they're made of granite-type rocks, they're amazingly different to anything else we see in the world." With Prof Gulick, Prof Morgan has assembled a 35-strong team to begin the process of unpacking the cores in Bremen. Little chunks of rock are being cut and bagged to be sent to labs all across the globe. The goal, broadly speaking, is to understand better how the crater formed, the energy involved in its excavation, and the volume of material that was dispersed. This will put new limits on the nature of the environmental changes that overtook the Earth and sent so many species - not just the dinosaurs - into oblivion. Prof Gulick told BBC News: "So, we think that this investigation will give us answers to some fundamental questions that people have been asking for decades, like the energy of the impact, maybe some information about the kill mechanisms that caused the mass extinction, and also fundamentally about how impact processes work [and] how impacts affect all planets in the rocky part of the Solar System." Only about a half of the recovered crater rocks are being used for the current study. The rest are being stored in the archive for a time when lab equipment is more advanced than it is today. It is certain that future teams will propose additional ideas about the impact which they will test with analytical tools not yet invented. The expedition to drill into Chicxulub Crater was conducted by the European Consortium for Ocean Research Drilling (ECORD) as part of the International Ocean Discovery Program (IODP). The expedition was also supported by the International Continental Scientific Drilling Program (ICDP). Formal results will be published in a slew of scholarly papers that should start appearing very soon. Topics of early interest will include the possibility that some vestige of the impactor itself can be found in the cores. A telltale of this meteoritic material will likely be high levels of the element iridium. The scientists should also be able to comment on the tsunamis that occurred when the asteroid struck what was then a shallow sea. Colossal volumes of water would have sloshed back and forth and this action ought to be recorded in cascades of sediment. Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos


News Article | December 19, 2016
Site: www.eurekalert.org

Biologists discover a new octopus species at more than 4,000 meters depth that guard their eggs, likely for years prior to hatching, and a community which may not survive without hard substrate such as manganese nodules Bremerhaven/Germany, 19 December 2016. Manganese nodules on the seabed of the Pacific Ocean are an important breeding ground for deep-sea octopuses. As reported by a German-American team of biologists in the current issue of the journal Current Biology, the octopuses deposit their eggs onto sponges that only grow locally on manganese nodules. The researchers had observed the previously unknown octopus species during diving expeditions in the Pacific at depths of more than 4000 metres - new record depths for these octopuses. Their specific dependence on manganese nodules for brooding eggs shows that the industrial extraction of resources in the deep sea must be preceded by thorough investigations into the ecological consequences of such actions. Do you know Casper? In February this year, the deep-sea octopus (Octopoda, suborder: Incirrina) became a social media star within only a few days. The US diving robot Deep Discovery detected the approximately ten centimetre marine creature off the Hawaiian Necker Island at a depth of 4290 metres, taking close-up video and publishing the footage online. The web community named the virtually transparent octopus Casper, after the famous cartoon ghost. The video was watched hundreds of thousands of times - but only now are researchers in the journal Current Biology revealing the extensive knowledge about life in the deep sea and the ecological significance of the manganese nodules that they have managed to tease out of the observation of this Hawaiian Casper octopus, and 28 additional observations of similar octopuses made elsewhere in the Pacific. Record depth: Octopuses guard their eggs at more than 4000 metres depth The appearance of the Hawaiian Casper octopus in front of the camera at a depth of 4290 metres is the greatest depth at which such finless octopuses have to date been observed. Six months earlier, researchers of the Alfred Wegener Institute, the GEOMAR, the Max Planck Institute for Marine Microbiology, and the Centre for Marine Environmental Sciences (MARUM) had filmed and photographed more specimens of this or similar hitherto unknown octopus species at a depth of 4120 to 4197 metres in the Peru Basin in the south-eastern Pacific Ocean. The photos and films of these octopuses were taken with diving robot ROV KIEL 6000 and a towed camera system (AWI-OFOS). "Until we made these observations, we had assumed that these octopuses only occur at depths of up to 2600 metres. But the species discovered can now be seen to colonise much greater depths," says lead author Dr Autun Purser of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). Without manganese nodules the octopuses cannot find a brooding ground Two of the octopuses were seen by the camera system to be guarding their eggs. "At a depth of 4000 metres, these animals had deposited their eggs onto the stems of dead sponges, which in turn had grown on manganese nodules. The nodules served as the only anchoring point for the sponges on the otherwise very muddy seafloor. This means that without the manganese nodules the sponges would not have been able to live in this spot, and without sponges the octopuses would not have found a place to lay their eggs," the AWI researcher explains. What's more: Even octopuses not actually brooding seek the proximity of manganese nodules and rocky protrusions. "The video footage indicates that the animals have cleaned the seabed around the nodules. It probably looks like that because the animals have been filmed using their arms to dig into the sediment around the nodules probably in search for food," says co-author Henk-Jan Hoving of the GEOMAR Helmholtz Centre for Ocean Research. The so-called DISCOL experiment from the late 1980s shows that many deep-sea animals need manganese nodules in their habitat. At the time, also in the Peru Basin, German researchers had removed manganese nodules by ploughing them into the seabed. In subsequent years, they observed the consequences of this human intervention on the deep-sea community. 26 years later, researchers of the expedition with RV Sonne returned to the place where the DISCOL experiment was carried out. Their conclusion: "The removal of the manganese nodules at that time caused the community of animals that are attached to the seafloor, which also includes sponges, to almost fully collapse. Even 26 years later many animal populations have not yet recovered," explain the authors in the new study. "Our new observations show that we have to know about the behaviour of deep-sea animals and the specific way in which they adapt to their habitat in order to draw up sustainable protective and usage concepts," says AWI researcher Antje Boetius, head of the Sonne expedition to the Peru Basin. Octopuses probably guard their spawn for many years She classifies Casper and similar species as "particularly endangered" - as research has shown many deep-sea octopuses to only lay very few eggs and have extremely long reproductive cycles. Offspring of octopuses that spawn when in water temperature of three degrees Celsius have been observed to hatch after four years of continuous brooding. However, at the bottom of the Peru Basin, water temperature is a mere 1.5 degrees Celsius. "We therefore suspect that the octopus embryos here need many years to develop fully," says Antje Boetius. Disturbances during this important period would in all likelihood have serious consequences for the octopus offspring. The observation data presented as part of the current study was collected during several expeditions. The shots from the Peru Basin were taken in the autumn 2015 during a research cruise by the German research vessel Sonne. The dives of the Deep Discovery robot near the Hawaiian Necker Island were part of an expedition of the US research vessel Okeanos Explorer and took place in February 2016. Further observations were made during a tour of the Kilo Moana research vessel in 2011. The research was funded by the EU project "Managing Impacts of Deep-seA reSource exploitation (MIDAS)". The work on board the Sonne research vessel was made possible by the German Federal Ministry of Education and Research as part of the "Mining Impact of the Joint Programming Initiative Healthy and Productive Seas and Oceans (JPIO)" project.


Weinkauf M.F.G.,University of Tübingen | Moller T.,University of Tübingen | Koch M.C.,Goethe University Frankfurt | Kucera M.,MARUM
Biogeosciences | Year: 2013

Planktonic Foraminifera are important marine calcifiers, and the ongoing change in the oceanic carbon system makes it essential to understand the influence of environmental factors on the biomineralization of their shells. The amount of calcite deposited by planktonic Foraminifera during calcification has been hypothesized to reflect a range of environmental factors. However, it has never been assessed whether their calcification only passively responds to the conditions of the ambient seawater or whether it reflects changes in resource allocation due to physiological stress. To disentangle these two end-member scenarios, an experiment is required where the two processes are separated. A natural analogue to such an experiment occurred during the deposition of the Mediterranean sapropels, where large changes in surface water composition and stratification at the onset of the sapropel deposition were decoupled from local extinctions of planktonic Foraminifera species. We took advantage of this natural experiment and investigated the reaction of calcification intensity, expressed as mean area density (MAD), of four species of planktonic Foraminifera to changing conditions during the onset of Sapropel S5 (126-121 ka) in a sediment core from the Levantine Basin. We observed a significant relationship between MAD and surface water properties, as reflected by stable isotopes in the calcite of Foraminifera shells, but we failed to observe any reaction of calcification intensity on ecological stress during times of decreasing abundance culminating in local extinction. The reaction of calcification intensity to surface water perturbation at the onset of the sapropel was observed only in surface-dwelling species, but all species calcified more strongly prior to the sapropel deposition and less strongly within the sapropel than at similar conditions during the present-day. These results indicate that the high-salinity environment of the glacial Mediterranean Sea prior to sapropel deposition induced a∼more intense calcification, whereas the freshwater injection to the surface waters associated with sapropel deposition inhibited calcification. The results are robust to changes in carbonate preservation and collectively imply that changes in normalized shell weight in planktonic Foraminifera should reflect mainly abiotic forcing. 2013 Author(s).


Harders R.,University of Kiel | Kutterolf S.,University of Kiel | Hensen C.,University of Kiel | Moerz T.,MARUM | Brueckmann W.,University of Kiel
Geochemistry, Geophysics, Geosystems | Year: 2010

Submarine slope failures occur at all continental margins, but the processes generating different mass wasting phenomena remain poorly understood. Multibeam bathymetry mapping of the Middle America Trench reveals numerous continental slope failures of different dimensions and origin. For example, large rotational slumps have been interpreted to be caused by slope collapse in the wake of subducting seamounts. In contrast, the mechanisms generating translational slides have not yet been described. Lithology, shear strength measurements, density, and pore water alkalinity from a sediment core across a slide plane indicate that a few centimeters thick intercalated volcanic tephra layer marks the detachment surface. The ash layer can be correlated to the San Antonio tephra, emplaced by the 6000 year old caldera-forming eruption from Masaya-Caldera, Nicaragua. The distal deposits of this eruption are widespread along the continental slope and ocean plate offshore Nicaragua. Grain size measurements permit us to estimate the reconstruction of the original ash layer thickness at the investigated slide. Direct shear test experiments on Middle American ashes show a high volume reduction during shearing. This indicates that marine tephra layers have the highest hydraulic conductivity of the different types of slope sediment, enabling significant volume reduction to take place under undrained conditions. This makes ash layers mechanically distinct within slope sediment sequences. Here we propose a mechanism by which ash layers may become weak planes that promote translational sliding. The mechanism implies that ground shaking by large earthquakes induces rearrangement of ash shards causing their compaction (volume reduction) and produces a rapid accumulation of water in the upper part of the layer that is capped by impermeable clay. The water-rich veneer abruptly reduces shear strength, creating a detachment plane for translational sliding. Tephra layers might act as slide detachment planes at convergent margins of subducting zones, at submarine slopes of volcanic islands, and at submerged volcano slopes in lakes. Copyright 2010 by the American Geophysical Union.

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