Immune cells to be tested on the International Space Station

The human body is fine-tuned to Earth’s gravity. A team headed by Professor Oliver Ullrich from the University of Zurich’s Institute of Anatomy is now conducting an experiment on the International Space Station (ISS) to study whether this also applies to human cells. On the evening of April 18, the transporter spaceship Dragon lifted off from the Cape Canaveral launch center in Florida with a cargo of UZH immune cells on board.We know the effect of gravity on muscles, bones and joints inside out; it has been studied extensively in medicine for centuries. For a long time, however, exactly how gravity affects the cells remained a mystery. Thanks to modern cell biology and space technology, we can now study precisely whether and how cells are also adapted to life on Earth. In zero gravity, for instance, various immune system functions are impaired: Phagocytes known as macrophages, which kill and destroy invading bacteria, are no longer capable of protecting the person optimally from infections, which is why astronauts often suffer them.Professor Oliver Ullrich from the University of Zurich’s Institute of Anatomy now wants to investigate how the structure and metabolism of these phagocytes change during a three-day stint in zero gravity. Samples with immune cells are currently on their way up to the International Space Station (ISS) on the so-called Cellbox Mission, where they will be studied in an experiment. The Dragon capsule carrying the fixed samples is due to splash down in the Pacific Ocean on May 18.Three days in zero gravityThe ISS experiment focuses on the long-term impact of zero gravity on human phagocytes — especially their cytoskeleton and molecules, which are important for cell communication. On parabolic flights with zero gravity for 22 seconds and in tests on research rockets with five minutes of zero gravity, Professor Ullrich’s team already discovered that cells from the human immune system already respond to the absence of gravity within seconds. Key molecular functions for cell-to-cell communication and cell migration are immediately impaired.Based on a three-day experiment, the researchers are now looking to investigate whether the vast number of changes that take place in seconds or minutes of zero gravity are actually processes of adaptation to a new environment or far-reaching, permanent problems. …

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Arctic melt season lengthening, ocean rapidly warming

The length of the melt season for Arctic sea ice is growing by several days each decade, and an earlier start to the melt season is allowing the Arctic Ocean to absorb enough additional solar radiation in some places to melt as much as four feet of the Arctic ice cap’s thickness, according to a new study by National Snow and Ice Data Center (NSIDC) and NASA researchers.Arctic sea ice has been in sharp decline during the last four decades. The sea ice cover is shrinking and thinning, making scientists think an ice-free Arctic Ocean during the summer might be reached this century. The seven lowest September sea ice extents in the satellite record have all occurred in the past seven years.”The Arctic is warming and this is causing the melt season to last longer,” said Julienne Stroeve, a senior scientist at NSIDC, Boulder and lead author of the new study, which has been accepted for publication in Geophysical Research Letters. “The lengthening of the melt season is allowing for more of the sun’s energy to get stored in the ocean and increase ice melt during the summer, overall weakening the sea ice cover.”To study the evolution of sea ice melt onset and freeze-up dates from 1979 to the present day, Stroeve’s team used passive microwave data from NASA’s Nimbus-7 Scanning Multichannel Microwave Radiometer, and the Special Sensor Microwave/Imager and the Special Sensor Microwave Imager and Sounder carried onboard Defense Meteorological Satellite Program spacecraft.When ice and snow begin to melt, the presence of water causes spikes in the microwave radiation that the snow grains emit, which these sensors can detect. Once the melt season is in full force, the microwave emissivity of the ice and snow stabilizes, and it doesn’t change again until the onset of the freezing season causes another set of spikes. Scientists can measure the changes in the ice’s microwave emissivity using a formula developed by Thorsten Markus, co-author of the paper and chief of the Cryospheric Sciences Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md.Results show that although the melt season is lengthening at both ends, with an earlier melt onset in the spring and a later freeze-up in the fall, the predominant phenomenon extending the melting is the later start of the freeze season. Some areas, such as the Beaufort and Chukchi Seas, are freezing up between six and 11 days later per decade. But while melt onset variations are smaller, the timing of the beginning of the melt season has a larger impact on the amount of solar radiation absorbed by the ocean, because its timing coincides with when the sun is higher and brighter in the Arctic sky.Despite large regional variations in the beginning and end of the melt season, the Arctic melt season has lengthened on average by five days per decade from 1979 to 2013.Still, weather makes the timing of the autumn freeze-up vary a lot from year to year.”There is a trend for later freeze-up, but we can’t tell whether a particular year is going to have an earlier or later freeze-up,” Stroeve said. “There remains a lot of variability from year to year as to the exact timing of when the ice will reform, making it difficult for industry to plan when to stop operations in the Arctic.”To measure changes in the amount of solar energy absorbed by the ice and ocean, the researchers looked at the evolution of sea surface temperatures and studied monthly surface albedo data (the amount of solar energy reflected by the ice and the ocean) together with the incoming solar radiation for the months of May through October. The albedo and sea surface temperature data the researchers used comes from the National Oceanic and Atmospheric Administration’s polar-orbiting satellites.They found that the ice pack and ocean waters are absorbing more and more sunlight due both to an earlier opening of the waters and a darkening of the sea ice. …

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Dust in the wind drove iron fertilization during ice age

Researchers from Princeton University and the Swiss Federal Institute of Technology in Zurich have confirmed that during the last ice age iron fertilization caused plankton to thrive in a region of the Southern Ocean.The study published in Science confirms a longstanding hypothesis that wind-borne dust carried iron to the region of the globe north of Antarctica, driving plankton growth and eventually leading to the removal of carbon dioxide from the atmosphere.Plankton remove the greenhouse gas carbon dioxide (CO2) from the atmosphere during growth and transfer it to the deep ocean when their remains sink to the bottom. Iron fertilization has previously been suggested as a possible cause of the lower CO2 levels that occur during ice ages. These decreases in atmospheric CO2 are believed to have “amplified” the ice ages, making them much colder, with some scientists believing that there would have been no ice ages at all without the CO2 depletion.Iron fertilization has also been suggested as one way to draw down the rising levels of CO2 associated with the burning of fossil fuels. Improved understanding of the drivers of ocean carbon storage could lead to better predictions of how the rise in manmade carbon dioxide will affect climate in the coming years.The role of iron in storing carbon dioxide during ice ages was first proposed in 1990 by the late John Martin, an oceanographer at Moss Landing Marine Laboratories in California who made the landmark discovery that iron limits plankton growth in large regions of the modern ocean.Based on evidence that there was more dust in the atmosphere during the ice ages, Martin hypothesized that this increased dust supply to the Southern Ocean allowed plankton to grow more rapidly, sending more of their biomass into the deep ocean and removing CO2 from the atmosphere. Martin focused on the Southern Ocean because its surface waters contain the nutrients nitrogen and phosphorus in abundance, allowing plankton to be fertilized by iron without running low on these necessary nutrients.The research confirms Martin’s hypothesis, said Daniel Sigman, Princeton’s Dusenbury Professor of Geological and Geophysical Sciences, and a co-leader of the study. “I was an undergraduate when Martin published his ‘ice age iron hypothesis,'” he said. “I remember being captivated by it, as was everyone else at the time. But I also remember thinking that Martin would have to be the luckiest person in the world to pose such a simple, beautiful explanation for the ice age CO2 paradox and then turn out to be right about it.”Previous efforts to test Martin’s hypothesis established a strong correlation of cold climate, high dust and productivity in the Subantarctic region, a band of ocean encircling the globe between roughly 40 and 50 degrees south latitude that lies in the path of the winds that blow off South America, South Africa and Australia. However, it was not clear whether the productivity was due to iron fertilization or the northward shift of a zone of naturally occurring productivity that today lies to the south of the Subantarctic. This uncertainty was made more acute by the finding that ice age productivity was lower in the Antarctic Ocean, which lies south of the Subantarctic region.To settle the matter, the research groups of Sigman at Princeton and Gerald Haug and Tim Eglinton at ETH Zurich teamed up to use a new method developed at Princeton. …

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Plankton make scents for seabirds and a cooler planet

The top predators of the Southern Ocean, far-ranging seabirds, are tied both to the health of the ocean ecosystem and to global climate regulation through a mutual relationship with phytoplankton, according to newly published work from the University of California, Davis.When phytoplankton are eaten by grazing crustaceans called krill, they release a chemical signal that calls in krill-eating birds. At the same time, this chemical signal — dimethyl sulfide, or DMS — forms sulfur compounds in the atmosphere that promote cloud formation and help cool the planet. Seabirds consume the grazers, and fertilize the phytoplankton with iron, which is scarce in the vast Southern Ocean. The work was published March 3 in the Proceedings of the National Academy of Sciences.”The data are really striking,” said Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis and co-author on the paper with graduate student Matthew Savoca. This suggests that marine top predators are important in climate regulation, although they are mostly left out of climate models, Nevitt said.”In addition to studying how these marine top predators are responding to climate change, our data suggest that more attention should be focused on how ecological systems, themselves, impact climate. Studying DMS as a signal molecule makes the connection,” she said.Nevitt has studied the sense of smell in ocean-going birds for about 25 years, and was the first to demonstrate that marine top predators use climate-regulating chemicals for foraging and navigation over the featureless ocean. DMS is now known to be an important signal for petrels and albatrosses, and the idea has been extended to various species of penguins, seals, sharks, sea turtles, coral reef fishes and possibly baleen whales, she said.Phytoplankton are the plants of the open ocean, absorbing carbon dioxide and sunlight to grow. When these plankton die, they release an enzyme that generates DMS.A role for DMS in regulating climate was proposed by Robert Charlson, James Lovelock, Meinrat Andreae and Stephen Warren in the 1980s. According to the CLAW hypothesis, warming oceans lead to more growth of green phytoplankton, which in turn release a precursor to DMS when they die. Rising levels of DMS in the atmosphere cause cloud formation, and clouds reflect sunlight, helping to cool the planet. …

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Eel expedition 2014 has arrived in The Sargasso Sea

The research vessel Dana is currently in the Sargasso Sea on an intensive research expedition to the European eel’s spawning grounds subsequently following the eel larvae’s drift back to Europe. The Sargasso Sea is a large oceanic area between Bermuda and the West Indies. There are 19 species of eel in the world. Two of them spawn in the Sargasso Sea: The American and The European Eel.In the past 30 years there has been a dramatic decline in the European eel population. Today, the number of young eel returning to the coasts of Europe is just 2-10 per cent of the quantities seen in the 1970s. In 2008, the dramatic decline in eel numbers led the International Union for Conservation of Nature (IUCN) to add the eel to its list of critically endangered species.A characteristic feature of the European eel is that spawning takes place far from the juvenile nursery grounds in Europe, requiring the eel larvae to ride the ocean currents for a 6,000 kilometre return journey across the Atlantic. The expedition will investigate whether climate-related changes in the eel’s spawning grounds or the ocean currents transporting the eel larvae to Europe are responsible for the eel’s sharp decline. The expedition will also gather information on the food preferences of the newly hatched eel — the understanding of eel larval feeding is a prerequisite for successful rearing of larvae and the farming of eel. Farmed eel can be used for re-stocking and using these for consumption would lower the fishing pressure on the population.The expedition brings together almost 40 experts from a wide range of research areas at both Danish and international universities and institutions (including French, German,Swedish and American participants). The expedition, which is headed by Senior Researcher Peter Munk from DTU Aqua, is funded by the Danish Centre for Marine Research and the Carlsberg Foundation. …

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Climatologists offer explanation for widening of Earth’s tropical belt

Recent studies have shown that Earth’s tropical belt — demarcated, roughly, by the Tropics of Cancer and Capricorn — has progressively expanded since at least the late 1970s. Several explanations for this widening have been proposed, such as radiative forcing due to greenhouse gas increase and stratospheric ozone depletion.Now, a team of climatologists, led by researchers at the University of California, Riverside, posits that the recent widening of the tropical belt is primarily caused by multi-decadal sea surface temperature variability in the Pacific Ocean. This variability includes the Pacific Decadal Oscillation (PDO), a long-lived El Nio-like pattern of Pacific climate variability that works like a switch every 30 years or so between two different circulation patterns in the North Pacific Ocean. It also includes, the researchers say, anthropogenic pollutants, which act to modify the PDO.Study results appear March 16 in Nature Geoscience.”Prior analyses have found that climate models underestimate the observed rate of tropical widening, leading to questions on possible model deficiencies, possible errors in the observations, and lack of confidence in future projections,” said Robert J. Allen, an assistant professor of climatology in UC Riverside’s Department of Earth Sciences, who led the study. “Furthermore, there has been no clear explanation for what is driving the widening.”Now Allen’s team has found that the recent tropical widening is largely driven by the PDO.”Although this widening is considered a ‘natural’ mode of climate variability, implying tropical widening is primarily driven by internal dynamics of the climate system, we also show that anthropogenic pollutants have driven trends in the PDO,” Allen said. “Thus, tropical widening is related to both the PDO and anthropogenic pollutants.”Widening concernsTropical widening is associated with several significant changes in our climate, including shifts in large-scale atmospheric circulation, like storm tracks, and major climate zones. For example, in Southern California, tropical widening may be associated with less precipitation.Of particular concern are the semi-arid regions poleward of the subtropical dry belts, including the Mediterranean, the southwestern United States and northern Mexico, southern Australia, southern Africa, and parts of South America. A poleward expansion of the tropics is likely to bring even drier conditions to these heavily populated regions, but may bring increased moisture to other areas.Widening of the tropics would also probably be associated with poleward movement of major extratropical climate zones due to changes in the position of jet streams, storm tracks, mean position of high and low pressure systems, and associated precipitation regimes. An increase in the width of the tropics could increase the area affected by tropical storms (hurricanes), or could change climatological tropical cyclone development regions and tracks.Belt contractionAllen’s research team also showed that prior to the recent (since ~1980 onwards) tropical widening, the tropical belt actually contracted for several decades, consistent with the reversal of the PDO during this earlier time period.”The reversal of the PDO, in turn, may be related to the global increase in anthropogenic pollutant emissions prior to the ~ early 1980s,” Allen said.AnalysisAllen’s team analyzed IPCC AR5 (5th Assessment Report) climate models, several observational and reanalysis data sets, and conducted their own climate model experiments to quantify tropical widening, and to isolate the main cause.”When we analyzed IPCC climate model experiments driven with the time-evolution of observed sea surface temperatures, we found much larger rates of tropical widening, in better agreement to the observed rate–particularly in the Northern Hemisphere,” Allen said. …

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First animals oxygenated the ocean

The evolution of the first animals may have oxygenated the earth’s oceans — contrary to the traditional view that a rise in oxygen triggered their development.New research led by the University of Exeter contests the long held belief that oxygenation of the atmosphere and oceans was a pre-requisite for the evolution of complex life forms.The study, published today in the leading journal Nature Geoscience, builds on the recent work of scientists in Denmark who found that sponges — the first animals to evolve — require only small amounts of oxygen.Professor Tim Lenton of the University of Exeter, who led the new study, said: “There had been enough oxygen in ocean surface waters for over 1.5 billion years before the first animals evolved, but the dark depths of the ocean remained devoid of oxygen. We argue that the evolution of the first animals could have played a key role in the widespread oxygenation of the deep oceans. This in turn may have facilitated the evolution of more complex, mobile animals.”The researchers considered mechanisms by which the deep ocean could have been oxygenated during the Neoproterozoic Era (from 1,000 to 542 million years ago) without requiring an increase in atmospheric oxygen.Crucial to determining oxygen levels in the deep ocean is the balance of oxygen supply and demand. Demand for oxygen is created by the sinking of dead organic material into the deep ocean. The new study argues that the first animals reduced this supply of organic matter — both directly and indirectly.Sponges feed by pumping water through their bodies, filtering out tiny particles of organic matter from the water, and thus helping oxygenate the shelf seas that they live in. This naturally selects for larger phytoplankton — the tiny plants of the ocean — which sink faster, also reducing oxygen demand in the water.By oxygenating more of the bottom waters of shelf seas, the first filter-feeding animals inadvertently increased the removal of the essential nutrient phosphorus in the ocean. This in turn reduced the productivity of the whole ocean ecosystem, suppressing oxygen demand and thus oxygenating the deep ocean.A more oxygen-rich ocean created ideal conditions for more mobile animals to evolve, because they have a higher requirement for oxygen. These included the first predatory animals with guts that started to eat one another, marking the beginning of a modern marine biosphere, with the type of food webs we are familiar with today.Professor Lenton added: “The effects we predict suggest that the first animals, far from being a passive response to rising atmospheric oxygen, were the active agents that oxygenated the ocean around 600 million years ago. They created a world in which more complex animals could evolve, including our very distant ancestors.”Professor Simon Poulton of the University of Leeds, who is a co-author of the study, added: ″This study provides a plausible mechanism for ocean oxygenation without the requirement for a rise in atmospheric oxygen. It therefore questions whether the long-standing belief that there was a major rise in atmospheric oxygen at this time is correct. …

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Arctic biodiversity under serious threat from climate change

Unique and irreplaceable Arctic wildlife and landscapes are crucially at risk due to global warming caused by human activities according to the Arctic Biodiversity Assessment (ABA), a new report prepared by 253 scientists from 15 countries under the auspices of the Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council.”An entire bio-climatic zone, the high Arctic, may disappear. Polar bears and the other highly adapted organisms cannot move further north, so they may go extinct. We risk losing several species forever,” says Hans Meltofte of Aarhus University, chief scientist of the report.From the iconic polar bear and elusive narwhal to the tiny Arctic flowers and lichens that paint the tundra in the summer months, the Arctic is home to a diversity of highly adapted animal, plant, fungal and microbial species. All told, there are more than 21,000 species.Maintaining biodiversity in the Arctic is important for many reasons. For Arctic peoples, biodiversity is a vital part of their material and spiritual existence. Arctic fisheries and tourism have global importance and represent immense economic value. Millions of Arctic birds and mammals that migrate and connect the Arctic to virtually all parts of the globe are also at risk from climate change in the Arctic as well as from development and hunting in temperate and tropical areas. Marine and terrestrial ecosystems such as vast areas of lowland tundra, wetlands, mountains, extensive shallow ocean shelves, millennia-old ice shelves and huge seabird cliffs are characteristic to the Arctic. These are now at stake, according to the report.”Climate change is by far the worst threat to Arctic biodiversity. Temperatures are expected to increase more in the Arctic compared to the global average, resulting in severe disruptions to Arctic biodiversity some of which are already visible,” warns Meltofte.A planetary increase of 2 C, the worldwide agreed upon acceptable limit of warming, is projected to result in vastly more heating in the Arctic with anticipated temperature increases of 2.8-7.8 C this century. …

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Pacific trade winds stall global surface warming … for now

The strongest trade winds have driven more of the heat from global warming into the oceans; but when those winds slow, that heat will rapidly return to the atmosphere causing an abrupt rise in global average temperatures.Heat stored in the western Pacific Ocean caused by an unprecedented strengthening of the equatorial trade winds appears to be largely responsible for the hiatus in surface warming observed over the past 13 years.New research published today in the journal Nature Climate Change indicates that the dramatic acceleration in winds has invigorated the circulation of the Pacific Ocean, causing more heat to be taken out of the atmosphere and transferred into the subsurface ocean, while bringing cooler waters to the surface.”Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures, but the mechanism behind the hiatus remained unclear” said Professor Matthew England, lead author of the study and a Chief Investigator at the ARC Centre of Excellence for Climate System Science.”But the heat uptake is by no means permanent: when the trade wind strength returns to normal — as it inevitably will — our research suggests heat will quickly accumulate in the atmosphere. So global temperatures look set to rise rapidly out of the hiatus, returning to the levels projected within as little as a decade.”The strengthening of the Pacific trade winds began during the 1990s and continues today. Previously, no climate models have incorporated a trade wind strengthening of the magnitude observed, and these models failed to capture the hiatus in warming. Once the trade winds were added by the researchers, the global average temperatures very closely resembled the observations during the hiatus.”The winds lead to extra ocean heat uptake, which stalled warming of the atmosphere. Accounting for this wind intensification in model projections produces a hiatus in global warming that is in striking agreement with observations,” Prof England said.”Unfortunately, however, when the hiatus ends, global warming looks set to be rapid.”The impact of the trade winds on global average temperatures is caused by the winds forcing heat to accumulate below surface of the Western Pacific Ocean.”This pumping of heat into the ocean is not very deep, however, and once the winds abate, heat is returned rapidly to the atmosphere” England explains.”Climate scientists have long understood that global average temperatures don’t rise in a continual upward trajectory, instead warming in a series of abrupt steps in between periods with more-or-less steady temperatures. Our work helps explain how this occurs,” said Prof England.”We should be very clear: the current hiatus offers no comfort — we are just seeing another pause in warming before the next inevitable rise in global temperatures.”Story Source:The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.

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Fish biomass in the ocean may be 10 times higher than estimated: Stock of mesopelagic fish changes from 1,000 to 10,000 million tons

With a stock estimated at 1,000 million tons so far, mesopelagic fish dominate the total biomass of fish in the ocean. However, a team of researchers with the participation of the Spanish National Research Council (CSIC) has found that their abundance could be at least 10 times higher. The results, published in Nature Communications journal, are based on the acoustic observations conducted during the circumnavigation of the Malaspina Expedition.Mesopelagic fishes, such as lantern fishes (Myctophidae) and cyclothonids (Gonostomatidae), live in the twilight zone of the ocean, between 200 and 1,000 meters deep. They are the most numerous vertebrates of the biosphere, but also the great unknowns of the open ocean, since there are gaps in the knowledge of their biology, ecology, adaptation and global biomass.During the 32,000 nautical miles traveled during the circumnavigation, the researchers of the Malaspina Expedition (a project led by CSIC researcher Carlos Duarte) took measurements between 40N and 40S, from 200 to 1,000 meters deep, during the day.Duarte states: “Malaspina has provided us the unique opportunity to assess the stock of mesopelagic fish in the ocean. Until now we only had the data provided by trawling. It has recently been discovered that these fishes are able to detect the nets and run, which turns trawling into a biased tool when it comes to count its biomass.”Transport of organic carbonXabier Irigoyen, researcher from AZTI-Tecnalia and KAUST (Saudi Arabia) and head of this research, states: “The fact that the biomass of mesopelagic fish (and therefore also the total biomass of fishes) is at least 10 times higher than previously thought, has significant implications in the understanding of carbon fluxes in the ocean and the operation of which, so far, we considered ocean deserts.”Mesopelagic fish come up at night to the upper layers of the ocean to feed, whereas they go back down during the day in order to avoid being detected by their predators. This behaviour speeds up the transport of organic matter into the ocean, the engine of the biological pump that removes CO2 from the atmosphere, because instead of slowly sinking from the surface, it is rapidly transported to 500 and 700 meters deep and released in the form of feces.Irigoyen adds: “Mesopelagic fish accelerate the flux for actively transporting organic matter from the upper layers of the water column, where most of the organic carbon coming from the flow of sedimentary particles is lost. Their role in the biogeochemical cycles of ocean ecosystems and global ocean has to be reconsidered, as it is likely that they are breathing between 1% and 10% of the primary production in deep waters.”According to researchers, the excretion of material from the surface could partly explain the unexpected microbial respiration registered in these deep layers of the ocean. Mesopelagic fishes would act therefore as a link between plankton and top predators, and they would have a key role in reducing the oxygen from the depths of the open ocean.Story Source:The above story is based on materials provided by Spanish National Research Council (CSIC). Note: Materials may be edited for content and length.

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Global ocean currents explain why Northern Hemisphere is the soggier one

Oct. 20, 2013 — A quick glance at a world precipitation map shows that most tropical rain falls in the Northern Hemisphere. The Palmyra Atoll, at 6 degrees north, gets 175 inches of rain a year, while an equal distance on the opposite side of the equator gets only 45 inches.Scientists long believed that this was a quirk of Earth’s geometry — that the ocean basins tilting diagonally while the planet spins pushed tropical rain bands north of the equator. But a new University of Washington study shows that the pattern arises from ocean currents originating from the poles, thousands of miles away.The findings, published Oct. 20 in Nature Geoscience, explain a fundamental feature of the planet’s climate, and show that icy waters affect seasonal rains that are crucial for growing crops in such places as Africa’s Sahel region and southern India.In general, hotter places are wetter because hot air rises and moisture precipitates out.”It rains more in the Northern Hemisphere because it’s warmer,” said corresponding author Dargan Frierson, a UW associate professor of atmospheric sciences. “The question is: What makes the Northern Hemisphere warmer? And we’ve found that it’s the ocean circulation.”Frierson and his co-authors first used detailed measurements from NASA’s Clouds and Earth’s Radiant Energy System, or CERES, satellites to show that sunlight actually provides more heat to the Southern Hemisphere — and so, by atmospheric radiation alone, the Southern Hemisphere should be the soggier one.After using other observations to calculate the ocean heat transport, the authors next used computer models to show the key role of the huge conveyor-belt current that sinks near Greenland, travels along the ocean bottom to Antarctica, and then rises and flows north along the surface. Eliminating this current flips the tropical rain bands to the south.The reason is that as the water moves north over many decades it gradually heats up, carrying some 400 trillion (that’s four with 14 zeroes after it) watts of power across the equator.For many years, slanting ocean basins have been the accepted reason for the asymmetry in tropical rainfall.”But at the same time, a lot of people didn’t really believe that explanation because it’s kind of a complicated argument. For such a major feature there’s usually a simpler explanation,” Frierson said.The ocean current they found to be responsible was made famous in the 2004 movie “The Day After Tomorrow,” in which the premise was that the overturning circulation shut down and New York froze over. While a sudden shutdown like in the movie won’t happen, a gradual slowing — which the recent United Nations report said was “very likely” by 2100 — could shift tropical rains south, the study suggests, as it probably has in the past.The slowdown of the currents is predicted because increasing rain and freshwater in the North Atlantic would make the water less dense and less prone to sinking.”This is really just another part of a big, growing body of evidence that’s come out in the last 10 or 15 years showing how important high latitudes are for other parts of the world,” Frierson said.Frierson’s earlier work shows how the changing temperature balance between hemispheres influences tropical rainfall. …

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World ocean systems undermined by climate change by 2100

Oct. 15, 2013 — An ambitious new study describes the full chain of events by which ocean biogeochemical changes triggered by humanmade greenhouse gas emissions may cascade through marine habitats and organisms, penetrating to the deep ocean and eventually influencing humans.Previous analyses have focused mainly on ocean warming and acidification, considerably underestimating the biological and social consequences of climate change. Factoring in predictable synergistic changes such as the depletion of dissolved oxygen in seawater and a decline in productivity of ocean ecosystems, the new study shows that no corner of the world ocean will be untouched by climate change by 2100.”When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity,” said lead author Camilo Mora, assistant professor at the Department of Geography in the College of Social Sciences at the University of Hawai’i at Mānoa (UH Mānoa). “The consequences of these co-occurring changes are massive — everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry.”The human ramifications of these changes are likely to be massive and disruptive. Food chains, fishing, and tourism could all be impacted. The study shows that some 470 to 870 million of the world’s poorest people rely on the ocean for food, jobs, and revenues, and live in countries where ocean goods and services could be compromised by multiple ocean biogeochemical changes.Mora and Craig Smith with UH Mānoa’s School of Ocean and Earth Science and Technology (SOEST) worked with a 28-person international collaboration of climate modelers, biogeochemists, oceanographers, and social scientists to develop the study, which is due for publication October 15 in the scientific journal PLOS Biology.The researchers used the most recent and robust models of projected climate change developed for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) to inform their analysis. They quantified the extent of co-occurrence of changes in temperature, pH, oxygen, and primary productivity based on two scenarios: a business-as-usual scenario wherein atmospheric CO2 concentrations could reach 900 ppm by 2100, and an alternative scenario under which concentrations only reach 550 ppm by 2100 (representing a concerted, rapid CO2 mitigation effort, beginning today).They discovered that most of the world’s ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. Only a very small fraction of the oceans, mostly in polar regions, will face the opposing effects of increases in oxygen or productivity, and nowhere will there be cooling or pH increase.”Even the seemingly positive changes at high latitudes are not necessary beneficial. Invasive species have been immigrating to these areas due to changing ocean conditions and will threaten the local species and the humans who depend on them,” said co-author Chih-Lin Wei, a postdoctoral fellow at Ocean Science Centre, Memorial University of Newfoundland, Canada.The researchers assembled global distribution maps of 32 marine habitats and biodiversity hotspots to assess their potential vulnerability to the changes. As a final step, they used available data on human dependency on ocean goods and services and social adaptability to estimate the vulnerability of coastal populations to the projected ocean biogeochemical changes.”Other studies have looked at small-scale impacts, but this is the first time that we’ve been able to look the entire world ocean and how co-occurring stressors will differentially impact the earth’s diverse habitats and people,” said co-author Andrew Thurber, a postdoctoral fellow at Oregon State University. …

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Unprecedented rate and scale of ocean acidification found in the Arctic

Sep. 12, 2013 — Acidification of the Arctic Ocean is occurring faster than projected, according to new findings published in the journal PLoS ONE. The increase in rate is being blamed on rapidly melting sea ice, a process that may have important consequences for health of the Arctic ecosystem.Ocean acidification is the process by which pH levels of seawater decrease due to greater amounts of carbon dioxide being absorbed by the oceans from the atmosphere. Currently oceans absorb about one-fourth of the greenhouse gas. Lower pH levels make water more acidic and lab studies have shown that more acidic water decrease calcification rates in many calcifying organisms, reducing their ability to build shells or skeletons. These changes, in species ranging from corals to shrimp, have the potential to impact species up and down the food web.The team of federal and university researchers found that the decline of sea ice in the Arctic summer has important consequences for the surface layer of the Arctic Ocean. As sea ice cover recedes to record lows, as it did late in the summer of 2012, the seawater beneath is exposed to carbon dioxide, which is the main driver of ocean acidification.In addition, the freshwater melted from sea ice dilutes the seawater, lowering pH levels and reducing the concentrations of calcium and carbonate, which are the constituents, or building blocks, of the mineral aragonite. Aragonite and other carbonate minerals make up the hard part of many marine micro-organisms’ skeletons and shells. The lowering of calcium and carbonate concentrations may impact the growth of organisms that many species rely on for food.The new research shows that acidification in surface waters of the Arctic Ocean is rapidly expanding into areas that were previously isolated from contact with the atmosphere due to the former widespread ice cover.”A remarkable 20 percent of the Canadian Basin has become more corrosive to carbonate minerals in an unprecedented short period of time. Nowhere on Earth have we documented such large scale, rapid ocean acidification” according to lead researcher and ocean acidification project chief, U.S. …

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Breaking deep-sea waves, as high as a skyscraper, reveal mechanism for global ocean mixing

Sep. 9, 2013 — Waves breaking over sandy beaches are captured in countless tourist photos. But enormous waves breaking deep in the ocean are seldom seen, although they play a crucial role in long-term climate cycles.A University of Washington study for the first time recorded such a wave breaking in a key bottleneck for circulation in the world’s largest ocean. The study was published online this month in the journal Geophysical Research Letters.The deep ocean is thought of as dark, cold and still. While this is mostly true, huge waves form between layers of water of different density. These skyscraper-tall waves transport heat, energy, carbon and nutrients around the globe. Where and how they break is important for the planet’s climate.”Climate models are really sensitive not only to how much turbulence there is in the deep ocean, but to where it is,” said lead author Matthew Alford, an oceanographer in the UW Applied Physics Laboratory. He led the expedition to the Samoan Passage, a narrow channel in the South Pacific Ocean that funnels water flowing from Antarctica.”The primary importance of understanding deep-ocean turbulence is to get the climate models right on long timescales,” Alford said.Dense water in Antarctica sinks to the deep Pacific, where it eventually surges through a 25-mile gap in the submarine landscape northeast of Samoa.”Basically the entire South Pacific flow is blocked by this huge submarine ridge,” Alford said. “The amount of water that’s trying to get northward through this gap is just tremendous — 6 million cubic meters of water per second, or about 35 Amazon Rivers.”In the 1990s a major expedition measured these currents through the Samoan Passage. The scientists inferred that a lot of mixing must also happen there, but couldn’t measure it.In the summer of 2012 the UW team embarked on a seven-week cruise to track the 800-foot-high waves that form atop the flow, 3 miles below the ocean’s surface. …

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Surprising underwater-sounds: Humpback whales also spend their winter in Antarctica

Sep. 9, 2013 — Biologists and physicists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, found out that not all of the Southern Hemisphere humpback whales (Megaptera novaeangliae) migrate towards the equator at the end of the Antarctic summer. Part of the population remains in Antarctic waters throughout the entire winter. The scientists report this in a current issue of scientific journal PLOS ONE. This surprising discovery based on underwater recordings from the Antarctic acoustic observatory PALAOA. It is located near the research base Neumayer Station III on the ice shelf and regularly records underwater sounds of humpback whales even in the austral winter months.Sometimes even scientists need the crucial little quantum of luck to obtain new research ideas. For instance Ilse Van Opzeeland, a marine biologist and expert on large whales at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). As she unlocked the door to her office one April morning and, as usual, switched on the live stream of PALAOA, the underwater acoustic observatory, the loudspeakers suddenly resounded with the calls of humpback whales — and this at a time during which the marine mammals should long have been swimming 7,000 kilometres further away in the warmer waters off Africa. “I was totally surprised, because the textbook-opinion until that day was that humpback whales migrate to Antarctic waters only in the austral summer months. And even then, standing believes were that they would only be feeding on krill in the ice-free regions around 60 degrees south latitude. …

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Climate change will upset vital ocean chemical cycles, research shows

Sep. 8, 2013 — New research from the University of East Anglia shows that rising ocean temperatures will upset natural cycles of carbon dioxide, nitrogen and phosphorus.Plankton plays an important role in the ocean’s carbon cycle by removing half of all CO2 from the atmosphere during photosynthesis and storing it deep under the sea — isolated from the atmosphere for centuries.Findings published today in the journal Nature Climate Change reveal that water temperature has a direct impact on maintaining the delicate plankton ecosystem of our oceans.The new research means that ocean warming will impact plankton, and in turn drive a vicious cycle of climate change.Researchers from UEA’s School of Environmental Sciences and the School of Computing Sciences investigated phytoplankton — microscopic plant-like organisms that rely on photosynthesis to reproduce and grow.Lead researcher Dr Thomas Mock, said: “Phytoplankton, including micro-algae, are responsible for half of the carbon dioxide that is naturally removed from the atmosphere. As well as being vital to climate control, it also creates enough oxygen for every other breath we take, and forms the base of the food chain for fisheries so it is incredibly important for food security.”Previous studies have shown that phytoplankton communities respond to global warming by changes in diversity and productivity. But with our study we show that warmer temperatures directly impact the chemical cycles in plankton, which has not been shown before.”Collaborators from the University of Exeter, who are co-authors of this study, developed computer generated models to create a global ecosystem model that took into account world ocean temperatures, 1.5 million plankton DNA sequences taken from samples, and biochemical data.”We found that temperature plays a critical role in driving the cycling of chemicals in marine micro-algae. It affects these reactions as much as nutrients and light, which was not known before,” said Dr Mock.”Under warmer temperatures, marine micro-algae do not seem to produce as many ribosomes as under lower temperatures. Ribosomes join up the building blocks of proteins in cells. They are rich in phosphorus and if they are being reduced, this will produce higher ratios of nitrogen compared to phosphorus, increasing the demand for nitrogen in the oceans.”This will eventually lead to a greater prevalence of blue-green algae called cyanobacteria which fix atmospheric nitrogen,” he added.

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Deep-ocean carbon sinks: Basic research on dark ocean microorganisms

Sep. 5, 2013 — Although microbes that live in the so-called “dark ocean” — below a depth of some 600 feet where light doesn’t penetrate — may not absorb enough carbon to curtail global warming, they do absorb considerable amounts of carbon and merit further study.That is one of the findings of a paper published in the International Society of Microbial Ecology (ISME) Journal by Tim Mattes, associate professor of civil and environmental engineering in the University of Iowa College of Engineering, and his colleagues.Mattes says that while many people are familiar with the concept of trees and grass absorbing carbon from the air, bacteria, and ancient single-celled organisms called “archaea” in the dark ocean hold between 300 million and 1.3 billion tons of carbon.”A significant amount of carbon fixation occurs in the dark ocean,” says Mattes. “What might make this surprising is that carbon fixation is typically linked to organisms using sunlight as the energy source.”Organisms in the dark ocean may not require sunlight to lock up carbon, but they do require an energy source.”In the dark ocean, carbon fixation can occur with reduced chemical energy sources such as sulfur, methane, and ferrous iron,” Mattes says. “The hotspots are hydrothermal vents that generate plumes rich in chemical energy sources that stimulate the growth of microorganisms forming the foundation for deep sea ecosystems.”The hydrothermal vents the team studied are located in a volcanic caldera at Axial Seamount, an active underwater volcano in the Pacific Ocean. The site is located some 300 miles west of Cannon Beach, Ore., and about 1,500 meters beneath the surface. Mattes’ colleague, Robert Morris, gathered data and collected samples used in the study during a 2011 cruise sponsored by the U.S. National Science Foundation.”Using protein-based techniques, we observed that sulfur-oxidizing microorganisms were numerically dominant in this particular hydrothermal vent plume and also converting carbon dioxide to biomass, as suggested by the title of our paper: ‘Sulfur oxidizers dominate carbon fixation at a biogeochemical hot spot in the dark ocean.'”With carbon fixation occurring on a large scale in the dark ocean, one might wonder about the contribution of such activity to offset carbon emissions widely believed to contribute to global warming, but Mattes sets aside any such speculation in favor of further study.”While it is true that these microbes are incorporating carbon dioxide into their cells in the deep ocean and thus having an impact on the global carbon cycle, there is no evidence to suggest that they could play any role in mitigating global warming,” he says.He adds that the primary value of the investigation is to better understand how microorganisms function in the dark ocean and to increase fundamental knowledge of global biogeochemical cycles.Mattes conducted this research at the University of Washington School of Oceanography while on developmental leave from the UI.Mattes’ colleagues in the study are: Brook Nunn, Katharine Marshall, Giora Proskurowski, Deborah Kelley, Orest Kawka, and Robert Morris of the University of Washington; David Goodlett of the University of Maryland; and Dennis Hansell of the University of Miami.The study, published online in July, was funded under grants from the National Science Foundation OCE-1232840 and OCE-0825790 and National Institutes of Health 5P30ES007033-12 and 1S10RR023044.

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Deep-sea squid with tentacle tips that ‘swim’ on their own

Sep. 3, 2013 — Many deep-sea animals such as anglerfish use parts of their body as lures to attract prey. Some deep-sea squids may use this strategy as well. In a recent paper, researchers associated with the Monterey Bay Aquarium Research Institute (MBARI) describe a deep-sea squid that appears to use a different method to lure prey — its tentacle tips flap and flutter as if swimming on their own. The researchers hypothesize that the motion of these tentacle tips may induce small shrimp and other animals to approach within reach of the squid’s arms.Most squids have eight arms and two longer “feeding” tentacles. The tips of the tentacles, which are often broader and armed with suckers or hooks, are known as “clubs.” Such squids hunt by rapidly extending their tentacles and then grabbing prey with their clubs. The squids also use the tentacles to carry captured prey to their mouths.The deep-sea squid Grimalditeuthis bonplandi seems to use a very different feeding strategy. A slow swimmer with a weak, gelatinous body, its tentacles are long, thin, fragile, and too weak to capture prey. Unlike any other known squid, its tentacles do not have any suckers, hooks, or photophores (glowing spots).Until just a few years ago, the marine biologists had only seen specimens of G. bonplandi that were dead or dying after having been captured in deep-sea trawl nets. …

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New ocean forecast could help predict fish habitat six months in advance

Aug. 30, 2013 — People are now used to long-term weather forecasts that predict what the coming winter may bring. But University of Washington researchers and federal scientists have developed the first long-term forecast of conditions that matter for Pacific Northwest fisheries.”Being able to predict future phytoplankton blooms, ocean temperatures and low-oxygen events could help fisheries managers,” said Samantha Siedlecki, a research scientist at the UW-based Joint Institute for the Study of the Atmosphere and Ocean.”This is an experiment to produce the first seasonal prediction system for the ocean ecosystem. We are excited about the initial results, but there is more to learn and explore about this tool — not only in terms of the science, but also in terms of its application,” she said.In January, when the prototype was launched, it predicted unusually low oxygen this summer off the Olympic coast. People scoffed. But when an unusual low-oxygen patch developed off the Washington coast in July, some skeptics began to take the tool more seriously. The new tool predicts that low-oxygen trend will continue, and worsen, in coming months.”We’re taking the global climate model simulations and applying them to our coastal waters,” said Nick Bond, a UW research meteorologist. “What’s cutting edge is how the tool connects the ocean chemistry and biology.”Bond’s research typically involves predicting ocean conditions decades in advance. But as Washington’s state climatologist he distributes quarterly forecasts of the weather. With this project he decided to combine the two, taking a seasonal approach to marine forecasts.The National Oceanographic and Atmospheric Administration funded the project to create the tool and publish the two initial forecasts.”Simply knowing if things are likely to get better, or worse, or stay the same, would be really useful,” said collaborator Phil Levin, a biologist at NOAA’s Northwest Fisheries Science Center.Early warning of negative trends, for example, could help to set quotas.”Once you overharvest, a lot of regulations kick in,” Levin said. …

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New Cassini data from Saturn’s largest moon Titan indicate a rigid, weathered ice shell

Aug. 28, 2013 — An analysis of gravity and topography data from Saturn’s largest moon, Titan, has revealed unexpected features of the moon’s outer ice shell. The best explanation for the findings, the authors said, is that Titan’s ice shell is rigid and that relatively small topographic features on the surface are associated with large roots extending into the underlying ocean. The study is published in the August 29 issue of the journal Nature.Led by planetary scientists Douglas Hemingway and Francis Nimmo at the University of California, Santa Cruz, the study used new data from NASA’s Cassini spacecraft. The researchers were surprised to find a negative correlation between the gravity and topography signals on Titan.”Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain. On Titan, when you fly over a mountain the gravity gets lower. That’s a very odd observation,” said Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz.To explain that observation, the researchers developed a model in which each bump in the topography on the surface of Titan is offset by a deeper “root” big enough to overwhelm the gravitational effect of the bump on the surface. The root is like an iceberg extending below the ice shell into the ocean underneath it. “Because ice is lower density than water, you get less gravity when you have a big chunk of ice there than when you have water,” Nimmo explained.An iceberg floating in water is in equilibrium, its buoyancy balancing out its weight. In this model of Titan, however, the roots extending below the ice sheet are so much bigger than the bumps on the surface that their buoyancy is pushing them up against the ice sheet. …

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