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Categories: Engineering: Biometric, Geoscience: Oceanography
Published Emergency atmospheric geoengineering wouldn't save the oceans
(via sciencedaily.com) Original source Climate change is heating the oceans, altering currents and circulation patterns responsible for regulating climate on a global scale. If temperatures dropped, some of that damage could theoretically be undone. But employing 'emergency' atmospheric geoengineering later this century in the face of continuous high carbon emissions would not be able to reverse changes to ocean currents, a new study finds. This would critically curtail the intervention's potential effectiveness on human-relevant timescales.
Published 80 mph speed record for glacier fracture helps reveal the physics of ice sheet collapse
(via sciencedaily.com) Original source New research documents the fastest-known large-scale breakage along an Antarctic ice shelf. A 6.5-mile crack formed in 2012 over 5-and-a-half minutes, showing that ice shelves can effectively shatter -- though the speed is limited by seawater rushing in. The results help inform large-scale ice sheet models and projections of future sea level rise.
Published Climate change threatens thousands of archaeological sites in coastal Georgia
(via sciencedaily.com) Original source Thousands of historic and archaeological sites in Georgia are at risk from tropical storm surges, and that number will increase with climate change, according to a new study.
Published Climate change shrinking fish
(via sciencedaily.com) Original source Fish weight in the western North Pacific Ocean dipped in the 2010s due to warmer water limiting food supplies, according to a new study. Researchers analyzed the individual weight and overall biomass of 13 species of fish. In the 1980s and 2010s, the fish were lighter. They attributed the first period of weight loss to greater numbers of Japanese sardine, which increased competition with other species for food. During the 2010s, while the number of Japanese sardine and chub mackerel moderately increased, the effect of climate change warming the ocean appears to have resulted in more competition for food, as cooler, nutrient-dense water could not easily rise to the surface. These results have implications for fisheries and policymakers trying to manage ocean resources under future climate change scenarios.
Published Researchers are first to see at-risk bat flying over open ocean
(via sciencedaily.com) Original source On a research cruise focused on marine mammals and seabirds, scientists earned an unexpected bonus: The first-ever documented sighting of a hoary bat flying over the open ocean.
Published Significant glacial retreat in West Antarctica began in 1940s
(via sciencedaily.com) Original source Among the vast expanse of Antarctica lies the Thwaites Glacier, the world's widest glacier measuring about 80 miles on the western edge of the continent. Despite its size, the massive landform is losing about 50 billion tons of ice more than it is receiving in snowfall, which places it in a precarious position in respect to its stability. Accelerating ice loss has been observed since the 1970s, but it is unclear when this significant melting initiated -- until now. A new study suggests that the significant glacial retreat of two glaciers on the west coast of Antarctica began in the 1940's, likely spurred by climate change.
Published Barriers against Antarctic ice melt disappearing at the double
(via sciencedaily.com) Original source Undersea anchors of ice that help prevent Antarctica's land ice from slipping into the ocean are shrinking at more than twice the rate compared with 50 years ago, research shows. More than a third of these frozen moorings, known as pinning points, have decreased in size since the turn of the century, experts say. Further deterioration of pinning points, which hold in place the floating ice sheets that fortify Antarctica's land ice, would accelerate the continent's contribution to rising sea levels, scientists warn.
Published Stronger storms free more nutrients from mud flats
(via sciencedaily.com) Original source If storms become stronger in the future due to climate change, more nitrogen may be released from the bottom of coastal seas.
Published Biggest Holocene volcano eruption found by seabed survey
(via sciencedaily.com) Original source A detailed survey of the volcanic underwater deposits around the Kikai caldera in Japan clarified the deposition mechanisms as well as the event's magnitude. As a result, the research team found that the event 7,300 years ago was the largest volcanic eruption in the Holocene by far.
Published Mercury levels in tuna remain nearly unchanged since 1971
(via sciencedaily.com) Original source Tuna is one of the most popular seafoods worldwide. But this protein-rich fish can build up high levels of methylmercury from feeding on contaminated prey, like smaller fish or crustaceans. Despite efforts to reduce mercury emissions into the environment, researchers report that levels in tuna appear to be unchanged since 1971. They warn that more aggressive emission reduction targets are needed to start nudging down tuna mercury levels.
Published Gulf corals still suffering more than a decade after Deepwater Horizon oil spill, scientists report
(via sciencedaily.com) Original source Deep-water corals in the Gulf of Mexico are still struggling to recover from the devastating Deepwater Horizon oil spill in 2010, scientists report at the Ocean Science Meeting in New Orleans. Comparing images of more than 300 corals over 13 years -- the longest time series of deep-sea corals to date -- reveals that in some areas, coral health continues to decline to this day.
Published Decline in microbial genetic richness in the western Arctic Ocean
(via sciencedaily.com) Original source Researchers analyzed archival samples of bacteria and archaea populations taken from the Beaufort Sea, bordering northwest Canada and Alaska. The samples were collected between 2004 and 2012, a period that included two years -- 2007 and 2012 -- in which the sea ice coverage was historically low. The researchers looked at samples taken from three levels of water: the summer mixed layer, the upper Arctic water below it and the Pacific-origin water at the deepest level. The study examined the microbes' genetic composition using bioinformatics and statistical analysis across the nine-year time span. Using this data, the researchers were able to see how changing environmental conditions were influencing the organisms' structure and function.
Published Viruses that can help 'dial up' carbon capture in the sea
(via sciencedaily.com) Original source Armed with a catalog of hundreds of thousands of DNA and RNA virus species in the world's oceans, scientists are now zeroing in on the viruses most likely to combat climate change by helping trap carbon dioxide in seawater or, using similar techniques, different viruses that may prevent methane's escape from thawing Arctic soil.
Published This tiny, tamper-proof ID tag can authenticate almost anything
(via sciencedaily.com) Original source A cryptographic tag uses terahertz waves to authenticate items by recognizing the unique pattern of microscopic metal particles that are mixed into the glue that sticks the tag to the item's surface.
Published Giant Antarctic sea spiders reproductive mystery solved
(via sciencedaily.com) Original source Instead of carrying the babies until they hatched, as in most species of sea spiders, one parent (likely the father) spent two days attaching the eggs to the rocky bottom where they developed for several months before hatching as tiny larvae.
Published Anoxic marine basins are among the best candidates for deep-sea carbon sequestration
(via sciencedaily.com) Original source Anoxic marine basins may be among the most viable places to conduct large-scale carbon sequestration in the deep ocean, while minimizing negative impacts to marine life. As we explore ways to actively draw down the levels of carbon in the atmosphere, sending plant biomass to these barren, oxygen-free zones on the seafloor becomes an option worth considering.
Published Beyond peak season: Bacteria in the Arctic seabed are active all year round
(via sciencedaily.com) Original source Researchers studied the composition and function of bacteria in the seabed off Svalbard, during alternating periods of polar night and midnight sun. To do this, they specially developed a sampling device, the Ellrott grab. In contrast with bacterial communities in the overlying water, the sediment bacteria hardly change with the seasons. This is probably due to the fact that in the seabed some hard-to-digest foods are available all year round.
Published Searching for clues in the history book of the ocean
(via sciencedaily.com) Original source New research has shown that the tropical subsurface ocean gained oxygen during the Paleocene-Eocene Thermal Maximum (commonly referred to as PETM). During this short-lived interval of time in Earth s history that occurred 56 million years ago the average temperatures rose by up to six degrees within a few thousand years.
Published Early-stage subduction invasion
(via sciencedaily.com) Original source Our planet's lithosphere is broken into several tectonic plates. Their configuration is ever-shifting, as supercontinents are assembled and broken up, and oceans form, grow, and then start to close in what is known as the Wilson cycle.
Published New 'time travel' study reveals future impact of climate change on coastal marshes
(via sciencedaily.com) Original source A new study offers a glimpse into the possible impact of climate change on coastal wetlands 50 years or longer into the future. Scientists are usually forced to rely on computer models to project the long-term effects of rising seas, but an unexpected set of circumstances enabled a real-world experiment along the Gulf Coast.