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Categories: Geoscience: Oceanography, Paleontology: Early Mammals and Birds
Published New deep-sea worm discovered at methane seep off Costa Rica
(via sciencedaily.com) Original source Marine biologists have discovered a new species of deep-sea worm living near a methane seep some 50 kilometers (30 miles) off the Pacific coast of Costa Rica.
Published After decades of Arctic sea ice getting faster and more hazardous for transport, models suggest a dramatic reversal is coming
(via sciencedaily.com) Original source Will ice floating in the Arctic Ocean move faster or slower over the coming decades? The answer to this question will tell us whether marine transportation can be expected to get more or less hazardous. It might also have important implications for the rate of ice cover loss, which is hugely consequential for Northern Indigenous communities, ecosystems, and the global climate system. While observational data suggest the trend has been towards faster sea ice speeds, climate models project that those speeds will slow down during the summer season. This contrast has led to some questions around the plausibility of the model projections.
Published We know the Arctic is warming -- What will changing river flows do to its environment?
(via sciencedaily.com) Original source Scientists recently combined satellite data, field observations and sophisticated numerical modeling to paint a picture of how 22.45 million square kilometers of the Arctic will change over the next 80 years. As expected, the overall region will be warmer and wetter, but the details -- up to 25% more runoff, 30% more subsurface runoff and a progressively drier southern Arctic, provides one of the clearest views yet of how the landscape will respond to climate change.
Published Fossil named 'Attenborough's strange bird' was the first in its kind without teeth
(via sciencedaily.com) Original source A new fossil, named 'Attenborough's strange bird' after naturalist and documentarian Sir David Attenborough, is the first of its kind to evolve a toothless beak. It's from a branch of the bird family tree that went extinct in the mass extinction 66 million years ago, and this strange bird is another puzzle piece that helps explain why some birds -- and their fellow dinosaurs -- went extinct, and others survived to today.
Published Arctic could become 'ice-free' within a decade
(via sciencedaily.com) Original source While summer sea ice loss in the Arctic is inevitable, it can be reversed if the planet cools down, researchers say.
Published Less ice in the Arctic Ocean has complex effects on marine ecosystems and ocean productivity
(via sciencedaily.com) Original source Most of the sunlight reaching the Arctic Ocean is reflected to space by sea ice, effectively shielding ocean ecosystems from sunlight. As the Arctic sea ice continues its downward trend, larger areas of the ocean become exposed to sunlight for longer periods, potentially allowing more primary production on the seafloor. However, according to a new study, this anticipated increase in primary production does not seem to be occurring uniformly across the Arctic Ocean.
Published Antarctica's coasts are becoming less icy
(via sciencedaily.com) Original source Scientists found unexpected evidence the area of polynyas around Antarctica is increasing dramatically, and it follows an intriguing cycle, growing and shrinking roughly every 16 years.
Published Researchers use GPS-tracked icebergs in novel study to improve climate models
(via sciencedaily.com) Original source Research unearthed new information to help scientists better understand circulation patterns of ocean water around glaciers. In the summers of 2014 and 2019, a group of pioneers in glacial research attached GPS devices to 13 icebergs and tracked hourly changes in their positions as they passed through Greenland's Ilulissat Icefjord toward the ocean. Study results showed circulation in the primary fjord is greatly affected by freshwater flow from connecting tributary fjords, which is critically important to consider in circulation models.
Published Slimming down a colossal fossil whale
(via sciencedaily.com) Original source A 30 million year-old fossil whale may not be the heaviest animal of all time after all, according to a new analysis by paleontologists. The new analysis puts Perucetus colossus back in the same weight range as modern whales and smaller than the largest blue whales ever recorded.
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 Killer instinct drove evolution of mammals' predatory ancestors
(via sciencedaily.com) Original source The evolutionary success of the first large predators on land was driven by their need to improve as killers, researchers suggest.
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.