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Categories: Geoscience: Oceanography, Physics: Acoustics and Ultrasound

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The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica's ice sheets. An international research team has now used sediments taken from the South Pacific to reconstruct the flow speed in the last 5.3 million years. Their data show that during glacial periods, the current slowed; during interglacials, it accelerated. Consequently, if the current global warming intensifies in the future, it could mean that the Southern Ocean stores less CO2 and that more heat reaches Antarctica.

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Coastal seas form a complex transition zone between the two largest CO2 sinks in the global carbon cycle: land and ocean. Ocean researchers have now succeeded for the first time in investigating the role of the coastal ocean in a seamless model representation.

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Biologists use a novel method of simultaneous acoustic tagging to gain insights into the link between whale communication and behavior

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Ground-based measuring devices and aircraft radar operated in the far northeast of Greenland show how much ice the 79 N-Glacier is losing. According to recent measurements, the thickness of the glacier has decreased by more than 160 meters since 1998. Warm ocean water flowing under the glacier tongue is melting the ice from below. High air temperatures cause lakes to form on the surface, whose water flows through huge channels in the ice into the ocean. One channel reached a height of 500 meters, while the ice above was only 190 meters thick.

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Claims that climate change is natural are inconsistent with new oceanic temperature trends.

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Oceans are subject to continuous change, mostly over extremely vast periods of time running into millions of years. Researchers have now used computer simulations to demonstrate that a subduction zone originating in the Western Mediterranean will propagate into the Atlantic under the Strait of Gibraltar. According to their model, this will create a new Atlantic subduction zone 50 million years into the future, which will then move down into the Earth's mantle. The new geodynamic model explains the evolution of the Gibraltar subduction zone and its likely development, which will contribute to the renewal of the Atlantic Ocean floor.

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When plastic ends up in the ocean, it gradually weathers and disintegrates into small particles. If marine animals ingest these particles, their health can be severely affected. Large accumulations of plastic can therefore disrupt the biological balance of marine ecosystems. But which areas are particularly affected?

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By evaluating sound vibrations produced by the airflow induced within the lungs and bronchial tree during normal breathing as well as those produced by the larynx during vocalizations, doctors can identify potential disease-related abnormalities within the respiratory system. Researchers demonstrate the efficacy of ultrasound technology to detect low-amplitude movements produced by vocalizations at the surface of the chest. They also demonstrated the possibility of using the airborne ultrasound surface motion camera to map these vibrations during short durations so as to illustrate their evolution.

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A new report uncovers how hydrogen gas, the energy of the future, provided energy in the past, at the origin of life 4 billion years ago. Hydrogen gas is clean fuel. It burns with oxygen in the air to provide energy with no CO2. Hydrogen is a key to sustainable energy for the future. Though humans are just now coming to realize the benefits of hydrogen gas (H2 in chemical shorthand), microbes have known that H2 is good fuel for as long as there has been life on Earth. Hydrogen is ancient energy.

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Everything is everywhere -- under certain conditions microbial communities can grow and thrive, even in places that are seemingly uninhabitable. This is the case at inactive hydrothermal vents on the sea floor. An international team is presently working to accurately quantify how much inorganic carbon can be bound in these environments.

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Researchers believe a group of killer whales observed hunting marine mammals including sperm whales, as well as a sea turtle, in the open ocean off California and Oregon could be a new population. Based on available evidence, the researchers posit that the 49 orcas could belong to a subpopulation of transient killer whales or a unique oceanic population found in waters off the coast of California and Oregon.

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A new study provides groundbreaking findings that offer insights on the migration and foraging patterns of leatherback sea turtles along the Northwest Atlantic shelf.

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Seattle may have experienced its own Swift Quake last July, but at an August 2023 concert Taylor Swift's fans in Los Angeles gave scientists a lot of shaking to ponder. After some debate, a research team concluded that it was likely the dancing and jumping motions of the audience at SoFi Stadium -- not the musical beats or reverberations of the sound system -- that generated the concert's distinct harmonic tremors.

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Biologists announce the discovery of numerous species of roundworm in the highly saline waters of Great Salt Lake, the vast terminal lake in northwestern Utah that supports millions of migratory birds. Previously, brine shrimp and brine flies were the only known multicellular animals living in the water column. The scientists found nematodes, belonging to a family known for inhabiting extreme environments, in the lake's microbialites, reef-like structures covering about a fifth of the lakebed.

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Marine heat waves in the northeast Pacific Ocean create ongoing and complex disruptions of the ocean food web that may benefit some species but threaten the future of many others, a new study has shown.

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Existing ship control systems using Model Predictive Control for Maritime Autonomous Surface Ships (MASS) do not consider the various forces acting on ships in real sea conditions. Addressing this gap, researchers developed a novel time-optimal control method, that accounts for the real wave loads acting on a ship, enabling effective planning and control of MASS at sea.

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Researchers have conducted the first large-scale observation and modeling study of northwest Greenland's Petermann Glacier. Their findings reveal the intrusion of warm ocean water beneath the ice as the culprit in the accelerated melting it has experienced since the turn of the century, and their computer predictions indicate that potential sea level rise will be much worse than previously estimated.

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Scientists have used the geological record of the deep sea to discover a connection between the orbits of Earth and Mars, past global warming patterns and the speeding up of deep ocean circulation. The patterns they discover suggest that warming seas could produce deep whirpools in ocean currents.

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Despite being scattered across more than a million square kilometers, new research has revealed that remote coral reefs across the Seychelles are closely related. Using genetic analyses and oceanographic modelling, researchers demonstrated for the first time that a network of ocean currents scatter significant numbers of larvae between these distant islands, acting as a 'coral superhighway.'

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A team develops an ultrasensitive broadband transparent ultrasound transducer.