Tag

Oceanography

All articles tagged with #oceanography

science1 day ago•5 min saved

Winds and continental drift unlocked the Antarctic Circumpolar Current

New simulations show the Antarctic Circumpolar Current formed around 34 million years ago only after Australia moved north and strong westerlies blew through the Tasman Gateway, aided by a CO2 drop from ~1,000 to ~600 ppm and Antarctic isolation. Once fully developed, the ACC helped stabilize global climate by linking ocean basins and keeping warmer waters away from the ice sheets. Today, climate warming may push the current southward and slow it by about 20% by 2050, risking biodiversity and ice-sheet stability.

via ScienceAlert|

#antarctic-circumpolar-current #climate-change #oceanography

science16 days ago•6 min saved

NASA’s SWOT Reveals Hidden Ocean Floor in Unprecedented Global Map

NASA's SWOT satellite has produced a high-resolution, global map of the seafloor by measuring subtle sea-surface height variations, revealing features like abyssal hills and tectonic structures that were previously hidden from space. This breakthrough accelerates ocean science, improves models of ocean circulation and climate, and has implications for resource management, shipping, hazard detection, and national security. The effort aims to complete a comprehensive global seafloor map by 2030, blending space-based observations with traditional ship-based mapping.

via Indian Defence Review|

#abyssal-hills #oceanography #satellite-remote-sensing

science17 days ago•3 min saved

NASA’s SWOT Satellite Maps the Ocean Floor From Space

NASA and CNES’s SWOT satellite uses gravity-driven sea-surface height data to map the seafloor, enabling detection of smaller features like seamounts and abyssal hills and potentially expanding the catalog from about 44,000 to up to 100,000. The effort aims to map the entire ocean floor by 2030, complementing ship-based sonar with near-global coverage every 21 days.

via BBC Sky at Night Magazine|

#nasa #oceanography #satellite

science23 days ago•4 min saved

Gigantic Subsea Waves Behind Greenland Melt Accelerate Glacier Loss

Researchers deployed a 10-km fiber-optic cable to monitor a Greenland glacier and detected massive underwater waves generated by iceberg calving. These internal waves keep warm seawater in contact with the glacier base, creating a calving multiplier that speeds up melt and could amplify ice loss and influence ocean circulation.

via The Daily Galaxy|

#climate-change #glaciology #greenland

science1 month ago•6 min saved

Southern Indian Ocean Rapid Freshening Rewrites Ocean Circulation

Six decades of observations show a historically salty patch in the Southern Indian Ocean is losing salt at a rapid pace, with the high-salinity region shrinking about 30% over the past 60 years as freshwater from the Indo-Pacific pool is transported southward by shifts in atmospheric circulation; scientists estimate the freshwater input is roughly 60% of Lake Tahoe’s annual inflow each year, gradually diluting surface waters and affecting global ocean circulation, including the Atlantic Meridional Overturning Circulation, though the study notes the freshening is a gradual process rather than a single dramatic event.

via Indian Defence Review|

#amoc #freshwater #indo-pacific

science1 month ago•4 min saved

Antarctica’s Cold Vent Breaks Hydrothermal Norms

British researchers have discovered Hook Ridge, a cold, irregular hydrothermal vent off Antarctica that emits a low-temperature plume rather than the hot fluids typical of vents, and shows no current life due to its irregular activity; a relict mineral chimney reveals past hydrothermal activity and warmth. The finding suggests unusual vents can still influence deep-sea biology and may act as stepping stones for genetic material across the oceans.

via The Daily Galaxy|

#antarctica #chemosynthesis #hook-ridge

science1 month ago•5 min saved

Geometric Yellow Brick Road Discovered on the Deep Pacific Seafloor

An Ocean Exploration Trust Nautilus dive at 3,000 meters depth near Nootka Seamount revealed a sharply geometric hyaloclastite formation dubbed a 'yellow brick road' due to 90-degree fractures likely from cooling during multiple eruptions. The find is part of the first visual survey of the Liliʻuokalani Seamounts within Papahānaumokuākea, with rock and microbial samples collected to date the formations and study deep-sea ecosystems, informing future monument management.

via The Daily Galaxy|

#deep-sea-exploration #geology #oceanography

science2 months ago•5 min saved

500-KM Oceanic Canyon Traced to a Tectonic Zipper, Not Erosion

Scientists mapped the King’s Trough, a 500+ km underwater canyon in the North Atlantic, and determined it formed over millions of years by the slow separation of the European and African plates via a tectonic 'zipper,' aided by unusually thick, hot crust from the Azores mantle plume. The finding, reported after METEOR expedition data and high‑resolution sonar, links deep mantle processes to surface tectonics and reshapes how we think about underwater canyon formation.

via The Daily Galaxy|

#geology #kings-trough #mantle-plume

science2 months ago•6 min saved

Antarctic Submersible Vanishes After Revealing Hidden Ice Structures

A robotic submersible named Ran, part of an international effort to study West Antarctic ice shelves, disappeared under the Dotson Ice Shelf in January 2024 after completing a detailed ~140 sq km survey that uncovered previously undocumented subglacial features, including teardrop-shaped melt formations; no beacon or debris has been found, the incident halts follow-up data collection in the Amundsen Sea, and investigators are weighing equipment failure or collision as possible causes, while the 2022 dataset continues to inform revised models of basal melting driven by warm Circumpolar Deep Water.

via Indian Defence Review|

#antarctica #dotson #ice-shelf

science2 months ago•6 min saved

Satellites Map Pacific Wave Field, Clarifying 35-Meter Wave Claims

New satellite-altimetry analyses show SWOT captured large-scale, two-dimensional ocean-height patterns during the 2025 Kamchatka tsunami and concurrent storm waves, helping refine rupture models and post-event understanding; however, the reported 35-meter waves were a misinterpretation of significant wave height, and real-time hazard alerts still rely on in-situ systems like DART buoys and meteorological models.

via The Daily Galaxy|

#dart #oceanography #satellite-altimetry

environment2 months ago•17 min saved

NASA opens 33-year weekly sea-level data to public, revealing faster rise and regional shifts

NASA has published 33 years of weekly sea-surface height maps from NASA-SSH, showing where the ocean surface sits above or below the long-term average to aid coastal risk monitoring. The data—derived from radar-altimeter measurements and gridded for comparability—reveal El Niño-driven swings and rapid local changes, but are anomalies with a two-week processing lag and coarse resolution (roughly 200 miles per cell). Long-term trends show accelerating sea-level rise, from about 0.2 cm/year in 1993 to about 0.46 cm/year in 2023, with 2024’s rise largely due to thermal expansion (~0.58 cm/year). The dataset supports research and planning but must be used with tide gauges, as local flooding depends on land motion and tides; NASA plans to extend the record and develop tools to translate anomalies into practical risk checks.

via Earth.com|

#climate-change #environment #nasa

science2 months ago•5 min saved

A Decade of Seafloor Silence: Deoxygenation Disrupts Deep-Sea Recycling

Scientists using the NEPTUNE observatory monitored Barkley Canyon for nearly 10 years and found an unexpected absence of decay activity around whale bones and wood, lacking typical scavengers and bone-eating organisms. The results suggest ocean deoxygenation and expanding oxygen minimum zones are suppressing the deep-sea recyclers (Osedax, Xylophaga), potentially slowing organic decomposition and nutrient cycling with ripple effects on the broader food web.

via Indian Defence Review|

#carbon-cycle #deep-sea #deoxygenation

science2 months ago•11 min saved

UK deep-sea landers to crack the mystery of dark oxygen

Two world‑first deep‑sea landers—Alisa and Kaia—will be deployed in the Pacific’s Clarion-Clipperton Zone to investigate how oxygen forms in complete darkness, testing whether manganese nodules interact with saltwater to produce electricity or if another electrochemical/biochemical process is at work, with an accompanying lander to measure oxygen flux; the three‑year project, backed by UNESCO as a UN Ocean Decade initiative, seeks to uncover the origins of dark oxygen and its implications for life in the deep ocean.

via Interesting Engineering|

#dark-oxygen #deep-ocean #landers

science2 months ago•4 min saved

NASA Spots a Ring of Blooms Around the Chatham Islands

NASA's VIIRS satellite captured a ring-shaped phytoplankton bloom around the Chatham Islands, where nutrient-rich upwelling from the Chatham Rise and the clash of cold Antarctic and warmer subtropical waters fuel rapid algae growth. The vivid greens and blues reveal a seasonal, highly productive marine ecosystem that supports fisheries and marine mammals, though the area is also known for mass strandings tied to its complex oceanography.

via The Daily Galaxy|

#chatham-islands #nasa #oceanography

science3 months ago•4 min saved

Mysterious Disappearances and Discoveries Beneath Antarctic Ice

Scientists used autonomous underwater vehicles to map the underside of Antarctica's Dotson Ice Shelf, revealing complex terrain and uneven melting patterns driven by warm ocean currents. During a follow-up mission in 2024, the vehicle disappeared, raising concerns about the stability of ice shelves and their role in sea level rise, as melting accelerates in specific areas.

via The Daily Galaxy|

#antarctica #climate-change #ice-shelf