Earth and Planetary Sciences · Atmospheric Science
A study finds that the Arctic Ocean and Nordic Seas were sometimes largely isolated from the North Atlantic during past ice ages. The connection appears to have reopened rapidly as the ice ages ended, raising questions about effects on the global ocean circulation system.
A review of observations, computer models and climate records finds strong evidence that Antarctic sea ice affects ocean and atmospheric circulation, ice sheets, marine productivity and the carbon cycle. Records from the past glacial cycle show that sea-ice changes occurred alongside shifts in ocean circulation, ocean productivity and carbon, although their individual effects are difficult to separate.
An extended test on Alaska’s North Slope extracted methane released from a gas-hydrate reservoir for 151 days. The produced gas was mostly secondary microbial methane, and the reservoir yielded an unexpectedly high amount of gas compared with water.
A study finds that Antarctica is very likely to experience mass loss during the twenty-first century, even under aggressive emissions-reduction scenarios. Under very high emissions, Antarctic ice loss could contribute up to 25.4 centimetres of sea-level rise by 2100, although the estimate remains uncertain.
Herring supplied more than half of the estimated annual energy needs of non-reproductive and pregnant female humpback whales, as well as juvenile and adult males, in an eastern British Columbia feeding ground. Juvenile and lactating females obtained between 25% and 50% of their estimated needs from herring.
Long ocean waves can bend Antarctic ice shelves, creating stresses that may amplify fractures and contribute to calving. Researchers developed and tested a model that can examine shelves with varied shapes, thicknesses, grounding and wave directions, including the Drygalski Ice Tongue.
