Oceanography
A new study indicates sea levels likely will continue to rise in the tropical Pacific Ocean off the coasts of the Philippines and northeastern Australia as humans continue to alter the climate.
The study authors combined past sea level data gathered from both satellite altimeters and traditional tide gauges to find out how much a naturally occurring climate phenomenon called the Pacific Decadal Oscillation, or PDO, influences sea rise patterns in the Pacific.
The PDO is a temperature pattern in the Pacific Ocean akin to El Niño but which lasts roughly 20 to 30 years and contributes…
As sea ice begins to melt back toward its late September minimum, it is being watched by researchers who have put sensors on and under ice in the Beaufort Sea.
The international effort hopes to figure out the physics of the ice edge in order to better understand and predict open water in Arctic seas.
"This has never been done at this level, over such a large area and for such a long period of time," said principal investigator Craig Lee, an oceanographer at the University of Washington's Applied Physics Laboratory. "We're really trying to resolve the physics over the course of an entire…
A new study on biological erosion of mesophotic tropical coral reefs - low energy reef environments between 30-150 meters deep - provides new insights into processes that affect the overall structure of these important ecosystems.
The purpose of the study was to better understand how bioerosion rates and distribution of bioeroding organisms, such as fish, mollusks and sponges, differ between mesophotic reefs and their shallow-water counterparts and the implications of those variations on the sustainability of the reef structure.
Due to major advancements in deeper underwater diving…
Changes to Antarctic winds have been implicated in southern Australia's drying climate but a new estimate says they may also have a profound impact on warming ocean temperatures under the ice shelves along the coastline of West and East Antarctic.
Projected changes in the winds circling the Antarctic may accelerate global sea level rise significantly more than previously believed. Most sea level rise studies focused on the rate of ice shelf melting due to the general warming of the ocean over large areas.
Using super computers at Australia's National Computational Infrastructure (NCI)…
Whales are relatively rare and so they probably don't make much of a difference in the overall ocean.
A team of biologists disagrees. They reviewed several decades of research on whales from around the world and found that whales make a huge difference and have a powerful and positive influence on the function of oceans, global carbon storage, and the health of commercial fisheries. "The decline in great whale numbers, estimated to be at least 66% and perhaps as high as 90%, has likely altered the structure and function of the oceans," claims University of Vermont conservationist Joe…
Iron is one of the essential elements of life. Found in enzymes like myoglobin and hemoglobin and cytochrome P450, iron is an essential cog in the biomachinery of every living cell.
Iron is present in tiny concentrations in seawater. On the order of a few billionths of a gram in a liter. Given that there is so little iron in seawater, one might conclude that its presence there is inconsequential, but its scarcity in the ocean, the earth's wellspring of life, only magnifies its importance.
"I did a calculation once on a ton of ocean water," says Seth John, an assistant…
A paper in Scientific Reports posits a new cause of the ice age that covered large parts of the Northern Hemisphere 2.6 million years ago.
The study found a previously unknown mechanism by which the joining of North and South America changed the salinity of the Pacific Ocean and caused major ice sheet growth across the Northern Hemisphere. The change in salinity encouraged sea ice to form which in turn created a change in wind patterns, leading to intensified monsoons. These provided moisture that caused an increase in snowfall and the growth of major ice sheets, some of which reached over a…
If your glass is half full, you recognize that in recent geological history, 90,000 of every 100,000 years have been ice ages, and it's been 12,000 years since the last one. In that light, global warming might be a good thing.
But why 100,000 year cycles? It wasn't always the case. Ice-age cycles uses to happen about every 41,000 years but then they became longer and more intense about 900,000 years ago. Researchers found that the deep ocean currents that move heat around the globe stalled or even stopped then, possibly due to expanding ice cover in the north. The slowing currents increased…
If the Greenland ice sheet ever gets past its stability threshold, it won't be the first time.
400,000 years ago, a nearly complete deglaciation of southern Greenland happened, raising global sea levels as much as 6 meters. Not quite what was predicted to have happened by 2016 in "An Inconvenient Truth", but a substantial rise nonetheless.
The study authors say this is one of the first to zero in on how the vast Greenland ice sheet responded to warmer temperatures during that period, which were caused by changes in the Earth's orbit around the sun.
A research team is hiking to sample…
The Greenland Ice Sheet is huge, a 1.7 million-square-kilometer, 2-mile thick layer of ice that covers Greenland.
In the last 40 years, ice loss from the Greenland Ice Sheet has increased four-fold, contributing to global sea level rise. Some of the melting at the surface of the ice sheet is due to a warmer atmosphere but the ocean's role in driving ice loss largely has been a mystery.
A new paper in Nature Geoscience sheds new light on the connection between the ocean and Greenland's outlet glaciers, and provides important data for future estimates of how fast the ice sheet might melt and…