Oceanography

Two ocean hot spots have been linked to the hottest summers on record for the central United States, in 1934 and 1936. Those two summers and the "Dust Bowl" that saw farming devastated were accompanied by the worst drought in America of the last 1,000 years. In 1934, giant dust storms and drought covered more than 75 percent of the country and affected 27 states severely. Silt from storms even covered the decks of ships 200 miles off the east coast.  In the years afterward, over-farming was blamed but new research instead blames unusually warm sea surface temperatures. In the…

Antarctica's massive ice sheet has recently lost twice the amount of ice in the west as what it  accumulated in the east, and the southern continent's ice cap is melting ever faster, according to a new study in which researchers "weighed" Antarctica's ice sheet using gravitational satellite data and found that from 2003 to 2014, the ice sheet lost 92 billion tons of ice per year. If stacked on the island of Manhattan, that amount of ice would be a mile high, more than five times the height of the Empire State Building. The vast majority of that loss was from West Antarctica, which is…

Researchers have discovered areas in the tropical North Atlantic, several hundred kilometers off the coast of West Africa, with extremely low levels of oxygen, making them uninhabitable for most marine animals. The levels measured in these 'dead zones' are the lowest ever recorded in Atlantic open waters. Dead zones are areas of the ocean depleted of oxygen. Most marine animals, like fish and crabs, cannot live within these regions, where only certain microorganisms can survive. In addition to the environmental impact, dead zones are an economic concern for commercial fishing, with very low…

Greenland climate during the last ice age was very unstable, the researchers say, characterized by a number of large, abrupt changes in mean annual temperature that each occurred within several decades. These so-called "Dansgaard-Oeschger events" took place every few thousand years during the last ice age. Temperature changes in Antarctica showed an opposite pattern, with Antarctica cooling when Greenland was warm, and vice versa. Today we see differences in climate between them as well. Evidence for and against global warming. A new study using evidence from a highly detailed ice core from…

The ocean sucks up heat-trapping carbon dioxide (CO2) building up in our atmosphere with help from tiny plankton. Like plants on land, plankton convert CO2 into organic carbon via photosynthesis and then can sink into the deep ocean, carrying carbon with them. They decompose when bacteria convert their remains back into CO2. This "biological pump," if it operated 100 percent efficiently, would mean nearly every atom of carbon drawn into the ocean would be converted to organic carbon, sink into the deep ocean, and remain sequestered from the atmosphere for millennia. But like hail stones that…

We are still trying to fully understand the extent of the damage caused by the Deepwater Horizon oil spill five years ago, one of the worst environmental disasters in US history. Following the Macondo well explosion in the deep waters of the Gulf of Mexico, five million barrels of oil were spilled in the deep-sea. In an attempt to avoid spills reaching coastlines, BP and government agencies sprayed over two million liters of oil dispersants – chemicals that break oil into small droplets – at depth for the first time in these conditions. The impact of the oil spill was readily apparent on Gulf…

Though some studies have linked icebergs to abrupt climate change cycles during the last glacial period - by introducing fresh water to the surface of the ocean and changing ocean currents, which changes climate - new findings present a contradictory narrative and suggest that icebergs generally arrived too late to trigger marked cooling across the North Atlantic. Abrupt climate change, characterized by transitions between warm and cold conditions across the North Atlantic, is a pervasive feature of the Late Pleistocene - the most recent period of repeated glacial cycles.  The occurrence…

The one common element in recent American weather has been its diversity. The West Coast has been drier than usual while the East Coast has had more snow. Fish are swimming into new waters and so hungry seals that don't follow them aare washing up on California beaches.  A long-lived patch of warm water off the West Coast, about 1 to 4 degrees Celsius (2 to 7 degrees Fahrenheit) above normal, is part of what's wreaking much of this mayhem, according to two papers Geophysical Research Letters. No, that warm blob was not caused by climate change, though it has many of the same effects…

Methane is a greenhouse gas with more warming impact than carbon dioxide but also fortunately a much shorter life in the atmosphere. Due to the popularity of much cleaner natural gas, which has caused CO2 emissions to drop, there are concerns about methane but the big source is nature herself - decomposition of organic material, a complex process involving bacteria and microbes, is a big culprit. Abiotic methane, formed by chemical reactions in the oceanic crust beneath the seafloor, is trapped by deep water gas hydrates, icy substances in the sediments, and one such reservoir was recently…

A new study demonstrates for the first time how elemental carbon became an important construction material of some forms of ocean life after one of the greatest mass extinctions in the history of Earth more than 252 million years ago.  As the Permian Period of the Paleozoic Era ended and the Triassic Period of the Mesozoic Era began, more than 90 percent of terrestrial and marine species became extinct. Various proposals have been suggested for this extinction event, including extensive volcanic activity, global heating, or even one or more extraterrestrial impacts. Enlarged image of…