© NOAA
A layer of Antarctic Bottom Water colder than 0ºC (colors, with darkest blue areas having the thickest layer, and white none) covers the ocean floor around Antarctica (center, shaded grey). Rates at which this layer is thinning during the study period (red numbers in meters per decade) are shown for for each deep basin (outlined by thin grey lines). These rates are estimated using data from repeated oceanographic expeditions (ship tracks shown by thick black lines). Note that seawater at the ocean surface stays liquid even at temperatures approaching -2ºC because of its high salt content.
A layer of Antarctic Bottom Water colder than 0ºC (colors, with darkest blue areas having the thickest layer, and white none) covers the ocean floor around Antarctica (center, shaded grey). Rates at which this layer is thinning during the study period (red numbers in meters per decade) are shown for for each deep basin (outlined by thin grey lines). These rates are estimated using data from repeated oceanographic expeditions (ship tracks shown by thick black lines). Note that seawater at the ocean surface stays liquid even at temperatures approaching -2ºC because of its high salt content.
The coldest deep ocean water that flows around Antarctica in the Southern Ocean has been mysteriously disappearing at a high rate over the last few decades, scientists have found.
This mass of water is called Antarctic Bottom Water, which is formed in a few distinct locations around Antarctica, where seawater is cooled by the overlying air and made saltier by ice formation (which leaves the salt behind in the unfrozen water). The cold, salty water is denser than the water around it, causing it to sink to the sea floor where it spreads northward, filling most of the deep ocean around the world as it slowly mixes with warmer waters above it.
The world's deep ocean currents play a critical role in transporting heat and carbon around the planet, which helps regulate the Earth's climate.
Previous studies had indicated that this deep water has become warmer and less salty over the past few decades, but a new study has found that significantly less of this water has also been formed during this time.
Oceanographers examined temperature data collected from 1980 to 2011 at about 10-year intervals by an international program of repeated ship-based oceanographic surveys in the Southern Ocean.
Comment: A three-minute difference and almost the same intensity? It is too much coincidence to let it pass unnoticed.