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Presents research which concluded that the formation of deep and intermediate waters in the North Atlantic wax and wane alternately on orbital and millennial timescales. Tie between ocean circulation and climate change; Study of subtropical gyres; Importance of such gyres; Nutrient concentrations in the North Atlantic subtropical gyre in the Last Glacial Maximum and today.

The article highlights trends in meridional overturning circulation (MOC) in the North Atlantic Ocean in 2013. Topics discussed include the mean variability of the MOC, the variability of transported properties, and the strength of the MOC. The lack of consistent trend in the MOC during the year is noted.

The existence in the ocean of deep western boundary currents, which connect the high-latitude regions where deep water is formed with upwelling regions as part of the global ocean circulation, was postulated more than 40 years ago. These ocean currents have been found adjacent to the continental slopes of all ocean basins, and have core depths between 1,500 and 4,000?m. In the Atlantic Ocean, the deep western boundary current is estimated to carry (10-40)×106?m3?s-1 of water, transporting North Atlantic Deep Water-from the overflow regions between Greenland and Scotland and from the Labrador Sea-into the South Atlantic and the Antarctic circumpolar current. Here we present direct velocity and water mass observations obtained in the period 2000 to 2003, as well as results from a numerical ocean circulation model, showing that the Atlantic deep western boundary current breaks up at 8°S. Southward of this latitude, the transport of North Atlantic Deep Water into the South Atlantic Ocean is accomplished by migrating eddies, rather than by a continuous flow. Our model simulation indicates that the deep western boundary current breaks up into eddies at the present intensity of meridional overturning circulation. For weaker overturning, continuation as a stable, laminar boundary flow seems possible. [ABSTRACT FROM AUTHOR]

The carbon isotopic composition (13C/12C, expressed as δ 13C) of fossil foraminifera is the primary tracer used to infer changes in past ocean ventilation, and its variations are interpreted by using the modern oceanic δ 13C distribution as a framework. However, the present ocean δ 13C distribution is strongly overprinted by isotopically light anthropogenic carbon dioxide. A correction for this oceanic C-13 Suess effect in the North Atlantic (NA) shows that the pristine NA δ 13C distribution has a richer and more detailed structure that is more clearly related to water mass distributions. Our results revise some fundamental perceptions regarding glacial-interglacial ocean δ 13C differences and allow paleo-δ 13C variations to be understood within the context of modern climate variability. [ABSTRACT FROM AUTHOR]

This article presents information on a report issued by researcher Harry Bryden of the National Oceanography Center (NOC) in Southampton, Great Britain related to the North Atlantic Ocean which is bringing less heat to warm Europe. The NOC group used seawater densities calculated from those observations, plus current measurements of the Gulf Stream passing by Florida and a few standard assumptions, to estimate the currents heading north and south through the depth of the Atlantic. The Gulf Stream remained steady through the 47-year period, and Atlantic flows remained much the same through the 1992 survey. But according to the NOC group's analysis, the conveyor appears to have slowed dramatically in 1998 and 2004. Fifty percent more Gulf Stream near-surface waters were turning back southward before reaching very far to the north, whereas part of the deep southward flow of cold water had decreased by 50%. All in all, the conveyor had slowed by 30%. The slowing, although sizable, is comparable to the estimated uncertainty of the observations. Observed temperature changes driving the conveyor slowdown in shallower waters in the west and in deeper waters are just what he would expect from salinity and circulation changes previously reported in the far north.

The article discusses the origin of thermostat in the North Atlantic Ocean. The paleoceanographers assumed that thermostat switch which began to melt the world over the last ice age lay somewhere in the North Atlantic Ocean. However, new evidence from the tropical places that it lay in the waters around Antarctica. According to a paleoceanographer Lowell Stott, studying the origin of it comes down to timing, and determining the timing of climate events can be tough as warming in the tropics is recorded in marine sediments, whereas warming in Antarctica is recorded in glacial ice.

The article cites an article published in a 2006 issue of the journal "Paleoceanography," on glacier meltwater addition to the North Atlantic Ocean (NAO) from the Laurentide Ice Sheet. The rapid addition of meltwater to the NAO has raised sea levels. The BØlling warming period of 14,600 years ago or the Older Dryas Cold event that ended BØlling, began with the flow of meltwater to NAO. Records of the North Atlantic Deep Water (NADW) flow show that meltwater pulse1a weakened the flow 14,600 years ago without any increase in sea levels. In conclusion it suggests that NADW formation and climate are not controlled only by the addition of meltwater but also by the location of meltwater addition.

The article presents information related to a study on deep ocean circulation patterns. Under the study, researchers examined neodymium isotopic abundance data gathered from Southern Hemisphere sites. With the help of the sites they were able to clearly distinguish between different circulation patterns. Researchers find that deep-water production in the North Atlantic began 33 million years ago, as suggested by the divergence of isotope records from the more southerly Maud Rise and the more northerly Walvis Ridge. The finding suggests that the Greenland-Iceland-Faeroes Ridge must have deepened at that time.

Reports that climate researchers set sail from the Canary Islands on February 26, 2004 to begin a four-year program that will assess the behavior of currents in the north Atlantic Oceans. Part of a wider investigation into rapid climate change; Program's detailed look at the strength, structure and variability of currents that carry warmth northwards in the Atlantic.

Reports research which showed that coral from the western North Atlantic reflected climate changes in deep currents at the end of the last Ice Age. Methods of paleoceanographers; Research by Adkins et al in this issue; Value of coral as an archive; Details on research; Impact of climate on ocean circulation; Carbon-14 levels in coral; Insights into the rates of ancient ocean circulation.