Gulf Stream

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Surface temperature in the western North Atlantic. North America appears black and dark blue (cold), the Gulf Stream red (warm). Source: NASA

The Gulf Stream is a rapidly flowing ocean current in the Atlantic . It is part of a global marine flow system often referred to as a global conveyor belt. In the direction of Europe , the Gulf Stream becomes the North Atlantic Current . It is part of the western boundary current and influences the climate in Northern Europe.

The Gulf Stream carries about 30 million  cubic meters of water per second (30 Sv ) on the Florida Current , at a speed of 1.8 meters per second, and a maximum of 150 million cubic meters of water per second (150 Sv) at 55 °  West . That is more than a hundred times as much water as flows into the sea over all the rivers in the world. It transports around 1.5 petawatts of power. This corresponds to the electrical output of approximately one million of the largest nuclear power plant units .

The name Gulf Stream was coined by Benjamin Franklin and refers to the Gulf of Mexico . It used to be called the “Florida Current”, on the maps of the 16th and 17th centuries the street of Florida is called Canal de Bahama .


Representation of the Gulf Stream, which continues west of the British Isles as the North Atlantic Current

The actual Gulf Stream is the ocean current between Cape Hatteras , North Carolina , up to approx. 2500 km east of it in the Atlantic. Its origins are the Florida and Antilles currents.

The Florida Current is the continuation of the Caribbean Current and thus the South Equatorial Current , the main supplier of water to the Gulf Stream. The Caribbean current flows through the narrow passage of the strait between Cuba and Yucatán into the Gulf of Mexico . This current, now called the Loop Current , then runs through the Gulf in a clockwise direction and is then pressed back into the Atlantic through an even narrower passage between Cuba and Florida .

North of the Bahamas , the Florida Current and the Antilles Current combine to form the actual Gulf Stream. In the Gulf of Mexico, the water masses have absorbed a lot of heat and initially move as a 100 to 200 km wide band along the coast of North America. In the vicinity of Cape Hatteras, the Gulf Stream breaks away from the coast as a jet stream and flows east into the North American Basin and into the open Atlantic Ocean (due to the geographic conditions below the water surface).

The Gulf Stream is part of the large current Atlantic ring consisting of the Portugal current , the Canary Current , the North Equatorial Current , the Antilles current, the current and the northeast Florida Atlantic current.

The river becomes unstable due to the east turn, it meanders and rings detach from the Gulf Stream. On its way through the Atlantic, parts split off and flow back south or west. The transported water mass is reduced by this flow separation and loses by evaporation also thermal energy .


In the formation of the Gulf Stream, in addition to the atmospheric circulation, the increasing northward effect of the Coriolis force on water movement plays a very important role.

The North Atlantic trade winds drive the surface water to the west. The coast of North America acts like a dam wall and allows the water to flow north along the coast. Due to the meeting with the Labrador Current and the Coriolis force, the water masses flowing north are diverted towards Europe.

The Gulf Stream is part of a circulation system that spans the oceans, to which the global thermohaline circulation also contributes. The thermohaline circulation arises from differences in density, which in turn can be traced back to differences in water temperature and salinity.


The temperature of the Gulf Stream and its current have a major impact on the ecology of the wildlife of the Atlantic. The plankton , which drifts with the current, is the basis of food for numerous animals. These in turn attract predators within the food chain. The submarine soil structures, which are touched and partially formed by the Gulf Stream, form the habitat of this fauna .

On its way, the Gulf Stream transports large amounts of plastic waste . Among other things, the garbage comes from the waste of the ship's crew. Rivers also wash large amounts of plastic into the oceans.


In 1969 the submersible Ben Franklin (PX-15) undertook a four-week drift trip in the Gulf Stream under Jacques Piccard as project manager, during which the six-person crew was on their own. The boat submerged off Florida and covered 2,400 km off Nova Scotia .

In 2005, an article by the British oceanographer Harry Bryden caused a stir, postulating a strong weakening of the Atlantic part of the global conveyor belt. Measurements of the currents in the area of ​​the Labrador Sea and east of the Caribbean under the leadership of IFM-Geomar in Kiel could not support Bryden's conclusions. Although the Kiel researchers also found considerable fluctuations, no long-term trends could be derived from these.

There were regular reports in the media that the Gulf Stream was weakening and that, in the worst case scenario, Europe would experience a new Ice Age, as was the subject of the 2004 film The Day After Tomorrow . This confuses the Gulf Stream and the North Atlantic part of the global conveyor belt.

The hypothesis that the Gulf Stream is an important source of heat for Europe was put forward in an oceanographic book by the naval officer and hydrograph Matthew Fontaine Maury in 1855 . Since then it has remained like a myth under the metaphor “Europe's central heating”. As the climate researcher Richard Seager from the Lamont-Doherty Earth Observatory showed in a detailed study in 2002, the actual influence of the Gulf Stream on the European climate is rather minimal when compared with the influence of air currents and local oceanic heat capacity.

Effects of global warming

Due to global warming, the ice sheets of Greenland, Antarctica and many glaciers on earth are shrinking. This leads to a decrease in the salt content in sea water and thus lowers its density. However, a relatively high salt content in the North Atlantic is a prerequisite for maintaining the deep current there, which is part of the global conveyor belt . One consequence of the decreasing salinity is the slowdown of the Atlantic portion of the global conveyor belt. According to a publication by Stefan Rahmstorf and colleagues , the flow rate decreased by 15% between the middle of the 20th century and 2018 , equivalent to a decrease of 3 million cubic meters per second - this amount corresponds to 15 times the volume of the runoff of the Amazon . Evidence of this slowdown arose both from the general drop in temperatures over a large area in the North Atlantic and from a temperature increase in the Gulf Stream on the east coast of the USA. That was also predicted with climate models of global warming. The weakening of the conveyor belt in the Atlantic was also confirmed by drill core surveys in the Labrador Sea, which were published in the same issue of Nature 2018. The direct measurement data from the British-American Rapid project with 226 anchored measuring instruments at 26.5 degrees north also show a weakening of the conveyor belt in the Atlantic since the measurements began in 2004.

Paradoxically, the immediate effects of the weakening of the conveyor belt in the Atlantic are initially heat waves in summer and increased storms in Central Europe due to the changed air pressure conditions, which favor the increased influx of warm air from southern Europe. The overall cooling of the sea water in the North Atlantic only has an effect later.


  • Matthew Fontaine Maury: The Physical Geography of the Sea , New York / London 1855, PDF
  • Hermann Lämmerhirt: The Gulf Stream: its origin and its influence on the climate of north-western Europe . Bremerhaven, 1887 ( urn : nbn: de: hbz: 061: 1-113588 )
  • Henry Stommel : The Gulf Stream. A physical and dynamic description . Cambridge University Press, London, 1958; 2nd ed. 1965.
  • Henry Stommel: The westward intensification of wind-driven ocean currents . In: Transactions of the American Geophysical Union , Vol. 29 (1948), pp. 202-206
  • Érik Orsenna : Praise of the Gulf Stream . CH Beck, Munich 2006, ISBN 3-406-54829-6 .
  • Jacques Piccard: Diving in the Gulf Stream . Brockhaus, Wiesbaden 1972, ISBN 3-7653-0247-3 .

Web links

Wiktionary: Gulf Stream  - Explanations of meanings, word origins, synonyms, translations
Commons : Gulf Stream  - Collection of images, videos and audio files

Individual evidence

  1. Joanna Gyory, Arthur J. Mariano, Edward H. Ryan: Surface Ocean Currents: The Gulf Stream ( English ) Cooperative Institute for Marine and Atmospheric Studies at the University of Miami. Retrieved July 23, 2010.
  2. ^ Lecture 26: Oceans . Boston University . January 6, 2009. Archived from the original on March 27, 2009. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved December 31, 2010. @1@ 2Template: Webachiv / IABot /
  3. Schultz et al., Sporthochseeschifferschein, Delius Klasing, ISBN 978-3-7688-1820-9
  4. ^ Henry Stommel: The westward intensification of wind-driven ocean currents . In: Transactions of the American Geophysical Union , Vol. 29 (1948), pp. 202-206
  5. Bryden, HL, Longworth, HR & Cunningham, SA (2005): Slowing of the Atlantic meridional overturning circulation at 25 degrees north . Nature, Vol. 438, Issue. 7068, pp. 655-657.
  6. Schiermeier, Quirin (2007): Ocean circulation noisy, not stalling . Nature, Vol. 448, Issue. 7156, pp. 844-845.
  7. R. Seager et al. (2002): Is the Gulf Stream responsible for Europe's mild winters? . Quarterly Journal of the Royal Meteorological Society Vol. 128 October 2002 Part B No. 586, pp. 2563–2586 (PDF)
  8. ^ L. Caesar, S. Rahmstorf, A. Robinson, G. Feulner, V. Saba: Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature, Volume 556, 2018, pp. 191-196, doi : 10.1038 / s41586-018-0006-5 .
  9. Thornalley et al. a., Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years, Nature, Volume 556, 2018, pp. 227-230
  10. Sven Titz: A system of ocean currents shows signs of fatigue In: Neue Zürcher Zeitung of April 13, 2018
  11. RAPID: monitoring the Atlantic Meridional Overturning Circulation at 26.5 ° N since 2004
  12. Rahmstorf, Stronger Evidence for a Weaker Gulf Stream System, Scilogs, April 11, 2018