Palaeoclimate data shows that the ocean's currents (like the Gulf Stream and its North Atlantic deep water partner) are capable of shifting gears very suddenly, but until now it wasn't clear how this occurred. Using a combination of modern observations, numerical models and palaeoclimate data scientists are increasingly realising that salt is the key.
Their results reveal that a build up of salty water can stimulate deep water circulation, while a diluting of the waters is linked to sluggish flow. "Salt plays a far more important role that we first thought," says Professor Rainer Zahn, a palaeoclimatologist at the Autonomous University of Barcelona in Spain.
Salt increases the density of water. Once a pocket of water becomes salty enough it sinks, drawing in additional water from surrounding areas, and initiates an ocean circulation loop called thermohaline overturning.
The scientists discovered that a build up of salt in the waters off the coast of South Africa could help to speed up ocean circulation in the North Atlantic, despite the two areas being thousands of kilometres apart. "A salt surge is enough to kick start circulation," says Zahn. Meanwhile, a decrease in saltiness in South African waters could be linked to a slowing down of the North Atlantic circulation.
Models and data both indicate that these changes in ocean circulation occur over very short time-scales, usually in less than a decade or two. Ocean water can't possibly travel this fast (it takes nearly a century for a parcel of water to move from the South Atlantic to the North Atlantic). Instead the scientists think that energy is transferred through the ocean along a deep pressure wave. "The surge of salt generates a pressure gradient in the ocean that sends energy to the north without water actually being transported," explains Zahn.
Regardless of whether ocean circulation speeds up or slows down it causes significant climate change, altering the hydrological cycle and affecting atmospheric circulation patterns too.
Currently there is no large-scale salt monitoring system in place in the southern hemisphere oceans. Zahn thinks that regular measurements taken in the waters around South Africa and New Zealand could be useful. "It could act as an early warning system for climate changes 10-20 years down the road," he says.
The work was presented at the Ocean Controls in Abrupt Climate Change conference, held at the University of Innsbruck Conference Centre in Obergurgl, Ötz Valley, Austria on 19-24 May 2007. The conference, which was attended by an international consortium of over 70 marine scientists and climate experts, was one of the series of research conferences organised by the ESF Research Conferences Scheme.
Thomas Lau | alfa
Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle
22.06.2018 | Technical University of Denmark
Polar ice may be softer than we thought
22.06.2018 | Eberhard Karls Universität Tübingen
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences