Atlantic Ocean water can take up to 2,800 years to travel around the planet, a study has found, taking in a ‘grand tour’ of the world’s oceans before returning home.
Almost half of it spends 1,000 years in the Pacific on a three-millennium trip that also includes a visit to the Indian and Southern oceans.
Researchers found that one third of Atlantic Ocean water takes about 300 years to return home, while around 20 per cent spends 700 years travelling to greater depths and making a detour into the Weddell Sea, off Antarctica.
Long journey: Atlantic Ocean water can take up to 2,800 years to travel around the planet, a study has found, taking in a ‘grand tour’ of the world’s oceans before returning home. The route it takes is shown above in a still image from an animated video
Around the world: Almost half of Atlantic Ocean water spends 1,000 years in the Pacific on a three-millennium trip that also includes a visit to the Indian and Southern oceans
HOW LONG DOES ATLANTIC WATER TAKE TO TRAVEL THE WORLD?
Researchers found that one third of Atlantic Ocean water takes about 300 years to return home, taking in the Pacific, Indian and Southern oceans on its journey.
Around 20 per cent spends 700 years circling the planet because it reaches greater depths and makes a detour into the Weddell Sea, off Antarctica.
But almost half of the water in the Atlantic Ocean can take 2,800 years to return, spending 1,000 years alone in the Pacific, oceanographers at the University of California San Diego said.
Both take in most of the world’s ocean basins on their journey, according to data collected over 25 years.
It has been analysed by oceanographers at the University of California San Diego, who wanted to estimate the length of time water takes to travel around the world’s ocean basins.
They said the research is the first to follow trajectories of water supported by such a large amount of real-world data while using a computer simulation known as Estimating the Circulation and Climate of the Ocean (ECCO).
The ocean model incorporates more than one billion data from sources that include satellites and robotic free-drifting floats.
It then merges this data into a global simulation of the oceans in a similar way to weather forecasts.
‘Thinking of the pathways water parcels take around the basins is a good way for us to conceptualise complex ocean circulation,’ said Mete Uz, from the National Science Foundation’s division of ocean sciences.
‘Doing this directly with drifting instruments would be prohibitively expensive, but computer models, which seek a solution consistent with all our measurements, provide an efficient way to do this kind of analysis.’
Last week cartographers at the National Geographic finally recognised Antarctica’s Southern Ocean on their maps, bringing their count of Earth’s oceans to five.
Each water parcel, classified as upper route, subpolar cell and abyssal cell, takes different lengths of time to travel the world. The upper route (about one third of the Atlantic) takes 300 years, the subpolar cell (around 20 per cent) 700 years and abyssal (nearly half) 2,800 years
These graphs show the average length of time each water parcel takes to travel the world
The society — which has been releasing maps of the world since 1915 — publicly announced its new policy to coincide with World Ocean Day.
National Geographic has defined the ocean as being bound by the current that flows around Antarctica — with a northernmost reach up to the 60th parallel south.
Meanwhile, earlier this year scientists returned precise measurements for the deepest points in each of the world’s five major oceans following one of the most adventurous ocean expeditions ever.
Data from the Five Deeps Expedition (FDE), which performed dives over the course of 10 months from 2018 to 2019, confirmed for the first time the locations of the deepest points of Indian Ocean and the Southern Ocean.
Flows: This image shows the water parcels travelling from the Atlantic to the Pacific, Indian and Southern oceans on their various trajectories
The routes were calculated and simulated using a computer model to show the various flows
The deepest point of the Indian Ocean is at 7,187 metres, within the Java Trench, just off the coast of Indonesia, the data reveals, while the deepest point of the Southern Ocean has a depth of 7,432 metres, within the South Sandwich Trench.
Prior to FDE, the deepest parts of some oceans were relatively well known, such as lowest point on Earth – the Challenger Deep, inside the Mariana Trench in the Pacific Ocean.
At a whopping 10,924 metre (6.8-miles), the Challenger Deep still holds the record for the deepest point on Earth, the expeditions confirmed.
While the deepest point in the Atlantic Ocean is called Brownson Deep in the Puerto Rico Trench, which descends an impressive 8.378 metres.
The study into the journey of the world’s ocean water is published in Science Advances.
ATLANTIC OCEAN CIRCULATION PLAYS A KEY ROLE IN REGULATING THE GLOBAL CLIMATE
When it comes to regulating global climate, the circulation of the Atlantic Ocean plays a key role.
This is due to a constantly moving system of deep-water circulation often referred to as the Global Ocean Conveyor Belt which sends warm, salty Gulf Stream water to the North Atlantic where it releases heat to the atmosphere and warms Western Europe.
The cooler water then sinks to great depths and travels all the way to Antarctica and eventually circulates back up to the Gulf Stream.
When it comes to regulating global climate, the circulation of the Atlantic Ocean plays a key role
This motion is fuelled by thermohaline currents – a combination of temperature and salt.
It takes thousands of years for water to complete a continuous journey around the world.
Researchers believe that as the North Atlantic began to warm near the end of the Little Ice Age, freshwater disrupted the system, called the Atlantic Meridional Overturning Circulation (AMOC).
Arctic sea ice, and ice sheets and glaciers surrounding the Arctic began to melt, forming a huge natural tap of fresh water that gushed into the North Atlantic.
This huge influx of freshwater diluted the surface seawater, making it lighter and less able to sink deep, slowing down the AMOC system.
Researchers found the AMOC has been weakening more rapidly since 1950 in response to recent global warming.