Study: Ocean tides once spread massive icebergs

Dec 08, 2004

Connection between changes in ocean circulation and future climate remains a matter of great interest

Labrador Sea ocean tides dislodged huge Arctic icebergs thousands of years ago, carrying gigantic ice-rafted debris across the ocean and contributing to the ice age's deep freeze, say an international team of university researchers.
The study, published in the November issue of Nature, is the first to suggest that ocean tides contributed to enigmatic Heinrich events, a phenomenon where colossal discharges of icebergs periodically flowed into the North Atlantic from about 60,000 to 10,000 years ago.

The events occurred during the deep throes of the ice age and the new study shows that tides added to the chill by breaking gigantic icebergs from the ice sheet covering northern Canada. “These findings provide a link between ocean tides, ice sheets and ocean circulation and a measure of the sensitivity of climate during the last ice age,” says University of Toronto physics professor Jerry Mitrovica, a co-author of the study. “This sensitivity is important to understand, because the connection between changes in ocean circulation and future climate remains a matter of great interest.”

To track ancient tides, Mitrovica, lead author Professor Brian Arbic of Princeton University and a team of researchers used a state-of-the-art computer model that captured current open-ocean tidal variances with an unprecedented 92 per cent accuracy. They then inputted ice-age simulations of sea-level changes over time. “The results showed that the tides were highest in the Labrador Sea at the same time the Heinrich events occurred,” says Mitrovica. “We can safely assume that the tides played a key role in breaking the ice and launching the icebergs into the ocean.”

Mitrovica is careful to note that ocean circulation is just one piece of the present-day climatic change puzzle. “As an example, the Antarctic ice sheet weakens due to warming and huge blocks have broken off where tides are highest. Future climatic changes involve many different factors, but it's important to note that in our ice-age past tides defined the weak spot and acted as a catalyst for large climate events.”

The study was funded by National Sciences Foundation and the Canadian Institute for Advanced Research. Other authors include Professor Douglas MacAyeal of the University of Chicago and Glenn Milne of the University of Durham, United Kingdom.

Source: University of Toronto

Explore further: NASA's Orion spacecraft back in Florida after test flight

add to favorites email to friend print save as pdf

Related Stories

Life can survive on much less water than you might think

Nov 04, 2014

"Follow the water" has long been the mantra of our scientific search for alien life in the Solar System and beyond. We continue seeking conditions where water can remain liquid either on a world's surface ...

Great Lakes welcome rising water levels

Jul 08, 2014

After years of parched shorelines, water levels in the Great Lakes have come rushing back. The crowds that flock to the Superior shoreline this summer are finding harbors deeper and beaches narrower than they've been in 15 ...

Recommended for you

Politics no problem, say US and Russian spacefarers

4 hours ago

US-Russian ties may have returned to Cold War levels, but an astronaut and a cosmonaut gearing up for the longest flight on the International Space Station said Thursday politics would not disrupt their work ...

Kepler proves it can still find planets

5 hours ago

To paraphrase Mark Twain, the report of the Kepler spacecraft's death was greatly exaggerated. Despite a malfunction that ended its primary mission in May 2013, Kepler is still alive and working. The evidence ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.