(Press-News.org) Scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have found between Greenland and Spitsbergen the scours left behind on the sea bed by gigantic icebergs. The five lineaments, at a depth of 1,200 metres, are the lowest-lying iceberg scours yet to be found on the Arctic sea floor. This finding provides new understanding of the dynamics of the Ice Age and the extent of the Arctic ice sheet thousands of years ago. In addition, the researchers could draw conclusions about the export of fresh water from the Arctic into the North Atlantic. The AWI scientists have published their findings in the online portal of the scientific journal Geophysical Research Letters.
"Whenever icebergs run aground, they leave scours on the seabed. Depending on their depth and location, those markings may continue to exist over long periods of time," explained Jan Erik Arndt, AWI bathymetrician and lead author for this paper.
It is traces exactly like this that he, together with three colleagues at AWI, discovered on the Hovgaard Ridge. The Hovgaard Ridge is a plateau in the deep Arctic Sea, located a good 400 kilometres off of Greenland's eastern coast. Found at a depth of 1,200 metres the five lineaments are the deepest iceberg scours found to date in the Arctic. The scours are as much as four kilometres long and 15 metres in depth. "Such scours are a window into the past. Thanks to these iceberg scours we now know that a few very large, but also many smaller icebergs, passed across the Hovgaard Ridge," the scientist said.
The discovery of the scours on Hovgaard Ridge was fortuitous and by no means the result of a defined search. Jan Erik Arndt and his colleagues discovered the lineaments when examining bathymetric data from the year 1990. The data were collected by the research ship Polarstern while preparing cartography for the Fram Strait. "When we examined the data once again and in greater detail, we became aware of the scours. Given their depth, it quickly became clear that we had found something very interesting," says Jan Erik Arndt.
The scientists today work with better hardware and software than what was available in the 1990s. This new technology allows closer scrutiny of the old data. That is why the scours have surfaced on the scientists' monitors only now, 24 years after the data were collected.
The scientists can, however, only roughly bracket the period within which the icebergs scoured the ridge crest. It is clear, however, that it must have taken place within the past 800,000 years. Since sea level during the glacial period was a good 120 metres lower than today, the icebergs reached to a depth of at least 1,080 metres below sea level. Since about a tenth of an iceberg will, as a rule, be exposed, AWI scientists estimate the height of the iceberg to be roughly 1,200 metres – about three times the height of the Empire State Building. "To calve such megascale icebergs, the edge of the ice sheet covering the Arctic Ocean must have been at least 1,200 metres thick," Jan Erik Arndt notes.
Today scientists search in vain for such megascale icebergs. "We currently find the largest icebergs in the Antarctic. The very biggest reach only 700 metres below the water's surface," noted the bathymetrician. One remaining riddle is the birthplace of the massive icebergs that scraped Hovgaard Ridge. The AWI scientists suggest that two areas off the northern coast of Russia are the most likely sites.
The researchers are interested in these scours not only because of the size of the icebergs. The traces have caused a flare up in the old discussion about how fresh water was transported from the Arctic and into the Atlantic Ocean. In the past, some scientists assumed that thick sea ice was primarily responsible for fresh water export from the Arctic. The newly discovered scours, however, support another hypothesis: Large icebergs drifted southward through the Fram Strait, carrying large volumes of frozen fresh water into the North Atlantic.
Numerous studies make the increased imports of fresh water responsible for the end of North Atlantic deep water formation at the close of the last ice age. As a consequence, the Gulf Stream ebbed, making for drastic cooling in Europe. Since the currents in the Atlantic are an important engine, driving the global system of circulation, the effects were perceived around the world. "The fact that icebergs of this order of magnitude were driven from the Arctic is clear evidence that icebergs played a more serious role in freshwater imports than what we had previously assumed," Jan Erik Arndt concludes.
INFORMATION:
Megascale icebergs run aground
Finding the deepest iceberg scours to date provides new insights into the Arctic's glacial past
2014-08-11
ELSE PRESS RELEASES FROM THIS DATE:
Western Wall weathering: Extreme erosion explained
2014-08-11
Visitors to the Western Wall in Jerusalem can see that some of its stones are extremely eroded. This is good news for people placing prayer notes in the wall's cracks and crevices, but presents a problem for engineers concerned about the structure's stability.
The Western Wall is a remnant of the ancient wall that surrounded the courtyard of the Jewish Temple in Jerusalem. It is located in Jerusalem's Old City at the foot of the Temple Mount.
To calculate the erosion in the different kinds of limestone that make up the Western Wall, researchers from the Hebrew University ...
Celebrity promotion of charities 'is largely ineffective,' says research
2014-08-11
Celebrity promotion of charities is ineffective at raising awareness, but can make the stars more popular with the public, new research says.
According to journal articles by three UK academics, "the ability of celebrity and advocacy to reach people is limited" and celebrities are "generally ineffective" at encouraging people to care about "distant suffering".
The research, by Professor Dan Brockington, of The University of Manchester, Professor Spensor Henson, University of Sussex, and Dr Martin Scott, University of East Anglia, is published at time when many celebrities ...
A new cause of osteoarthritis identified by research on a rare disease
2014-08-11
A new mechanism of joint destruction caused by a natural material that grinds away healthy cartilage and worsens osteoarthritis has been identified in human hip joints for the first time by University of Liverpool scientists.
The scientists, with Professor Alan Boyde and colleagues from Queen Mary University of London, were studying the hip of a man with the genetic condition, alkaptonuria (AKU), This is a metabolic disease in which a substance called homogentisic acid accumulates in joint cartilage, causing changes to its physical properties.
The study revealed ...
Challenges and strategies for women pursuing STEM careers
2014-08-11
As a national push continues to recruit talented girls and young women into math and science-related careers, a new study underlines the importance of mentoring and other social support systems for women pursuing those research professions. Mary Jean Amon, a doctoral student in the University of Cincinnati's psychology program, will present her findings at the annual convention of the American Psychological Association in Washington, D.C.
Amon's study uncovered three themes that emerged as women examined the effects of gender stereotypes in STEM fields: career strategies, ...
Sensitive acid sensor controls insulin production
2014-08-11
This news release is available in German. Many human metabolic functions only run smoothly if the acid level in the body remains neutral and stable. For humans, normal blood pH values lie between 7.35 and 7.45. By way of comparison, an empty stomach is extremely acidic, with a pH value of 1.5.
The body constantly monitors this narrow pH band and quickly restores the ideal pH values in the event of any deviations. This is because many proteins cease to function properly if fluids in the body become even slightly more acidic. These proteins become unstable and alter ...
Testosterone in healthy men increases their brains' response to threat
2014-08-11
Philadelphia, PA, August 11, 2014 – Testosterone, a steroid hormone, is well known to contribute to aggressive behavior in males, but the neural circuits through which testosterone exerts these effects have not been clear.
Prior studies found that the administration of a single dose of testosterone influenced brain circuit function. Surprisingly, however, these studies were conducted exclusively in women.
Researchers, led by Dr. Justin Carré, sought to rectify this gap by conducting a study of the effects of testosterone on the brain's response to threat cues in healthy ...
Emergency gallbladder surgery: do you need it, or can you afford to wait?
2014-08-11
Rochester, Minn. — Gallstone pain is one of the most common reasons patients visit emergency rooms. Figuring out who needs emergency gallbladder removal and who can go home and schedule surgery at their convenience is sometimes a tricky question, and it isn't always answered correctly. A new Mayo Clinic study found that 1 in 5 patients who went to the emergency room with gallbladder pain and were sent home to schedule surgery returned to the ER within 30 days needing emergency gallbladder removal. The surgical complication rate rises with the time lag before surgery, the ...
New global research reveals most adults need to double fruit and vegetable intake
2014-08-11
New research published in the September issue of the British Journal of Nutrition and featured in the just released Global Phytonutrient Report highlights a significant shortfall in fruit and vegetable consumption in people's diets around the world. Commissioned by the Nutrilite Health Institute of Amway, the research finds the majority of adults worldwide would have to at least double their current consumption of fruits and vegetables to meet the World Health Organization's minimum recommendation of five servings (400 grams) per day. Additionally, the vast majority of ...
LSUHSC research shows program to combat childhood obesity gets kids in daycare moving
2014-08-11
New Orleans, LA – Research led by Dr. Melinda Sothern, Professor and Director of Behavioral & Community Health at the LSU Health Sciences Center New Orleans School of Public Health, reports that a turn-key intervention program significantly increased physical activity levels among children in daycare. The treatment groups also achieved 91% of the physical activity goals in the improvement plans submitted by the directors of the daycare centers where the program was implemented. The results are published in the August 2014 issue of the journal, Childhood Obesity.
"Physical ...
Crime rates may fluctuate depending on authority in charge
2014-08-11
In 2011, the U.S. Supreme Court forced California to deal with the massive overcrowding in its prison system. The resulting reform shifted administrative and budgetary responsibility for low-level criminals from the state prison system to county jails. As a result, local California jails now face more overcrowding than ever, and local law enforcement is saddled with additional costs for imprisoning arrestees.
A new study evaluating the exact opposite reform in Israel, published in the Journal of Public Economics, offers insight into the long-term impact of the California ...
LAST 30 PRESS RELEASES:
Call for papers: 14th Asia-Pacific Conference on Transportation and the Environment (APTE 2025)
A novel disturbance rejection optimal guidance method for enhancing precision landing performance of reusable rockets
New scan method unveils lung function secrets
Searching for hidden medieval stories from the island of the Sagas
Breakthrough study reveals bumetanide treatment restores early social communication in fragile X syndrome mouse model
Neuroscience leader reveals oxytocin's crucial role beyond the 'love hormone' label
Twelve questions to ask your doctor for better brain health in the new year
Microelectronics Science Research Centers to lead charge on next-generation designs and prototypes
Study identifies genetic cause for yellow nail syndrome
New drug to prevent migraine may start working right away
Good news for people with MS: COVID-19 infection not tied to worsening symptoms
Department of Energy announces $179 million for Microelectronics Science Research Centers
Human-related activities continue to threaten global climate and productivity
Public shows greater acceptance of RSV vaccine as vaccine hesitancy appears to have plateaued
Unraveling the power and influence of language
Gene editing tool reduces Alzheimer’s plaque precursor in mice
TNF inhibitors prevent complications in kids with Crohn's disease, recommended as first-line therapies
Twisted Edison: Bright, elliptically polarized incandescent light
Structural cell protein also directly regulates gene transcription
Breaking boundaries: Researchers isolate quantum coherence in classical light systems
Brain map clarifies neuronal connectivity behind motor function
Researchers find compromised indoor air in homes following Marshall Fire
Months after Colorado's Marshall Fire, residents of surviving homes reported health symptoms, poor air quality
Identification of chemical constituents and blood-absorbed components of Shenqi Fuzheng extract based on UPLC-triple-TOF/MS technology
'Glass fences' hinder Japanese female faculty in international research, study finds
Vector winds forecast by numerical weather prediction models still in need of optimization
New research identifies key cellular mechanism driving Alzheimer’s disease
Trends in buprenorphine dispensing among adolescents and young adults in the US
Emergency department physicians vary widely in their likelihood of hospitalizing a patient, even within the same facility
Firearm and motor vehicle pediatric deaths— intersections of age, sex, race, and ethnicity
[Press-News.org] Megascale icebergs run agroundFinding the deepest iceberg scours to date provides new insights into the Arctic's glacial past