Devastating Earthquake May Threaten Middle East's Near Future, Geologist Predicts

Source:

http://www.sciencedaily.com/releases/2007/10/071003142432.htm

Science Daily — The best seismologists in the world don’t know when the next big earthquake will hit. But a Tel Aviv University geologist suggests that earthquake patterns recorded in historical documents of Middle Eastern countries indicate that the region’s next significant quake is long overdue.

A major quake of magnitude seven on the Richter scale in the politically-fragile region of the Middle East could have dire consequences for precious holy sites and even world peace, says Tel Aviv University geologist Dr. Shmulik Marco. In light of this imminent danger, Marco, from the school’s Department of Geophysics and Planetary Sciences, has taken an historical approach to earthquake forecasting by using ancient records from the Vatican and other religious sources in his assessment. The past holds the key to the future, he says.
“All of us in the region should be worried,” explains Marco, who dedicates his career to piecing together ancient clues.
Based on the translations of hundreds of documents -- some of the originals of which he assumes reside in Vatican vaults -- Marco has helped determine that a series of devastating earthquakes have hit the Holy Land over the last two thousand years. The major ones were recorded along the Jordan Valley in the years 31 B.C.E., 363 C.E., 749 C.E., and 1033 C.E. “So roughly,” warns Marco, “we are talking about an interval of every 400 years. If we follow the patterns of nature, a major quake should be expected any time because almost a whole millennium has passed since the last strong earthquake of 1033.”
Written by monks and clergy, the documents, which span about two millenia, can help determine the location and impact of future quakes on several fault planes cutting through Israel and its neighboring countries, Marco believes. “We use the records, written in churches and monasteries or by hermits in the desert, to find patterns,” he says. Marco credits the help of an international team of historians, who have deciphered the Latin, Greek, and Arabic of the original correspondence.
He continues, “Even if these papers were not ‘officially’ recording history, they hold a lot of information. ... Some are letters to Europe asking for funding of church repairs. And while many of these accounts are told in an archaic religious manner, they help us confirm the dates and location of major calamities. Following these patterns in the past can be a good predictor of the future.”
One of the most cited Christian chroniclers in history upon whom Marco bases some of his conclusions is a ninth-century Byzantine aristocratic monk named Theophanes, venerated today by Catholics. In one manuscript, Theophanes wrote, “A great earthquake in Palestine, by the Jordan and in all of Syria on 18 January in the 4th hour. Numberless multitudes perished, churches and monasteries collapsed especially in the desert of the Holy City.”
While Christian sources helped Marco confirm ancient catastrophes and cast light on future ones, Jewish sources from the Bible also gave him small pieces of the puzzle. A verse in Zachariah (Ch. 14) describes two instances of earthquakes, one of which split apart the Mount of Olives, he says. Muslim clergy have also collected ancient correspondence, which further broadens the picture.
”Earthquakes are a manifestation of deeper processes inside the earth,” Marco says. “My questions and analysis examine how often they occur and whether there is pattern to them, temporally or spatially. I am looking for patterns and I can say that based on ancient records, the pattern in Israel around the Dead Sea region is the most disturbing to us.
“When it strikes and it will this quake will affect Amman, Jordan as well as Ramallah, Bethlehem, and Jerusalem. Earthquakes don’t care about religion or political boundaries,” Marco concludes.
Note: This story has been adapted from material provided by Tel Aviv University.

Fausto Intilla

www.oloscience.com

Carbon Dioxide Did Not End The Last Ice Age, Study Says

Source:

http://www.sciencedaily.com/releases/2007/09/070927154905.htm

Science Daily — Carbon dioxide did not cause the end of the last ice age, a new study in Science suggests, contrary to past inferences from ice core records.

"There has been this continual reference to the correspondence between CO2 and climate change as reflected in ice core records as justification for the role of CO2 in climate change," said USC geologist Lowell Stott, lead author of the study, slated for advance online publication Sept. 27 in Science Express.
"You can no longer argue that CO2 alone caused the end of the ice ages."
Deep-sea temperatures warmed about 1,300 years before the tropical surface ocean and well before the rise in atmospheric CO2, the study found. The finding suggests the rise in greenhouse gas was likely a result of warming and may have accelerated the meltdown -- but was not its main cause.
The study does not question the fact that CO2 plays a key role in climate.
"I don't want anyone to leave thinking that this is evidence that CO2 doesn't affect climate," Stott cautioned. "It does, but the important point is that CO2 is not the beginning and end of climate change."
While an increase in atmospheric CO2 and the end of the ice ages occurred at roughly the same time, scientists have debated whether CO2 caused the warming or was released later by an already warming sea.
The best estimate from other studies of when CO2 began to rise is no earlier than 18,000 years ago. Yet this study shows that the deep sea, which reflects oceanic temperature trends, started warming about 19,000 years ago.
"What this means is that a lot of energy went into the ocean long before the rise in atmospheric CO2," Stott said.
But where did this energy come from" Evidence pointed southward.
Water's salinity and temperature are properties that can be used to trace its origin -- and the warming deep water appeared to come from the Antarctic Ocean, the scientists wrote.
This water then was transported northward over 1,000 years via well-known deep-sea currents, a conclusion supported by carbon-dating evidence.
In addition, the researchers noted that deep-sea temperature increases coincided with the retreat of Antarctic sea ice, both occurring 19,000 years ago, before the northern hemisphere's ice retreat began.
Finally, Stott and colleagues found a correlation between melting Antarctic sea ice and increased springtime solar radiation over Antarctica, suggesting this might be the energy source.
As the sun pumped in heat, the warming accelerated because of sea-ice albedo feedbacks, in which retreating ice exposes ocean water that reflects less light and absorbs more heat, much like a dark T-shirt on a hot day.
In addition, the authors' model showed how changed ocean conditions may have been responsible for the release of CO2 from the ocean into the atmosphere, also accelerating the warming.
The link between the sun and ice age cycles is not new. The theory of Milankovitch cycles states that periodic changes in Earth's orbit cause increased summertime sun radiation in the northern hemisphere, which controls ice size.
However, this study suggests that the pace-keeper of ice sheet growth and retreat lies in the southern hemisphere's spring rather than the northern hemisphere's summer.
The conclusions also underscore the importance of regional climate dynamics, Stott said. "Here is an example of how a regional climate response translated into a global climate change," he explained.
Stott and colleagues arrived at their results by studying a unique sediment core from the western Pacific composed of fossilized surface-dwelling (planktonic) and bottom-dwelling (benthic) organisms.
These organisms -- foraminifera -- incorporate different isotopes of oxygen from ocean water into their calcite shells, depending on the temperature. By measuring the change in these isotopes in shells of different ages, it is possible to reconstruct how the deep and surface ocean temperatures changed through time.
If CO2 caused the warming, one would expect surface temperatures to increase before deep-sea temperatures, since the heat slowly would spread from top to bottom. Instead, carbon-dating showed that the water used by the bottom-dwelling organisms began warming about 1,300 years before the water used by surface-dwelling ones, suggesting that the warming spread bottom-up instead.
"The climate dynamic is much more complex than simply saying that CO2 rises and the temperature warms," Stott said. The complexities "have to be understood in order to appreciate how the climate system has changed in the past and how it will change in the future."
Stott's collaborators were Axel Timmermann of the University of Hawaii and Robert Thunell of the University of South Carolina. Stott was supported by the National Science Foundation and Timmerman by the International Pacific Research Center.
Stott is an expert in paleoclimatology and was a reviewer for the Intergovernmental Panel on Climate Change. He also recently co-authored a paper in Geophysical Research Letters tracing a 900-year history of monsoon variability in India.
The study, which analyzed isotopes in cave stalagmites, found correlations between recorded famines and monsoon failures, and found that some past monsoon failures appear to have lasted much longer than those that occurred during recorded history. The ongoing research is aimed at shedding light on the monsoon's poorly understood but vital role in Earth's climate.
Note: This story has been adapted from material provided by University of Southern California.

Fausto Intilla

www.oloscience.com

Satellite Paints Picture Of World's Oceans Over Last Decade

Source:

http://www.sciencedaily.com/releases/2007/09/070919154814.htm

Science Daily — The NASA-managed Sea-viewing Wide Field-of-view Sensor (SeaWiFS) instrument settled into orbit around Earth in 1997 and took its first measurements of ocean color. A decade later, the satellite's data has proved instrumental in countless applications and helped researchers paint a picture of a changing climate. NASA recognized the satellite's tenth anniversary September 19 with briefings at the Goddard Space Flight Center in Greenbelt, Md.

NASA and GeoEye's SeaWiFS instrument has given researchers the first global look at ocean biological productivity. Its data have applications for understanding and monitoring the impacts of climate change, setting pollution standards, and sustaining coastal economies that depend on tourism and fisheries.
"SeaWiFS allows us to observe ocean changes and the mechanisms linking ocean physics and biology, and that's important for our ability to predict the future health of the oceans in a changing climate," said Gene Carl Feldman, SeaWiFS project manager at Goddard.
Researchers used SeaWiFS data to identify factors controlling the unusual timing of the 2005 phytoplankton bloom in the California Current System that led to the die-off of Oregon coast seabirds. The blooming tiny microscopic plants are key indicators of ocean health, form the base of marine food webs, and absorb carbon dioxide -- a major greenhouse gas -- from Earth's atmosphere.
"Long-term observations of the California coast and other sensitive regions is essential to understanding how changing global climate impacted ecosystems in the past, and how it may do so in the future," said Stephanie Henson of the University of Maine, lead author of a study published last month in the American Geophysical Union's "Journal of Geophysical Research -- Oceans." "This type of large-scale, long-term monitoring can only be achieved using satellite instrumentation," she added.
The SeaWiFS instrument orbits Earth fourteen times a day, measuring visible light over every area of cloud-free land and ocean once every 48 hours. The result is a map of Earth with colors spanning the spectrum of visible light. Variations in the color of the ocean, particularly in shades of blue and green, allow researchers to determine how the numbers of the single-celled plants called phytoplankton are distributed in the oceans over space and time.
In other research, Mike Behrenfeld of Oregon State University, Corvallis, Ore., and colleagues were the first to use SeaWiFS to quantify biological changes in the oceans as a response to El Niño, which they described in a landmark 2001 study in Science.
"The 2001 study is significant because it marked the first time that global productivity was measured from a single sensor," said Paula Bontempi, program manager for the Biology and Biogeochemistry Research Program at NASA Headquarters in Washington. "The simplicity of SeaWiFS -- a single sensor designed only to measure ocean color -- has made it the gold standard for all ocean color monitoring instruments."
More recently, Zhiqiang Chen and colleagues at the University of South Florida, St. Petersburg, showed that SeaWiFS data have direct application for state and federal regulators looking to better define water quality standards. The team reported in "Remote Sensing of Environment" that instead of relying on the infrequent measurements collected from ships or buoys, SeaWiFS data can be used to monitor coastal water quality almost daily, providing managers with a more frequent and complete picture of changes over time.
SeaWiFS has revolutionized our understanding of the ocean's response to environmental change. Here's one example: over the last ten years, the instrument has gathered daily global bio-productivity readings. When coupled with daily sea surface temperature readings over the same time span, we immediately see a relationship between temperature and productivity.
Beyond the realm of ocean observations, however, SeaWiFS has "revolutionized the way people do research," Feldman said. SeaWiFS was one of the first missions to open up data access online to researchers, students and educators around the world. The mission was able to capitalize on advances in data processing and storage technologies and ride the crest of the World Wide Web's growth from its beginning.
When the SeaWiFS program launched in 1997, the goal was to place a sensor in space capable of routinely monitoring ocean color to better understand the interplay between the ocean and atmosphere and most importantly, the ocean's role in the global carbon cycle. A decade later, Feldman said, "SeaWiFS has exceeded everyone's expectations."
Note: This story has been adapted from a news release issued by NASA/Goddard Space Flight Center.

Fausto Intilla

www.oloscience.com

Deep Earth Model Challenged By New Experiment

Source:

http://www.sciencedaily.com/releases/2007/09/070920145537.htm

Science Daily — In the first experiments able to mimic the crushing, searing conditions found in Earth's lower mantle, and simultaneously probe tell-tale properties of iron, scientists* have discovered that material there behaves very differently than predicted by models. The research also points to the likelihood of a new zone deep in the Earth.

Surface phenomena such as volcanoes and earthquakes are generated by what goes on in Earth's interior. To understand some of these surface dynamics, scientists have to probe deep into the planet. The lower mantle is between 400 and 1,740 miles deep (650 km- 2,800 km) and sits atop the outer core.
Coauthor of the paper, Viktor Struzhkin of the Carnegie Institution's Geophysical Laboratory explains: "The deeper you go, the higher the pressures and temperatures become. Under these extreme conditions, the atoms and electrons of the rocks become squeezed so close together that they interact very peculiarly. In fact, spinning electrons in iron, which is prevalent throughout the inner Earth, are forced to pair up. When this spin state changes from unpaired electrons--called a high-spin state--to paired electrons--a low-spin state--the density, sound velocities, conductivity, and other properties of the materials can change. Understanding these conditions helps scientists piece together the complex puzzle of the interior/surface interactions."
The pressures in the lower mantle are brutal, ranging from about 230,000 times the atmospheric pressure at sea level (23 GPa), to almost 1.35 million times sea-level pressure (135 GPa). The heat is equally extreme--from about 2,800 to 6,700 degrees Fahrenheit (1800 K--4000 K).
Using a laser-heated diamond anvil cell to heat and compress the samples, the scientists subjected ferropericlase to almost 940,000 atmospheres and 3,140 °F. They analyzed it using so-called X-ray emission spectroscopy. As its name suggests, ferropericlase is iron-laden.
It is also the second most prevalent material found in the lower mantle. Previous to this study, ferropericlase has been subjected to high pressures, but only to room temperatures. The new experiments are the highest pressures and temperatures attained to probe the spin state of iron in the mineral at lower-mantle conditions.
Under the less-intense conditions of the former experiments, the high-spin to low-spin transition occurs in a narrow pressure range. In the new study, however, both spin states coexisted in the same crystal structure and the spin transition was also continuous over a large pressure range, indicating that the mineral is in a complex state over a large range in depth in the planet.
"We were expecting to find a transition zone, but did not know how extended it may be in the Earth's mantle," commented Struzhkin. "Our findings suggest that there is a region or 'spin-transition zone' from about 620 miles to 1,365 miles deep, where high spin, unpaired electrons, transition to low spin, paired electrons. The transitioning appears to be continuous over these depths. At pressures representing a lower depth of about 1,365 miles the transition stops and ferropericlase is dominated by low-spin electrons."
Since measurements that scientists use to determine the composition and density of the inner Earth, such as sound velocities, are influenced by the ratio of high-spin/low- spin states, the new finding calls into question the traditional techniques for modeling this region of the planet.
In addition, a continuous spin transition zone may explain some interesting experimental findings including why there has been no significant iron partitioning, or separating, into ferropericlase or perovskite, the most prevalent mineral in the region. The research also suggests that the depth of the transition zone is less than scientists had speculated.
The existence of this transition zone may also account for seismic-wave behavior at those depths. The fact that the lowermost area is dominated by denser low-spin material could also affect the temperature stability of mantle upwellings--the generators of volcanic hotspots, such as those in Hawaii.
"This paper solves only part of the puzzle," cautioned Struzhkin. "Since the major lower mantle mineral perovskite has not been measured yet with this technique, we know there are more surprises to come."
"The spin transition zone of iron needs to be considered in future models of the lower mantle," said Choong-Shik Yoo, a former staff member at LLNL and now a professor at Washington State University. "In the past, geophysicists had neglected the effects of the spin transition when studying the Earth's interior.
Since we identified this zone, the next step is to study the properties of lower mantle oxides and silicates across the zone. This research also calls for future seismic and geodynamic tests in order to understand the properties of the spin transition zone."
"The benchmark techniques developed here have profound implications for understanding the electronic transitions in lanthanoid and actinoid compounds under extreme conditions because their properties would be affected by the electronic transitions," said Valentin Iota, a staff member in LLNL's Physics and Advanced Technologies Directorate.
The work is published in the September 21, 2007, issue of Science.
*Authors on this paper are Jung-Fu Lin, Lawrence Livermore National Laboratory (LLNL); György Vankó, KFKI Research Institute for Particle and Nuclear Physics and the European Synchrotron Radiation Facility; Steven Jacobsen, Northwestern University; Viktor Struzhkin, Carnegie Institution's Geophysical Laboratory; Vitali Prakapenka, University of Chicago; Alexie Kuznetsov, University of Chicago; and Choong-Shik Yoo LLNL.
Note: This story has been adapted from a news release issued by Carnegie Institution.

Fausto Intilla

www.oloscience.com

Does Underground Water Regulate Earthquakes?

Source:

http://www.sciencedaily.com/releases/2007/09/070915105639.htm

Science Daily — Earthquakes happen to be surface (shallow-focus), intermediate and deep ones. Seismologists mark out the boundary between the first two types at the depth of about 70 kilometers, its nature being still unclear.
Russian researchers, specialists of the Institute of Maritime Geology and Geophysics (Far-Eastern Branch, Russian Academy of Sciences), Geophysical Center of the Russian Academy of Sciences and the P.P. Shirshov Institute of Oceanology (Russian Academy of Sciences) have put forward a hypothesis that the seismic boundary is simultaneously the lower boundary of hydrosphere. The earthquakes character depends on underground water.
Earthquakes taking place “at different sides of the boundary” differ from each other not only by the depth. Shallow-focus earthquakes – they account for about 85% of all recorded events - often take place under the influence of periodic external effects, for example, rising tides, which disturb the entire lithosphere of the Earth. Periodicity is not inherent to deeper earthquakes, they always occur by chance. The conclusion was made by the researchers who had analyzed the world ISC/NEIC catalogues data that covers the 1964-2005 period and takes into account about 80,000 events.
Seismologists connect existence of the 70-kilometer boundary with water state changes in the interior of the Earth. The deeper the water molecules are located, the more compressed they are. At the depth of about 70 kilometers, the water compression strain index increases up to 1.3. This is the way water molecules are squeezed in the crystal lattice. Above this boundary, water exists mainly in free phase, below the boundary – water embeds into the rock crystallite composition.
The rock containing free water (above the boundary) promptly reacts to periodic tidal effects, even the faintest ones. Pressure changes and respective environment density changes cause formation of a crack system, where free water rushes to. The cracks widen, increase, and rock decay gives birth to a seismic focus. In the rock, where free water is absent (below the boundary), weak tidal effects are not accumulated and deformation does not grow.
So, the seismic boundary at the depth of about 70 kilometers (where, according to the researchers’ assumption, the lower hydrosphere boundary runs) separates the events that are able to react to external action and the ones incapable of such reaction. Therefore, this boundary separates different types of earthquakes. However, it is still a hypothesis that requires experimental validation.
Note: This story has been adapted from a news release issued by Russian Academy Of Sciences.

Fausto Intilla
www.oloscience.com

Northwest Passage Opens: Arctic Sea Ice Reaches New Low

Source:

http://www.sciencedaily.com/releases/2007/09/070914095358.htm

Science Daily — The area covered by sea ice in the Arctic has now (September 14, 2007) shrunk to its lowest level since satellite measurements began nearly 30 years ago, opening up the Northwest Passage – a long-sought short cut between Europe and Asia that has been historically impassable.

Leif Toudal Pedersen from the Danish National Space Centre said: "We have seen the ice-covered area drop to just around 3 million sq km which is about 1 million sq km less than the previous minima of 2005 and 2006. There has been a reduction of the ice cover over the last 10 years of about 100 000 sq km per year on average, so a drop of 1 million sq km in just one year is extreme.
"The strong reduction in just one year certainly raises flags that the ice (in summer) may disappear much sooner than expected and that we urgently need to understand better the processes involved."
Arctic sea ice naturally extends its surface coverage each northern winter and recedes each northern summer, but the rate of overall loss since 1978 when satellite records began has accelerated.
The most direct route of the Northwest Passage across northern Canada is now fully navigable, while the Northeast Passage along the Siberian coast remains only partially blocked. To date, the Northwest Passage has been predicted to remain closed even during reduced ice cover by multi-year ice pack – sea ice that survives one or more summers. However, according to Pedersen, this year’s extreme event has shown the passage may well open sooner than expected.
The previous record low was in 2005 when the Arctic area covered by sea ice was just 4 million sq km. Even then, the most direct Northwest Passage did not fully open.
The Polar Regions are very sensitive indicators of climate change. The UN’s Intergovernmental Panel on Climate Change showed these regions are highly vulnerable to rising temperatures and predicted the Arctic would be virtually ice free by the summer of 2070. Still other scientists predict it could become ice free as early as 2040 due to rising temperatures and sea ice decline.
Because sea ice has a bright surface, the majority of solar energy that hits it is reflected back into space. When sea ice melts, the dark-coloured ocean surface is exposed. Solar energy is then absorbed rather than reflected, so the oceans get warmer and temperatures rise, making it difficult for new ice to form.
The Arctic is one of Earth’s most inaccessible areas, so obtaining measurements of sea ice was difficult before the advent of satellites. For more than 20 years, ESA has been providing satellite data to the cryosphere communities. Currently, ESA is contributing to the International Polar Year (IPY) – a large worldwide science programme focused on the Arctic and Antarctic.
Since 2006, ESA has supported Polar View, a satellite remote-sensing programme funded through the Earthwatch GMES Service Element (GSE) that focuses on the Arctic and the Antarctic.
In 2009, ESA will make another significant contribution to cryosphere research with the launch of CryoSat-2. The observations made over the three-year lifetime of the mission will provide conclusive evidence on the rates at which ice cover is diminishing.
Note: This story has been adapted from a news release issued by European Space Agency.

Fausto Intilla

www.oloscience.com

Sea Ice Is Getting Thinner

Source:

http://www.sciencedaily.com/releases/2007/09/070913133001.htm

Science Daily — Large areas of the Arctic sea-ice are only one metre thick this year, equating to an approximate 50 percent thinning as compared to the year 2001. These are the initial results from the latest Alfred-Wegener-Institute for Polar and Marine Research in the Helmholtz Association lead expedition to the North Polar Sea.

Fifty scientists have been on board the Research ship- Polarstern for two and a half months, their main aim; to carry out research on the sea-ice areas in the central Arctic. Amongst other things, they have found out that not only the ocean currents are changing, but community structures in the Arctic are also altering. Autonomous measuring-buoys have been placed out, and they will contribute valuable data, also after the expedition is finished, to the study of the environmental changes occurring in this region.
“The ice cover in the North Polar Sea is dwindling, the ocean and the atmosphere are becoming steadily warmer, the ocean currents are changing” said chief scientist Dr Ursula Schauer, from the Alfred Wegener Institute for Polar and Marine Research part of the Helmholtz community, when commenting on the latest results from the current expedition. She is currently in the Arctic, underway with 50 Scientists from Germany, Russia, Finland, the Netherlands, Spain, the USA, Switzerland, Japan, France and China, where they are investigating ocean and sea-ice conditions.
“We are in the midst of phase of dramatic change in the Arctic, and the International Polar Year 2007/08 offers us a unique opportunity to study this dwindling ocean in collaboration with international researchers” said Schauer. Oceanographers on board the research ship Polarstern are investigating the composition and circulation of the water masses, physical characteristics of sea-ice and transport of biological and geochemical components in ice and seawater. Sea-ice ecosystems in the seawater and on the ocean floor will also be a focus of investigations. Scientists will take sediments from the ocean floor in order to reconstruct the climatic history of the surrounding continents.
Oceanographic measuring buoys were set out in all regions of the Arctic ocean for the first time during this International Polar Year. They are able to drift freely in the Arctic Ocean whilst collecting data on currents, temperature, and salt content of the seawater. The buoys will continuously collect data over and send them back to the scientists via satellite.
In addition, the deployment of a new titanium measuring system which allows contamination free sample collection of trace elements for the first time due to its high effectiveness. These studies will take place within the context of different research projects, all taking place during the International Polar Year: SPACE (Synoptic Pan-Arctic Climate and Environment Study), iAOOS (Integrated Arctic Ocean Observing System) and GEOTRACES (Trace Elements in the Arctic). At the same time, a large component of the work is supported by the European Union Program DAMOCLES (Developing Arctic Modelling and Observing Capabilities for Long-term Environment Studies).
Changes in sea-ice
The thickness of the arctic sea-ice has decreased since 1979, and at the moment measures about a metre in diameter in the central Arctic Basin. In addition, oceanographers have found a particularly high concentration of melt-water in the ocean and a large number of melt-ponds. These data, collected from on board the Polarstern, and also from helicopter flights allow the scientists to better interpret their satellite images.
Sea-Ice biologists from the Institute of Polar Ecology at the University of Kiel are studying the animals and plants living in and beneath the ice. They are using the opportunity to investigate the threatened ecosystem. According to the newest models, the Arctic could be ice free in less than 50 years in case of further warming. This may cause the extinction of many organisms that are adapted to this habitat.
Ocean currents
The Arctic Ocean currents are an important part of global ocean circulation. Warm water masses flowing in from the Atlantic are changed in the Arctic through water cooling and ice formation, and sink to great depths. Constant monitoring by the Alfred-Wegener-Institute for Polar and Marine Research over the last ten years have recorded significant changes, and have demonstrated a warming of the incoming current from the Atlantic Ocean. During this expedition, the propagation of these warming events along each of the currents in the North Polar Sea will be investigated.
The large rivers of Siberia and North America transport huge amounts of freshwater to the Arctic. The freshwater appears to function as an insulating layer, controling the warmth transfer between the ocean, the ice and the atmosphere.
The study area stretches from the shelf areas of the Barents Sea, the Kara Sea and the Laptev Sea, across Nansen and Amundsen bays right up to Makarow Bay.
Between Norway and Siberia and up to the Canadian Bay the scientists have taken temperature, salinity, and current measurements at more than 100 places. First results have shown that the temperatures of the influx of water from the Atlantic are lower as compared to previous years. The temperatures and salinity levels in the Arctic deep sea are also slowly changing.
The changes are small here, but the areas go down to great depths, and enormous water volumes are therefore involved. In order to follow the circulation patterns in winter, oceanographic measuring buoys will be attached to ice floes, and continuous measurements will be taken whilst they float along with the ice. The measurements will be relayed back via satellite.
In addition to the ocean currents and sea-ice, zooplankton, sediment samples from the sea floor as well as trace elements will be taken. Zooplankton are at the base of the food chain for many marine creatures, and are therefore an important indicator for the health of the ecosystem. The deposits found on the ocean floor of the North Polar Sea read like a diary of the history of climate change for the surrounding continents. Through sediment cores, the scientists may be able to unlock the key to the glaciation of northern Siberia.
In addition, the members of the expedition will be able to measure trace elements from Siberian rivers and shelf areas, that through polar drift are being pushed towards the Atlantic.
Further information on this project can be found on the German contribution to the International Polar Year website (http://www.polarjahr.de/).
Note: This story has been adapted from a news release issued by Alfred Wegener Institute for Polar and Marine Research.

Fausto Intilla

www.oloscience.com