Saturday, February 11, 2012

Remembering Mike deGruy and Andrew Wight

Underwater filmmaker Mike deGruy has spent decades looking intimately at the ocean.
A consummate storyteller, he takes the stage at Mission Blue to share his awe and excitement — and his fears — about the blue heart of our planet.
(Hooked by an octopus : recorded on the Mission Blue Voyage, April 2010 on the National Geographic Endeavor, the Galápagos Islands, Ecuador)


On Friday, February 3rd, the world lost two outstanding individuals in a tragic helicopter crash in Australia.
Filmmakers Mike deGruy and Andrew Wight were working on a production together outside of Sydney for renowned filmmaker, James Cameron and National Geographic, when reportedly a malfunction caused the helicopter to crash at take-off.

"Life is not measured by the number of breaths we take,
but by the moments that take our breath away." Maya Angelou

This loss is heartbreaking for many of us in the Ocean and Filmmaking communities where Mike and Andrew had such an impact.
Both men were exceptional individuals whose influence both professionally and personally will live on through their films.

Mike deGruy and his team of fish scientists squeak to each other with hysterical helium voices as they frantically chase a new species of fish.
Sadly, Mike's fish collecting skills aren't what they once were!
"Mike, have a star, you've earned it!"

Friday, February 10, 2012

America and Eurasia 'to meet at north pole'

No boats required.
In the distant future, most if not all of today's continents (brown fragments, depicted with current-day outlines) will assemble into a single landmass called Amasia (shown approximately 100 million years from now).

From BBC

America and Eurasia will crash into each other over the North Pole in 50-200 million years time, according to scientists at Yale University.

They predict Africa and Australia will join the new "supercontinent" too, which will mark the next coming together of the Earth's land masses.
The continents are last thought to have come together 300 million years ago into a supercontinent called Pangaea.
Details are published in the journal Nature.

The land masses of the Earth are constantly moving as the Earth's tectonic activity occurs.
This generates areas such as the Mid-Atlantic Ridge, where Iceland has formed, and areas such as that off the coast of Japan, where one plate rides over another.
Geologists believe that, over billions of years, these shifting plates have driven the continents together periodically, creating the hypothesised supercontinents of Nuna 1.8 billion years ago, Rodinia a billion years ago, and then Pangaea 300 million years ago.

The next supercontinent has already been given the working title of Amasia, as it is expected to involve the convergence of the Americas and Asia.
What the researchers have set out to do is predict when and where it will form by looking back at where its predecessors emerged.

"We're all pretty familiar with the concept of Pangaea, but there hasn't been much convincing data to suggest how the supercontinents take shape," Ross Mitchell of Yale University told BBC News.
"In our model, we actually have North America and South America joining by closing the Caribbean Sea and the Arctic Sea closing and connecting the Americas and Asia."

'Better insight'

The model puts the repositioned Americas within what is known as the Pacific "ring of fire". Europe, part of the Eurasian land mass, Africa and Australia are predicted to join the merging continent, with only Antarctica left out.

The prediction is based on analysis of magnetic data locked into rocks around the world which betray the magnetic orientation of those rocks in past ages.

"Ancient rocks when they form, whether it's lava cooling or sedimentary rock solidifying, will lock in the magnetic orientation," explained Mr Mitchell. "But while this indicates latitude very accurately, historically we haven't had indicators of longitude.
"We found that after each historical supercontinent had assembled, this whole supercontinent would undergo a series of back-and-forth rotations about a stable axis on the equator."

In this animation, plate motions for the past 500 million years demonstrate the rise and fall of last supercontinent Pangaea.
New research by researchers at Yale University predicts a future supercontinent forms at the edge of the previous supercontinent (blue), 90 degrees away from the centre of the previous supercontinent (yellow).
The new supercontinent, dubbed Amasia, is predicted to form in between 50 and 200 million years from now.
This movie corresponds to the orthoversion model, wherein the minimum moment of inertia (Imin) shifts 90° between supercontinents

This led them to the view that that each successive supercontinent forms 90 degrees away from its predecessor.
Previous studies have suggested supercontinents would form either in the same part of the globe or on alternating sides of the globe.

Commenting on the paper, Dr David Rothery, a geologist with the Open University, said the new research offered us a better insight into the history of our planet.

"We can understand past environments better if we know exactly where they were," he told BBC News. "I don't think as a European I care whether continents are going to converge over the North Pole or whether Britain crashes into America in the far future. Predicting into the future is of far less concern than what happened in the past."

Thursday, February 9, 2012

UNH ocean scientists shed new light on Mariana Trench

>>> geolocalization with the Marine GeoGarage <<<

From UNH

An ocean mapping expedition has shed new light on deepest place on Earth, the 2,500-kilometer long Mariana Trench in the western Pacific Ocean near Guam.
Using a multibeam echo sounder, state-of-the-art equipment for mapping the ocean floor, scientists from the University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center found four "bridges" spanning the trench and measured its deepest point with greater precision than ever before.

Perspective view of bathymetry of Dutton Ridge as it is being subducted into the Mariana Trench. Numerous extensional faults (red lines) disrupt the seafloor and the ridge proper. Vertical exaggeration 5x.

Research professor James Gardner and affiliate professor Andrew Armstrong, both of UNH's Center for Coastal and Ocean Mapping/UNH-NOAA Joint Hydrographic Center (CCOM/JHC), presented their findings at the recent American Geophysical Union meeting in San Francisco, the world's largest annual meeting of Earth and planetary scientists.

Mapping the entire Mariana Trench – approximately 400,000 square kilometers -- from August through October 2010, the researchers discovered four bridges spanning the trench and rising as high as 2,500 meters above its floor.
While satellite images had suggested the trench might be spanned by one such ridge, Gardner says the mapping mission confirmed the existence of four such features.
"That got me excited," he says.

Perspective view of bathymetry looking at the guyots and ridge approaching the Mariana Trench. Vertical exaggeration 5x.

The ridges are being formed as the 180-million-year-old Pacific and far younger Philippine tectonic plates collide.
Because the ocean's crust cools as it ages, "the Pacific crust is much, much older, so it's diving underneath the Philippine plate," Gardner says.
As seamounts on the Pacific plate are pulled beneath the Philippine plate, they are compacted against the wall of the trench, forming these ridges.

"It's incredibly complex geology. These seamounts haven't been completely subducted, they're getting jammed up against the plate," Gardner says.
He surmises that the bridges are related to earthquake subduction zones, such as the one that caused the March 2011 earthquake in Japan.

The expedition also yielded the most precise measurement yet of Challenger Deep, the trench's (and the Earth's) deepest point, finding it to be 10,994 meters deep, plus or minus 40 meters.
Calculated from thousands of depth soundings as well as detailed analysis of how the how the water column can alter the echo sounding signals, the new measurement is similar to other claims of the Challenger Deep's depth, some of which are deeper.

"When you're dealing with something that's 11 kilometers deep, you have to deal with inherent uncertainties in the system," says Gardner, noting that Challenger Deep is deeper than Mount Everest is high.

Map view of bathymetry of southern Mariana Trench Challenger Deep area.
Arrow points to circle that identifies the location of the deepest sounding in the trench (10,994 meters).
White contours are 10,000-meter isobath.

Multibeam echo sounders measure depth by sending sound energy to the ocean floor then analyzing the returning signal.
Mounted beneath a ship, the instruments produce a fan-shaped swath of coverage of the seafloor.
The resolution of the resulting images, at one pixel to every 100 meters, is far more precise than other earlier measurement systems.
Hydrographers and ocean mappers such as Armstrong and Gardner describe the process of mapping an area as like "mowing the lawn," making overlapping tracks over the area in question.

This mission to the Mariana Trench, the third and fourth cruises to that area by UNH scientists, was undertaken to gather data that can be used to support an extended continental shelf under Article 76 of the United Nations Convention of the Law of the Sea (UNCLOS).

Links :

Wednesday, February 8, 2012

Russian scientists drill to sub-glacial Antarctic Vostok lake

From WP

After drilling for two decades through more than two miles of antarctic ice, Russian scientists are on the verge of entering a vast, dark Vostok lake that hasn’t been touched by light for more than 20 million years.

Scientists are enormously excited about what life-forms might be found there but are equally worried about contaminating the lake with drilling fluids and bacteria, and the potentially explosive “de-gassing” of a body of water that has especially high concentrations of oxygen and nitrogen.

To prevent a sudden release of gas, the Russian team will not push the drill far into the lake but just deep enough for a limited amount of water — or the slushy ice on the lake’s surface — to flow up the borehole, where it will then freeze.

Reaching Lake Vostok would represent the first direct contact with what scientists now know is a web of more than 200 subglacial lakes in Antarctica — some of which existed when the continent was connected to Australia and was much warmer.
They stay liquid because of heat from the core of the planet.

“This is a huge moment for science and exploration, breaking through to this enormous lake that we didn’t even know existed until the 1990s,” said John Priscu, a researcher at Montana State University who has long been involved in antarctic research, including a study of Vostok ice cores.

“If it goes well, a breakthrough opens up a whole new chapter in our understanding of our planet and possibly moons in our solar system and planets far beyond,” he said.
“If it doesn’t go well, it casts a pall over the whole effort to explore this wet underside of Antarctica.”

Priscu said Russian scientists on the scene e-mailed him last week to say they had stopped drilling about 40 feet from the expected waterline to measure the pressure levels deep below.
Priscu said he expected that they were also sending down a special “hot water” drill to make the final push, but a message from the Russian team Monday reported “no news.”

If the Russians break through as planned within the next week, it will cap more than 50 years of research in what are considered the harshest conditions in the world — where the surface temperatures drop to 100 degrees below zero.
That extreme cold is likely to return within a few weeks, at the end of the antarctic summer, putting pressure on the Russians to make the final push or pull out until the next antarctic drilling season, starting in December.

The extreme cold, which limited drilling time, contributed to the long duration of the project. The Russian team also ran into delays caused by financial strains and by efforts to address international worries about their drilling operation.

Valery Lukin, who is leading the effort for the Russians, is on the ice.
Last year, he told Reuters that their work is “like exploring an alien planet where no one has been before. We don’t know what we’ll find.”

The ‘crown jewel’

American and English teams are planning drilling campaigns next year into much smaller antarctic lakes as scientists work to understand the dynamics of the continent, which holds more than 70 percent of the world’s fresh water.
But Vostok — where the former Soviet Union began work after the United States settled in at the South Pole more than 50 years ago — is now acknowledged to be the “crown jewel” of Antarctica from a scientific perspective.

In recent years, researchers have discovered that microbes live in the ice wherever they explore in Antarctica, including deep in the Vostok borehole.
This finding has revolutionized thinking about the snow- and ice-covered continent and has encouraged researchers, including Priscu, to conclude that life almost certainly will be found in Vostok and the other subglacial lakes.

Vostok station

If microbes are found in Vostok, the discovery would have particular significance for astrobiology, the search for life beyond Earth.
That’s because Jupiter’s moon Europa and Saturn’s moon Enceladus have deep ice crusts that scientists think cover large amounts of liquid water warmed by sources other than the sun — just like Vostok.

The subglacial Lake Vostok

Because of the stakes involved, the Russian effort has drawn criticism for its extensive use of kerosene, Freon and other chemicals to enable the drilling and to keep the borehole open during the long winter.
Priscu said the Russians have worked with an international group he helped form to come up with cleaner ways to drill the final section of the hole.

Organizations including the Antarctic and Southern Ocean Coalition, which is the official environmental umbrella group sitting at Antarctic Treaty organization meetings, have spoken against the drilling methods used by the Russians.
Some other groups have called for a ban on scientific research beneath the antarctic ice sheet so the area can remain pristine.

Claire Christian, director of the coalition’s secretariat, said her group generally supports study of the subglacial antarctic lakes but wishes that the first entry would not take place at Vostok because of its importance.
Of the Russian team, she said, “They have responded to some concerns but are not drilling to the highest standards available.”
The Russian team could not be reached for comment.

Researchers such as Robin Bell, of the Lamont-Doherty Earth Observatory at Columbia University, said learning more about the subglacial world in Antarctica is essential to understanding the changing climate and how it may effect Earth.
Because the continent has so much of the world’s freshwater ice, significant changes there would have a major impact on sea-level rise.

Bell, who has studied Vostok using satellite imaging and other above-surface instruments, said the lake is part of a complex system in which ice sheets bring in meltwater at their bottoms and later carry refrozen water elsewhere.
She said that although the lake has not “felt the wind” in 20 million to 30 million years, the water in it is not as ancient — in the 100,000s to low millions of years old.
The only ancient water present, she said, is probably in the sediment at the bottom.

She, too, has concerns about contamination and equipment failures but said the Russians see their Vostok work as a high-profile symbol of scientific exploration and prowess and so are taking extra care.

Danger of giant geyser

Vostok, which is about the size of New Jersey, is the world’s third-largest lake by volume of water.
Priscu said the gas in the lake makes it like a can of carbonated soda: Open it under high pressure, and it will spurt out.

He said the doomsday scenario for the Russian breakthrough would be if the suddenly released water pushed its way past machinery to block it and shot up the borehole, which is six to eight inches in diameter at the top.
The result, he said, could be an enormous geyser that could empty a quarter of the lake.
Priscu said he didn’t expect that to happen, but if it did, the sudden addition of substantial water vapor to the antarctic atmosphere could change the continent’s weather in unpredictable ways.

Some American Antarctica specialists think the combination of the Russian technique and the fact that the team is sampling from the “top” of the subterranean lake means that its chances of finding microbes is lower than if it went deeper into the water.
Priscu and his former student Brent Christner, now a professor at Louisiana State University, published a paper in 2006 describing a variety of microbes in a Vostok ice core sample, but the Russian team has generally written off the microbes found as contamination.

American researchers will begin drilling into the Whillans Ice Stream in western Antarctica late this year, and the British will drill into the much deeper Lake Ellsworth, also in western Antarctica.
Both are using techniques more consistent with best drilling practices than the Russians are doing at Vostok and are better equipped to find microbial life.

“Hopefully, all three projects will succeed, and then we’ll enter a new era of science and maybe cooperation,” Priscu said.
“I could imagine an international team going back to Vostok and starting a project to drill much further into the lake with a higher level of technology and innovation.”

Links :

Tuesday, February 7, 2012

New bathymetry in Google Earth

Global seafloor update in Google Earth
To see more of what's changed, Google has created this short video to give you a tour

From Scripps

Internet information giant Google updated ocean data in its Google Earth application this week, reflecting new bathymetry data assembled by Scripps Institution of Oceanography, UC San Diego, NOAA researchers and many other ocean mapping groups from around the world.

The newest version of Google Earth includes more accurate imagery in several key areas of ocean using data collected by research cruises over the past three years.

"The original version of Google Ocean was a newly developed prototype map that had high resolution but also contained thousands of blunders related to the original archived ship data," said David Sandwell, a Scripps geophysicist.
"UCSD undergraduate students spent the past three years identifying and correcting the blunders as well as adding all the multibeam echosounder data archived at the National Geophysical Data Center in Boulder, Colorado."

The Mediterranean Sea: before (left) and after (right) Example of a place you’ll notice an improvement in the ocean terrain data is the Mediterranean Sea, particularly south of Cyprus, where the boundary between the Eurasian and Arabian plates is now more clearly defined.

"The Google map now matches the map used in the research community, which makes the Google Earth program much more useful as a tool for planning cruises to uncharted areas," Sandwell added.

Previous terrain data showed what appeared to be a city grid on the ocean floor (left), which was confused for the lost city of Atlantis.
Updated data more accurately reflects the seafloor terrain (right).

For example, the updated, more precise data corrects a grid-like artifact on the seafloor that was misinterpreted in the popular press as evidence of the lost city of Atlantis off the coast of North Africa.

Guam and Mariana’s Trench before (left) and after (right)
Our last example shows improvements to the land-sea mask along the coastline of Guam.
You’ll notice a dramatic improvement in the resolution of both the coastline and neighboring Mariana’s Trench, the deepest trench in the world.

Through several rounds of upgrades, Google Earth now has 15 percent of the seafloor image derived from shipboard soundings at 1-kilometer resolution.
Previous versions only derived about 10 percent of their data from ship soundings and the rest from depths predicted by Sandwell and NOAA researcher Walter Smith using satellite gravity measurements.
The two developed the prediction technique in 1994.
The satellite and sounding data are combined with land topography from the NASA Shuttle Radar Topography Mission (SRTM) to create a global topography and bathymetry grid called SRTM30_PLUS.
On 11th January 2012, Google replaced its global bathymetry SRTM30_PLUS V4.0 with the newer version V7.0.
This has increased the area of seafloor covered at 1km resolution from 10% to 15%.
The new version also corrected thousands of errors in the old data and includes all of the multibeam bathymetry data collected by U.S. research vessels over the past three decades including 287 Scripps expeditions from research vessels Washington, Melville and Revelle.
UCSD undergraduate student Alexis Shakas processed all the U.S. multibeam data and then worked with Google researchers on the global integration.

The next major upgrade to the grid will occur later this year using a new gravity model having twice the accuracy of previous models.
The new gravity information is being collected by a European Space Agency satellite called CryoSat that was launched in February 2010.

Data from Scripps, NOAA sharpen resolution of seafloor maps.

By visiting Google Earth, you can use the 'historical imagery' flag to see old versus new.
This KLM File shows some improvements and differences, like Atlantis being less clearly visible, the improvements offshore Ireland and the Mariana Trench, as well as in the Californian Gulf, Great Barrier Reef and the Clarian fracture zone in the Pacific.
Also a sea mount that was vague now is made visible.

Links :

Monday, February 6, 2012

Tasman Sea a “hotspot” for ocean warming

Surface (orange) and deeper (blue) currents are shifting south, bringing warmer waters to the Tasman Sea. (Credit:CSIRO)

From AustraliaGeoGraphic

The temperature of waters east of Tasmania are rising rapidly, as balmy ocean currents shift toward the poles.

THE GLOBAL OCEAN is warming, but some places are feeling the heat more than others.
The Tasman Sea, east of Australia, has been identified in a new study as one of five global ocean "hotspots".

>>> geolocalization with the Marine GeoGarage <<<

Temperatures here have risen here by 2ºC over the past 60 years - three times the average rate of warming in the the world's oceans.
The warming has been triggered by strengthening wind systems - a result of climate change - which have driven warm ocean currents toward the poles, beyond their known boundaries.

The rising temperatures could have stark consequences not only for marine life, but for the ocean's capacity to take up heat and carbon from the atmosphere.

"We have more warm water coming from [just outside the tropics] - that's the major cause of this intense warming," says co-author Dr Wenju Cai, a marine and atmospheric scientist with the CSIRO in Melbourne. "And there's strong support that it's due to climate change."

The study was published this week in the journal, Nature Climate Change. The other four global ocean hotspots occupy the western edges of the North Atlantic, South Atlantic, Indian Ocean and North Pacific

One of the hottest hotspots

Wenju and the team combined computer simulations with long-term observations, including monthly measurements that have been taken by the CSIRO since 1945, to understand how ocean circulation patterns are changing all over the world.

The hotspots have formed where fast-flowing ocean currents carry warm water westward, to arrive at the eastern edge of the major continents. In Australia's case, the East Australian Current has shifted around 350km further south, making the Tasman Sea "one of the hottest hotspots," Wenju told Australian Geographic.

What's most surprising about the results, he says, is that changes in the hotspots have been highly synchronised, which points to a global cause.

" All these major western boundary currents are in fact behaving in the same way," he says. "It really points to a global increase in greenhouse gases as a cause."

Adapt, migrate, or die

Ecosystems in the Tasman Sea are already seeing the effects of rising temperatures. As their environment warms, marine species must adapt, migrate, or face extinction.

"We are seeing a lot of sea urchins migrating south from NSW to Tasmanian water," Wenju says.
"There, they eat out all the Tasmanian kelp."
Because kelp forests provide food and shelter to a huge variety of marine species, their destruction can have severe knock-on effects."

Warming waters have implications for aquaculture, too.
"If you want to farm salmon (the source of a $350 million industry in Tasmania), they need a very particular range of temperatures in order to grow," he says.

Professor Matthew England, joint director of the University of New South Wales' Climate Change Research Centre, agrees that the rising temperatures could have major repercussions for marine life.
"Warming in the Tasman Sea has been particularly rapid," Matthew says. "
And with ecosystems sensitive to temperature change, this has implications for marine life in Australian waters."

Hindering heat absorption

In addition to the ecological effects, elevated temperatures reduce the ability of the ocean to take up heat and carbon from the atmosphere.

When warm water flows into polar areas, it creates a stable layer at the surface - because warm water is lighter.
With the surface layer less intergrated into the deeper ocean, less heat and carbon can be sucked downward.
And this could lead to accelerated warming.

"This is an important study," Matthew says. "It shows how global warming can profoundly alter ocean circulation patterns, which can in turn enhance the rate of warming in certain regions."

The next step in the research, Wenju says, is to deploy a series of moored ocean sensors across the Eastern Australian Current, to monitor changes more accurately. "Because if you want to detect changes associated with global warming," he says, "observing these hotspots will be very effective."

Links :
  • ABC : Scientists say global warming changes currents

Sunday, February 5, 2012

Walk on the wild side

Who's the boss ?

Skipper's biggest challenge :
Getting the keel out of the water and keeping it there requires precision sailing and knowing the boat inside out.
From his position at the helm, Ross Daniel, the skipper cannot see either Alex Thomson or the jet ski, so he relies on the information given to him by the spotter (port side of stern / left back).

Required wind speed: 17 – 19 knots

Required sea state: slight (waves 0.5 – 1.25 metros)
Requires sailing speed: 9 knots
Sailing angle of yacht to lift keel out of the water: 45°
Maximum angle of yacht: 70°
Maximum sailing time with keel out of the water: 45 – 60 seconds

Major risks:
- The boat coming down on top of Alex, the jet ski and its driver.
- The wind is unpredictable; a momentary gust or drop will affect the direction and speed of the boat in an instant.
- The keel hitting Alex – 4 tonnes of lead moving at 10mph – the equivalent of being charged by an elephant!