The Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and the TU Dresden’s Institute for Cartography (Germany) are presenting their joint three-dimensional map of the Antarctic continent and the seafloor of the Southern Ocean at this year’s International Cartographic Conference in Rio de Janeiro, Brazil.
For the first time, the map simultaneously shows viewers three geographic layers: the Antarctic ice sheet, the land masses it conceals and the surrounding underwater landscape.
The map covers a total depth range of over 12,000 metres: from the ice sheet, down to the depths of the surrounding Southern Ocean.
The so-called lenticular print is a novelty; the scientists portrayed Antarctic ice sheet, which is up to 4,800 metres thick, as a honeycombed grid structure, allowing viewers to see through it to the mountain ranges below.
Another new feature is that the scope of depth includes the entire z-axis.
In the past, it was only possible to show deeper areas or, in the case of world maps, the corresponding ocean regions but without any depth, according to Lars Radig.
2 sources combined
One major source of data for the new 3D visualisation was the International Bathymetric Chart of the Southern Ocean (IBCSO), a digital representation of the entire Antarctic seafloor south of the 60th parallel that was released in 2013 under the auspices of the Alfred Wegener Institute.
The second key source was provided by Bedmap2, a three-dimensional digital map of Antarctica that depicts the bedrock under the Antarctic ice sheet.
The new True-3D visualisation is the first of its kind to combine the two datasets.
The first scientific evidence that trawling in waters deeper than 600
metres is ecologically damaging and provides poor economic return is
reigniting debate about the controversial fishing practice.
For
years, European scientists, environmentalists, politicians and
commercial fishermen have debated whether or how to limit deep-sea
trawling, which critics say causes huge damage to ocean ecosystems.
The
latest findings, which use survey data to assess how the ratio of
undesired fish to commercially valuable ones changes with depth, are
published in Current Biology.
“I
think they’re pretty robust,” says Les Watling, a deep-sea biologist at
the University of Hawaii at Manoa, of the results.
“They are basically
saying you are wasting your time fishing below 600 metres.”
Watling, who has worked as a science adviser for environmental groups
pushing for a ban on trawling, adds, “This is the first really good set
of science data that essentially ratifies the idea that having some
kind of depth limit to deep-sea trawling would be worthwhile and would
not create an economic hardship."
photo of the Roundnose Grenadier, a deep water fish
credit : Marine Scotland Science
Debates and delays
After
much debate and several delays, in December 2013 the European
Parliament approved restrictions on deep-sea trawling in European Union
(EU) waters — a practice in which weighted nets are dragged along the
sea floor to harvest commercially valuable fish species — but stopped
short of an outright ban.
Moreover, these restrictions are not yet in
force, because they must still be approved by ministers from member
states.
Some fishers have subsequently agreed a voluntary 800 meters
limit for trawling.
Deep-sea trawling often
captures more undesired species than those actually being targeted for
sale, and it can destroy sea-floor habitat such as corals.
Although
trawling damage has been well documented, data were lacking on how to
set the most effective limits.
In the latest
study, researchers analyzed catches from experimental trawls conducted
in the 240–1,500-metre zone of the northeastern Atlantic Ocean.
They
found that the volume of unwanted species, or by-catch, increases
markedly relative to the volume of target commercial species in the
600–800-meters zone.
The increase was especially pronounced for sharks
and rays, including some threatened species.
The analysis also revealed that the economic value of catches decreases in the same zone.
“We
weren’t sure there were going to be any overarching trends and were
really surprised to see significant change,” says study co-author Jo
Clarke, a marine biologist at the University of Glasgow, UK.
“I think
it’s going to be an interesting, extra body of evidence to go into the
discussions.”
Clarke hopes that this work will
now inform similar analyses in other regions that have also debated
their deep-sea trawling practices, to see if similar patterns are found
in non-European waters. “Probably New Zealand is the place where the
ripple effects would be strongest,” says Watling.
End of the line?
European
debates over deep-sea trawling bans have been contentious, especially
in France and Spain, where the few EU boats that fish at depths more
than 600 meters are registered.
Trawling at such depths, which happens
mainly west of Scotland and Ireland, is limited.
France, for instance,
has just ten such fishing vessels, owned by three companies and
supported in part by government subsidies.
Watling
is among many who would like to see the EU ratify its ban, and bring in
a 600 meters depth limit. He says that a shallower limit would help to
prevent expansion of deeper trawling.
New
species are discovered all the time in well-traversed places such as the
Atlantic, says Watling. “Anything you can do to protect that
biodiversity I think is important.” Links :
Sea levels are 3 inches higher than they were in 1992. "It's very likely to get worse in the future."
A panel of NASA scientists said Wednesday that new data shows sea levels are, on average, three inches higher than they were in 1992 due to melting ice from both mountain glaciers and the polar ice caps, as well as warmer oceans.
Greenland Ice Mass Loss: Jan. 2004 - June 2014
GRACE consists of twin co-orbiting satellites that fly in a near polar orbit separated by a distance of 220 km. GRACE precisely measures the distance between the two spacecraft in order to make detailed measurements of the Earth's gravitational field.
Since its launch in 2002, GRACE has provided a continuous record of changes in the mass of the Earth's ice sheets. This animation shows the change in the Greenland Ice Sheet between January 2004 and June 2014.
The 1-arc-deg NASA GSFC mascon solution data was resampled to a 998 x 1800 data array using Kriging interpolation.
A color scale was applied in the range of +250 to -250 centimeters of equivalent water height, where blue values indicate an increase in the ice sheet mass while red shades indicate a decrease.
In addition, the running sum total of the accumulated mass change over the Greenland Ice Sheet is shown on a graph overlay in gigatons.
Global sea level has been measured accurately and continuously by satellites since 1993. Credit: Steve Nerem, University of Colorado
The changes are concerning and “it’s very likely to get worse in the future,” Steve Nerem, a University of Colorado geophysicist and a member of the panel, said in a conference call, Reuters reported.
In 2013, a United Nations panel reported sea levels were projected to rise between 1 and 3 feet by 2100; the NASA panel said data indicates the level rise would be on the higher end of that projection.
As measured by the TOPEX/Jason satellites, sea level change in the short-term (top) and longer-term (bottom) can be very different. Credit: Nerem
The sea level change is an average; in some areas, sea levels rose more than 9 inches, and in others—such as along the West Coast, sea levels are falling.
For over 20 years NASA has been tracking the global surface topography of the ocean in order to understand the important role it plays in our daily lives.
Climate change is causing our Ocean to warm and glaciers to melt, resulting in sea level rise.
Since 1880, the global sea level has risen 8 inches; by 2100, it is projected to rise another 1 to 4 feet.
Scientists warn that we haven’t seen the worst of it yet; ocean currents and weather cycles have actually offset some sea level changes in the Pacific, which means the West Coast could see a huge jump in sea levels in the next 20 years.
NASA’s Gravity Recovery and Climate Experiment (GRACE) twin satellites have measured the loss of ice mass from Earth’s polar ice sheets since 2002. Credit: Nerem/CU-Boulder
The panel warned that forecasting the melting rate of the polar ice caps is nearly impossible.
And even if the pattern were to stall and reverse, it would take centuries to return to original pre-climate change levels.
Before Tarzan was swimming his way to American gold medals, there was Duke.
Before fellow Olympian Jim Thorpe was similarly being cast as a tribal chief in Hollywood, there was Duke.
And
right before the current American president was born in Honolulu,
elected as that area’s sheriff for the final time was Duke.
Duke Kahanamoku, born on this day in 1890, is one of the greatest U.S.
athletes many Americans have never heard of.
And fortunately for his
legacy, today Duke — before even Thorpe and Olympic
swimmer-turned-“Tarzan the Ape Man” actor Johnny Weissmuller — is being
celebrated with a Google Doodle.
Which is a wonderful nod to (and
swell of recognition for) the great man, because had he been born a
century later, his name might well be as popularly known as that of
Michael Phelps, Kelly Slater or Laird Hamilton.
The farther you
get from the beach, the less likely, it seems, you hear the name Duke
Kahanamoku.
But when you move close to breaking waves (as my family did,
to San Diego, when I was a boy), the more often you surely will hear
references to “the Duke,” the father of modern surfing.
“Out of
the water, I am nothing,” the Duke resonantly said before he fully
became recognized as the “ambassador of Aloha” and Hawaiian culture.
Fortunately, Hawaii celebrates Duke as a favorite son who was indeed
quite something as a ceremonial envoy on land, as well.
But when you
have achieved such greatness in the pool and in the pipeline, it should also be underscored that, to invert that quote: In the water, he was everything.
Duke Kahanamoku is pictured with his surfboard. He is the subject of a Google Doodle today. (Bishop Museum Archives)
In
1912, for instance, Duke was the marine version of Thorpe, that master
on the field and track, at the Stockholm Olympics.
The two men, both of
whom were about 6 feet, stood particularly tall at those Games as
multiple medalists.
While Thorpe was winning the pentathlon and
decathlon, “the Big Kahuna” was winning swimming gold in the 100-meter
freestyle and silver in the 4×200 free.
Duke, who was called “the
king of all swimmers,” would go on to be a double gold medalist in
those two events at the 1920 Antwerp Games.
Four years later, Duke would
medal for a third time (silver) in the 100 free, beating his brother,
bronze medalist Samuel Kahanamoku, in the event won by his pal
Weissmuller (the future Hollywood Tarzan) at the Paris Games.
Duke ended
his Olympic career in his 40s, when he was an alternate for the U.S.
water polo team.
An article from the Salt Lake Tribune, in 1913.
Duke was the first athlete inducted into the Halls of Fame for both
swimming and surfing, and the swimming exhibitions he gave, buoyed by
his Olympic fame, provided him with opportunities to popularize surfing,
as well, from the California coast to the waters off Australia, where a
1914 trip helped the sport take hold Down Under. Wherever he paddled
his 16-foot wood longboard around the world, he was also proudly
peddling surfing’s greatness.
(Duke’s California fame also grew in 1925, when — in what the
Honolulu Star-Bulletin called a “superhuman” rescue — he used his
surfboard to help save a dozen stranded fishermen during the vessel
Thelma’s fatal wreck off the coast of Newport Beach.)
Duke Kahanamoku, Waikiki, 1930s.
Photo: Tom Blake/SHF
Shortly
after the Paris Games, Duke also became a Hollywood actor, sometimes
(like Thorpe) playing tribal characters; three decades later, in the
Oscar-nominated 1955 war film “Mister Roberts,” he played a “native
chief,” still fit of body and regal of bearing.
Duke himself was a
military police officer during World War II, and sheriff of Honolulu
till 1961 (the year that Obama was born, yes, there).
In the ’60s, after
having helped push for Hawaii’s 1959 statehood, he portrayed himself in
surfing documentaries, and had a stake in Duke’s, the Waikiki club that
was home to Don Ho and his band.
Duke Paoa Kahinu Mokoe
Hulikohola Kahanamoku was born on this day in 1890 in Hawaii, where he
would die 78 years later, as the island state’s ambassador the globe
over.
“Despite his charisma on the screen and two decades of
Olympic triumphs, it is perhaps for moments like these [his rescue
heroics off Newport Beach] — for his character, for his ease in the
water, his deep and unending love of Hawaii and her oceans — that Duke
Kahanamoku is remembered most,” writes Google, in celebrating the great man’s 125th birthday with artist Matt Cruickshank’s tropical, longboarding Doodle.
Long live the Duke, the ambassador of Aloha.
Links :
NYTimes : Duke Kahanamoku, Legendary Surfer and Swimmer, Gets Google Tribute
CSMonitor : Duke Kahanamoku and the one mile-long wave that made him a legend
Ah, the summertime sizzle of a shell-strewn beach, the bracing odour of the briny sea. There's nothing quite like it really.
If you happen to be on a beautiful beach, do take a good, deep, invigorating sniff!
What does it remind you of?
Amid the saltiness, a hint of sulphur perhaps?
A slight edge of boiled cabbage? Or something even more unpleasant?
Well, maybe that's just me...
Seaside odours are generally composed of dimethyl sulfide, a pongy gas produced by bacteria feasting on phytoplankton.
In the atmosphere, it is changed chemically to sulphate, which in turn becomes the seeds of clouds.
Solid organic matter from large collections of phytoplankton blooms can also help with cloud formation.
This blooming ocean can give rise to a specky scum, from which tiny bubbles get lofted into the air by the churn of the sea.
Water vapour condenses around them, tiny droplets form and the fluffy billows of the sky emerge.
Gobsmacked
So what does this ocean-coloured scene have to do with a warming planet?
Well, researchers say that the type of clouds produced from sea gas and plankton particles, especially in the Southern Ocean, are not your common or garden cumulus.
Scientists were surprised to discover that clouds in the Southern Ocean
were highly reflective in summer
Clouds reflect sunlight back into space depending on the size of the droplets and the amount of liquid suspended in them.
The more liquid that is suspended in the cloud, the brighter and more reflective they are - swotty philosophers of the skies!
The experts have long understood that in winter, when seas are stormy and the spray is flying, there will be more of these types of droplets and thus more sun bounced back into space.
In the balmy, calm of summer at sea they expected the clouds to be far less reflective.
They were astonished to discover that, in the Southern Ocean, this was not the case at all.
In fact they concluded that the plankton particle effect was strongest in the warmer months - on average they found that ocean life doubled the number of droplets in summer.
"The amount of sunlight that's reflected by those clouds in this region is about 125 watts per metre squared," said co-author Dr Susannah Burrows, from the US Department of Energy's Pacific Northwest National Laboratory.
"What we're finding is evidence for a change in that reflectivity of 10 watts per metre squared, that would be attributed to the phytoplankton - so about 8% of the reflection of sunlight on those clouds."
"It is quite a bit!" she said.
Brightening the clouds
So can this new understanding of the role of sea smells and clouds make a difference to global warming?
Well, yes, say the researchers but not necessarily in the ways you might think.
The scientists are excited about the findings because for the first time it gives them a clue about the total number of aerosols that are up in the air over the Southern Ocean.
But could this new understanding give a boost to ideas about geo-engineering our way out of warming hell?
Scientists have been studying the ability of clouds to reflect sunlight back into space
In recent years a number of researchers have suggested that brightening the clouds could be a low-impact way of cooling the planet.
Does this Southern Ocean research make this a more feasible prospect?
"In principle it is possible to strongly modify and brighten marine clouds by injecting particles into the marine atmosphere," says Dr Burrows.
"But I think whether or not that's a good idea is really a political question that needs to be discussed within society."
Something to mull over while lying on the beach with the sea air in your nostrils.
