Fish farms at sea: the ground truth from Google Maps

The scanned Mediterranean coast with assigned place mark to each aggregation of fish cages.
The results of the the first study to estimate seafood production using satellite imagery
demonstrate the reliability of recent FAO farmed fish production statistics for the Mediterranean as well as the promise of Google Earth to collect and ground truth data.

From PlosOne

In the face of global overfishing of wild-caught seafood, ocean fish farming has augmented the supply of fresh fish to western markets and become one of the fastest growing global industries.

Accurate reporting of quantities of wild-caught fish has been problematic and we questioned whether similar discrepancies in data exist in statistics for farmed fish production.
In the Mediterranean Sea, ocean fish farming is prevalent and stationary cages can be seen off the coasts of 16 countries using satellite imagery available through Google Earth.
Using this tool, we demonstrate here that a few trained scientists now have the capacity to ground truth farmed fish production data reported by the Mediterranean countries.

The Great Wall of China is not the only thing you can see from space.
Fish farming cages are clearly visible through Google Earth's satellite images and University of British Columbia researchers have used them to estimate the amount of fish being cultivated in the Mediterranean.
Example image from Google Earth showing a fish farm off the coast of Greece
>>> geolocalization with the Marine GeoGarage <<<

With Google Earth, we could examine 91% of the Mediterranean coast and count 248 tuna cages (circular cages >40 m diameter) and 20,976 other fish cages within 10 km offshore, the majority of which were off Greece (49%) and Turkey (31%).

Combining satellite imagery with assumptions about cage volume, fish density, harvest rates, and seasonal capacity, we make a conservative approximation of ocean-farmed finfish production for 16 Mediterranean countries.

Fish farming, Aegean sea (Greece)

"Our colleagues have repeatedly shown that accurate reporting of wild-caught fish has been a problem, and we wondered whether there might be similar issues for fish farming," says lead author Pablo Trujillo, an Oceans Science Advisor for Greenpeace International, who conducted the study while a research assistant at the UBC Fisheries Centre.

"We chose the Mediterranean because it had excellent satellite coverage and because it was of personal interest," says Chiara Piroddi, co-author and an ecosystem modeler at the UBC Fisheries Centre.
"We hand counted 20,976 finfish cages and 248 tuna cages, which you can differentiate due to their extremely large size – each tuna cage measured at more than 40 metres across."

Almost half the cages were located off the coast of Greece and nearly one-third off of Turkey – and both countries appear to underreport their farmed fish production.
The researchers note that not all areas had full satellite coverage – for instance, images were missing for large portions of the coasts of France and Israel, for reasons the authors do not fully understand.

Dimitri Messinis/AP/SIPA

Combining cage counts with available information on cage volume, fish density, harvest rates, and seasonal capacity, the research team estimated ocean finfish production for 16 Mediterranean countries at 225,736 tonnes (excluding tuna).
The estimate corresponded with government reports for the region, suggesting that, while there are discrepancies at the level of individual countries, overall, the Mediterranean countries are giving accurate counts.

Trujillo adds that Google Earth, with its high-resolution images and consistent time series, can be a powerful tool for scientists and non-governmental organizations to monitor activities related to ocean zoning and capture fisheries.
"The results are reassuring, and the methods are inspiring," says co-author Jennifer Jacquet, a post-doctoral researcher with UBC's Sea Around Us Project.
"This shows the promise of Google Earth for collecting and verifying data, which means a few trained scientists can use a freely available program to fact-check governments and other large institutions."

Links :

• TheScientist : Satellites spy on fish farms

'The Birds' died from poisoned plankton : Alfred Hitchcock's thriller source revealed

Photograph: Thomas P Peschak/Save our Seas

From HuffingtonPost

The mystery behind the avian outbreak that inspired one of Alfred Hitchcock's greatest films may have finally been solved.

Hitchcock's 1963 film "The Birds" was inspired by both a Daphne du Maurier short story and a mass outbreak of avian insanity that took place in California's Monterey Bay two years earlier.

According to a team of researchers, that outbreak was caused by the least suspenseful thing of all time: poisoned plankton.

Sibel Bargu of Louisiana State University led a team of researchers that determined that 79 percent of the plankton that the squid and other creatures that the birds ate contained toxin-making algae, which was passed along through prey to predator.

In the film, the birds attack people, while in real life they suffered seizures and confusion and then died, plummeting down on houses and cars when they dropped from the sky.

As USA Today points out, the poison may have been caused by leaky septic tanks in the rapidly expanding housing market in the area, giving the story a moral lesson after all.

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)

From Blue

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!"

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."

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 :

• UNH : Amstrong cruise report / Gardner cruise report