Saturday, April 25, 2015

Underwater macro footage


From MNN

In this exquisite "macro symphony," underwater photographer Kay Burn Lim gives viewers a glimpse of the awe-inspiring creatures that live under the waves of Indonesia's Lembeh Strait, a passage of water between Lembeh Island and the mainland city of Bitung.
The shallow strait is considered to be the premier muck diving capital of the world, and underwater photographers like Lim come from all over the world to document the wealth of creatures that lay hidden beneath these fragile sandy bottoms.

With the exception of the puffer fish (above) and the moray eel, all of the gorgeous marine critters you see in this video are no larger than two inches, and some of them are only as big as a grain of rice!
One of the most remarkable creatures featured in the video is the little leaf sheep nudibranch (Costasiella kuroshimae, pictured below), which is named for its obvious resemblance to, well, a sheep made of leafy greens!
Measuring only a few millimeters in length, these tiny photogenic sea slugs spend their days grazing on ocean algae — and perfecting their pok√©mon-like cuteness.

Friday, April 24, 2015

Europe's Goce gravity satellite probes Earth's mantle


 Goce detects deep plumes of mantle material rising from more than 2,000km down

From BBC by Jonathan Amos

Europe's Goce gravity satellite has provided striking new visualisations of the Earth's deep interior.
Its gravity data has enabled the effect of variations in the density of rock to be traced up to more than 2,000km below the surface.
The maps, published by the journal Nature Geoscience, help to show how material moves up and down, driving a range of geological phenomena.
These include subduction zones, where the great tectonic slabs covering the Earth's surface dive under one another.
"Ultimately, volcanic activity and earthquakes occur because of these slow movements inside the Earth's mantle," explained Dr Isabelle Panet from the Institute for Geographic Information and Forestry, Paris, France.
"The volcanoes and earthquakes are, if you like, just the surface expression of these deep dynamics," she told BBC News.

By tracking the speed at which waves of energy from tremors propagate through rock, scientists can determine the structure of the Earth's interior - a technique known as seismic tomography.
But to convert these speed variations into densities, seismic tomography leans on quite a few assumptions, including the temperature and composition of the rock at various depths.
Determining these density differences is, however, essential to derive the relative buoyancy of material.
This might be hotter, lighter material on its way up, such as in a plume of magma; or cold dense rock on its way down, such as a swathe of oceanic crust descending at one of those subduction zones.

Goce offers some complementary information.
The satellite, which flew from March 2009 until November last year, gathered unprecedented information on the subtle changes in the pull of gravity around the Earth.
These deviations reflect differences in the mass, and by extension the density, of material at depth.
By viewing the rate of change, or gradient, in the acceleration due to gravity in three separate directions, Dr Panet and colleagues have been able to pull out a number of interesting features from the data.

 The satellite finds traces (circled red regions) of ancient subduction zones
running deep under Asia and along the Americas

These include major mantle plumes in the Pacific and south-east of Africa.
Also visible are ancient subduction zones running deep under Asia and along the Americas.
What Goce is probably seeing is the buried remnants of old plate material of Jurassic age (older than 150 million years ago) in the case of Asia, and of roughly Cretaceous age (older than about 60 million years ago) in the case of the Americas.

In addition, the satellite's gravity data contains a residual signal of the former Tethys Ocean. Subducted material is seen in the maps stretching from the Mediterranean to the Himalayas.
The Tethys Ocean is thought to have closed in the past 40-50 million years as India and Asia collided.
Dr Panet said: "The main interest of these gravity gradient data is to use them in combination with seismic tomography because the maps of seismic velocity anomalies - they do not give you the mass.
"And the mass is a very important parameter to understand the dynamics of the mantle because it creates the buoyancy forces that drive material up and down. Now, by combining the structural information from seismic tomography and the mass sensitivity of the Goce data, we can better understand the dynamics of the mantle's convective fluids."

Goce's ability to sense the uneven distribution of mass through the Earth has already allowed scientists to map the boundary globally between the Earth's crust and the mantle - the so-called Moho boundary.
The famous "discontinuity" lies some 10-70km below the surface and marks a sharp change in rock properties.
Other researchers are investigating old plate movements by linking gravity signals on different continents, such as on Africa and South America, to show how they were once joined together.
"What we are seeing is that Goce data enable us to sense features from really quite shallow regions in the crust, down to very deep in the mantle," commented Dr Rune Floberghagen, the European Space Agency's mission manager for Goce.

 The circled blue region reflects remnants of the old Tethys Ocean

 Note : The Eotvos is a unit for the rate of variation of the gravitational acceleration.

Links :

Thursday, April 23, 2015

Oceans are world's seventh largest economy worth $24tn, says WWF report

‘The oceans are in a bad state that is rapidly getting worse.
Fisheries are starting to collapse, there are record levels of pollution, such as plastic pollution, and there is climate change.’
Photograph: David Fleetham/naturepl.com/WWF

From The Guardian by Oliver Milman

Vast economic worth of world’s oceans includes fishing, tourism and shipping but is declining due to pollution, climate change and overfishing

The monetary value of the world’s oceans has been estimated at US$24tn in a new report that warns that overfishing, pollution and climate change are putting an unprecedented strain upon marine ecosystems.
The report, commissioned by WWF, states the asset value of oceans is $24tn and values the annual “goods and services” it provides, such as food, at $2.5tn.
This economic clout would make the oceans the seventh largest economy in the world although the report’s authors, which include the Boston Consulting Group, say this is an underestimate as it does not factor in things such as oil, wind power and intangibles, such as the ocean’s role in climate regulation.
The economic value is largely comprised of fisheries, tourism, shipping lanes and the coastal protection provided by corals and mangroves.


However, the oceans are facing mounting pressures.
They soak up around half of the carbon dioxide pumped into the atmosphere by human activity, a process that is warming the water and increasing the acidification of the ocean.
The report warns that nearly two-thirds of the world’s fisheries are “fully exploited” with most of the rest overexploited.
The biological diversity of the oceans slumped by 39% between 1970 and 2010, while half of the world’s corals and nearly a third of its seagrasses have disappeared in this time.


Professor Ove Hoegh-Guldberg, lead author of the report and director of the Australia-based Global Change Institute, said it was important that the business community understood the value of the oceans so that a strategy could be devised to reverse its decline.
“If you don’t look after an asset like the ocean it starts to degrade so it’s important we start to solve these problems now on an international basis,” he said.
“The oceans are in a bad state that is rapidly getting worse. Fisheries are starting to collapse, there are record levels of pollution, such as plastic pollution, and there is climate change.”
Hoegh-Guldberg said the “shocking” rate of change in the world’s oceans was illustrated in the latest report by the UN’s climate science panel, which stated that changes in the ocean’s chemistry due to an increase in CO2 emissions was faster than at any point in the past 65m years.
Warming temperatures can make life challenging for some marine species, while the acidification of the ocean hampers the ability of creatures such as corals and molluscs to form their shells and skeletons.


“The changes we are making will take 10,000 years at least to turnaround, so we don’t want to go down this pathway,” Hoegh-Guldberg said.
“This generation of humans is defining the future of 300 generations of humans. We are conducting these experiments with our world despite the consequences for people.”
Hoegh-Guldberg said that nations should do more to manage localised issues such as pollution and overfishing to help oceans deal with climate change.
“If you protect marine areas and regulate fishing, you can help corals survive the impact of climate change,” he said.
“If we solve these local problems we can buy some time while we deal with the global climate issue. But let’s not pretend here – if we don’t get off the current CO2-rich pathway we’re on now, all the attempts to control local factors won’t work. Coral reefs will become a distant memory and the ability to feed people will be severely degraded.”
The report calls for eight key steps to revive the health of the oceans, including a stronger focus in UN agreements on oceans, deep cuts to emissions, at least 30% of marine areas to be protected by 2030 and greater action to tackle illegal fishing.

Links :

Wednesday, April 22, 2015

Image of the week : winter blooms in the Arabian Sea

acquired February 14, 2015


Phytoplankton in the Arabian Sea (NASA, acquired February 22, 2005)

From NASA

Winter is the prime season to see filaments of phytoplankton twist and curl amid the Arabian Sea.
On February 14, 2015, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image of the region’s winter blooms.

Why winter?
It turns out that in this part of the world, seasonal wind patterns have a large effect on blooms.
The winter monsoon brings a reversal of wind direction—from southwesterly to northeasterly—which stirs up nutrients that help phytoplankton thrive.


Phytoplankton Bloom in the Arabian Sea (NASA, acquired October 6, 2004)
 

Not all phytoplankton are the same, however, and research has shown that the composition of the communities in the Arabian Sea has shifted.
A study published in 2008 reported that an unusual abundance of Noctiluca scintillans (also called Nocticula miliaris) has started showing up in winter blooms over the last decade.
The newcomers have replaced the populations of diatoms that previously prevailed.

Research published in 2014 confirmed that the outbreak of N. scintillans in the Arabian Sea is due to an unprecedented amount of oxygen-deficient water near the sea’s surface.
The exact reason for the influx is still under investigation.
What is apparent, however, is that N. scintillans is better equipped to handle the low-oxygen environment.


Phytoplankton Bloom in the Arabian Sea (NASA
acquired February 18, 2010

The shift could have implications for the food web of the Arabian Sea.
In the past, fish ate the copepods that fed on the plentiful diatoms.
In contrast to the diatoms, N. scintillans appears to be too large for consumption by copepods and instead feed creatures like jellyfish and salps.
How this disruption to the traditional food chain will impact regional fisheries remains to be seen.

Links :

Tuesday, April 21, 2015

NOAA, partners, survey 'amazingly intact' historic WWII-era aircraft carrier

Features on an historic photo of USS Independence CVL 22 are captured in a three-dimensional (3D) low-resolution sonar image of the shipwreck in Monterey Bay National Marine Sanctuary.
The Coda Octopus Echoscope 3D sonar, integrated on the Boeing Autonomous Underwater Vehicle (AUV) Echo Ranger, imaged the shipwreck during the first maritime archaeological survey.
The sonar image with oranges color tones (lower) shows an outline of a possible airplane in the forward aircraft elevator hatch opening.
Credit: NOAA, Boeing, and Coda Octopus

From NOAA

NOAA, working with private industry partners and the U.S. Navy, has confirmed the location and condition of the USS Independence, the lead ship of its class of light aircraft carriers that were critical during the American naval offensive in the Pacific during World War II.
Resting in 2,600 feet of water off California's Farallon Islands, the carrier is "amazingly intact," said NOAA scientists, with its hull and flight deck clearly visible, and what appears to be a plane in the carrier's hangar bay.

 Aerial view of ex-USS Independence at anchor in San Francisco Bay, California, January 1951. There is visible damage from the atomic bomb tests at Bikini Atoll.
Credit: San Francisco Maritime National Historical Park

Independence (CVL 22) operated in the central and western Pacific from November 1943 through August 1945 and later was one of more than 90 vessels assembled as a target fleet for the Bikini Atoll atomic bomb tests in 1946.
Damaged by shock waves, heat and radiation, Independence survived the Bikini Atoll tests and, like dozens of other Operation Crossroads ships, returned to the United States.
While moored at San Francisco's Hunters Point Naval Shipyard, Independence was the primary focus of the Navy's studies on decontamination until age and the possibility of its sinking led the Navy to tow the blast-damaged carrier to sea for scuttling on Jan. 26, 1951.
"After 64 years on the seafloor, Independence sits on the bottom as if ready to launch its planes," said James Delgado, chief scientist on the Independence mission and maritime heritage director for NOAA's Office of National Marine Sanctuaries.
"This ship fought a long, hard war in the Pacific and after the war was subjected to two atomic blasts that ripped through the ship. It is a reminder of the industrial might and skill of the "greatest generation' that sent not only this ship, but their loved ones to war."

NOAA's interest in Independence is part of a mandated and ongoing two-year mission to locate, map and study historic shipwrecks in Gulf of the Farallones National Marine Sanctuary and nearby waters. The carrier is one of an estimated 300 wrecks in the waters off San Francisco, and the deepest known shipwreck in the sanctuary.

 Boeing has developed an autonomous, unmanned, underwater vehicle -- Echo Ranger -- that can dive 10,000 feet below the ocean's surface to perform a variety of long-endurance, deep-dive missions.
Echo Ranger recently recorded its first autonomous surface exit as it dove 40 feet below the surface of the Pacific on a pre-programmed course.
It later maneuvered to a depth of 400 feet -- all the while sending telemetry to Boeing Marine Systems engineers on tracking boats on the surface above.
Echo Ranger is 18.5 feet long, weighs more than five tons and is capable of traveling up to eight knots and as far as 80 miles without resurfacing.

The mission was conducted last month using an 18.5-foot-long autonomous underwater vehicle (AUV), Echo Ranger, provided by The Boeing Company through a cooperative research and development agreement with NOAA's Office of Oceanic and Atmospheric Research.
Boeing also partnered with technology company Coda Octopus to integrate its 3D-imaging sonar system, Echoscope, into the AUV.
"Boeing is excited for the opportunity to partner with NOAA to utilize this state of the art technology," said Fred Sheldon, Boeing project manager for AUVs.
"The Echo Ranger is uniquely suited for this type of mission and performed perfectly allowing us to conduct a thorough survey of the USS Independence."

Scientists and technicians on the sanctuary vessel R/V Fulmar followed the AUV as it glided 150 feet above the wreck and successfully surveyed the carrier's nearly intact hull.
The survey determined that Independence is upright, slightly listing to starboard, with much of its flight deck intact, and with gaping holes leading to the hangar decks that once housed the carrier's aircraft.

The shipwreck site of the former aircraft carrier, Independence, is located in the northern region of Monterey Bay National Marine Sanctuary.
Half Moon Bay, California was the port of operations for the Independence survey mission.
The first multibeam sonar survey of the Independence site was conducted by the NOAA ship Okeanos Explorer in 2009.

"By using technology to create three-dimensional maps of the seafloor and wrecks like Independence, we can not only explore, but share what we've learned with the public and other scientists," said Frank Cantelas, archaeologist with NOAA's Office of Ocean Exploration and Research, who joined the mission along with Robert Schwemmer, west coast regional maritime heritage coordinator for NOAA's Office of National Marine Sanctuaries.

Delgado, primary author of a 1990 scientific report on the history and archaeology of the ships sunk at Bikini Atoll in the Marshall Islands, said currently there are no plans to enter the vessel or survey drums of hazardous and radioactive waste that were dumped in the sanctuary between 1946 and 1970. No trace of the drums or radiation was observed during the mission, Delgado said.

Gulf of the Farallones National Marine Sanctuary encompasses nearly 3,300 square miles of ocean and coastal waters beyond California's Golden Gate Bridge.
The sanctuary supports an abundance of species including the largest breeding seabird rookery in the contiguous United States, and other species such as whales and white sharks.

Links :

Monday, April 20, 2015

Migrants can't be left to die in the seas of Europe

The "Door of Europe" monument, which commemorates migrants who died on their journey, on the southern Italian island of Lampedusa.
Up to 700 people are believed to have died after a boat capsized in the Mediterranean in the night from Saturday to Sunday.
Photo : Reuters

From The Guardian by Patrick Kingsley

The EU needs to find better answers on immigration as ending the Mare Nostrum search-and-rescue operation has not stopped desperate people from attempting this perilous journey

Tragically, it’s Groundhog Day in the Mediterranean.
Around 400 migrants are feared dead after drowning between Libya and Italy.
And just two days ago, Italian coastguards rescued over 6,000 stricken migrants who had attempted to reach Europe from the north African coast.

 Map of the routes taken by refugees on their way to Europe

Both scenarios are desperately familiar.
The former echoes disasters in February 2015 and September 2014. And, in fact, most of last summer, which saw record numbers die in the Mediterranean.
Coverage of the latter could have been almost entirely copied from reports published 12 months ago to the week, when a similar number were hauled from the sea during the equivalent weekend of 2014.
There were some who hoped that 2015 might be different.


Last autumn, the EU opted not to create a like-for-like replacement for Operation Mare Nostrum, a huge Italian-run search-and-rescue operation that saved up to 100,000 lives in the Mediterranean last year.
In the words of one British minister, Baroness Anelay, Mare Nostrum created “an unintended ‘pull factor’, encouraging more migrants to attempt the dangerous sea crossing and thereby leading to more tragic and unnecessary deaths”.

Six months on, the facts suggest otherwise.
The number of people who attempted to cross the sea to Italy in the first quarter of 2015 was only fractionally smaller than the number who crossed in the same period last year.
In January and February, when stormy seas usually act as a deterrent to all but the bravest, there were even higher numbers than in 2014
 Only a quiet March brought the overall figure down, and as this week’s news suggests, April constitutes a return to higher levels.


Perhaps more significantly, the number of drownings in the Mediterranean during the first quarter of 2015 rose tenfold.
In fact, if the 2015 death toll continues at the current rate, it will easily pass last year’s record of more than 3,400.
A logical conclusion is that the decision to end Mare Nostrum has so far neither acted as a deterrent, nor prevented more death.

I have spent the past few weeks interviewing migrants who intend to make the journey from the Egyptian coast (second only to Libya as a launchpad for those hoping to reach Italy), as well as the smugglers who they pay to take them.
The message from the smugglers is that business continues as usual.
The message from the migrants is that the dangers they are fleeing from constitute a far greater threat than the risk of drowning at sea.
Many display some awareness of the decision to end Mare Nostrum, but no one says its closure would put them off.
“Even if there was a government decision to drown the migrant boats, there will still be people going by boat because the individual considers himself dead already,” says Abu Jana, who will make for Europe in the coming weeks.
“I don’t think that even if they decided to bomb migrant boats it would change peoples’ decision to go.”
The experience of someone like Abu Jana shows why.
A wanted man in Syria, he cannot return home, and is referred to here by a pseudonym.
Nor can he get a new passport from the Syrian embassy in Cairo, which means he cannot travel legally. Even if he could, most Arab countries are now closed to Syrians.

 photo : National Geographic

Lacking the right paperwork, Abu Jana cannot legally work in Egypt, get a proper rent contract, or register the existence of his two toddler daughters with any national body.
And even if he could, life would hardly be brighter: those Syrians who do live a fuller life in Egypt often encounter xenophobia.
The EU appears to realise that its current policies are unsustainable.
However much it would like migrants to simply disappear, the boats are likely to keep coming as long as repression and conflict in the Middle East and Africa continue to drive the largest wave of mass migration since the second world war.
A revamp of EU migration policies, scheduled for May, is an implicit recognition of this fact.


But it remains to be seen whether the policy reset will lead to long-term solutions.
Leaked ideas include establishing offshore asylum centres in north Africa, and paying the Egyptian and Tunisian authorities to patrol their own maritime borders.
But how would this scheme differ to the patrols and arrests that Egypt already makes?
And could over-burdened offshore centres process migrants fast enough to deter them from the quicker option of the sea?
Without proper solutions, April 2016 will see the same headlines as this year and last.

Links :


Sunday, April 19, 2015

Easter Island environmental opportunity: protecting Rapa Nui’s ocean


The monumental sculpted heads of Chile's Easter Island have stood sentinel over this natural wonder, known as Rapa Nui in local Polynesian language, for centuries.


But the islanders' connection to their bountiful home waters stretches even farther back in history than the statues—as residents make clear in their own voices in this mini-documentary.
Today, Easter Island's surrounding seas—and the islanders themselves—are under threat from illegal fishing.

 Easter Island with the Marine GeoGarage (UKHO chart)

That's why The Pew Charitable Trusts is working with the Rapa Nui community and the Chilean government to create a large, fully protected marine reserve in these ecologically important waters
If designated, the reserve would be one of the largest of its kind in the world, safeguarding the island’s unique ocean environment and traditional fishing practices.