Squids and octopuses — the ‘weeds of the sea’ — are on the rise

(The National Aquarium of New Zealand via AP)

From The Washington Post by Rachel Feltman

I for one welcome our cephalopod overlords.
The number of cephalopods — squid, octopus and other squishy sea aliens — has shot up over the past six decades, even as humanity's influence on the ocean (read: climate change, pollution and overfishing) has caused many marine populations to plummet, according to a study published Monday in Current Biology.

 Japan: Giant deep sea squid swims in bay

In other words, the ocean is becoming a more difficult place to live — and all of that empty space means everything is coming up octopus.
"Cephalopods are often called 'weeds of the sea' as they have a unique set of biological traits, including rapid growth, short lifespans and flexible development," study author Zoë Doubleday of the University of Adelaide said in a statement.
"These allow them to adapt to changing environmental conditions (such as temperature) more quickly than many other marine species, which suggests that they may be benefiting from a changing ocean environment."

The researchers analyzed the rate at which cephalopods have shown up in fishing catches or sampling efforts from 1953 to 2013.
The study included 35 cephalopod species or genera representing six families.
As a whole, they found that the group was thriving and becoming more prolific.

Giant Australian cuttlefish in Spencer Gulf, South Australia. (Scott Portelli)

Doubleday didn't set out trying to show that these populations were booming.
In fact, she and her colleagues were troubled by the apparent decline of the giant Australian cuttlefish.
Luckily, it looks as if things are on the up-and-up for that population as well.
"To determine if similar patterns were occurring elsewhere, we compiled this global-scale database," she explained. "Surprisingly, analyses revealed that cephalopods, as a whole, are in fact increasing; and since this study, cuttlefish numbers from this iconic population near Whyalla are luckily bouncing back."

But while that's great news for the giant Australian cuttlefish, scientists aren't so sure how to feel about an ocean where squid, cuttlefish and other octopods are all on the rise.
“I guess if you're a squid or octopus fisherman, these increases may seem like a great thing,” Benjamin Halpern from the University of California, who wasn't involved in the study, told the Atlantic magazine.
“But such dramatic global changes are quite worrisome. When we change the oceans this much, we move things into a new state — one that we know much less about. We might have more squid on our plates in the short run. What are we risking losing in the long run?”

The point is that we don't really know how an influx of these voracious predators will change the ocean — and that's a little scary.
So should we prepare for a future with a lot more tentacles?
That's unlikely.
Cephalopods may be super versatile, but their population booms are expected to rise and fall in a pretty self-regulating fashion — as was the case with the giant Australian cuttlefish.
In fact, the researchers don't think cephalopods are necessarily safe from the same overfishing that's helped them prosper.
It "will be critical to manage cephalopod stocks appropriately so they do not face the same fate as many of their longer-lived counterparts," they write in the study.

Links :

• Gizmodo : Swarms of Octopus Are Taking Over the Oceans 
• The Guardian : Squids and octopuses thrive as 'weeds of the sea' warm to hotter oceans

‘Biodegradable’ plastics are a big fat lie

 Sailing seas of plastic :

How much plastic is floating in our oceans ?

Explore the map

From HuffingtonPost by Chris d'Angelo

A prediction that the world’s oceans will contain more plastic than fish by 2050 is likely to intensify the push for sustainable, environmentally friendly alternatives.
Biodegradable plastics have long been touted as a “greener” technology, but a new report from the United Nations says these plastics do little, if anything, to actually protect the planet and marine creatures.
“Plastics marked as ‘biodegradable’ do not degrade rapidly in the ocean,” says the report, published Monday.

 Lemon shark is pictured with plastic bag caught around its gills in the Bahamas 

Jonathan Bird via Getty Images

The 179-page report on plastic marine debris is one of several documents released in time for the United Nations Environment Assembly, which kicked off Monday in Nairobi, Kenya.
Plastics, which can cause serious ecological harm, “are now ubiquitous in the ocean, found in every ocean and on every shoreline from the Arctic through the tropics to the Antarctic,” the report states.
Biodegradable plastics — which have been used for shopping bags, water bottles and food containers — are designed to be less durable and capable of degrading quickly in the environment. But the problem, according to the U.N., is that the conditions required for such plastics to break down exist almost exclusively in industrial composters, not in the ocean.
The description is “well-intentioned but wrong,” Jacqueline McGlade, chief scientist at the U.N. Environment Program, told The Guardian.
“A lot of plastics labelled biodegradable, like shopping bags, will only break down in temperatures of [122 degrees Fahrenheit] and that is not the ocean,” McGlade told the publication.
“They are also not buoyant, so they’re going to sink, so they’re not going to be exposed to UV and break down.”

 Plastic garbage is pictured on Eastern Island, in the Northwest Hawaiian Islands.

Roberta Olenick via Getty Images

The U.N. estimates that global plastic production grew 4 percent from 2013 to 2014, exceeding 311 million metric tons. At least 8 million metric tons — the equivalent of one garbage truck every minute — leak into the ocean each year, according to the World Economic Forum.
The U.N. says improving waste collection and management is the “most urgent solution” to reducing plastic litter, but social attitudes are also critical.
“There is a moral argument that we should not allow the ocean to become further polluted with plastic waste, and that marine littering should be considered a ‘common concern of humankind,’” the report says.
In other words, don’t pat yourself on the back the next time you reach for those biodegradable plastic bags.
We need to do a lot more than that.

Links :

• The Guardian : Biodegradable plastic 'false solution' for ocean waste problem 
• GeoGraage blog : A plastic ocean / Plastic by the numbers in the Atlantic Ocean / We can solve the ocean plastic problem / Mediterranean Sea as afflicted by plastic dumping as the big oceans / Study finds rising levels of plastics in oceans / Full scale of plastic in the world's oceans revealed for first time / First of its kind map reveals extent of ocean plastic / Ocean garbage patch is mysteriously disappearing / How much plastic is in the ocean ? / "Recycled Island" turns ocean plastic into a paradise

How can modern satellites photos possibly be accurate to 20 centimeters in 10 kilometers?

3D WorldView-1 satellite view showing some of the ground survey points in PhotoSat’s Eritrea test area.

 From GIScafé by Gerry Mitchell (Photosat)

My intuition rebels at the notion that a satellite orbiting 750 kilometers above the earth, traveling at 7 kilometers per second could possibly take photos of the ground accurate to 20 centimeters in 10 kilometers.
When I realize that these satellites have scanning cameras which take their photos like push brooms, with the north end of the photo taken a few milliseconds before or after the south end, and that the whole satellite is vibrating while the photos are taken, my mind boggles.
It just does not seem that such high accuracy should be possible.
The satellite photos themselves, checked with tens of thousands of ground survey points, clearly demonstrate that the accuracy is real.

How do the satellites and cameras work?

We engineers and geoscientists in the commercial realm don’t actually know how these satellites and cameras really work.
Almost all of the technical details of the imaging satellites, their cameras and their ground processing stations, are classified.
Or if they are not classified they are certainly very difficult to discover.
I have had many conversations with satellite engineers who seem like they would love to tell me why their satellites perform so amazingly well.
However, sadly, they are not allowed to.
They simply can’t discuss classified technology with anyone who doesn't have the appropriate security clearances.

Whenever I have one of these conversations it always seems to me that part of what the engineer knows is public and part is classified but the engineer cannot be sure that he or she can remember what is still classified and what isn’t.
Since the engineers don’t have perfect memories it is safest to say nothing.
I have had satellite engineers decline to confirm information that is published on their own company’s websites.
This can make for some very awkward conversations.
We engineers and geoscientists in the commercial world only have access to the satellite photos themselves and very general public information about the satellites and their cameras.

How accurate are the satellite photos?

When the Digital Globe WorldView-1 ( WV1) satellite photos first became commercially available in 2008, PhotoSat acquired stereo photos for a test area in and Eritrea where we had over 45,000 precisely surveyed ground points.
When we shifted the WV1 photos three meters horizontally to match any survey point we were amazed to discover that all of the survey points within 10 kilometers matched the satellite photos to within 20 centimeters.
We eventually documented this discovery in an accuracy study white paper that we presented at conferences and is now published on our web site.

Now, eight years after that initial WorldView-1 accuracy study of the Eritrea test area, we have processed hundreds of satellite photos from the WorldView, Pleiades, SPOT and KOMPSAT satellites and have come to expect this incredible accuracy.
I am still in awe that this is possible and I still don’t know how it is achieved.
I do know that the photos are amazingly accurate.

WorldView-1 satellite photo over the PhotoSat test area in Eritrea.

The over 15,000 ground survey points used to confirm that the satellite photo accuracy is better than 20 centimeters in 10 kilometers are shown as black dots.

The completely black areas are survey points every 20 meters along lines separated by 100 meters.

Colour image of a one meter PhotoSat survey grid produced from the WorldView-1 satellite photos.  The ground survey points demonstrate that the PhotoSat grid is accurate to 35 centimeters in elevation.

Cavitation explained

Cavitation is the formation of vapour cavities in a liquid – i.e. small liquid-free zones ("bubbles" or "voids") – that are the consequence of forces acting upon the liquid. 

t usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low.

When subjected to higher pressure, the voids implode and can generate an intense shock wave.

EgyptAir Flight MS804 crashed in deep seas near underwater mountains

Timeline of the crash

From NBCnews

Investigators searching for wreckage from EgyptAir Flight MS804 may face similar problems to those seeking the missing Malaysia Airlines jet — including tough terrain on the ocean floor and deep, heavy seas, experts said Friday.
Floating debris and personal belongings have been found in the Mediterranean Sea, Egypt's military said, but the hunt continues for the rest of the doomed plane including "black boxes" that could yield vital clues.
Key parts of the Airbus A320 have likely sunk to the seabed and could be hidden by ridges and underwater volcanoes as high as the Alps, according to Simon Boxall from Britain's National Oceanography Centre in Southampton, England.
"This is still a very inaccessible part of the planet," Boxall told NBC News, adding: "Oceans are very good at keeping their secrets."

 Hunt for EgyptAir flight 804 intensifies :

Even modest seas represent a big challenge for searching

While the Mediterranean is usually associated with sunshine and balmy waters, the sea where the jet is thought to have crashed — about 180 miles north of Alexandria, Egypt — is deep and often choppy.
"The depth in that area is in the region of 1.8 miles, which is significant and not much shallower than the area in the Indian Ocean where they are looking for [missing Malaysia Airlines flight] MH370," Boxall said. "We are not talking shallow waters … this is well below what divers could reach."
Flight MS804, which was traveling from Paris to Cairo, disappeared from radar screens early Thursday with 66 people on board. Officials say it descended rapidly from cruising height, making a sharp left turn followed by a 360-degree turn to the right.

Area of the crash in the GeoGarage platform

290 km North of Alexandria (according Egyptian Army)

EgyptAir MS804 wreckage may be on one of the deepest parts of the Mediterranean.
(courtesy of MarineTraffic / video)

"Any substantial parts will likely by now be on the seabed which in this area is quite rocky with mountains and lots of ridges," Boxall said.
"It is not a simple area in which to search and recover things from the seabed. The assumption is that the Med is sunny and calm but I've worked in that area and when it gets rough, it gets very rough."
The faster debris can be recovered from the water, the more experts will be able to discover about what happened to the plane, former NTSB air accident investigator Greg Feith told NBC's TODAY.
"As long as it doesn't get washed ... as long as the exposed parts aren't continually being washed either by wave or tidal action or any kind of grit or sand on the bottom, there should be [explosive] residue ... that forensic folks can actually determine whether or not there was an explosion or ... some sort of deformation due to overload or some sort of breakup of the aircraft."

Swath bathymetry of East Mediterranean

International bathymetric chart of the Mediterranean (IBCM) :

thickness of the Plio-quatenary sediments (IBCM-PQ)

The difficulty of the task will also be determined by the speed and angle at which the jet entered the water.
"If the aircraft hit the sea directly then it will have broken up under the sheer force of impact, but if it was a low angle of approach there could be large sections relatively intact," U.K.-based consultant marine archaeologist Tim Akers said.
"Natural buoyancy could keep some of those parts afloat for a good few days."

 Sentinel-1A detects slick

The Sentinel-1A radar satellite detected a slick in the eastern Mediterranean Sea – in the same area that EgyptAir flight MS804 disappeared early morning of 19 May 2016 on its way from Paris to Cairo. Sentinel-1A acquired this image later in the day at 16:00 GMT (18:00 CEST) in ‘extra-wide swath mode’ of 400 km with horizontal polarisation.

ESA provided it to the relevant authorities to support the search operations.

The 2 km-long slick is located at 33°32' N / 29°13' E – about 40 km southeast of the last known location of the aircraft. Although there is no guarantee that the slick is from the missing airplane, this information could be helpful for the search.
(courtesy of ESA / closer view)

Despite the difficulties, the search for MS804 has several advantages compared to the fruitless two-year hunt for MH370.
Authorities quickly had clear picture of where there plane was last seen, compared to the case of MH370 in which it took days to piece together clues from satellite data.
"The search is much more limited — a small fraction of the area being covered in the Indian Ocean," Boxall said.
"Not only that, but it is in a busy shipping area and is within the flying range of helicopters. The MH370 search area was three days away from the nearest ship and search planes had to turn back for fuel after only a couple of hours."
The Mediterranean Sea is also heavily mapped — in contrast to the uncharted southern Indian Ocean where MH370 searchers had to spend weeks building up a profile of underwater mountains and other potential hazards before sonar searching could begin.

The speedier search also increases the chances that experts can identify the battery-powered "ping" signal from the aircraft's bright orange cockpit voice recorder and flight data recorder.
"The black boxes will still be 'pinging' if they haven't been damaged and it should still be a clear signal," Boxall said.
"It would seem to be a case of 'when' the wreckage is found, rather than 'if.'"

Links :

• The Conversation : EgyptAir MS804: search and rescue at sea is never easy
• The Daily Beast : The Scandal at the Heart of EgyptAir 804: Relying on ’60s Tech to Find It