Whale poo: the ocean's miracle grow

Whales play an important role in fertilizing the ocean, by carrying nutrients from the deeper water toward the surface, where they defecate.

Meanwhile, fish and zooplankton excrete nutrients in a way that pushes them deeper into the water.

From LiveScience

While many mammals produce excrement in clumps, whale poop is more of a slurry.
"Very liquidy, a flocculent plume," says whale expert Joe Roman at the University of Vermont.
Flocculence is a state of fluffiness, akin to a tuft of wool.

Whale poop doesn't sink to the bottom of the ocean.
Rather the fluffy plume floats at the surface.
And in a new study, Roman and colleague James McCarthy at Harvard University found this phenomenon explains an important way for ocean ecosystems are fertilized.

Smaller organisms, like microbes, plankton and fish, are typically thought of as the stars of the cycling of nutrients through ocean food chains.
However, marine mammals, as big as many of them are, have often been overlooked as players here, according to the researchers.

Whales, by virtue of their nutrient-rich feces, play an important role in transporting nutrients from where they feed, in deep waters, up to the surface, where they often do their business and fertilize tiny, floating plants called phytoplankton, the researchers explain.

"We think whales form a really important direct influence on the production of plants at the base of this food web," McCarthy said.

As part of the research, the team analyzed 16 fecal samples from humpback whales in the Gulf of Maine during two whale-tagging cruises, finding nitrogen concentrations in the humpback whale samples was elevated by as much as two orders of magnitude above typical in this area.
They also incubated the samples, with their constituent microbes and phytoplankton.
Results showed a strong link between the production rate of a form of nitrogen used by microbes and phytoplankton, and whale-poop nitrogen.

The presence of whales allows more phytoplankton to grow, pushing up the production of creatures that eat the phytoplankton, the researchers say of the findings.
The result: "bigger fisheries and higher abundances throughout regions where whales occur in high densities," Roman said.

In some parts of the ocean, nutrient pollution, such as agricultural runoff, over-fertilizes the water creating dead zones, as in the Gulf of Mexico.
However, many areas in the Northern Hemisphere lack sufficient nutrients, including the Gulf of Maine, where this study was conducted.
During the summer, productivity is limited there because of limited nitrogen, such that adding nitrogen to the waters, say, in the form of whale poop, should trigger phytoplankton growth.

The size of whale populations before they were decimated by whaling is not clear, although some genetic evidence indicates that about 10 percent of the original populations remain, according to Roman.

"Anyway you look at it, whales played a much bigger role in ecosystems in the past than they do now," Roman said.

In light of this finding, calls to loosen international restrictions on whaling are ill-conceived, they said.

Links :

• University of Vermont : whale poop pumps up ocean health
• work was published Oct. 11 in the open-access-journal PLoS ONE.

Horizon : the death of the oceans

BBC parts : I / II / III / IV

Sir David Attenborough reveals in this BBC documentary the findings of one of the most ambitious scientific studies of our time - an investigation into what is happening to our oceans. He looks at whether it is too late to save their remarkable biodiversity.

Horizon travels from the cold waters of the North Atlantic to the tropical waters of the Great Barrier Reef to meet the scientists who are transforming our understanding of this unique habitat.
Attenborough explores some of the ways in which we are affecting marine life - from over-fishing to the acidification of sea water.

The film also uncovers the disturbing story of how shipping noise is deafening whales and dolphins, affecting their survival in the future.

Links : Horizon, the death of the oceans? reviews

• TheArtDesk
  
• TheGuardian
• TheIndependant
  

Atlantic, a vast ocean of a million stories

From The Telegraph

In 1903, from a windswept Cape Cod cliff, a Marconi station sent out the first radio message from one head of state to another as President Roosevelt and Edward VII congratulated one another on this remarkable advance.
That day, as Simon Winchester says: 'all the other present-day miracles of long-distance communication began their fantastic and improbably swift spasm of evolution’ (although he does not mention the fact that Guglielmo Marconi also believed his technology could pick up the voices of long-dead men who had drowned in the Atlantic).
Only 50 years before, America and Europe were irrevocably tethered by the first underwater telegraph cable, laid with great difficulty from Ireland to Newfoundland.
Within a century, the Atlantic would be reduced to a six-hour flight and instantaneous communication via satellites circling miles above.
It is such illuminating scenes that Winchester evokes in his wonderful, encyclopedic book, pinpointing key moments in the narrative of an entire ocean and our relationship to it.

We all have our own Atlantics, especially in this island nation whose very identity is shaped by the sea.
Growing up in the port city of Southampton, I was ever aware of the proximity and importance of the Atlantic, from the foghorns I heard from my bedroom and the crates of bananas unloaded in the docks (complete with Caribbean spiders), to my father’s job, testing those same underwater telephone cables.

The Atlantic’s sense of mystery and adventure is perennial, and Winchester charts it in an enthralling manner: from its Permian formation out of the tectonic shifts of Pangaea, to its first encounter with human beings who ventured out on to the beaches of southern Africa at Cape Agulhas, a place where, symbolically, the compass needle swings from magnetic to true north.
Fittingly, it was only when Homo sapiens moved northwards that the ocean asserted its true importance, and even we took our time.
To the classical world, the inland sea of the Mediterranean was an all-encompassing arena; anything beyond the Pillars of Hercules (Gibraltar) represented the fearful, monster-filled unknown.
It was the Vikings and the Basques who opened up the Atlantic to western influence, a process that would lead ultimately to a modern monster of power, Nato.

Following those routes of exploration and exploitation, Winchester’s highly readable prose roves to the extremes of north and south, east and west.
He moves deftly from 18th-century terraces in St Helena, 'a Georgian sanctuary-in-miniature for passing merchants’, via the terrible triangle of the slave trade – from England to Africa and the West Indies and back again, holds filled successively with iron, human beings and sugar – and then to the coeval commerce in whales, through whose 'profound’ legacy America made its first mark on a global economy.

Yet another trade in the ocean’s denizens was as important: that of cod, whose 'white, motherly, nourishing flesh’ not only prompted the Basques’ first epic journeys to the rich fishing grounds of the Grand Banks but also, in its salted form, provided the personal fuel for those voyages.
Winchester excels in such nice detail.
He describes the first packet ships plying the Atlantic from New York to Liverpool, and how their habit of sailing 'in line’ created the notion of ocean 'liner’. In its mid-Victorian heyday, Manhattan’s East River was lined with 500 ships 'like so many waiting stallions’, their forests of masts pointing to the coming American domination of Atlantic trade.

More violent are accounts of the sea as a battlefield, from the Armada and Trafalgar to Scapa Floe and the Falklands. As the ocean swallowed up its dead, it drew a veil over the horror of thousands of men burned, blown up and drowned. Travelling over an unusually calm Bay of Biscay as I did recently, it was hard to imagine that its innocent waters could contain such tragedies.

For a writer, as much as any 'water-gazer’ (to quote Melville), the sense of an invisible past is a potent stimulus to the imagination. Nowadays our only experience of the ocean is a casual glimpse through clouds from a pressurised cabin.
Winchester brings us down to sea level and makes us realise what we owe to the Atlantic.

He also sees storms ahead: 'A great ocean is not a thing to regard with casual disdain. The consequences are myriad, and they are invariably malign.’
In the 20th century, the cod of the Grand Banks fell victim to greed: eight million tons were taken in the first 15 years of factory fishing, as many as were taken in the entire previous century.
We replaced them with our rubbish, including 29,000 tons of radioactive waste dumped by Britain into the sea in the Seventies.

Top-heavy container ships, lacking their predecessors’ charm, create as much carbon as airliners. In a final, chilling chapter, Winchester describes the effects of climate change which he has witnessed first hand.
He concludes that the Atlantic will abide, 'always just minding its business, always just going on’. Whether we will be there to witness it is another matter.

Links :

• TheGuardian : Atlantic, a vast ocean of a million stories by Simon Winchester – review
  

The robotic otter: underwater robot that swims with flippers and can be controlled with a tablet computer

A video of the robot operating in tethered mode shows its ability to react to these visual tags in real time and transmit video back to the underwater tablet.

From DailyMail

Scientists have developed a remote-controlled robot that can receive and carry out commands while underwater.
AQUA is small and nimble, with flippers rather than propellers, and is designed for intricate data collection from shipwrecks and reefs.
The robot, designed by a team of universities from Canada, can be controlled wirelessly using a waterproof tablet computer.
While underwater, divers can program the tablet to display tags onscreen, similar to barcodes read by smartphones. The robot's on-board camera then scans these two-dimensional tags to receive and carry out commands.

Cutting the cord on underwater robots has been a longstanding challenge for scientists.
Water interferes with radio signals, hindering traditional wireless communication via modem. Tethered communication is cumbersome and can create safety issues for divers.
'Having a robot tethered to a vehicle above water creates a scenario where communication between the diver, robot, and surface operator becomes quite complicated,' says Michael Jenkin, professor at York University’s Faculty of Science & Engineering
'Investigating a shipwreck, for example, is a very delicate operation and the diver and robot need to be able to react quickly to changes in the environment. An error or a lag in communication could be dangerous,' Jenkin says.
Realizing there was no device on the market that fit the bill, Jenkin and his team at York's Centre for Vision Research, including the paper's lead author, MSc student Bart Verzijlenberg, set to work constructing a prototype.
The resulting device, fittingly dubbed AQUATablet, is watertight to a depth of 60 feet. Aluminum housing with a clear acrylic cover protects the tablet computer, which can be controlled by a diver using toggle-switches and on-screen prompts.

'A diver at 60 feet can actually teleoperate AQUA 30-40 feet deeper. Needless to say this is much easier on the diver, physically, and much safer,' Jenkin says.
The tablet also allows divers to command the robot much as if they were using a video game joystick; turn the tablet right and AQUA turns right, too.
In this mode, the robot is connected to the tablet by a slim length of optical cable, circumventing many of the issues of a robot-to-surface tether. The optical cable also allows AQUA to provide video feedback from its camera to the operator.
In wireless mode, the robot acknowledges prompts by flashing its on-board light. Its cameras can be used to build 3-D models of the environment which can then be used to guide the robot to particular tasks.
'This is a huge improvement on [a robot] having to travel to the surface to communicate with its operators,' Jenkin says.
In past, divers have used laminated flashcards to visually communicate with robots while underwater. However, these limit the diver to a pre-set sequence of commands.
'It's impossible to anticipate everything you're going to want the robot to do once you get underwater. We wanted to develop a system where we could create commands on the fly, in response to the environment,' he says.

Links :

• Swimming with robots : human robot communication at depth
• A visually guided swimming robot
  

Watch sea traffic from space : S-AIS

Space based Automatic Identification System (S-AIS)

Automatic Identification System (AIS) is a shipboard broadcast system that transmits a vessel's identification, position and other critical data that can be used to assist in navigation and improve maritime safety.

During its last mission, astronauts from the Space Shuttle Atlantis installed an Automatic Identification System antenna on the outside of the International Space Station that will allow astronauts aboard the ISS to monitor signals from the AIS transmitters mandated to be installed on most large ocean-going craft.

Although these VHF signals can be monitored from the Earth's surface, their horizontal range is generally limited to about 75 km (46 mi), leaving large areas of the ocean unwatched.
However, the signals easily reach the 400 km (250 mi) orbit of the ISS.
The European Space Agency sees this experiment as a test platform for a future AIS-monitoring fleet of satellites that will eventually provide worldwide coverage of sea traffic."

Some other players on the market propose S-AIS solutions : SpaceQuest, ORBCOMM, ExactEarth (COMDEV Int.), NSC Norwegian Space Centre all have space based AIS systems using NTS, or Nanosatellite Tracking Ships

A space based receiving system for signals of the automatic identification system (AIS) will extend the coverage of the existing ground network, which is limited to the coastal zone to open seas.
With newly available satellite-based AIS receivers, the complete global ocean shipping fleet of about 60,000 ships (AIS Class A) can be tracked.
The safe processing and distribution of satellite-based AIS messages to authorized users by a public traffic monitoring centre will contribute to a significantly enhanced maritime safety and security.

Links :

• BBC : Norway launches AISSat ship-tracking spacecraft
• ORBCOMM : Worldwide AIS data from Space
  
• ExactEarth : Satellite detection of AIS-SART-EPIRB sea trials
• ESA : Space Station keeps watch on world’s sea traffic