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
  

Wild seals work as oceanographers’ lab assistants

Elephant seals with electronic tags glued to their heads transmit information tracking the depth of their dives, allowing oceanographers to better map the seafloor (Image: D. Costa)

From ScienceNews

Seals diving for their dinner near Antarctica have surfaced with an extra morsel: information, gathered by electronic tags on the animals’ heads, about the shape of the seafloor there.

The work has revealed previously unknown undersea channels, through which warm water might flow toward fragile ice shelves. And the seals do it all for a fraction of the cost of traditional seafloor mapping done from ships.

“It gives you a much denser picture of what the water depth is than anything you can conceivably do with ship tracks,” says Laurence Padman, an oceanographer at Earth & Space Research in Corvallis, Ore., and a coauthor of an upcoming paper in Geophysical Research Letters describing the technique.

Seals, walruses, whales and other large marine creatures have moonlighted as oceanographers before. Scientists typically glue sensors to the animals’ bodies that measures factors like temperature and salinity. Researchers have used this information to study water temperatures around Greenland, among other topics.

But the new work is the first to extract information on the shape of the seafloor — known as bathymetry — from the sensors, which also measure pressure and hence depth. “You can actually map the ocean floor,” says team member Daniel Costa, a marine biologist at the University of California, Santa Cruz.

The data came from 57 elephant seals, tagged by Costa’s group over five summers at the U.S. Antarctic Marine Living Resources camp in the South Shetland Islands. As the animals swim, the tags record information every few seconds, then relay it via satellite once the seals surface. About 30 percent of the time seals dive all the way to the bottom to forage for food, says Padman, so by studying enough dives for each animal — some 200,000 dives in total — the researchers can deduce where the seafloor lies.

“It’s a novel and useful technique for gathering bathymetry data,” comments Paul Holland, an ocean modeler at the British Antarctic Survey in Cambridge, England.

Within the seal data Padman’s team discovered several significant troughs cutting across the continental slope off the west side of the Antarctic Peninsula. These features hadn’t been mapped before, says Padman, yet they play an important role in ocean circulation. Warm water can flow through such channels and up under the floating ice shelves that extend off Antarctica, such as the Wilkins ice shelf that partially disintegrated in 2008.

Better information on underwater topography could lead to improved models of how the ocean will respond to climate change, says Padman.

Other researchers might now be inspired to dig through seal data to see what features could be mapped, he adds. Ships can cost tens of thousands of dollars a day to operate in Antarctic waters, whereas there is a wealth of readily available information available on seal tags.

“We want to encourage other people who work with seal data to look into it,” says Padman.
“We just thought it was really cool.”

Links :

• NASA : satellites and sea lions, working together to improve ocean models
• NOAA : chart of overwinter movement patterns of Antarctic fur seals
• TOPP : Antarctic Weddell seal tagging project
  

New deep-sea hot springs discovered in the Atlantic

From ScienceDaily

Scientists from the MARUM Center for Marine Environmental Sciences and the Max Planck Institute for Marine Microbiology in Bremen on board the German research vessel Meteor have discovered a new hydrothermal vent 500 kilometres south-west of the Azores.

The vent with chimneys as high as one meter and fluids with temperatures up to 300 degrees Celsius was found at one thousand metres water depth in the middle of the Atlantic Ocean.
The discovery of the new deep-sea vent is remarkable because the area in which it was found has been intensively studied during previous research cruises.
The MARUM and Max Planck researchers describe their discovery in their video blog.

The Bremen scientists were able to find the hydrothermal vent by using the new, latest-generation multibeam echosounder on board the research vessel Meteor that allows the imaging of the water column above the ocean floor with previously unattained precision.
The scientists saw a plume of gas bubbles in the water column at a site about 5 kilometers away from the known large vent field Menez Gwen that they were working on.
A dive with the remote-controlled submarine MARUM-QUEST revealed the new hydrothermal site with smokers and animals typically found at vents on the Mid-Atlantic Ridge.

Since the discovery of the new vent, the scientists have been intensively searching the water column with the multibeam echosounder.
To their astonishment, they have already found at least five other sites with gas plumes.
Some even lie outside the volcanically active spreading zone in areas where hydrothermal activity was previously not assumed to occur.

"Our results indicate that many more of these small active sites exist along the Mid-Atlantic Ridge than previously assumed," said Dr. Nicole Dubilier, the chief scientist of the expedition. "This could change our understanding of the contribution of hydrothermal activity to the thermal budget of the oceans. Our discovery is also exciting because it could provide the answer to a long standing mystery: we do not know how animals travel between the large hydrothermal vents, which are often separated by hundreds to thousands of kilometres from each other. They may be using these smaller sites as stepping stones for their dispersal."

Research on deep-sea hydrothermal vents in the Atlantic is the objective of the 30 marine scientists from Hamburg, Bremen, Kiel, Portugal, and France who have been on board the German research vessel Meteor since September 6th.
The expedition to the submarine volcano Menez Gwen near the Azores is financed by MARUM, the Center for Marine Environmental Sciences in Bremen.
"One of the questions that the team would like to answer is why the hydrothermal sources in this area emit so much methane -- a very potent greenhouse gas," says chief scientist Nicole Dubilier, who is also a member of the Steering Committee of the Census of Marine Life Vents and Seeps project ChEss (Chemosynthetic Ecosystem Science). "Another important focus of the research is the deep-sea mussels that live at the hydrothermal vents and host symbiotic bacteria in their gills. The mussels obtain their nutrition from these bacteria."

Video blog: "News from the main deck"
An expedition on a research vessel is not only marked by great moments, like this discovery; everyday life on the Meteor is also filled with other exciting activities and events. Work on a research vessel goes on round the clock throughout the entire expedition.
In his video podcast "Neues vom Peildeck / News from the observation deck," available through the Hamburg-based newspaper Abendblatt, and in German and English on YouTube, Dennis Fink, a doctoral student at the Max Planck Institute for Marine Microbiology, reports on the activities of the ship's remote-operated vehicle (ROV) MARUM-QUEST, the various instruments used by the scientists and life on board the ship.
In the two-minute video blogs, Fink and his colleagues show fascinating images direct from the sea floor.

Links :

• Wired : Deep-sea vent discovery sets hydrothermal life’s new depth record
  
• WHOI video : Hydrothermal vents

Shipwreck may yield secrets of Antiquity

An ancient shipwreck was found off the coast of Cyprus.
Diver Anastasia Stathara from Greece, a volunteer member of the archaeology team, swims among the cargo amphoras of the wreck.
Credit: University of Cyprus, ARU/Andonis Neofytou

From LiveScience

The examination of a Mediterranean shipwreck from the 4th century B.C. could shed light on ancient sea routes and trade, researchers say.

The remains of a merchant vessel, full of amphoras that probably had been filled with wine, were discovered in 2006 on the seafloor south of the island of Cyprus. A team has been excavating the site, diving and dredging up important pieces, since then.

The wreck was first discovered in 2006 by fishermen. One of the ship's anchors was also uncovered.

The particularly well-preserved remains, especially the amphoras, which were oval, narrow-necked vases, reveal many clues about the ship's story, the research team says in a new paper.

"We know by having studied a lot of these ceramic containers — we have created catalogs with different shapes — we know where they come from and where they date," said Stella Demesticha, a professor of maritime archaeology at the University of Cyprus, who is leading the shipwreck research team.

The amphoras found at this site, she said, are very typical of those made on the Greek island of Chios in the Aegean Sea.

"We know the red wine from Chios was praised," Demesticha told LiveScience. "It was very good quality, very expensive."

A large collection of olive pits was also discovered at the shipwreck site. The scientists don't know whether the olives were packed as a source of food for sailors or were a commodity to be sold.

The archaeologists aren't sure what caused the vessel to sink, but said the fact that it was found pretty far offshore suggests it was probably downed by a storm or a fire.

"There's a lot to learn from this wreck," Demesticha said. "We know that wine commerce was flourishing in antiquity. But because we haven't excavated many shipwrecks, we don't know many details about how exactly this was happening."

For example, she said, researchers would like to know how cargo was stowed on ships, as well as how trade deals were brokered and how many transactions took place, particularly between people from the Aegean (between Greece and Turkey) and the rest of the Mediterranean, including Cyprus.

"By studying the cargo of the ship, we're going to find more details about contacts between the two areas in that period," Demesticha said.

The findings so far are detailed in a paper in the December 2010 issue of the International Journal of Nautical Archaeology.

Brazil DHN update in the Marine GeoGarage

Rio Paraguai

31 charts have been updated on the Marine GeoGarage (10-09-28 DHN update) in the set of 226 charts :

• 3300 DA ISLA BANCO MORALES À BAHÍA DE ASUNCIÓN
• 3301 DO PUERTO BOTÁNICO À PUENTE REMANSO CASTILLO
• 3302 DO RIACHO SAN FRANCISCO (BOCA INFERIOR) À VILLA HAYES
• 3303 DE PIQUETE-CUÉ À VUELTA ARECUTACUÁ
• 3321 DO PASO ROMERO-CUÉ A ISLA SAN ALFREDO
• 3322 DA ISLA SAN ALFREDO A ISLA SAN JUAN
• 3323 DO PUERTO SAN JUAN AO PUERTO LA NOVIA
• 3324 DO PUERTO LA NOVIA A ISLA SAN CARLOS
• 3325 DA ISLA SAN CARLOS A ISLA PIQUETE-CAMBÁ
• 3326 DA ISLA PIQUETE-CAMBÁ AO PASO ITÁ-PUCÚ-MÍ
• 3327 DO PASO ITÁ-PUCÚ-MÍ AO PUERTO MAX
• 3328 DA ISLA CAÁ-PUCÚ-MÍ A ISLA CARAYACITO
• 3329 DE ITACUÁ AO PUERTO RISSO
• 3330 DO PUERTO RISSO A ISLA DALMACIA
• 3331 DA ISLA DALMACIA A ISLA SAN ROQUE
• 3367 DA VOLTA DO GATO A ILHA DO SOBRADINHO OU PESCADOR
• 3368 DO PASSO DO PESCADOR A ILHA PASSARINHO PRETO
• 3369 DA CANCHA DO TUIUIU A CANCHA DO PIUVAL
• 3370 DA VOLTA MORCEGUEIRO AO PASSO DA FAIA
• 3371 DO PASSO DA FAIA A VOLTA GRANDE
• 3372 DA VOLTA GRANDE A ILHA ESTREITA OU PIMENTEIRA
• 3373 DA VOLTA DA SARACURA AO ESTIRÃO DOMINGOS RAMOS
• 3374 DO PASSO DOMINGOS RAMOS INFERIOR AO PASSO DOMINGOS RAMOS SUPERIOR
• 3375 DA VOLTA DO CARANDAZINHO A VOLTA DO CURURU
• 3378 DO PASSO DO TUCANO À ORÇADA LARANJEIRA
• 3379 DA ORÇADA LARANJEIRA À ILHA LARANJEIRA
• 3388 DA ILHA DA FIGUEIRA AO RIO BOCA DO JOÃO
• 3390 DO MORRO DOURADOS À BOCA DO AMOLAR
• 3391 DO AMOLAR À BOCA DE SÃO GONÇALO
• 3392 DA BOCA SÃO GONÇALO AO ESTIRÃO ZÉ DIAS
• 21010 DE CAYENNE AO CABO GURUPI