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Scientists studying ocean productivity have uncovered a volcanic lost world teeming with marine life off the Tasmanian coast.

Fly through of seamount chain from CSIRO

From CSIRO by Matt Marrison

Scientists studying ocean productivity have uncovered a volcanic lost world teeming with marine life off the Tasmanian coast.

The lost world was uncovered during detailed seafloor mapping by CSIRO research vessel Investigator while on a 25-day research voyage led by scientists from the Australian National University (ANU).

 CSIRO research vessel Investigator ©Owen Foley

The mapping has revealed, for the first time, a diverse chain of volcanic seamounts located in deep water about 400km east of Tasmania.

 Seamounts east of Tasmania with the GeoGarage platform

(not displayed on AHS nautical chart)

The seamounts tower up to 3000m from the surrounding seafloor but the highest peaks are still far beneath the waves, at nearly 2000m below the surface.

Multibeam mapping of Tasmanian seamount chain

Dr Tara Martin, from the CSIRO mapping team, said the mapping offered a window into a previously unseen and spectacular underwater world.
“Our multibeam mapping has revealed in vibrant detail, for the first time, a chain of volcanic seamounts rising up from an abyssal plain about 5000m deep, Dr Martin said.
"The seamounts vary in size and shape, with some having sharp peaks while others have wide flat plateaus, dotted with small conical hills that would have been formed by ancient volcanic activity.
“Having detailed maps of such areas is important to help us better manage and protect these unique marine environments, and provides a stepping stone for future research.
“This is a very diverse landscape and will undoubtedly be a biological hotspot that supports a dazzling array of marine life,” she said.

Mapped chain of volcanic seamounts

Ship data collected during the voyage revealed spikes in ocean productivity over the chain of seamounts, with increased phytoplankton activity and marine animal observations in the area.

Dr Eric Woehler from BirdLife Tasmania, who was on Investigator with a team conducting seabird and marine mammal surveys, was astounded by the amount of life they saw above the seamounts.
“While we were over the chain of seamounts, the ship was visited by large numbers of humpback and long-finned pilot whales,” Dr Woehler said.
“We estimated that at least 28 individual humpback whales visited us on one day, followed by a pod of 60-80 long-finned pilot whales the next.
We also saw large numbers of seabirds in the area including four species of albatross and four species of petrel.”
“Clearly, these seamounts are a biological hotspot that supports life, both directly on them, as well as in the ocean above,” he said.

Black-browed albatross ©Eric Woehler

 

Humpback whales ©Eric Woehler

Research indicates that seamounts may be vital stopping points for some migratory animals, especially whales.
Whales may use these seafloor features as navigational aids during their migration.
“These seamounts may act as an important signpost on an underwater migratory highway for the humpback whales we saw moving from their winter breeding to summer feeding grounds,” Dr Woehler said.
“Lucky for us and our research, we parked right on top of this highway of marine life!”

The life and origin of the seamounts will be further studied later this year when Investigator returns to the region for two further research voyages departing in November and December.

A range of surveys will be conducted on these voyages, including capturing high resolution video of marine life on the seamounts using deep water cameras, and collecting rock samples to better understand their formation and origin.

Dr Woehler will be on the first of these voyages and expects further surprises on the return visit.
“We expect that these seamounts will be a biological hotspot year round, and the summer visit will give us another opportunity to uncover the mysteries of the marine life they support,” said Dr Woehler.

Other seamounts south of Tasmania

 also poorly reported on AHS nautical charts

Research vessel Investigator is Australia’s only research vessel dedicated to blue-water research, and is owned and operated by CSIRO – Australia’s national science agency.
The vessel conducts research year round, and is made available to Australian researchers and their international collaborators.

Links :

• ABC : Whales, seabirds drawn to chain of volcanic seamounts off Tasmanian coast
• CSIRO : Seamounts ecosystems / The Tasmanian seamount chain
• Marine Institute : The Seabed – our final frontier
• GeoGarage blog : Seamounts identified as significant, unexplored ... / Seamount discovery /
  Christmas Island seamounts: is the mystery finally ... / Life thriving on UK's biggest underwater mountains / Scripps mapping subsea mountains taller than Mt ... / New map reveals New Zealand's seafloor in ... / New map exposes previously unseen details of ... / The deep ocean: plunging to new depths to discover ...

The hurricanes, and climate-change questions, keep coming. Yes, They’re linked.

Rising ocean temperatures have fueled some of the most devastating storms in recent years.

Kendra Pierre-Louis, a reporter on The New York Times’s climate team, explains how.

From NYTimes by Henry Fountain

Scientists are increasingly confident of the links between global warming and hurricanes.

In a warming world, they say, hurricanes will be stronger, for a simple reason: Warmer water provides more energy that feeds them.

Hurricanes and other extreme storms will also be wetter, for a simple reason: Warmer air holds more moisture.

And, storm surges from hurricanes will be worse, for a simple reason that has nothing to do with the storms themselves: Sea levels are rising.

 NOAA satellite image of Hurricane Michael off the Gulf Coast, (10/10/2018)

Researchers cannot say, however, that global warming is to blame for the specifics of the latest storm, Hurricane Michael, which grew to Category 4 with sustained winds of 155 miles an hour, as it hit the Florida Panhandle on Wednesday.
Such attribution may come later, when scientists compare the real-world storm to a fantasy-world computer simulation in which humans did not pump billions of tons of carbon dioxide into the atmosphere.

There are already tantalizing suggestions, however, that the warming caused by all those greenhouse-gas emissions has had an impact on Michael.
A 2013 study showed that sea-surface temperatures in the eastern Gulf of Mexico have warmed over the past century by more than what would be expected from natural variability.
These are the waters that the hurricane churned across as it headed toward the Panhandle and its maximum wind speeds more than doubled.

“That general region has been one where there has been long-term climate warming,” said Thomas R. Knutson, a climate scientist with the National Oceanic and Atmospheric Administration and lead author of the study.
“We have reason to believe humans have made the water warmer.”

While there is debate over whether global warming will lead to more frequent hurricanes — many models suggest there may actually be fewer in the future, although with a greater proportion of major ones — scientists are generally agreed about the effects of warming on intensity, as measured by wind speeds.
“We have a very clear theory on how tropical cyclones intensify,” said Suzana J. Camargo, an ocean and climate physicist at Lamont-Doherty Earth Observatory in Palisades, N.Y.

The theory, largely the work of Kerry Emanuel, a scientist at the Massachusetts Institute of Technology, holds that the temperature difference between ocean and upper atmosphere determines how much a storm intensifies.
A bigger temperature difference leads to the release of more energy into the storm.
“The warmer you have the ocean, the bigger the difference,” Dr. Camargo said.

The theory has been reinforced by computer simulations that produce more intense storms with rising ocean temperatures.
“We understand the theory behind it, and we have seen it in the models,” Dr. Camargo said.

As for storms producing more precipitation, the Intergovernmental Panel on Climate Change has concluded that human-caused warming has affected the amount of water vapor in the air, and that extreme precipitation events have already increased in many parts of the world.
The group’s latest report, issued this week, found that such extreme precipitation will likely further increase if the world cannot limit overall warming to 1.5 degrees Celsius (about 2.7 degrees Fahrenheit).

Dr. Knutson cautioned that while this increase in rain and snow amounts has been seen in extreme events in general, of which hurricanes are a subset, “we haven’t actually seen this in the data for hurricanes yet.”
But if a given amount of air flowing into a hurricane carries more water vapor, he said, “that enhances the water supply to the storm so it can create higher rain rates.”

Photo 10/10/2018, 11:52 PM ; source : NOAA

As Hurricane Michael approached land on Wednesday, forecasters warned that the worst damage could come from a storm surge of as much as 13 feet.
Florida, both along the Gulf and the Atlantic Ocean, is exceptionally vulnerable to storm surge, with strings of low-lying communities on the coasts and along waterways that are connected to the sea.

Storm surge occurs when winds pile water up as it approaches land, and many factors — including the contours of the seafloor, topography of bays and inlets and the stage of the tide when the surge hits — can affect it.
But rising sea levels can have an impact, too.
“What’s not emphasized enough is the sea level-rise connection,” Dr. Camargo said.
“Even if there weren’t changes in the hurricane itself, just because you have sea-level rise you end up having more flooding.”

Seas are rising for two main reasons: water expands slightly as it warms, and glaciers and ice sheets add more water as they melt.
But the rise can vary because of local factors like uplift or subsidence of the land.

In the past four decades, global average sea levels have risen by about four inches. That may not seem like much, and in a 15-foot storm surge it may not add much to the destruction.
“But we’re not talking about a few inches anymore by the end of the century,” Dr. Camargo said.
“We’re talking about a foot or so. Then, it makes a difference.”

Links :

• Time : Hurricane Michael Is the Third Most Powerful Storm to Ever Hit the U.S. Mainland
• The Guardian : Hurricane Michael: 'truly historic' category 4 storm on track to hit Florida  / Victims of Hurricane Michael voted for climate deniers / 'It's hyped up': climate change skeptics in the path of Hurricane Florence
• ThinkProgress : Climate change is making monster hurricanes like Michael harder to forecast
• NOLA : Category 6? Climate change could cause hurricanes to strengthen more quickly
• InsideClimateNews : Hurricane Florence’s Unusual Extremes Worsened by Climate Change
• Weather : Climate Change’s Influence on Hurricane Florence: a Wetter and Larger Storm?
• National Geographic : Hurricane Florence's Rains May Be 50% Worse Thanks to Climate Change 
• CleanEnergy blog : Hurricane Michael and Climate Change: What We Know
• AP : Climate change is making hurricanes way more intense
• Inverse : The Relationship Between Hurricane Season and Climate Change, Explained 
• Forbes : What Is 'ACE' That Meteorologists Talk About During Hurricane Season?
• WP : Tracking Tropical Storm Michael 

A 500-year-old map used by Columbus reveals its secrets

Previously hidden text on a 500-year old map reveals new clues about the cartographer’s sources and its influences on important maps that came later.

Images by Lazarus project / Megavision / Rit / Emel, courtesy of the Beinecke library, Yale university

From National Geographic by Greg Miller

Newly uncovered text opens a time capsule of one of history’s most influential maps.

This 1491 map is the best surviving map of the world as Christopher Columbus knew it as he made his first voyage across the Atlantic.
In fact, Columbus likely used a copy of it in planning his journey

Much of the text on the 1491 map by Martellus map had faded to the point of illegibility (top), until researchers used modern imaging tools to uncover much of it (bottom).

The map, created by the German cartographer Henricus Martellus, was originally covered with dozens of legends and bits of descriptive text, all in Latin.
Most of it has faded over the centuries.

 Multispectral imaging uses different wavelengths of light

in different combinations to reveal otherwise invisible features.

These images show the southern tip of India on Martellus’s map.

Invisible with regular light (left), a legend describing the panotii, a type of large-eared, part-human monster was revealed with multispectral imaging. 

This fragment of text on the Martellus map, revealed by multispectral imaging, appears to describe a porcupine that lives in a cave near the northern coast of Asia and throws its spines at men and dogs who hunt them.

But now researchers have used modern technology to uncover much of this previously illegible text.
In the process, they’ve discovered new clues about the sources Martellus used to make his map and confirmed the huge influence it had on later maps, including a famous 1507 map by Martin Waldseemuller that was the first to use the name “America.”

Martellus and Colombus

Contrary to popular myth, 15th-century Europeans did not believe that Columbus would sail off the edge of a flat Earth, says Chet Van Duzer, the map scholar who led the study.
But their understanding of the world was quite different from ours, and Martellus’s map reflects that.

Its depiction of Europe and the Mediterranean Sea is more or less accurate, or at least recognizable.
But southern Africa is oddly shaped like a boot with its toe pointing to the east, and Asia is also twisted out of shape.
The large island in the South Pacific roughly where Australia can actually be found must have been a lucky guess, Van Duzer says, as Europeans wouldn’t discover that continent for another century.
Martellus filled the southern Pacific Ocean with imaginary islands, apparently sharing the common mapmakers’ aversion to empty spaces.

Another quirk of Martellus’s geography helps tie his map to Columbus’s journey: the orientation of Japan.
At the time the map was created, Europeans knew Japan existed, but knew very little about its geography.
Marco Polo’s journals, the best available source of information about East Asia at the time, had nothing to say about the island’s orientation.

When Columbus made landfall in the West Indies on October 12, 1492, he began looking for Japan, still believing that he’d achieved his goal of finding a route to Asia.
He was likely convinced Japan must be near because he’d travelled roughly the same distance that Martellus’s map suggests lay between Europe and Japan, Van Duzer argues in a new book detailing his findings.

Van Duzer says it’s reasonable to speculate that as Columbus sailed down the coast of Central and South America on later voyages, he pictured himself sailing down the coast of Asia as depicted on Martellus’s map.

Multispectral imaging revealed remarkable detail about the rivers, mountains,

and cities of southern Africa on Martellus’s map.

Restoring a time capsule

The map is roughly 3.5 by 6 feet.
Such a large map would have been a luxury object, likely commissioned by a member of the nobility, but there’s no shield or dedication to indicate who that might have been.
It was donated anonymously to Yale University in 1962 and remains in the university’s Beinecke Rare Book & Manuscript Library.

Over time, much of the text had faded to almost perfectly match the background, making it impossible to read.
But in 2014 Van Duzer won a grant from the National Endowment for the Humanities that allowed him and a team of collaborators to use a technique called multispectral imaging to try to uncover the hidden text.

The method involved taking many hundreds of photographs of the map with different wavelengths of light and processing the images to find the combination of wavelengths that best improves legibility on each part of the map.

interactive map created by one of Van Duzer’s colleagues here

Many of the map legends describe the regions of the world and their inhabitants.
“Here are found the Hippopodes: they have a human form but the feet of horses,” reads one previously illegible text over Central Asia.
Another describes “monsters similar to humans whose ears are so large that they can cover their whole body.” Many of these fantastical creatures can be traced to texts written by the ancient Greeks.

The most surprising revelation, however, was in the interior of Africa, Van Duzer says.
Martellus included many details and place names that appear to trace back to an Ethiopian delegation that visited Florence in 1441.
Van Duzer says he knows of no other 15th-century European map that has this much information about the geography of Africa, let alone information derived from native Africans instead of European explorers.
“I was blown away,” he says.

The imaging also strengthens the case that Martellus’s map was a major source for two even more famous cartographic objects: the oldest surviving terrestrial globe, created by Martin Behaim in 1492, and Martin Waldseemuller’s 1507 world map, the first to apply the label “America” to the continents of the western hemisphere.
(The Library of Congress purchased Waldseemuller’s map for a record $10 million in 2003.)

Waldseemuller liberally copied text from Martellus, Van Duzer found after comparing the two maps.
The practice was common in those days—in fact, Martellus himself apparently copied the sea monsters on his map from an encyclopedia published in 1491, an observation that helps date the map.

Despite their commonalities, the maps by Martellus and Waldseemuller have one glaring difference.
Martellus depicts Europe and Africa nearly at the left edge of his map, with only water beyond.
Waldseemuller’s map extends further to the west and depicts new lands on the other side of the Atlantic.
Only 16 years had passed between the making of the two maps, but the world had changed forever.

Martellus’s map shows it running north-south.
Correct, but almost certainly another lucky guess says Van Duzer, as no other known map of the time shows Japan unambiguously oriented this way.
Columbus’s son Ferdinand later wrote that his father believed Japan to be oriented north-south, indicating that he very likely used Martellus’s map as a reference.

Links :

• GeoGarage blog : Map Lab uncovering hidden text on a 500-year-old ... / A map that may have led Columbus to America is ...

Race to clean up fuel spill as container ships collide in the Mediterranean leaving a 12-mile slick off Corsica

The Copernicus Sentinel-1 mission has imaged the oil spill in the Mediterranean following a collision between two merchant ships on Sunday 7 October 2018.

A Tunisian cargo ship is reported to have struck the hull of a Cypriot container ship in waters north of the French island of Corsica.

There were no casualties, but the collision caused a fuel leak – which has resulted in an oil slick about 20 km long.

Although the collision occurred in French waters, the cleanup operation is part of a joint pact between France, Italy and Monaco to address pollution accidents in the Mediterranean.
This image of the slick, which can be seen as a dark patch north of the tip of Corsica, was captured by the Sentinel-1A satellite today at 05:28 GMT (07:28 CEST).
Sentinel-1 is a two-satellite constellation built for the European Commission’s Copernicus environmental monitoring programme. The identical satellites each carry an advanced radar instrument that can ‘see’ through the dark and through clouds.

Its wide swath allows large areas of Earth’s surface to be imaged so that events such as this can be detected and monitored easily.

Sentinel-1 images are used by the European Maritime Safety Agency as part of CleanSeaNet, the European satellite-based oil spill and vessel detection service.
Note: other dark areas show patterns featuring low reflectivity of the radar signal, for instance very calm waters.

From DailyMail by Henry Martin 

A Tunisian freighter rammed into a Cyprus-based vessel off the coast of Corsica

The crash occurred on Sunday roughly 20 miles off the tip of the French island
France and Italy are working to avoid 'ecological consequences' after the crash

French and Italian maritime authorities have begun cleaning up a fuel spill that has spread 12.5 miles in the Mediterranean Sea after two cargo ships collided north of the island of Corsica.

position North of Cap Corse with the GeoGarage platform (SHOM nautical chart)

 picture : MarineTraffic
 

The incident occurred early Sunday when The Ulysse, a Tunisian freighter operated by CTN, rammed into a Cyprus-based CLS Virginia, which was anchored about 20 miles off the northern tip of the French island and not carrying any cargo.

 Images: Alexandre Groyer/French Marine Nationale

The ship's hull was pierced and at least one fuel tank began leaking into the sea off the holiday island of Corsica.

Italy's coast guard said yesterday it is recovering some of the polluted material and monitoring the spill amid changing weather conditions.

According to the CTN's published shipping schedule, the Ulysse was travelling from Genoa in Italy to the Tunisian port at Rades near Tunis.

French Environment Minister Francois de Rugy said some 600 tonnes of propulsion fuel had spilled into the sea.
He condemned the 'abnormal behaviour' of the Tunisian ship in a press briefing at Corsica's Bastia airport after surveying the affected area by helicopter.

Officers of France's paramilitary gendarme police force had been airlifted to the ships to investigate the incident, but it was too early to say what had happened, he added.

Italian anti-pollution vessels have begun pumping the slick, Rugy said, adding that while the collision occurred near the Cap Corse marine reserve, the spill remained outside the park and moving away from Corsica.

The island is known for its pristine waters and beaches.

Aerial views of the area by Falcon 50 @NationalMarine this morning.
French and Italian resources (including Italian tugboat Our Taurus in photo) on site to start treating pollution ribbon.
Credits ©National Navy

'All means are mobilised, civil and military teams, French and Italian are working hard and doing everything so that this accident does not have ecological consequences,' he said.
'The first priority is to extricate the two boats,' Rugy said, adding the operation was 'very complicated', with the Tunisian boat wedged into the Cyprus-based CLS Virginia.

A criminal investigation has been launched for 'pollution' brought on by a 'maritime accident', Marseille prosecutor Xavier Tarabeux said.

Writing on Twitter, Corsica leader Gilles Simeoni said earlier he was determined to find what caused the accident, which occurred in relatively calm seas with good visibility.