NIWA survey reveals deep water canyons off Otago coast (NZ)

Survey coverage of part of the Otago canyon complex offshore East Coast, South Island extending from Waitaki Canyon in the north to Hoopers Canyon in the south.

Image is a sun-illuminated digital elevation model.

Depth range 100m (red) to 2000m (purple).
>>> geolocalization with the Marine GeoGarage <<<

From Stuff.co.nz

The first detailed map of part of the Great South Basin provides clues to the area's seafloor life, along with data that could be useful in any exploration of the area for petroleum.
Niwa research ship Tangaroa mapped a 16,000sq km area off the Otago coast last month.

Detail of the survey coverage of the Otago canyon complex. 

It revealed the structure of nine canyons which are part of a much larger system which ends about 1100km east of New Zealand in a large deep apron-shaped sediment deposit in the Bounty Trough.
Niwa said the Great South Basin had not been mapped in detail before.
The survey provided new information about geological processes in the region, as well as clues about the types of seafloor life that might live there.

 Map of survey area Canterbury and Great South Basins.

Niwa geologist Dr Helen Neil said the intricate map showed the detail of many near-shore canyons along the eastern South Island continental slope.
They formed a set of tributaries sending sediment to the deep sea.
“It gives us a far greater idea of the structure of the Otago canyon complex. This entire system has a really long history," she said.

 NIWA seafloor mapping of Auckland’s doorstep

Hauraki Gulf Bathymetry
>>> geolocalization with the Marine GeoGarage <<<

The map can also help with the development of a biodiversity assessment of the area that could be used to establish an environmental baseline, evaluate the potential environmental effects of any oil drilling, and help establish environmental guidelines specific to the area.

“We know something about the animals that live in the shallow areas of the canyons, but we don’t know what is in the really deep parts, particularly in the trough where oil drilling may occur in the future,” Niwa seabed ecologist Dr Ashley Rowden said.

Previous sampling of the shallower areas at the heads of the canyons, down to about 200 metres, had provided information about the make up of the seafloor communities in those areas, which included worms, crabs and fish.

The maps also showed pock marks - about 20 metres deep and 200 metres in diameter - along the margin at depths of between 550 metres and 875 metres.

That was the typical depth for methane seepage.
The marks formed when gas or fluid was released.
If methane was still seeping out of those areas they could support particular types of communities where micro-organisms generated energy from the gas.

Another group of organisms, such as clams and tubeworms, kept those micro-organisms inside them. Dr Neil said canyons in the area mapped reached depths of around 750 metres, around 5km to 15km along their length.
They extended in the North, Central and South channels which ultimately merged to form Bounty Channel, which runs through the Bounty Trough.
The trough formed when the Chatham Rise to the north and the Campbell Plateau to the south pulled apart in a tectonic rift about 55 to 60 million years ago.

Since that time some form of channel in the area had been feeding sediment from the land to the deep sea.
The depression was now more than 1000km long and several hundred kilometres wide, Dr Neil said.

Layers of sediment were laid down when big mixtures of material came down the canyon system and overflowed it.
Such events happened repeatedly, although the amount of time between events varied.
Sediment was not being distributed now in the way it had been in the past as the sea level was higher and New Zealand did not have an aggressive glacial environment.
There was also less erosion from the Southern Alps.
Most of the sediment that did come down was trapped in lakes, Dr Neil said.

Canyon, channel, fan systems were important sources of information about climatic events, oceanographic changes, and events onshore.
The sedimentary record that accumulated in those systems could give important insights into major tectonic, climatic and sea level changes of the past.
In the wider Bounty Trough region some research had been done looking through sediments, either physically by taking sediment cores, or by taking a seismic record penetrating through the seafloor.

In the newly mapped area maybe only four or five sites had been sampled, and that was purely for exploratory geology, not for biodiversity, Dr Neil said.

Using the map the seabed could be divided into different types of area, such as channels, flats and slopes, which provided target areas to sample.
Representative areas could then be sampled to find out what organisms were present.
Niwa said data from the survey could also support petroleum exploration of the area.

Links :

• FIS : NIWA undertakes sea floor mapping survey

Oceans, into the Blue

From BBC 

As an air-breathing animal, the human is not built to survive in water.

But people have found ways to live an almost aquatic life so they can exploit the sea's riches.

From a 'shark-whisperer' in the Pacific to Brazilian fishermen collaborating with dolphins to catch mullet, this journey into the blue reveals astonishing tales of ingenuity and bravery.

Daredevil Galician barnacle-collectors defy death on the rocks for a catch worth £200 per kilo.

In Indonesia an epic whale-hunt, using traditional hand-made boats and harpoons, brings in a sperm whale.

The Bajau 'sea Gypsies' of the Sulu Sea spend so much time on water they get 'land sick' when they set foot on the land!

We dive 40 metres down to the dangerous world of the Pa-aling fishermen, where dozens of young men, breathing air through a tangled web of pipes attached to a diesel engine, capture thousands of fish in a vast net.

We see how surfing has its origins in the ancient beliefs of the ocean-loving Polynesians, and we join a Borneo free-diving spear-fisherman on a breath-taking journey 20 metres down in search of supper.

Image of the week : Tropical storm Isaac in the Caribbean

Tropical Storm Isaac still lacks organization in its inner core and limited strengthening is expected before the cyclone begins to interact with Hispaniola in the next 24 hours.

Isaac is forecast to change little as it moves over portions of Cuba, but has opportunities to strengthen once it moves over the Straights of Florida and into the Gulf of Mexico.

This image was taken by GOES East at 1315Z on August 24, 2012.

Links :

• Google Crisis Response : State of Florida emergency / Tropical storm Isaac
• ESRI : Hurricane & Cyclone map
• Weather Channel (Stamen) : Hurricane tracker
• StormAdvisory
  

Dazzling map shows more than 150 years of hurricanes

Hurricanes and tropical storms since 1851, as far as we can tell.

You are looking up at the Earth; Antarctica at center, the Americas to the right, Australia and Asia to the left, and Africa at the bottom. (source IDVSolutions)

From OurAmazingPlanet

A new map done up in glowing colors reveals the swirling paths hurricanes and tropical storms have tread across our planet since 1851.

If it looks a little odd at first, it's because this hurricane map offers a unique perspective of the Earth; Antarctica is smack in the middle, and the rest of the planet unfurls around it like the petals of a tulip.
The Americas are on the right, Asia is on the left; the storms plotted on the map grow brighter as their intensity increases.

 Here are 33 years of hurricane seasons lobbed into a bloated and clunky animation (it may take a few moments to fully paint in) : only retained the newest 33 years of data, sourced form the original visualization of hurricanes since 1851, to get a baseline sense of activity all over the globe (collection was less consistent in earlier years).

The effect is not only informative — more than 150 years of hurricane data show that certain regions are consistently in the storms' crosshairs — but also arresting.

 This test image reveals a timeline visualization of where storm data is collected around the world.

Mapmaker John Nelson, the user experience and mapping manager for IDV Solutions, a data visualization company, said that this oddball point of view was the best way to tell the story of the data.
"When I put it onto a rectangular map it was neat looking, but a little bit disappointing," Nelson told OurAmazingPlanet.
But the unorthodox, bottom-up perspective allowed the curving paths the storms make across the world's oceans to shine, he said.

Nelson used U.S. government data on tropical storms and hurricanes from 1851 through 2010.
A quick glance at the map shows that the number of storms leapt up in the latter half of the 20th century, though that's because of technological advances.

With the advent of satellites and hurricane-hunting aircraft, officials at the National Oceanic and Atmospheric Administration began to see storms that their predecessors in earlier ages would have missed.

 The storm is producing thunderstorms and strong winds.

Hurricane Chris, the first of the 2012 Atlantic hurricane season, is a perfect example.
That storm stayed far out to sea from birth to death, and likely wouldn't have made it into the record in the first half of the 20th century.

In addition, the dearth of storms in the Eastern and Southern Hemispheres is also a product of a lack of data.
The United States began to add storms from these regions to the archive beginning only in 1978.

The hurricane map is the latest in a series of maps Nelson has made that showcase the planet's natural phenomena in arresting ways.

 

More than 100 years of earthquakes glow on a world map.
Credit: John Nelson, IDV Solutions.

A map of the world's earthquakes since 1898 and a map of the rise in U.S. wildfires since 2001 also offer unique, wide-scale looks at natural disasters.

Could man-made clouds halt global warming by reflecting sunlight?

Clouds and skies: The paper by University of Washington physicist Rob Wood suggests the scientific community should explore cloud-seeding ideas

Scientist calls for experiments using ships which shoot seawater into the sky
Washington University physicist says concept should be explored and tested despite ethical concerns
Idea is controversial in case governments use weather-technology for combat or political control

From DailyMail

Researchers are exploring a controversial idea that uses ships to shoot saltwater high into the sky over the oceans, creating clouds that reflect sunlight and thus counter global warming.
University of Washington atmospheric physicist Rob Wood is urging the scientific community to explore the possibility of seeding clouds to reflect more sunlight, saying that ethical ramifications - such as what would happen if a government used weather-changing technology for political reasons - should not be a barrier to research.
His paper, published this month, looks at kind of ship would be best to spray the salt water into the sky, how large the water droplets should be and the potential climatological impacts.

A conceptualized image of an unmanned, wind-powered, remotely controlled ship

that could be used to implement cloud brightening. (John McNeill)

Wood describes ways to run experiments to test the concept in a paper published this month in the Philosophical Transactions of the Royal Society.
Wood said that, with enough interest in cloud brightening from the scientific community, funding for an experiment may become possible.
He said: 'What we're trying to do is make the case that this is a beneficial experiment to do.'
Wood aims to encourage more scientists to consider the idea of marine cloud brightening and even poke holes in it.
The theory behind so-called marine cloud brightening is that adding particles, in this case sea salt, to the sky over the ocean would form large, long-lived clouds.
Clouds appear when water forms around particles.
Since there is a limited amount of water in the air, adding more particles creates more, but smaller, droplets.
Wood said: 'It turns out that a greater number of smaller drops has a greater surface area, so it means the clouds reflect a greater amount of light back into space.'
This creates a cooling effect on Earth.
Marine cloud brightening is part of a broader concept known as geoengineering which encompasses efforts to use technology to manipulate the environment.
Brightening, like other geoengineering proposals, is controversial for its ethical and political ramifications and the uncertainty around its impact. But those aren't reasons not to study it, Wood said.
'I would rather that responsible scientists test the idea than groups that might have a vested interest in proving its success,' he said.
The danger with private organizations experimenting with geoengineering is that 'there is an assumption that it's got to work,' he said.
Wood notes that running the experiment would advance knowledge around how particles like pollutants impact the climate, although the main reason to do it would be to test the geoengineering idea.

These may look like airplane contrails, but the streaky clouds shown in this photo-like image formed around the exhaust left in the wake of ships traveling the Northern Pacific Ocean

A phenomenon that inspired marine cloud brightening is ship trails: clouds that form behind the paths of ships crossing the ocean, similar to the trails that airplanes leave across the sky.
Ship trails form around particles released from burning fuel.
But in some cases ship trails make clouds darker.
'We don't really know why that is,' Wood said.
Despite increasing interest from scientists like Wood, there is still strong resistance to cloud brightening.
'It's a quick-fix idea when really what we need to do is move toward a low-carbon emission economy, which is turning out to be a long process,' Wood said.
'I think we ought to know about the possibilities, just in case.'
The authors of the paper are treading cautiously.
'We stress that there would be no justification for deployment of [marine cloud brightening] unless it was clearly established that no significant adverse consequences would result.
There would also need to be an international agreement firmly in favor of such action,' they wrote in the paper's summary.

How it works ? Cloud seeding
Wood and his colleagues propose trying a small-scale experiment to test feasibility and begin to study effects.
The test should start by deploying sprayers on a ship or barge to ensure that they can inject enough particles of the targeted size to the appropriate elevation, Wood and a colleague wrote in the report.
An airplane equipped with sensors would study the physical and chemical characteristics of the particles and how they disperse.
The next step would be to use additional airplanes to study how the cloud develops and how long it remains.
The final phase of the experiment would send out five to 10 ships spread out across a 100 kilometer, or 62 mile, stretch.
The resulting clouds would be large enough so that scientists could use satellites to examine them and their ability to reflect light.
Wood said there is very little chance of long-term effects from such an experiment.
Based on studies of pollutants, which emit particles that cause a similar reaction in clouds, scientists know that the impact of adding particles to clouds lasts only a few days.
Still, such an experiment would be unusual in the world of climate science, where scientists observe rather than actually try to change the atmosphere.