Saturday, January 15, 2011

Barrier reef braces for flood impact

Flood water levels based on mapping by Brisbane City Council and computer modeling
by the Australian Bureau of Meteorology.

From BBCNews

As floodwaters in the
Queensland capital Brisbane begin to recede, scientists are casting their eyes out to sea and wondering whether the region's greatest natural feature, the Great Barrier Reef, will be scarred by the experience.

-> Position in the Marine GeoGarage

This is the world's largest reef system - in fact, the largest thing on Earth made by living organisms, stretching for 2,600km along the coast.
Its myriad of islands and tendrils teem with fish, also supporting dugongs, dolphins, turtles and shellfish - and because of all that, a tourist trade worth several billion dollars per year.

flood waters emerging from Brisbane itself are not a major concern, as the reef lies further north.
But northern rivers are also seeing flow rates way above normal.
As the water floods into the seas west of the reef, it inevitably freshens the environment around the reef; which is not good news.

Flood devastation mapped by high-res sky cams from NearMap
View large map

"Freshwater kills corals, and there is nothing we can do about it," says
Katharina Fabricius, principal research scientist with the Australian Institute of Marine Science.

Queensland is a heavily agricultural state.
And this means that the floodwater brings with it another threat.
Pesticides, herbicides, fertilizers and sediment - mud - are washed off the farms, into the rivers and then onto the reef.
The fertilizers do in the sea what they do on land - stimulate the growth of plants.

But here, that is a problem, as the marine plants cover growing coral, choking it to death.
The sediment also hurts the reef, blocking sunlight and covering the coral fronds.
This run-off degrades the reef at the best of times; but in flood conditions, it becomes much more serious.
"The young corals are highly sensitive to exposure to organically enriched sediments," Dr Fabricius tells BBC News.
"That retards the ability of reefs to recover from the freshwater damage.
"My own research has also shown that increasing levels of nutrients can lead to more seaweed - up to a five-fold increase - and reduce coral biodiversity, with half of the coral species potentially lost from the exposed sites."

Local issue

The sites at highest risk are reefs close to the shore and close to the mouths of rivers discharging floodwater.
For example, the
Keppel group of islands lies about 10km from the shore, in the path of water rushing from the mouth of the Fitzroy River.

Scientists monitoring coral there say they have already seen indications of coral damage, but that is is too early to tell how big the impact is likely to be.

As the floodwater spreads further from land, it dissipates in the seas - but can still have major consequences.
"The waters discharging from the Fitzroy River are moving hundreds of kilometres north and 50-100km offshore," says
Michelle Devlin, a coral reef ecologist from James Cook University in Townsville.
"There is the potential for large areas of the reef to experience river plume water, with potentially damaging levels of nutrients, sediments and pesticides."

Recovery hopes

On their own, the floods would not necessarily be a significant threat.
The region has had them regularly down the years
(see BOM reports)
1991 saw major damage to inshore coral - but it recovered.
"The 1991 flood was extremely hard for the reef - pretty much most of the corals were wiped out down to about six to eight metres of depth, and it took about 10 years for them to recover," says
Alison Jones from Central Queensland University in Rockhampton, through which the Fitzroy flows.
"But they recovered magnificently; we're very spoiled here in terms of the amount of coral and the speed at which it can grow and recover."

However, what concerns scientists most is that this is just one more hit for an ecosystem that is already struggling to cope with many long-term threats.
These include overfishing, climate change, disease, chronic pollution and shipping.
"The problem is that all forms of disturbances, loads of sediments/nutrients/pesticides, as well as bleaching events from warming seawaters, more intense cyclones and more frequent outbreaks of coral predators such as the crown-of-thorns starfish, all increase in frequency and intensity," says Katharine Fabricius.
"This gives the reefs often not enough time to recover before they get hit again."

The crown-of-thorns starfish is a good example of how the various threats interact.
It eats coral polyps, the organisms that actually build reefs.
Overfishing of one of its few predators, the giant triton, allows the starfish population to expand. Meanwhile, in at least one reef system, fertiliser run-off has stimulated the growth of algae, which has provided predators with an alternative food.

Reefs stressed by climatic factors, pollution and disease will be less resilient to attack by the voracious starfish.

Climate of concern

It is likely to be several weeks at least before scientists are able to gauge the true scale of the flood's short-term impacts.
The continuing threat of bad weather means that travel to the reef is constrained.
And it will be some time - the exact period dependend again on weather - before all of the flood's cargo has travelled through the multifarious fronds of the reef system.

The hope is that it will prove to be a one-off hit from which corals, fish and everything else can recover.
The long-term threats, though, remain, despite recent initiatives to reduce agricultural run-off, constrain shipping and fishing, and tackle the crown-of-thorns.

Climate change is likely to hit reefs in the middle of the tropics harder and faster than the Great Barrier Reef.
Neverless, along with ocean acidification also caused by carbon dioxide emissions, it remains the most significant issue for the region, with a 2007 report by the
Great Barrier Reef Marine Park Authority concluding:
"Projections of future sea temperatures suggest that coral bleaching could become an annual phenomenon in the course of this century, threatening to undermine the physical and ecological foundations of this diverse and productive ecosystem."

Links :
  • NASA : Heavy rains in Queensland
  • NASA (2007) : River plumes threaten Great Barrier Reef
  • ESA : Swamped down under
  • GeoSciencesAustralia : Satellite images show flood spread
  • ABCNews : Great Barrier Reef 'should recover' from flood damage

Friday, January 14, 2011

Marine GeoGarage URL generator

Some webmasters of marine websites asked us how to help them to automatically generate some Marine GeoGarage URL from a list of geographical positions (Lat/Lon).
see also : Sharing Marine GeoGarage places

So, this
link is a basic user interface allowing to get a direct access to a geographical position in the Marine GeoGarage.
Notes :

  • Latitude/Longitude (WGS84) : in decimal degrees (DD.DDDDD)
e.g. : 37.91 / -122.35 with plus (+) for North/East & minus (-) for South/West

Note : Got coordinates in degree-minute-second degrees and need them in decimal format fast ?
So calculate DD.DDDDD = DD+MM/60+SS.SSS/3600 or DD+MM.MMM/60
or go to
Zonums for example

  • Chart layer codes :
  1. USA (NOAA) : noa
  2. Bahamas (WaveyLine) : wl
  3. New Zealand (Linz) : nz
  4. Brazil (DHN) : dhn
  5. Argentina (SHN) : shn
  6. UK & misc. (Brit. Adm.) : uk
  7. Canada (CHS) : chs
  8. Australia (AHS) : ahs
  9. ...
  • Zoom : maps on Google Maps have an integer "zoom level" which defines the resolution of the current view. Zoom levels between 0 (the lowest zoom level, in which the entire world can be seen on one map) to 21+ (down to individual buildings) are possible within the default roadmap maps view. Google Maps sets zoom level 0 to encompass the entire earth. Each succeeding zoom level doubles the precision in both horizontal and vertical dimensions. Note: not all zoom levels appear at all locations on the earth. Zoom levels vary depending on location, as data in some parts of the globe is more granular than in other locations.

In the case of multiple geographical positions, it's possible to use in a Unix terminal window the following command-line tool. So passing parameters for lat, lon and code :

curl -d lat=37.91 -d lon=-122.35 -d z=15 -d code=noa

you get the following Marine GeoGarage URL for the corresponding Lat/Lon geographical position (
e.g. : 37.91N/122.35W) :

Swimming stars : dolphins vs humans

From Richard Hammond's Invisible Worlds

In the high speed world, water becomes thick, dense - an alien environment that we struggle to get through.

Over time a strong swimmer can manage about 2 miles an hour.
But that’s nothing compared to other mammals like the dolphin, that can reach speeds 5 times faster.
But it's only in slow motion that we can see why the dolphin is so much at home here, and why we aren't.
Water is 800 times thicker than air - so thick that it pulls and distorts our soft bodies as we swim, causing drag which holds us back.
The water doesn't distort the dolphin's body at all, passing smoothly over it.
The dolphin has much thicker skin, like rubber, that stops his blubber from flapping.

So while we struggle to make headway, the dolphin is barely trying, and when they need to go faster, they can make it look effortless.

Using state-of-the-art technologies,
Richard Hammond goes beyond the limits of the naked eye and explores the hidden secrets of the invisible world around us.

What we can’t see is the rest.
That’s all matter that reflects or emits light over the other 99.99% percent of the spectrum.
In fact, we’re almost blind.

Thursday, January 13, 2011

Fixing incorrect information in Google Maps

We got a couple of emails from users that would like to report incorrect information regarding Google Maps info.
Perhaps a misspelled marina name, incorrect building name in some harbor, etc.

You can read all of your options on this
help page, but in most cases you'll simply want to use the "Report a Problem" link in Google Maps.


Note : that is for Google Maps.
Regarding nautical charts and Marine GeoGarage overlays, don't hesitate to contact us directly and we will redirect the info to the Hydrographic Service concerned by the issue.

What freediving does to the body

Two and a half minutes on one breath.
freedives on one breath to 20 metres to catch a fish.

From BBCNews

With sea levels rising, can humans adapt to a more watery world?
What does this do to the body?

Take a deep breath in - how long until the urge to gasp for air becomes too much?
Perhaps it comes after 30 or 40 seconds.
But the bodies of habitual freedivers, who hold their breath for minutes at a time, can change to be better adapted to the water.

The Bajau people, sometimes known as the sea gypsies of Malaysia and Indonesia, are renowned natural freedivers.
Traditionally, they are born, live and die at sea, and fish by diving 20m (more than 65ft) underwater for minutes at a time on one breath.
At this depth, water pressure is almost three times what it is on the surface, squeezing lungs already deprived of oxygen.

Filmed underwater in real time for the
BBC's Human Planet (see exclusive series trailer), Bajau fisherman Sulbin demonstrates his techniques off the east coast of Sabah, Borneo.
Wearing hand-made wooden goggles and armed with a spear, he first prepares himself mentally.
"I focus my mind on breathing. I only dive once I'm totally relaxed," says Sulbin, who goes into a trance-like state before entering the water.

This degree of mind control is crucial, says freediving instructor
Emma Farrell, the author of One Breath, A Reflection on Freediving.
"You have to be warm and relaxed - you don't want to hyperventilate before taking your last breath."

A Bajau stilt village, built on a coral reef - some settlements are far off shore
The mammalian dive reflex - seen in aquatic animals such as dolphins and otters, and in humans to a lesser extent - helps, says Farrell.
"It's a series of automatic adjustments we make when submerged in cold water. It reduces the heart rate and metabolism to slow the rate you use oxygen."

During breath-holding, oxygen stores reduce and the body starts diverting blood from hands and feet to the vital organs.
Our bodies have a way to compensate.
Underwater pressure constricts the spleen, squeezing out extra haemoglobin, the protein in red corpuscles that carry oxygen around the body.

"Not enough research has been done to know if it wears off when you're not diving," says Farrell. "But I know people who do a lot of deep training - as Sulbin does - whose blood is like that of people living at high altitude."
In high altitudes, there is less oxygen and so the amount of haemoglobin in blood increases.

Seeing underwater

For most of their history, the Bajau have lived on houseboats, or in stilt houses built on coral reefs - some far from shore.
Many report feeling "landsick" on the rare occasions they spend time on dry land.

Thanks to time spent in the water as children when the eyes are developing, the Bajau, in common with other coastal dwelling people, have unusually strong underwater vision.
Their eye muscles have adapted to constrict the pupils more, and to change the lens shape to increase light refraction.

This makes their underwater eyesight twice as strong, according to Anna Gislen, of Sweden's Lund University, who from 2003 has compared the water vision of sea gypsy children of Thailand and Burma with that of European children.
A gap that can narrow with training.

One part of the Bajau body that hasn't fared well is the eardrum, which ruptures at a young age, says Human Planet director Tom Hugh-Jones.
"Sulbin's hearing is shot because he doesn't equalise the pressure in his ears as he dives. He's never had formal dive training. He was taught by his father to hold his breath."

There are evolutionary theories - not widely accepted, he adds - that an early ancestor of modern humans had to adapt to a partially aquatic environment.
The aquatic ape theory suggests this is why humans are largely hairless and have a subcutaneous layer of fat for underwater insulation, and so are better adapted to swimming than near relations such as the great ape.

Bajau children's underwater vision is less blurred than landlubbers of the same age.
But Sulbin and other Bajau divers have little body fat.
The wiry frame of these subsistence fisherman may actually help.

A lean physique is more efficient at using oxygen.
And having little body fat makes Sulbin less buoyant, able to walk across the reef bed with ease.
"This type of freediving - repeatedly diving to depths of 10 to 20m - carries the greatest risk of decompression sickness," says Farrell.
"But you are less likely to get the bends if you are lean, or very well hydrated."

Some Bajau die of the bends from diving - also a risk for compression divers in the Philippines encountered by the Human Planet team.
"Anyone who thinks this is an example of what a non-smoker's lungs can do will be disappointed," says Hugh-Jones.
"Sulbin smokes like a chimney. He says it relaxes his chest."

Links :
  • YouTube : Pa-aling divers, one of the most dangerous fishing methods of all. A 100 strong crew in the Philippines dive to 40 metres, breathing air pumped through makeshift tangled tubes by a rusty compressor.
  • TheGuardian : Unsustainable sea-farers, the last Bajau sea nomads

Wednesday, January 12, 2011

Under pressure: stormy weather sensor for hurricane forecasting

Hurricane Bill nears Cuba in 2009.
A vertical profile from the Cloud-Aerosol Lidar and Infrared Pathfinder satellite (CALIPSO) is overlaid on an image from the Moderate-resolution Imaging Spectroradiometer (MODIS). Credit: NASA


It’s hard to believe that, in this day and age, we don’t have a way to measure sea-level air pressure during hurricanes.
NASA researchers, however, are working on a system that will improve forecasting of severe ocean weather by doing just that.
The device measures sea-level air pressure, a critical component of hurricane formation – and one that has been extremely difficult to capture.

The Differential Absorption Barometric Radar (DIABAR) prototype is scheduled to make its second flight early this year.

DIABAR remotely senses barometric pressure at sea level, which is important in the prediction and forecasting of severe weather, especially hurricanes, over oceans.

But the ability to measure sea-level air pressure is a major missing link in storm observation, says Dr. Bing Lin, an atmospheric scientist at
NASA Langley Research Center in Hampton, Va.

“Air pressure is a driving force of weather systems, especially under severe weather conditions like hurricanes,” he said.
“For severe storms, the forecasts of the intensity and track can be significantly improved by pressure measurements.”

A Hurricane’s Life

A hurricane begins as a tropical wave, a westward-moving area of low air pressure.
As warm, moist air over the ocean rises in the low air-pressure area, surrounding air replaces it, and circulation forms.
This produces strong gusty winds, heavy rain and thunderclouds – a tropical disturbance.

As air pressure drops and winds sustain at 38 mph or more, the disturbance becomes a tropical depression, then a tropical storm, and finally a hurricane with sustained winds of over 73 mph.

Lin hopes eventually to be able to measure sea-level air pressure from aircraft flyovers and space-based satellites.
The local coverage provide by flyovers, combined with a broad perspective from space, will provide enough information to significantly improve the ability of forecasters to determine how intense a hurricane is and where it’s headed.

“Large and frequent sea surface measurements are critically needed,” he said.
“These measurements cannot be made from buoys and aircraft dropsondes. The only hope is from remote sensing using aircraft, unmanned aerial vehicles, and satellites.”

An effort to remotely sense barometric pressure at sea-surface level using microwaves was undertaken at
NASA’s Jet Propulsion Laboratory in Pasadena, Calif., in the 1980s.
“JPL has extensive experience on spaceborne microwave sensors,” said Lin.

First Flight

DIABAR was first deployed on a Navy MH-60S helicopter in 2009 at Naval Air Station Patuxent River in Maryland.

“We flew it, got the results, and it looks great,” said Lin.

The next step is testing this year on a blimp called the
Bullet™ Class 580, the world’s largest airship. E-Green Technologies Inc. in Alabama makes the aircraft.

The 235-foot long, 65-foot diameter lighter-than-air vehicle is designed to fly on algae-based biofuel at speeds up to 74 mph and altitudes up to 20,000 feet.
It will be stationed in a hanger at Moffett Federal Airfield at
NASA Ames Research Center in California.

DIABAR is a partnership between NASA Langley,
Old Dominion University in Norfolk, Va., and the State University of New York at Albany.

Links :
  • NASA's Hurricane ressource page

Tuesday, January 11, 2011

Mountain glacier melt to contribute 12 centimetres to world sea-level increases by 2100

Icebergs along Princess Ragnhild Coast, Antarctica (NASA)

From UniversityBritishColumbiaScience

Melt off from small mountain glaciers and ice caps will contribute about 12 centimetres to world sea-level increases by 2100, according to UBC research published this week in Nature GeoScience (Regionally differentiated contribution of mountain glaciers and ice caps to future sea-level rise).








Radic’s projections don’t include glacier calving--the production of icebergs.



Links :
  • OurAmazingPlanet : Melt of small glaciers could have outsize effect on sea level

Monday, January 10, 2011

Earth's magnetic field shifts

From LiveScience

This means two Florida airports are renumbering their runways.

Odd as this connection may appear on the surface, the

U.S. Geological Survey's Geomagnetism Program.

As if this wasn't enough of a nuisance for navigators, the



Declination also varies depending on location.
Longitude also factors in.



What's going on in Florida?

Travelers have struggled with the complexity of





Every five years, federal agencies tabulate and publish a value called
magnetic variation, which varies by location.




A Much Bigger Change?




end of the world."

Links :

Sunday, January 9, 2011

"Solemates", a superyacht controlled by iPad

From CNN

What do you get when you combine the latest superyacht with an Apple iPad?
Answer: The world's most exclusive app.

Custom-made software from German luxury yacht firm
Lurssen gives passengers control of everything but the captain's steering wheel -- all with the most leisurely brush of their iPad.
"Solemates," the first pleasure yacht to carry the technology, is currently playing host to flamboyant rap tycoon Sean "P. Diddy" Combs, girlfriend Kim Porter and their daughters D'Lila and Jessie, confirmed the yacht's charter firm.

Using complimentary iPads, the millionaire mogul and his family will have control of all the shipboard entertainment and climate systems, the blinds and lights in their cabins, and could even have their Pina Coladas topped-up at the tap of an icon.

"You won't find this app for download in the Apple store any time soon," said Rupert Connor, central agent from chartering firm the Luxury Yacht Group.

Connor, whose company is responsible for leasing "Solemates" on behalf of its owner, says that guests are given the option to customize the app's homepage to suit their preferences.
"For instance, if we have a client who we know is a music industry bigwig, then we'll program the app's homepage to have a prominent shortcut to our high-speed media server's music library, and we'll do our research to make sure we have all the music they'd want to listen to."

Aside from ultra-lux furnishings, a bounty of Jacuzzis and enough flat-screen LCD panels to tile a roof, Connor says "Solemates" also lets guests keep fit in style.
"We've a top-of-the-range al-fresco gym on board, but if you prefer keeping in shape on the dance floor then it converts into a disco, with an $80,000 integrated light and sound system," he said.
And that's not all.
After a round on the inflatable floating trampoline, jet-powered surfboards or James Bond-style underwater "sea bobs," whoever's lucky enough to commandeer the master cabin can wash off in what Connor believes is the world's first yacht-board aromatherapy shower.
"This is aromatherapy direct from the shower-head," said Connor. "It comes in four different flavors: eucalyptus, pine needle, citrus, and peppermint."

However, beyond the high-tech toys and luxury linens, the gizmo-clad superyacht's greatest asset is its crew, says Connor.
"We've an amazingly experienced crew which includes a chef who's worked in some of the best restaurants in Paris and England, a stewardess who speaks five languages and another who is also a cardiothoracic nurse."
After blowing just shy of $1 million in a week, let's hope she's on standby when Diddy sees the bill.

Links :