Greenland glacier calves island four times the size of Manhattan

From University of Delaware

A University of Delaware researcher reports that an "ice island" four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962.

"In the early morning hours of August 5, 2010, an ice island four times the size of Manhattan was born in northern Greenland," said Andreas Muenchow, associate professor of physical ocean science and engineering at the University of Delaware's College of Earth, Ocean, and Environment. Muenchow's research in Nares Strait, between Greenland and Canada, is supported by the National Science Foundation (NSF).

Satellite imagery of this remote area at 81 degrees N latitude and 61 degrees W longitude (position in the Marine GeoGarage), about 620 miles [1,000 km] south of the North Pole, reveals that Petermann Glacier lost about one-quarter of its 43-mile long [70 km] floating ice-shelf.

Trudy Wohlleben of the Canadian Ice Service discovered the ice island within hours after NASA's MODIS-Aqua satellite took the data on Aug. 5, at 8:40 UTC (4:40 EDT), Muenchow said.
These raw data were downloaded, processed, and analyzed at the University of Delaware in near real-time as part of Muenchow's NSF research.

Petermann Glacier, the parent of the new ice island, is one of the two largest remaining glaciers in Greenland that terminate in floating shelves. The glacier connects the great Greenland ice sheet directly with the ocean.

The new ice island has an area of at least 100 square miles and a thickness up to half the height of the Empire State Building.

"The freshwater stored in this ice island could keep the Delaware or Hudson rivers flowing for more than two years. It could also keep all U.S. public tap water flowing for 120 days," Muenchow said.

The island will enter Nares Strait, a deep waterway between northern Greenland and Canada where, since 2003, a University of Delaware ocean and ice observing array has been maintained by Muenchow with collaborators in Oregon (Prof. Kelly Falkner), British Columbia (Prof. Humfrey Melling), and England (Prof. Helen Johnson).

"In Nares Strait, the ice island will encounter real islands that are all much smaller in size," Muenchow said. "The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents. From there, it will likely follow along the coasts of Baffin Island and Labrador, to reach the Atlantic within the next two years."

The last time such a massive ice island formed was in 1962 when Ward Hunt Ice Shelf calved a 230 square-mile island, smaller pieces of which became lodged between real islands inside Nares Strait.
Petermann Glacier spawned smaller ice islands in 2001 (34 square miles) and 2008 (10 square miles). In 2005, the Ayles Ice Shelf disintegrated and became an ice island (34 square miles) about 60 miles to the west of Petermann Fjord.

Links :

• Wired : Enormous ice block breaks off Greenland glacier
  

Sable island : the graveyard of the Atlantic

Map: known shipwrecks since 1583

From Maritime Museum of the Atlantic

Sable Island, a 44-km-long sand bar about 150 miles east south east of Halifax, Nova Scotia, is renowned for its wild horses (position in the Marine GeoGarage).

For sailors, it was the graveyard of the Atlantic, an island hidden by waves, storms and fog that meant only death and destruction.
Since 1583 there have been over 350 recorded shipwrecks on Sable Island.
Very little now remains of the ships that were wrecked on the island: a shoe buckle, a few coins, ship name boards, timbers buried in the sand.

courtesy of Geographicus

Why so many wrecks?

• Location: Sable lies near one of the world's richest fishing grounds. It is also near one of the major shipping routes between Europe and North America. Hundreds of vessels sailed past each year.

• It's a very stormy place: Sable lies right in the path of most storms that track up the Atlantic coast of North America. Storms were extremely treacherous for sailing ships. Vessels were simply blown onto Sable.

• Fog shrouds the island: in summer warm air from the Gulf Stream produces dense banks of fog when it hits air cooled by the Labrador Current around Sable. Sable has 125 days of fog a year. Toronto has 35.

• The currents around Sable are tricky: Sable lies near the junction of three major ocean currents, the Gulf Stream, the Labrador Current and the Belle Isle Current.

There have been few shipwrecks on Sable since 1947.
Prior to then the sextant was the principal instrument used to fix a ship's position.
Sextants were accurate, but they worked by taking a sighting from the sun or the stars.
They were useless in dense fog or cloudy skies.

In bad weather, the captain navigated by "dead reckoning", using the ship's speed and direction to estimate his position.
But even in good conditions this was educated guessing.
Currents and storms confused the calculations of the best skippers.
Many accounts of shipwrecks report that the captain simply lost his way: he misjudged his ship's position and bumped into Sable Island by mistake.

After World War II radar and other advanced navigational equipment became widely used on commercial vessels.
Sable ceased to be a major threat to shipping.
Only one vessel has been lost since 1947, the small yacht Merrimac which sank on July 27, 1999.

Links :

• Sable island : a story of survival
• Strange map : the graveyard of the Atlantic
• Virtual Museum
• Video
  

Generating energy from ocean waters off Hawaii

The $250 million successful USA renewable energy effort dismissed with one paragraph in 1997 and dropped even from the NREL website

From ScienceDaily

Researchers at the University of Hawaii at Manoa say that the Leeward side of Hawaiian Islands may be ideal for future ocean-based renewable energy plants that would use seawater from the oceans' depths to drive massive heat engines and produce steady amounts of renewable energy.

The technology, referred to as Ocean Thermal Energy Conversion (OTEC), is described in the Journal of Renewable and Sustainable Energy, which is published by the American Institute of Physics (AIP).

It involves placing a heat engine between warm water collected at the ocean's surface and cold water pumped from the deep ocean.
Like a ball rolling downhill, heat flows from the warm reservoir to the cool one.
The greater the temperature difference, the stronger the flow of heat that can be used to do useful work such as spinning a turbine and generating electricity.

The history of OTEC dates back more than a half century.
However, the technology has never taken off -- largely because of the relatively low cost of oil and other fossil fuels.
But if there are any places on Earth where large OTEC facilities would be most cost competitive, it is where the ocean temperature differentials are the greatest.

Analyzing data from the National Oceanic and Atmospheric Administration's National Oceanographic Data Center, the University of Hawaii's Gérard Nihous says that the warm-cold temperature differential is about one degree Celsius greater on the leeward (western) side of the Hawaiian Islands than that on the windward (eastern) side.

This small difference translates to 15 percent more power for an OTEC plant, says Nihous, whose theoretical work focuses on driving down cost and increasing efficiency of future facilities, the biggest hurdles to bringing the technology to the mainstream.

"Testing that was done in the 1980s clearly demonstrates the feasibility of this technology," he says. "Now it's just a matter of paying for it."

Links :

• OTEC News
  
• U.S. Department of Energy selects Lockheed Martin to advance OTEC utility power plans
• Sarasvati project
  

UK update in the Marine GeoGarage

Chart 4148 Approaches to Table Bay (South Africa)

745 charts from UK are now integrated and updated in the Marine GeoGarage UK 'private' layer (+24 since the previous update).

15 charts have been updated from the previous update :

• 675 Harbours and Anchorages on the Coast of Sudan
• 1534 Great Yarrmouth and Approaches
• 1535 Lowestoft and Approaches
• 1543 Winterton Ness to Orford Ness
• 2154 Newhaven Harbour
• 2249 Orkney Islands Western Sheet
• 2250 Orkney Islands Eastern Sheet
• 2695 Plans on the East Coast of England
• 2715 Killala and Donegal
• 3292 Eastern Approaches to Yell Sound, Colgrave Sound and Bluemull Sound
• 3294 Shetland Islands Harbours in Southern Mainland
• 3418 Langstone and Chichester Harbours
• 3741 Rivers Colne and Blackwater
• 3783 Mesaieed (Musay'id or Umm Said)
• 4158 Republic of South Africa - South Coast, Plans in Algoa Bay

Note : new chart data obtained under license with the UKHO and some other international Hydrographic Services :

• Argentina ‑ Servicio de Hidrografia Naval (SHN)
• Belgium ‑Vlaamse Hydrografie
• Spain‑ Instituto Hidrográfico de la Marina
• Croatia ‑ Hvratski Hidrografski Institute (HHI)
• Iceland ‑ Hydrographic Department of the Icelandic Coast Guard
• Malta ‑ Malta Maritime Authority
• Netherlands ‑ Netherlands Hydrographic Office I Dienst De Hydrografie
• Oman‑ National Hydrographic Office, Sultanate of Oman (NHOSO)
• South Africa ‑ South African Navy Hydrographic Office

are right now displayed in the UK layer.

8 charts for Argentina :

• 227 Church Point to Cape Longing including James Ross Island
• Rio Parana - Rosario to Parana
• 2505 Approaches to the Falkland Islands
• 2517 North-Western Approaches to the Falkland Islands
• 2519 South-Western Approaches to the Falkland Islands
• 3560 Gerlache Strait Northern Part
• 3566 Gerlache Strait Southern Part
• 4207 Falkland Islands to Cabo Corrientes and Northeast Georgia Rise

12 charts for Belgium & Netherlands :

• 99 Entrances to Rivers in Guyana and Suriname
• 130 Anguilla to Puerto Rico showing the Approaches to the Virgin Islands
• 266 North Sea Offshore Charts Sheet 11
• 572 Essequibo River to Corentyn River
• 1187 Outer Silver Pit
• 1408 North Sea, Harwich and Rotterdam to Cromer and Terschelling.
• 1503 Outer Dowsing to Smiths Knoll including Indefatigable Banks.
• 1504 Cromer to Orford Ness
• 1630 West Hinder and Outer Gabbard to Vlissingen and Scheveningen
• 1631 DW Routes to Ijmuiden and Texel
• 1632 DW Routes and Friesland Junction to Vlieland
• 2047 Approaches to Anguilla

5 charts for Malta :

• 36 Marsaxlokk
• 177 Valletta Harbours
• 211 Plans in the Maltese Islands
• 2537 Ghawdex (Gozo), Kemmuna (Comino) and the Northern Part of Malta
• 2538 Malta

3 charts for Oman :

• 2854 Northern approaches to Masirah
• 3171 Southern Approaches to the Strait of Hormuz
• 3511 Wudam and Approaches

47 charts for South Africa :

• 578 Cape Columbine to Cape Seal
• 632 Hollandsbird Island to Cape Columbine
• 643 Durban Harbour
• 1236 Saldanha Bay
• 1769 Islands and Anchorages in the South Atlantic Ocean
• 1806 Baia dos Tigres to Conception Bay
• 1846 Table Bay Docks and Approaches
• 1922 RSA - Simon's Bay
• 2078 Port Nolloth to Island Point
• 2086 East London to Port S Johns
• 2087 Port St John's to Durban
• 2088 Durban to Cape Vidal
• 2095 Cape St Blaize to Port S. John's
• 3793 Shixini Point to Port S Johns
• 3794 Port S Johns to Port Shepstone
• 3795 Port Shepstone to Cooper Light
• 3797 Green Point to Tongaat Bluff
• 3859 Cape Cross to Conception Bay
• 3860 Mutzel Bay to Spencer Bay
• 3870 Chamais Bay to Port Nolloth
• 4132 Kunene River to Sand Table Hill
• 4133 Sand Table Hill to Cape Cross
• 4136 Harbours on the West Coasts of Namibia and South Africa
• 4141 Island Point to Cape Deseada
• 4142 Saldanha Bay Harbour
• 4145 Approaches to Saldanha Bay
• 4146 Cape Columbine to Table Bay
• 4148 Approaches to Table Bay
• 4150 Republic of South Africa, South West Coast, Table Bay to Valsbaai
• 4151 Cape Deseada to Table Bay
• 4152 Republic of South Africa, South West Coast, Table Bay to Cape Agulhas
• 4153 Republic of South Africa, South Coast, Cape Agulhas to Cape St. Blaize
• 4154 Mossel Bay
• 4155 Cape St Blaize to Cape St Francis
• 4156 South Africa, Cape St Francis to Great Fish Point
• 4157 South Africa, Approaches to Port Elizabeth
• 4158 Republic of South Africa - South Coast, Plans in Algoa Bay.
• 4159 Great Fish Point to Mbashe Point
• 4162 Approaches to East London
• 4170 Approaches to Durban
• 4172 Tugela River to Ponta do Ouro
• 4173 Approaches to Richards Bay
• 4174 Richards Bay Harbour
• 4204 Walvis Bay to Maputo
• 4205 Agulhas Plateau to Discovery Seamounts
• 4700 Port Elizabeth to Mauritius
• 4160 Ngqura Harbour

10 charts for Spain & Portugal :

• 144 Mediterranean Sea, Gibraltar
• 690 Cabo Delgado to Mikindani Bay
• 1448 Gibraltar Bay
• 1455 Algeciras
• 1727 Bolama and Approaches
• 1740 Livingston Island, Bond Point to Brunow Bay including Juan Carlos 1 Base and Half Moon Island
• 142 Strait of Gibraltar
• 1595 Ilhas do Principe, de Sao Tome and Isla Pagalu
• 3578 Eastern Approaches to the Strait of Gibraltar
• 310 Ponta Grossa to Kuene River

We hope to include charts for Croatia, Iceland plus more charts for Spain and Portugal in our next update.

Note : don't forget to visit the UKHO Notice to Mariners web page for updates to Admiralty Charts by Chart or NM number

Scientists plumb the depths to ask how many fish in the sea

From The Guardian

It has been the biggest and most comprehensive attempt ever to answer that age-old question – how many fish are there in the sea?

Published today, a 10-year study of the diversity, distribution and abundance of life in the world's oceans attempts just that. The Census of Marine Life, which hopes to paint a baseline of marine life, estimates there are more than 230,000 species in our oceans.

"From coast to the open ocean, from the shallows to the deep, from little things like microbes to large things such as fish and whales," said Patricia Miloslavich of Universidad Simón Bolívar, Venezuela and co-senior scientist of the COML. The study also covers crabs, plankton, birds, sponges, worms, squids, sharks and slugs.

A team of more than 360 scientists around the world have spent the past decade surveying 25 regions, from the Antarctic through the temperate and tropical seas to the Arctic to count the different types of plants and animals.

The results show that around a fifth of the world's marine species are crustaceans such as crabs, lobsters, krill and barnacles. Add in molluscs (squid and octopus) and fish (including sharks) and that accounts for up to half of the number of species in the world's seas. The charismatic species often used in conservation campaigning – whales, sea lions, turtles and sea birds – account for less than 2% of the species in the world's oceans.

The surveys have also highlighted major areas of concern for conservationists. "In every region, they've got the same story of a major collapse of what were usually very abundant fish stocks or crabs or crustaceans that are now only 5-10% of what they used to be," said Mark Costello of the Leigh Marine Laboratory, University of Auckland in New Zealand. "These are largely due to over-harvesting and poor management of those fisheries. That's probably the biggest and most consistent threat to marine biodiversity around the world."

The main threats to date include overfishing, degraded habitats, pollution and the arrival of invasive species. But more problems are around the corner: rising water temperatures and acidification thanks to climate change and the growth in areas of the ocean that are low in oxygen and, therefore, unable to support life.

The COML identified enclosed seas such as the Mediterranean, Gulf of Mexico, China's shelves, Baltic, and the Caribbean as having the most threatened biodiversity. "Enclosed seas have the risk that, when you impact it and throw chemicals or other garbage into it, it will not go away so easily as it will from the open ocean," said Miloslavich.

Dense coastal populations of humans also tend to be packed along enclosed seas, meaning increased pollution and extraction of more biodiversity from the water.

The Mediterranean, which contains almost 17,000 identified species, scored the maximum threat rating of five for four of the categories. Scientists studying the Mediterranean identified problems related to increased litter from shipping and munitions across the sea as well as bombs discharged during the Kosovo war.

The Mediterranean also faces problems because of invasive species displacing the creatures that already live there. This sea had the most alien species out of all the 25 regions surveyed by the COML, with more than 600 (4% of the all species present). Most had arrived from the Red Sea via the Suez Canal.

The most diverse regions identified by the COML are around Australia and south-east Asia. "It's also a hotspot for terrestrial biodiversity as well and this has been known for about 100 years," said Costello.

"It looks like that region with the coral reefs has always had a very high rate of speciation. It also has a very diverse range of habitats – from the deepest areas of the oceans to large areas of shallow seas, which can support coral reefs."

Both Australian and Japanese waters contain more than 30,000 species each and are among the most biologically diverse in the world. Next in line are the oceans off China, the Mediterranean Sea and the Gulf of Mexico.

Apart from algae and the seabirds and mammals that travel around the sea, the COML identified the manylight viperfish (Chauliodus sloani) as the most "cosmopolitan" marine creature. Its presence was recorded in around a quarter of the world's seas.

"This inventory was urgently needed for two reasons," said Costello. "First, dwindling expertise in taxonomy impairs society's ability to discover and describe new species. And secondly, marine species have suffered major declines – in some cases 90% losses – because of human activities and may be heading for extinction, as happened to many species on land."

Miloslavich said the COML data would "allow policy-makers to make better and more informed decisions on what areas should be protected for the better management of resources and the ecosystems as well, in order that they keep providing good services."

The results of the survey are published today online at the PLoS ONE journal.
More detailed results will be published in October, at which time the COML will confirm how many species it estimates are in the world's oceans.

And for every marine species of all kinds known to science, COML scientists estimate that at least four have yet to be discovered. They said that around 70% of species of fish have been discovered, for example, but for most other groups likely less than one-third are known.
As of February, the number of marine fish species known to science stood at 16,764, and was growing at around 100 a year.

Scientists estimate that there are almost 22,000 fish species in the world.
The most fruitful potential areas for discovery include the tropics, deep seas and southern hemisphere.

"At the end of the Census of Marine Life, most ocean organisms still remain nameless and their numbers unknown," said Nancy Knowlton, a biologist at the Smithsonian Institution, leader of the COML's coral reef project.
"This is not an admission of failure. The ocean is simply so vast that, after 10 years of hard work, we still have only snapshots, though sometimes detailed, of what the sea contains. But it is an important and impressive start."

Links :

• CoML video / Bizarre species found