Saturday, April 17, 2010
Friday, April 16, 2010
The world's smallest sea horse
In 2003, marine biologist Sara Lourie, a member of the University of British Columbia-based Project Seahorse marine conservation team, has identified the world's smallest known species of seahorse. The pygmy seahorse called Hippocampus Denise averages 16 mm (.64 inch) in size, smaller than a fingernail, and lives in coral in the tropical waters of the western Pacific.
In 2009, five new pygmy seahorse species were found in the Red Sea.
Hippocampus satomiae, little bigger than a pea, has been recently found on reefs in Indonesia.
Note : animal names ending in -ae honor women, in this case Satomi Onishi, a diving guide who collected the first specimen.
Little bigger than a pea, the smallest known sea horse, was discovered at a depth of about 15 meters on reefs in Indonesia, from Derawan island off Kalimantan to northern Sulawesi and Borneo.
Like other pygmy sea horses, its size and camouflage make it difficult to spot. This species resembles, in texture and color, the sea fans with which it lives. It has a pouch in which it carries its young, which are only 3mm in length.
The sea horse is displayed at the Quentin Wheeler International Institute for Species Exploration, Arizona State University.
The seahorses are a genus of fishes within the family syngnathidae, which also includes the pipefishes.
There are more than 80 species of seahorse, mainly found in shallow tropical and temperate waters throughout the world.
They prefer to live in sheltered areas such as seagrass beds, coral reefs, or mangroves.
Seahorse populations are said to have been endangered in the recent years due to overfishing and habitat destruction.
Links :
Thursday, April 15, 2010
Earth's core, magnetic field changing fast, study says
from Kimberly Johnson's article for National Geographic News, June 2008
Rapid changes in the churning movement of Earth's liquid outer core are weakening the magnetic field in some regions of the planet's surface, a new study says.
"What is so surprising is that rapid, almost sudden, changes take place in the Earth's magnetic field," said study co-author Nils Olsen, a geophysicist at the Danish National Space Center in Copenhagen.
The findings suggest similarly quick changes are simultaneously occurring in the liquid metal, 1,900 miles (3,000 kilometers) below the surface, he said.
The swirling flow of molten iron and nickel around Earth's solid center triggers an electrical current, which generates the planet's magnetic field.
The study, published recently in Nature Geoscience, modeled Earth's magnetic field using nine years of highly accurate satellite data.
Fluctuations in the magnetic field have occurred in several far-flung regions of Earth, the researchers found.
In 2003 scientists found pronounced changes in the magnetic field in the Australasian region. In 2004, however, the changes were focused on Southern Africa.
The changes "may suggest the possibility of an upcoming reversal of the geomagnetic field," said study co-author Mioara Mandea, a scientist at the German Research Centre for Geosciences in Potsdam.
Earth's magnetic field has reversed hundreds of times over the past billion years, and the process could take thousands of years to complete.
The decline in the magnetic field also is opening Earth's upper atmosphere to intense charged particle radiation, scientists say.
Satellite data show the geomagnetic field decreasing in the South Atlantic region, Mandea said, adding that an oval-shaped area east of Brazil is significantly weaker than similar latitudes in other parts of the world.
"It is in this region that the shielding effect of the magnetic field is severely reduced, thus allowing high energy particles of the hard radiation belt to penetrate deep into the upper atmosphere to altitudes below a hundred kilometers (62 miles)" Mandea said.
This radiation does not influence temperatures on Earth. The particles, however, do affect technical and radio equipment and can damage electronic equipment on satellites and airplanes, Olsen of the Danish space center said.
The study documents just how rapidly the flow in Earth's core is changing, said Peter Olson, a geophysics professor at Johns Hopkins University in Baltimore, Maryland, who was not involved with the research.
By using satellite imagery, researchers have a nearly continuous measurement of changes, he said." They provide a good rationale to continue this monitoring longer," Olson said.
On a sailing point of view, this will definitively affect the Magnetic declination calculation.
Links :
Wednesday, April 14, 2010
Scientists learn red grouper operate as underwater architects
By Juliet Eilperin
Washington Post Staff Writer
March 8, 2010
Red grouper are known for a few key characteristics -- their hue, which can range from pink to bright orange; their tastiness, whether they're grilled or sautéed; and their predation method, in which they ambush fellow sea creatures and swallow them whole.
But their least-known attribute might be the most valuable of all: they operate as underwater architects, transforming the seascape for myriad other forms of underwater life, rather than just residing there. That surprising discovery is forcing scientists and policymakers to recalibrate their approach to preserving the ocean's natural order -- and heightening tensions with those who fish for a living or as a hobby.
A team of scientists, led by Florida State University's Felicia Coleman, recently found that the red grouper off Florida's east and west coasts and throughout the Gulf of Mexico have created entire ocean communities by digging large holes in the sea's sandy bottom. In the same way beavers construct dams, red grouper excavate and maintain distinct holes whose rocky surfaces provide a place for coral, sponges and other marine life to congregate.
The discovery, published in January in the Open Fish Science Journal, highlights the extent to which researchers are just beginning to grasp the complexity of marine creatures' behavior.
"Our view of fish is changing," said Marine Conservation Biology Institute president Elliott Norse, whose group helped fund Coleman's research. "We now see fish as living, breathing entities, not only as meat."
This new understanding is changing the way federal and state authorities manage ocean habitats and is creating a stark new rift with fishermen. "The people who are in control want to prohibit fishing as much as possible," said Bob Jones, executive director of the Southeastern Fisheries Association. He added that the recent revelations about red grouper amount to an "excuse they can use to restrict fishing, commercial or recreational."
But to many researchers, fishery officials and even some fishermen, the fact that fish act as environmental engineers provides a compelling reason to protect them from exploitation.
More about the ‘Frank Lloyd Wright’ of the sea : see Washington Post original article
Link :
Washington Post Staff Writer
March 8, 2010
Red grouper are known for a few key characteristics -- their hue, which can range from pink to bright orange; their tastiness, whether they're grilled or sautéed; and their predation method, in which they ambush fellow sea creatures and swallow them whole.
But their least-known attribute might be the most valuable of all: they operate as underwater architects, transforming the seascape for myriad other forms of underwater life, rather than just residing there. That surprising discovery is forcing scientists and policymakers to recalibrate their approach to preserving the ocean's natural order -- and heightening tensions with those who fish for a living or as a hobby.
A team of scientists, led by Florida State University's Felicia Coleman, recently found that the red grouper off Florida's east and west coasts and throughout the Gulf of Mexico have created entire ocean communities by digging large holes in the sea's sandy bottom. In the same way beavers construct dams, red grouper excavate and maintain distinct holes whose rocky surfaces provide a place for coral, sponges and other marine life to congregate.
The discovery, published in January in the Open Fish Science Journal, highlights the extent to which researchers are just beginning to grasp the complexity of marine creatures' behavior.
"Our view of fish is changing," said Marine Conservation Biology Institute president Elliott Norse, whose group helped fund Coleman's research. "We now see fish as living, breathing entities, not only as meat."
This new understanding is changing the way federal and state authorities manage ocean habitats and is creating a stark new rift with fishermen. "The people who are in control want to prohibit fishing as much as possible," said Bob Jones, executive director of the Southeastern Fisheries Association. He added that the recent revelations about red grouper amount to an "excuse they can use to restrict fishing, commercial or recreational."
But to many researchers, fishery officials and even some fishermen, the fact that fish act as environmental engineers provides a compelling reason to protect them from exploitation.
More about the ‘Frank Lloyd Wright’ of the sea : see Washington Post original article
Link :
Tuesday, April 13, 2010
Illuminating the hidden planet: the future of seafloor observatory science
© National Geographic , video from the University of Victoria & Neptune Canada
Nearly 500 miles of data-transmitting cable will make Neptune Canada's new Pacific Ocean observatory the largest of its kind. Underwater cameras will also capture seafloor wildlife.
This week, scientists in British Columbia began collecting data from hundreds of scientific instruments on the seafloor of the Pacific Ocean using the largest and most advanced cabled ocean observatory in the world.
While data collection is its primary goal, underwater cameras add to the allure of this project, so scientists can see the animals living on and near the ocean floor.
Nearly 500 miles of looped cable carries both electricity and fiber optic lines for data transmission in both directions for the project known as Neptune Canada, an acronym for North-East Pacific Time-series Underwater Networked Experiments. The observatory, with 6 sites for data collection, stretches from Vancouver Island, over the Pacific continental shelf, and into deep ocean.
The projects data collection is available to the public- scientists and students can log onto the internet to see the information. Neptune Canada and its sister program Venus (Victoria Experimental Network Under the Sea) intend to enhance scientists abilities to gather ocean data allowing 24/7 collection, rather than data from infrequent voyages and dives.
With Venus and Neptune, the scientific team can be there any time, to see whats happening on the sea floor and making decisions on how to sample, even though the group is scattered between Victoria and St. Johns.
Part of Neptune Canada aims include applications in the areas of climate change, earthquake and tsunami research, ocean productivity, non-renewable marine resources, and marine animal studies.
Neptune Canada has been in the making for a decade, and its expected to provide information about the ocean floor for the next 25 years.
- Ocean view (Innovation Canada)
Monday, April 12, 2010
This marine animal lives forever
Turritopsis nutricula may be the world’s only “immortal” creature.
Jellyfish usually die after propagating but Turritopsis reverts to a sexually immature stage after reaching adulthood and is capable of rejuvenating itself.
The 4-5mm diameter creature, technically known as a hydrozoan, is the only known animal that is capable of reverting to its juvenile polyp state.
Theoretically, this cycle can repeat indefinitely, rendering it potentially immortal.
Though solitary, they are predatory creatures and mature asexually from a polyp stage.
The jellyfish and its reversal of the ageing process is now the focus of research by marine biologists and geneticists. It is thought to achieve the feat through the cell development process of transdifferentiation, in which cells transform from one type to another.
The switching of cell roles is usually seen only when parts of an organ regenerate. However, it appears to occur normally in the Turritopsis life cycle.
Marine biologists say the jellyfish numbers are rocketing because they need not die. Dr Maria Miglietta of the Smithsonian Tropical Marine Institute said: "We are looking at a worldwide silent invasion."
The jellyfish are originally from the Caribbean but have spread all over the world. Found in warm tropical waters Turritopsis is believed to be spreading across the world as ships’ ballast water is discharged in ports.
Sunday, April 11, 2010
Oceans' fury
French movie from Jean-René Kéruzoré, "Kéru" (Air Vide et Eau)
For celebrating the late arrival of sunny days, after a long stormy winter.
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