Archive for 08/16/2011

Hydro International –

The mission to find and study the deep sea vent field on the mid Atlantic Ridge was undertaken from the Irish research vessel, RV Celtic Explorer.  The deep-rated ROV Holland 1 was required to operate in the challenging conditions created by hydrothermal vents.  These vents occur where cracks in the Earth’s crust allow sea water to penetrate downwards into areas of subterranean volcanic activity. 

The seawater is not only heated to boiling point, but also permeated with dissolved minerals and suspended solids from the molten rock. This heated seawater then gushes back upwards into the ocean giving rise to what looks like miniature erupting volcanoes.

 “On the first dive, we found the edge of the vent field within two hours of arriving on the seafloor,” said Dr Andy Wheeler, who led the expedition. “The ROV descended a seemingly bottomless underwater cliff into the abyss.

We never reached the bottom, but rising up from below were these chimneys of metal sulphides belching black plumes of mineral-rich superheated water. Often the search for vents takes much longer, and our success is a testament to the excellent equipment on board and the hard work and skill of everyone involved.”  

Because of the extreme depth and the importance of monitoring the precise location of the ROV as it navigated the difficult conditions, the research team selected Sonardyne’s Ranger 2 acoustic positioning technology. 

This system is specifically designed for deep water, long range tracking of underwater vehicles and is widely used throughout the offshore oil, ocean science and marine survey industries.

Sonardyne’s engineers fitted Holland 1 with a high-power acoustic transponder communicating with a transceiver mounted onboard the RV Celtic Explorer.  From this, the system is able to calculate the range and bearing of the underwater target with great precision. 

Ranger 2 incorporates the latest Wideband 2 signal technology which allows the vehicle’s real time position to be accurately monitored despite the noise pollution generated by the hydrothermal vent plumes.

Full story…

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RT –

The Royal Dutch Shell oil spill in the North Sea is the most substantial in the last decade but will disperse naturally, say both the company and the UK government.

The global oil and gas company Shell estimated on Monday that 54,600 gallons of oil have spilled into the North Sea from its oil rig off the Scottish coast.

This is a significant spill in the context of annual amounts of oil spilled in the North Sea,” said Glen Cayley, technical director of Shell’s exploration and production activities in Europe.

Cayley added he believed the waves would disperse the oil and the spill was not expected to reach the shore.

The forecast was backed up by the UK Department of Energy and Climate Change.

It is not anticipated that the oil will reach the shore and indeed it is expected that it will be dispersed naturally,” they were quoted as saying by The Daily Telegraph newspaper.

Nevertheless, the government finds the volume of leaked oil substantial enough for the country’s continental shelf, even if the leak is small compared to the BP spill in the Gulf of Mexico last year, which dumped 206 million gallons of oil into the Gulf.

The government has commissioned the Maritime and Coastguard Agency, which monitors the waters around Britain, to make daily flights over the area to monitor the situation in the North Sea. The Scottish authorities also say they are following the incident, but they are pressing Shell for more transparency.

The spill, which began five days ago some 180km in the sea off the city of Aberdeen, was only acknowledged by the oil giant two days later. According to Shell, the leak is still ongoing at the volume of some five barrels a day. The company also says there is some hydraulic fluid in the spill, but all the people on the oil rig are safe and the platform is still operating.

Full story…

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John DeLapp –

A potentially dangerous fish has made its way to the Texas Coast and it is not far from Galveston.

Three separate lionfish have been spotted at Flower Garden Banks National Maritime Sanctuary, which lies east of Galveston and about 100 miles south of the Texas-Louisiana border. The coral reefs there are popular among scuba divers and fishing enthusiasts.

The lionfish is a distinctive-looking animal native to the semitropical waters off Southeast Asia. It is striped, has long, venomous spines and large fins. Adults are about 12 inches long.

But it is not the way the lionfish looks that has people concerned. It’s the fact that it is a voracious predator.

“It lives off (reefs and structures like oil rigs) and feeds on other important recreational and commercial fish, like grouper and snapper,” said Lance Robinson, executive director of coastal fisheries for the Texas Parks and Wildlife Department.

Emma Hickerson, a research coordinator at Flower Garden Banks, agreed.

“They are pretty indiscriminate. They eat fish, crabs, shrimp, everything,” she said.

The species is also extremely thorough.

“What we have seen in the Tortugas and the Florida Keys is that they dominate and there are no small fish left,” Hickerson said.

The presence of the lionfish also can create a cascade of problems. It often feeds on parrotfish, which eat algae. If there are no parrotfish, the algae will grow unabated and can smother the coral.

That’s why organizations like TPWD and the National Oceanic and Atmospheric Administration, which oversees Flower Garden Banks, have been studying the lionfish for some time.

“We have been tracking its range for about a half dozen years now,” Robinson said.

What they have seen is a steady expansion of the lionfish’s territory. The species was first seen off South Florida in the 1990s. Through the years, it moved up the Atlantic coast as far as Long Island, infested all of the Caribbean and also spread to the Gulf Coast.

There, the lionfish traveled from Florida to Alabama to Mississippi to Louisiana and from Cuba to the Yucatán Peninsula to northern Mexico.

Full story…