Hudson River Canyon Mapped

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Scientists Map 'New Frontier' Deep Within Ocean

http://pubs.usgs.gov/of/2004/1441/images/sht2_thumb_300.jpg

aol_news (http://articles.news.aol.com/news/_a/scientists-map-new-frontier-deep-within/20060903102009990001?cid=2194)
By JEFFREY GOLD, AP
September 4, 2006

NEW BRUNSWICK, N.J. (Sept. 4) - Although just 100 miles off the New Jersey-New York coast, the features of the Hudson Canyon are have been largely hidden beneath hundreds of feet of water.

Created by the Hudson River centuries ago, parts of the massive, undersea region rival the Grand Canyon in scale. Now, for the first time, scientists have a vivid picture of what the mysterious region looks like.

A four-year study using high-tech tools has produced maps of an undersea region the size of Connecticut. Scientists said the maps will allow them to study many things, including whether methane gas trapped in frozen sediment below the sea floor is escaping and exacerbating global warming.

Also of interest is whether gas releases could spark undersea landslides that produce tsunamis. In addition to producing giant waves, landslides could cleave the undersea phone cables that handle much of the nation's overseas communications, said Peter A. Rona, a Rutgers University professor who led the team that produced the maps.

It is also possible that the methane could be harvested as an energy source, although no technology yet exists to extract the gas, which is dispersed under the ocean floor over millions of square miles in this and other areas of the world, Rona said.

"These are the aspects that are completely unexplored," Rona said as he examined the 3 1/2-by-5-foot maps at the Institute of Marine & Coastal Sciences at Rutgers' Cook College campus. "This region, the Hudson Canyon, is on the doorstep of one of the largest metropolitan areas of the world, and it is an exploration frontier."

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Mel Evans, AP
"The Hudson Canyon is on the doorstep
of one of the largest metropolitan areas
of the world," Professor Peter Rona said.
"It is an exploration frontier."

The maps became available this summer, free from the U.S. Geological Survey at http://pubs.usgs.gov/of/2004/1441/index.html, and researchers not involved in the project gave the results good reviews.

The map "adds significant new detail to the Hudson Canyon subsea landscape," said William Ryan, a senior scholar at the Lamont-Doherty Earth Observatory of Columbia University. "The map reveals for the first time all of the tributaries of an extraordinary underwater drainage network that is strikingly similar to terrestrial rivers."

Indeed, the undersea canyon acts at times like a river, Ryan said, noting, "Tidal currents sweep up and down the channel. On occasion during big storms cold ocean water is pushed up the Hudson Canyon to spread out on the shelf."

Another marine geologist at Lamont-Doherty, Cecilia M. McHugh, said, the new maps are great work that will allow scientists to track contaminants from six abandoned dump sites off New York Harbor.

The response is gratifying to professor Rona, who spent three weeks in 2002 on a research vessel traversing the region to gather the data. Starting 200 miles out at sea, the Ronald L. Brown would travel on a 60-mile line roughly parallel to the coast as a multi-beamed sonar system attached to the keel bounced sound waves off the ocean floor more than a mile below.

The shape and depth of the sea floor was determined by how long it takes for the sound to return to the ship and the speed of sound through the water.

After completing each line, the vessel would then move closer to the coast to scan a new 60-mile long swath. It repeated this process about 50 times, covering a rectangle 100 miles long and 60 miles wide - 6,000 square miles.

The vessel, provided by the National Oceanic and Atmospheric Administration, readily weathered a hurricane and 25-foot waves.

"You can't do much. You hang on," said Rona, whose career has carried him across the seven seas, including time in tiny submarines 3 1/2 miles under the ocean surface.

Over the next four years, Rona and his team "cleaned" the data, removing extraneous matter caused by waves and other noises.

"It was all done for less than $1 million. It was very cost-effective," Rona said.

The team included researchers from Rutgers, the U.S. Geological Survey, Woods Hole Oceanographic Institution in Massachusetts, and Stony Brook University in New York.

Rona said the map is the most comprehensive ever done of the region, yet it only illuminated formations larger than a football field.

He is seeking funding to get greater detail by sending unmanned submarines to locations of special interest. These diving robots can take photos, sediment samples and measure ocean chemistry.

Rona said he suspects that such data could give clues on whether collapsed pits seen on the ocean floor resulted from old or recent landslides, and whether methane is being emitted.

The area's centerpiece is the giant underwater chasm called the Hudson Canyon. "It's the largest submarine canyon off the East Coast of the United States, and one of the largest submarine canyons in the world," Rona said.

From its shallow beginning at the mouth of the Hudson River in New York Harbor, the Hudson Shelf Valley becomes the Hudson Canyon, which extends some 450 miles out from shore. In places its walls rise three-quarters of a mile from the canyon floor.

That makes it comparable to the Grand Canyon, whose rims are over a mile above the Colorado River, which winds through the gorge for over 270 miles.

Much of the Hudson Canyon was formed during the last Ice Age, over 10,000 years ago, when the sea level was about 400 feet lower and the mouth of the Hudson River was near the edge of the continental shelf, about 100 miles east of its present site. The river discharged sediment that helped carve the canyon, aided by underwater avalanches of mud and sand, scientists said.

© 2006 America Online, Inc.
Copyright 2006 The Associated Press

***

Sea Floor Topography and Backscatter Intensity of the Hudson Canyon Region Offshore of New York and New Jersey

By Bradford Butman1, David C. Twichell1, Peter A. Rona2, Brian E. Tucholke3, Tammie J. Middleton4, and James M. Robb1

usgs.gov (http://usgs.gov/of/2004/1441/index.html)
2006

Introduction (http://pubs.usgs.gov/of/2004/1441/html/intro.html)

These maps show the sea floor topography and backscatter intensity of the Hudson Canyon region on the continental slope and rise offshore of New Jersey and New York. Sheet 1 (http://pubs.usgs.gov/of/2004/1441/images/pdf/sht1_shaded.pdf) shows sea floor topography as shaded relief. Sheet 2 (http://pubs.usgs.gov/of/2004/1441/images/pdf/sht2_back.pdf) shows sea floor topography as shaded relief with backscatter intensity superimposed in color. Both sheets are at a scale of 1:300,000 and also show smoothed topographic contours at selected intervals. The maps are based on new multibeam echo-sounder data collected on an 18-day cruise carried out aboard the National Oceanic and Atmospheric Administration (NOAA) Ship Ronald H. Brown during August and September 2002. Additional multibeam data of the Hudson Canyon collected by the Woods Hole Oceanographic Institution (WHOI), on the continental shelf collected by the STRATAFORM project (Goff and others, 1999), and a survey of the Hudson Shelf Valley (Butman and others, 2003), and a compilation of bathymetric data from the National Geophysical Data Center (NGDC) Coastal Relief Model provide coverage of areas surrounding Hudson Canyon. Interpretations of the surficial geology also utilize widely spaced 3.5- and 10-kiloHertz (kHz) high-resolution seismic profiles collected by the U.S. Geological Survey.

***

[NYatKNIGHT]

Unbelievable. I knew of the existence of hudson Canyon from fishing, initially, and subsequently from sea charts, but I had no idea of its scale and complexity. These maps are fantastic.

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Paradise for Fishermen Becomes One for Scientists

NY TIMES (http://www.nytimes.com/2010/07/13/science/13canyon.html?ref=nyregion)
By WILLIAM J. BROAD
July 12, 2010

MAP (http://www.nytimes.com/imagepages/2010/07/13/science/13canyon_graphic.html?ref=science)

Just off New York City lies the Hudson Canyon, a deep gash in the seabed that runs for hundreds of miles. Charter boats and commercial fishermen have long known that the canyon’s headwaters swarm with tuna, swordfish, monkfish, tilefish, red crabs and other sea life.

Now, scientists have discovered a surprising potential reason for at least part of the canyon’s riches — methane bubbling up from the seabed.

A team from Rutgers University and the National Oceanic and Atmospheric Administration has made three trips to the canyon since 2007 and is preparing another voyage next month. It has already found high levels of methane in the waters and, tracking chemical and geologic clues, now sees the natural gas, which is associated with oil deposits, as a possible first meal in a long food chain.

On the coming expedition, the team plans to use a robotic submersible equipped with a camera to photograph areas of the floor and sides of the canyon for the first time. The scientists hope to gather evidence of deep creatures that live directly and indirectly on the methane, perhaps including clams and crabs, mussels and tube worms.

Such bizarre ecosystems occur globally. Oil and gas seeping out of the Gulf of Mexico seabed result in riots of deep life, as do petrochemical seeps off Angola, Chile, Indonesia, Peru and Trinidad. But scientists have never found such habitats in close proximity to New York City.

The dark ecosystems are known as chemosynthetic because the microbes that serve as their foundation derive their energy from chemicals, in contrast to plants that use sunlight for photosynthesis.

“The big find would be a chemosynthetic ecosystem,” Peter A. Rona, a marine scientist at Rutgers who is a leader of the expeditions, said in an interview.

“Someone once said, ‘You stick your toe in the water and you’re in a wilderness,’ ” Dr. Rona noted. “It’s true.”

Roughly 10,000 years ago, the warming earth sent glaciers retreating northward. The melting ice resulted in churning water that rushed seaward heavy with rocks and debris. Scientists say the torrent cut the Hudson Canyon, its gash up to three-quarters of a mile deep — almost as deep as the Grand Canyon. The big drop-off starts roughly 100 miles southeast of the Hudson.

The canyon got little study until 2002 when Dr. Rona, the United States Geological Survey, the Woods Hole Oceanographic Institution and the federal oceans agency teamed up for a voyage of exploration. The NOAA ship Ron Brown used sound to chart the canyon’s recesses in great detail.

With this first map in hand, scientists turned to the question of what made the canyon such a biological hotspot, as well as whether its nooks and crannies might harbor some of nature’s more exotic creatures and ecosystems.

“We have a mandate to protect delicate habitats,” said Dr. Vincent G. Guida, a biologist at the NOAA Northeast Fisheries Science Center who led later expeditions with Dr. Rona.

In 2007, the scientists deployed a free-swimming robot that mapped the canyon’s head in greater detail. It came from the National Institute for Undersea Science and Technology, a joint venture of NOAA and the University of Mississippi. In 2008, the scientists discovered high levels of methane in the water, and confirmed that finding in 2009.

The maps made last year revealed the icy seabed to be riddled with giant pits. Dr. Rona said such features are well known around the world, geologists linking them to the shrinkage and collapse of methane ice, known as methane hydrates.

“We found whole families of these things,” he said. The seabed pits ranged from the size of Ping-Pong tables to giant craters almost a half mile across.

Last December, Dr. Rona, Dr. Guida and 10 other scientists presented their Hudson Canyon findings to the annual fall meeting of the American Geophysical Union. Dr. Mary Scranton of Stony Brook University did the methane analysis.

Next month, the scientists plan to deploy into the sunless depths a new kind of robot from the National Institute for Undersea Science and Technology. The robot’s lights and cameras — both still and video — promise to illuminate the wilderness, revealing much.

The discovery of dark ecosystems, Dr. Rona said, would suggest new rounds of research seeking to understand the role of chemosynthetic habitats in maintaining the canyon’s overall vitality.

“There could be systems of organisms that go up the food chain,” as in the Gulf of Mexico, he said.

Dr. Rona added that the canyon probably held more surprises. “It’s right at the doorstep of metropolitan New York,” he said. “But it’s largely unexplored.”

Copyright 2010 The New York Times Company