Blake Plateau

The Blake Plateau lies in the western Atlantic Ocean off the southeastern United States coasts of North Carolina, South Carolina, Georgia and Florida. The Blake Plateau lies between the North American continental shelf and the deep ocean basin extending about 145 kilometers (90 miles) east and west by 170 kilometers (106 miles) north and south, with a depth of about 500 meters (1,640 feet) inshore sloping to about 1,000 meters (3,281 feet) about 375 kilometers (233 miles) off shore, where the Blake Escarpment drops steeply to the deep basin.[1] The Blake Plateau, associated Blake Ridge and Blake Basin are named for the U.S. Coast and Geodetic Survey steamer George S. Blake, in service 1874-1905,[2] that first used steel cable for oceanographic operations and pioneered deep ocean and Gulf Stream exploration.[3] Survey lines of the steamer Blake first defined the plateau that now bears the ship's name.[4]

Southeastern United States continental shelf
Blake Plateau (National Oceanic and Atmospheric Administration)
Coast and Geodetic Survey steamer BLAKE Washington Navy Yard
Coast and Geodetic Survey steamer Blake c. 1880.

History

In July 1880 Blake under the command of Commander John R. Bartlett, [Note 1] U.S.N., was working with sounding gear designed by Lieutenant Commander Sigsbee in cooperation with Alexander Agassiz collecting biological samples and examining the Gulf Stream running eastward from Cape Romain when, in taking frequent soundings eastward, "depths on this line were unexpectedly small, the axis of the Gulf Stream being crossed before a depth of three hundred fathoms (1,800 feet/549 meters) was found" with a bottom of "hard coral" and little life.[5] This was early indication of the plateau that would in the future carry the ship's name. In 1882 Commander Bartlett described the plateau:

Instead of a deep channel in the course of the Stream as reported by Lieutenants Maffit and Craven, and published in the Coast Survey Reports, our later soundings show an extensive and nearly level plateau, extending from a point to the eastward of the Little Bahama Banks to Cape Hatteras—off Cape Canaveral nearly 200 miles wide, and gradually contracting in width to the northward until reaching Hatteras, where the depth is more than 1000 fathoms within thirty miles of shore. This plateau has a general depth of 400 fathoms, suddenly dropping off on its eastern edge to over 2000 fathoms.[6][7]

Bartlett reported the scouring effect of the current on the plateau, noting that on each side of the current the sounding cylinder, a device for sampling the nature of the bottom with the sounding, brought up ooze. Within the current the "bottom was washed nearly bare", with particles being small and broken pieces of coral rock and so hard the sharp edge of the brass cylinder was bent.[8]

Characteristics

Blake Plateau profile comparison
A typical continental margin profile found at latitude 35°N (a) is significantly different from that of latitude 31° 30′N (b). Both profiles are drawn using the same scale. (National Oceanic and Atmospheric Administration, Ocean Explorer)

Geology

Due to unusual features of the plateau, particularly scouring by the Florida Current and the Antilles Current that merge over the plateau to form the Gulf Stream,[9] mineral deposits, particularly manganese nodules, have long been of interest.[10][11] Methane and other gas hydrates are also found on the plateau.[12]

Biology

The Blake Plateau, although described as a "bleak, current-swept plain," has biological communities including Lophelia pertusa reefs that support communities[13] as well as communities supported by gas hydrates.[12] Commercial fishermen have begun exploiting deep sea fish on the plateau with studies being undertaken on the viability as these fish, although large, grow slowly.[14] Biological sampling of the deep, hard bottom is difficult under the Gulf Stream with the consequence that the fauna is relatively poorly known.[15][16]

See also

Notes

  1. ^ The Navy oceanographic ship USNS Bartlett (T-AGOR-13) was named in his honor.

References

  1. ^ Leslie R. Sautter. "A Profile of the Southeast U.S. Continental Margin". NOAA Ocean Explorer. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  2. ^ National Oceanic and Atmospheric Administration (NOAA). "George S. Blake". NOAA History-Coast and Geodetic Survey Ships. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  3. ^ National Oceanic and Atmospheric Administration (NOAA). "History of NOAA Ocean Exploration-Exploration Intensifis (1872-1888)". NOAA Ocean Explorer. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  4. ^ A. Lindenkohl (1882). "Southern half of rough draft of Chart of Atlantic Ocean by A. Lindenkohl. This survey was conducted by the Coast and Geodetic Survey Steamer BLAKE and shows the discovery of the Blake Plateau north of the Bahama Islands and south of Cape Hatteras". Chart (Image ID: cgs05430, NOAA's Historic Coast & Geodetic Survey (C&GS) Collection ). Coast and Geodetic Survey. Retrieved 8 February 2012.
  5. ^ U.S. Coast and Geodetic Survey (1883). Report of the Superintendent of the Coast and Geodetic Survey Showing the Progress of the Work During the Fiscal Year Ending with June, 1881 (pdf). Washington, D.C.: U.S. Government Printing Office. pp. 29–30.
  6. ^ Bartlett,, Commander John R.,USN (1882). "The Gulf Stream". Proceedings of the United States Naval Institute. United States Naval Institute. VIII (20): 224.
  7. ^ Pillsbury, John Elliot. "The Gulf Stream-Chapter III-Gulf Stream Investigations made by the U.S. Coast Survey Until 1884 and those Contemporary with Them". NOAA History. National Oceanic and Atmospheric Administration (NOAA). Retrieved 8 February 2012.
  8. ^ U.S. Coast and Geodetic Survey (1883). Report of the Superintendent of the Coast and Geodetic Survey Showing the Progress of the Work During the Fiscal Year Ending with June, 1882 (pdf). Washington, D.C.: U.S. Government Printing Office. pp. 36–37.
  9. ^ U.S. Geological Survey (2007). "U.S. Geological Survey GLORIA Mapping Program, USGS Coastal and Marine Geology Program, U.S. EEZ Atlantic Continental Margin GLORIA, GLORIA Geology Interpretation (See Blake Plateau)". U.S. Geological Survey. Retrieved 7 February 2012.
  10. ^ Pratt RM, McFarlin PF. (1966). "Manganese pavements on the blake plateau. (Abstract)". Science. Science. 1966 Mar 4. 151: 1080–2. doi:10.1126/science.151.3714.1080. PMID 17739590.
  11. ^ John R. Clarke. "Those Curious Manganese Nodules: from Intelligence History to Science Mystery". Retrieved 7 February 2012.
  12. ^ a b National Oceanic and Atmospheric Administration (NOAA). "Interview with Dr. Cindy Lee Van Dover". NOAA Ocean Explorer. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  13. ^ South Atlantic Fishery Management Council (2012). "Lophelia pertusa". Habitat Management - Deepwater Corals. South Atlantic Fishery Management Council. Archived from the original on 4 February 2012. Retrieved 7 February 2012.
  14. ^ Kelly Filer. "Expanding Fisheries and Fishery Potential on the Blake Plateau". NOAA Ocean Explorer. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  15. ^ George Sedberry. "Estuary to the Abyss: Exploring Along the Latitude 31-30 Transect September 1, 2004". NOAA Ocean Explorer. National Oceanic and Atmospheric Administration (NOAA). Retrieved 7 February 2012.
  16. ^ "An Overview of Marine Biodiversity in United States Waters (See "Blake Plateau")". Public Library of Science. 2010. Archived from the original on 11 November 2012. Retrieved 7 February 2012.

External links

Coordinates: 31°N 79°W / 31°N 79°W

Blake Basin

The Blake Basin, also called the Blake–Bahama Basin, is a deep area of the Atlantic Ocean which runs along the east coast of the United States. It starts at the northern part of the Bahamas and continues up toward New York. Depth exceeds 5400 meters between the Blake Plateau and Blake Escarpment to the South and West, and the Blake Bahama Outer Ridge.

Redeye gaper

The redeye gaper, Chaunax stigmaeus, is a sedentary species of anglerfish in the family Chaunacidae. It is native to deep waters in the western North Atlantic from the Georges Bank off New England southward to the Blake Plateau off South Carolina. The species is found on the outer continental shelf and upper continental slope at a depth of 90–730 m and among dense beds of dead coral (Lophelia pertusa) rubble, their preferred habitat. The original type specimen was caught in a trawl off Atlantic City on March 1, 1946, and donated to the Academy of Natural Sciences by Carroll B. Atkinson. The name stigmaeus means "speckled" in Greek.The redeye gaper has a rounded, slightly compressed body and a very large head. The mouth is large, with a protruding lower jaw and teeth arranged in bands. The skin is soft, loose, and very pliable (especially on the underside), forming folds over much of the head and body. The fish is covered with minute spinules that give it a velvety texture. The lateral line system has prominent open canals. The pectoral fins are small, with 14 fin rays. The first dorsal fin ray is modified into an angling apparatus (the illicium) with a lure (the esca). The esca consists of a cluster of filaments of varying thickness and is black to blue to greenish gray in front, and brilliant white behind. The illicium has two dark rings, though this is faint or absent in a few individuals.The coloration is olive green above with large irregular blotches surrounded by smaller circular spots, extending into the rays of the dorsal, pectoral, and caudal fins. There is often a kidney- or figure-8-shaped blotch on the nape. These spots appear darker than the background in preserved specimens, but are a lighter greenish-yellow color in life. The underside is rose-colored with large, diffuse lighter patches; the red color extends up the sides of the head forward of the eyes, encompassing the jaws. The fin membranes are also shades of red. The iris is a deep rose red. This species attains a maximum of 30.5 cm total length.Redeye gapers are sedentary ambush predators that spend most of their time resting on the sea floor on their pectoral and pelvic fins, moving only to capture prey or avoid predators. They attract prey to them using their movable esca. If threatened, they raise themselves up on their pelvic fins and rapidly take in water to increase the size of their bodies. Redeye gapers are known to be able to survive the temperature and pressure changes from being brought to the surface.

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.