WEEKLY OCEAN NEWS

DATASTREME OCEAN WEEK SIX: 10-14 October 2005

Ocean in the News

(Thurs.) Ancient marine reptiles liked shellfish -- Paleontologists report finding two Australian fossils of marine reptiles called plesiosaurs that developed more than 200 million years ago and appear to have grazed upon a variety of underwater shellfish. [New Scientist]
(Thurs.) Aquarium fish suppliers overfishing Hawaiian species -- Some exotic tropical fish suppliers worry that taking too many attractive species will harm the lucrative local economy of Hawaii, currently several million dollars per year. [CNN]
(Thurs.) Indian Ocean supplies warm rings to Atlantic -- Indian Ocean warm rings off the Agulhas Current have been tracked into the South Atlantic. Accurately tracking the rings will improve ocean circulation models. [Netherlands Organisation for Scientific Research]
(Thurs.) North Sea shows coastal oceans are most efficient CO₂ absorbers -- Dutch researchers have shown that CO₂ is not absorbed uniformly by ocean waters, with coastal areas being more efficient. [Netherlands Organisation for Scientific Research]
(Tues.) More hurricanes foreseen -- Hurricane forecasters with the National Hurricane Center and Colorado State University warn that another potentially major hurricane could strike the continental US before then end of the year, since conditions that resulted in the formation of Hurricanes Katrina and Rita appear to remain in place. [USA Today]
(Tues.) Blaming climatic change for sickness onboard cruise ships -- An official with the Alaska Department of Health and Social Services blamed the four outbreaks of illness among those who ate raw shellfish on a cruise ship during the summer of 2004 upon warmer than anticipated waters off the Alaskan coast where the oysters were caught. [ENN]
(Tues.) Long-distance travels of sharks monitored -- Shark experts recently reported on the long-distance travels of several varieties of sharks, including that of a great white shark that swam more than 12,000 miles across the Indian Ocean in a round trip between Africa and Australia. [ENN]
Satellites are being used to track the migration of salmon sharks from the warm Pacific to the cold waters off Alaska. [EurekAlert!]
(Tues.) A milestone reached in GEOSS reached -- With the recent deployment of the last of 1250 instrumented global drifter buoys in the North Atlantic off Nova Scotia, the first components of both the Global Ocean Observing System and Global Earth Observation System of Systems (GEOSS) were completed. [NOAA News]
(Tues.) Tahitian sea level expedition sets sail -- An international team of scientists recently set sail on a 6-week Integrated Ocean Drilling Program, Tahiti Sea Level Expedition, that is intended to investigate global sea level rise during the last 23,000 years. [Integrated Ocean Drilling Program]
Celebrate Earth Science Week -- The National Oceanic and Atmospheric Administration, including the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized this coming week (9-15 October) as Earth Science Week to help the public gain a better understanding and appreciation for the earth sciences and to encourage stewardship of the Earth. This year's theme is "Geoscientists Explore our Earth" and will focus on earth science careers. Learn about what geoscientists do, how their work is important to society and what is needed to become a geoscientist. [American Geological Institute]
Another hurricane forms -- Hurricane Vince formed over the far eastern tropical Atlantic Ocean on the weekend, becoming the eleventh hurricane and the twentieth named tropical cyclone of the season this hurricane season in the North Atlantic basin, which is now the second most active season since records began in 1851. [USA Today]
A three-dimensional look at a hurricane -- A team of scientists from NASA, NOAA and ten universities has begun releasing their analyses of data obtained during CAMEX-4 (the fourth Convection And Moisture EXperiment) in August-September 2001, which was designed to improve hurricane tracking and intensity predictions. A 3-dimensional picture of the eye of Hurricane Erin was constructed from satellite and dropwindsonde data, indicating the importance of temperatures measured at an extremely high altitudes above a hurricane's eye can be used to study how hurricanes change intensity. [NASA GSFC]
CryoSat satellite destroyed -- A Russian space agency official reported that the CryoSat satellite, a European Space Agency satellite that would have collected data on polar sea ice during a three-year mission, was destroyed following launch from a facility in northern Russia. [CNN]
Mudslide death toll due to Stan climbs -- A mudslide in Guatemala that resulted from torrential rains from the remnants of Hurricane Stan may have been responsible for the deaths of 1400 Maya Indians in addition to approximately 400 fatalities elsewhere in Central America associated with the hurricane. [CNN]
Death toll from typhoon floods increases in China -- Chinese officials announced that at least 80 paramilitary police officers were killed by floods associated with Typhoon Longwang. [USA Today]
Response to hazardous materials released by hurricanes to continue -- The NOAA Office of Response and Restoration is prepared to spend more than a year responding to the cleaning of hazardous chemical and oil spills produced by Hurricanes Katrina and Rita. [NOAA News] Currently, a multi-agency task force headed by NOAA charged with cleanup efforts have found the number of sunken ships and fuel tanks in Gulf Coast waters are making the cleanup a monumental task. [US Water News Online]
Hurricane Rita exacerbates Gulf fishery failure -- The US Commerce Secretary announced last week that a fishery failure was determined along the coastal regions of the Louisiana and Texas because of Hurricane Rita. This declaration comes in the wake of a similar declaration made earlier for the central Gulf coast from Louisiana eastward to the Florida Panhandle following Hurricane Katrina. [NOAA News]
Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Abyssal Storms

Until recently, ocean scientists thought of the deep ocean abyss as a dark, cold but serene place where small particles rained gently onto the ocean floor. However, instruments lowered to the sea floor to measure ocean motion or currents and resulting mobilization of bottom sediments detected a much more active environment. Scientists found that bottom currents and abyssal storms occasionally scour the ocean bottom, generating moving clouds of suspended sediment. A surface current of 5 knots (250 cm/sec) is considered relatively strong. A bottom current of 1 knot ( 50 cm/sec) is ripping. Although this may be called an abyssal storm, the water motion pales by comparison to wind speeds in atmospheric storms.

Abyssal currents and storms apparently derive their energy from surface ocean currents. Wind-driven surface ocean currents flow about the margins of the ocean basins as gyres centered near 30 degrees latitude. (Refer to Figure 6.6, page 131, in your DataStreme Ocean textbook.) Viewed from above, these subtropical gyres rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. For reasons given in Chapter 6 of your textbook and this week's Supplemental Information, surface currents flow faster, are narrower, and extend to greater depths on the western arm of the gyres. These are known as western boundary currents and include, for example, the Gulf Stream of the North Atlantic basin. Abyssal currents are also most vigorous on the western side of the ocean basins, moving along the base of the continental rise, which is on the order of several kilometers deep.

Abyssal storms may be linked to or may actually be eddies (rings) that occasionally break off from the main current of the Gulf Stream (and other western boundary currents). During an abyssal storm, the eddy or ring may actually reach to the bottom of the ocean where the velocity of a bottom current increases ten-fold to about 1.5 km (1 mi) per hr. While that is an unimpressive wind speed, water is much denser than air so that its erosive and sediment-transport capacity is significant even at 1.5 km per hr. At this higher speed, the suspended sediment load in the bottom current increases by a factor of ten. Abyssal storms scour the sea floor leaving behind long furrows in the sediment. After a few days to a few weeks, the current weakens or the eddy (ring) is reabsorbed into the main surface circulation and the suspended load settles to the ocean floor. In this way, abyssal storms can transport tons of sediment long distances, disrupting the orderly sequence of layers of deep-sea sediments. Scientists must take this disruption into account when interpreting the environmental significance of deep-sea sediment cores.

Concept of the Week: Questions

In the subtropical ocean gyres, boundary currents flow faster on the [(western)(eastern)] side of an ocean basin.
Currents in an abyssal storm erode, transport, and redeposit sediments that have accumulated on the [(continental shelf)(deep ocean bottom)].

Historical Events

10-16 October 1780...The most deadly Western Hemisphere hurricane on record raged across the Caribbean Sea. This "Great Hurricane of 1780" killed 22,000 people on the islands of Martinique, St. Eustatius, and Barbados. Thousands more died at sea. (The Weather Doctor)
10 October 1845...Naval School, renamed the U.S. Naval Academy, opened in Annapolis, MD with 50 midshipmen students and seven faculty. (Navy Historical Center)
10 October 1861...Fridtjof Nansen, the Norwegian explorer, oceanographer, statesman, and humanitarian was born. Nansen led a number of expeditions to the Arctic (1888, 1893, 1895-96) and oceanographic expeditions in the North Atlantic (1900, 1910-14). He wrote The Oceanography of the North Polar Basin (1902). For his relief work after World War I, he was awarded the Nobel Prize for Peace in 1922. (Today in Science)
10 October 1913...President Woodrow Wilson with the aid of a telegraph signal sent from Washington, DC triggered the demolition of the Gamboa Dike, allowing water to fill the Culebra Cut and create Lake Gatun, at 85 ft above sea level, the largest man-made lake at that time. This act signaled the completion of construction of the Panama Canal, which would eventually open to ship traffic between the Atlantic and Pacific Oceans on 14 August 1914. (Wikipedia, Today in Science)
11 October 1737...A deadly cyclone and storm surge of 42 ft raced up the Hooghly River in India and through the city of Calcutta destroying an estimated 40,000 boats and drowning as many as 300,000 people. (The Weather Doctor)
11 October 1846...A very intense hurricane caused great destruction in the Florida Keys. Key West was virtually destroyed with 5 feet of water reported in the city. Fort Taylor was reduced to ruins. (Intellicast)
11 October 1897...Property saved at Cape Hatteras, NC. During a severe storm, the surf threatened to wash away a fish house, with valuable nets and other gear. Surfmen saved the property and took it to a place of safety. They also assisted a lighthouse keeper to remove lenses of the beacon to a secure place. The lighthouse was in danger of being washed away by the sea. (US Coast Guard Historian's Office)
12 October 1492--Italian explorer Christopher Columbus sighted and landed on an island (possibly Watling Island) in the Bahamas during his travels westward across the Atlantic Ocean in search of an ocean route to eastern Asia. Apparently he underestimated the size of the world and assumed that he had reached East Asia after setting sail with three ships from Palos, Spain on 3 August 1492. During this expedition, which was the first known European expedition to the Americas since the 10^th century Viking colonies in Newfoundland, he sighted Cuba and landed on Hispaniola. (The History Channel)
12 October 1886...A hurricane made landfall between Sabine Pass, TX and Johnson's Bayou, LA. Waves were said to be as high as 2-story buildings. The surge extended 20 mi inland, with 150 people killed. Survivors clung to trees or floated on mattresses. Only two of 100 homes in Sabine Pass were reparable. (Accord Weather Calendar)
12 October 1954...Hurricane Hazel pounded Haiti and the island of Hispaniola with winds of 125 mph. Many villages were reported totally destroyed and more than 1000 Haitians died. (The Weather Doctor)
12 October 1965...End of Project Sealab II where teams of naval divers and scientists spent 15 days in Sealab moored 205 feet below surface near La Jolla, CA. (Navy Historical Center)
12 October 1979...The lowest observed sea-level barometric pressure (870 millibars or 25.69 inches of mercury) was recorded near Guam in the western Pacific Ocean at the center of Typhoon Tip. (The Weather Doctor)
13 October 1775...Birthday of U.S. Navy. The Continental Congress established the Continental Navy, later the U.S. Navy. (Naval Historical Center)
13 October 1884...The longitude that passes through the principal Transit Instrument at the Observatory in Greenwich, England was selected as the single universal meridian at the International Meridian Conference held in Washington, DC. A universal day was also selected. (Today in Science)
15 October 1947...A hurricane made a hairpin turn off the Georgia coast after being seeded with dry ice. The storm passed over Savannah and tracked inland through Georgia. (Intellicast)
15 October 1954...Hurricane Hazel struck the Carolina coastline near Cape Fear, NC. The hurricane (category 4 on the Saffir-Simpson Scale) demolished every pier along a 170-mile stretch from Myrtle Beach, SC to Cedar Island, NC, and obliterated rows of beach homes. At Long Beach, 300 homes vanished; no debris remained. Hurricane Hazel also destroyed 1500 homes as it made landfall with 17-ft tides. Winds between Myrtle Beach, SC and Cape Fear, NC gusted to 150 mph. Later, the remnants of Hazel moved northward into Ontario and became the most remembered storm in Canadian history. Winds gusted to 75 mph and as much as 7.2 inches of rain fell. Eighty people died, mostly from flooding in the Toronto area (David Ludlum) (The Weather Channel) (The Weather Doctor)
15 October 1999...A waterspout (a tornado over water) moved onshore at Fort Lauderdale Beach, FL and blew out a plate glass window in a bar, injuring 8 patrons. The waterspout also overturned a vehicle and caused other significant damage on Los Olas Blvd. (Accord Weather Calendar)
16 October 1877...Bjørn Helland-Hansen, the Norwegian pioneer of modern oceanography, was born on this date. His studies of the physical structure and dynamics of the ocean were instrumental in transforming oceanography from a descriptive science to one based on the principles of physics and chemistry. (Today in Science)