Weekly Ocean News

WEEKLY OCEAN NEWS

ONLINE OCEAN STUDIES WEEK SIX: 8-12 OCTOBER 2007

Ocean in the News

(Thurs.) Coral reef conservation efforts to receive funding -- The National Fish and Wildlife Foundation and NOAA’s Coral Reef Conservation Program recently announced that 29 grants worth more than $3.5 million will be awarded to various local governmental agencies and conservation organizations along the Pacific, Atlantic, Caribbean and Gulf coasts to assist in education and management efforts for coral reefs as part of the Coral Reef Conservation Fund. [NOAA News]
(Thurs.) British tidal power plan endorsed -- The Sustainable Development Commission, an influential advisory body in the United Kingdom's government has endorsed a proposal that would have a tidal barrage stretch across the Severn estuary so as to harness the power of the tides to generate electricity, which according to projections would account for approximately 10 percent of that nation's electricity. [BBC News]
(Thurs.) Hatcheries could cause a loss in salmonid reproduction -- A recent study at Oregon State University reports that steelhead trout, a salmonid species, reared in hatcheries showed a dramatic drop in reproduction rates in the wild, leading to questions concerning traditional hatchery practices for raising steelhead and salmon. [EurekAlert!]
(Tues.) Celebrate Earth Science Week -- The National Oceanic and Atmospheric Administration, to include the National Weather Service, along with NASA, the US Geological Survey and several professional scientific organizations such as the American Geological Institute have recognized next week (14-20 October 2007) 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 for the 10th annual Earth Science Week is "The Pulse of Earth Science", designed to promote public and professional awareness of the status of earth science in education and society. [American Geological Institute]
(Tues.) New phase of Narragansett Bay debris cleanup efforts launched -- Last week, officials from the state of Rhode Island and NOAA launched "Clean Sweep II.", the next phase in a project designed to clean up the waters and shoreline of the state's Narragansett Bay. [NOAA News]
(Tues.) Upwelling effects seen on Lake Michigan -- High-resolution temperature data collected by MODIS sensors on NASA's satellites show that surface temperatures on Lake Michigan, just offshore of eastern Wisconsin and northeast Illinois, were in the mid 40s and low 50s last week. This is nearly 20 Fahrenheit degrees lower than on smaller lakes across the Badger State, most notably Lake Winnebago. The lower temperatures of the nearshore waters of Lake Michigan were caused by upwelling due to a prolonged spell of southwest and west winds across the Upper Midwest. [Milwaukee/Sullivan National Weather Service Forecast Office]
(Tues.) Causes for record low level on Lake Superior examined -- Scientists with NOAA's Great Lakes Environmental Research Laboratory are among various people attempting to explain the occurrence of the lowest lake level of Lake Superior in 81 years. The ongoing drought along with unseasonably warm weather appear to be the main culprits. [USA Today]
(Tues.) Shipwrecks caused by storm waves are simulated -- Researchers at the University of Michigan have developed a new computer program and analysis method that they have used to simulate the development of sufficiently large water waves that could cause shipwrecks, such as the storm-driven waves that contributed to the loss of the ore carrier Edmund Fitzgerald on Lake Superior in November 1975. [University of Michigan]
Eye on the tropics ---
- As of Sunday afternoon, no tropical cyclones had formed during the past week in the North Atlantic, eastern North Pacific or central North Pacific basins. However, several areas of low pressure, including tropical waves, had developed in the Atlantic basin, which includes the Caribbean and Gulf of Mexico.
- Earlier in the week, Tropical Storm Juliette dissipated over the eastern North Pacific several hundred miles offshore of the southern tip of Mexico's Baja California Peninsula.
- In the western North Pacific basin , Typhoon Lekima formed early last week in the South China Sea, reaching a minimal category 1 typhoon (on the Saffir-Simpson Scale). By late in the week, this typhoon made landfall along the northern coast of Viet Nam, where at least 46 fatalities were reported as of Sunday due to flooding and landslides caused by the typhoon's torrential rain. [USA Today]
  Typhoon Krosa (Cambodian word for crane) formed east of Luzon in the northern Philippines and moved northwestward, intensifying to a category 4 typhoon late in the week as maximum sustained surface winds reached 130 mph. This system traveled across northern sections of Taiwan, where five fatalities were reported. By Sunday afternoon (local time) the system made landfall on the southeast coast of mainland China. Torrential rain fell across southeastern China, where more than one million people were evacuated. [USA Today] A MODIS image from NASA's Aqua satellite from late last week shows the spiral swirl of clouds surrounding the central eye of Typhoon Krosa, which is a characteristic of tropical cyclones. [NASA Earth Observatory] A day earlier, an image from the Japanese MTSAT satellite shows the clouds ass ociated with Typhoons Lekima and Krosa across the western Pacific and southeast Asia. [NOAA OSEI]
- At the start of the week, the hurricane research team of Professor Bill Gray and Phil Klotzbach at Colorado State University made an updated hurricane forecast for the North Atlantic covering the months of October and November in which they predicted four additional named tropical cyclones, including only two additional hurricanes, both of which could become severe. [USA Today]
Environmental Literacy Grant Recipients for 2007 announced-- NOAA recently announced the names of the 2007 recipients of the NOAA Environmental Literacy Grants, awards designed to support educational projects aimed at increasing the public's environmental literacy. [NOAA News]
Volcano erupts in the Red Sea -- A volcano erupted on a Yemeni island in the Red Sea early last week killing at least four people. [BBC News] A MODIS image from NASA's Aqua satellite shows the plume of ash and steam spreading out across the Red Sea. [NOAA OSEI]
Alaskan walruses head for shore -- Conservation officials from a variety of federal and state agencies, along with conservation groups, have voiced concern that thousands of Alaskan walruses have abandoned the melting sea ice surrounding Alaska and have taken up residence along the state's northwest coast. [USA Today]
A space-view of tropical atolls -- Images obtained by NASA’s Landsat 7 satellite show two Pacific Ocean atolls, or coral islands that encircle lagoons in the Republic of the Marshall Islands. [NASA Earth Observatory]
Global and US Hazards/Climate Extremes -- A review and analysis of the global impacts of various weather-related events, including drought, floods, and storms during the current month. [NCDC]
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 and 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

9 October 1873...LT Charles Belknap called a meeting at the Naval Academy to establish the U.S. Naval Institute for the purpose of disseminating scientific and professional knowledge throughout the U.S. Navy. (Navy Historical Center)
9 October 1967...A cyclone of relatively small dimension with a surface width of only 31 miles, hit India's coast at Orissa and moved to the northeast along the coast for 75 miles. As many as 1000 people and 50,000 head of cattle died. A surge in the storm's wake penetrated 16 miles inland. (Accord Weather Guide Calendar)
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 History)
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 History)
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 by removing lenses from 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 History)