Weekly Ocean News

WEEKLY OCEAN NEWS

DATASTREME OCEAN WEEK SIX: 25-29 February 2008

Ocean in the News

(Thurs.) Coastal and ocean management awards are announced -- NOAA officials recently announced the names of the recipients of the 2008 Walter B. Jones Awards and NOAA Awards for Excellence in Coastal and Ocean Management. [NOAA News]
(Thurs.) Tracking the white shark -- Researchers from Stanford University and other institutions have been using satellite-tracking systems and acoustic sensors to track the behavior of the elusive white shark as part of the Census of Marine Life project called Tagging of Pacific Predators. [EurekAlert!]
(Tues.) Research cruise to study climate-relevant gases -- More than 30 scientists will embark later this week from Punta Arenas, Chile upon a six-week research cruise to the Southern Ocean on the NOAA ship Ronald H. Brown as part of the Southern Ocean Gas Exchange Experiment, designed to study the movement of gases such as carbon dioxide between atmosphere and ocean in an effort to improve the accuracy of climate models and predictions. [NOAA News]
(Tues.) Health oceans could lead to healthy people -- The head of NOAA Oceans and Human Health Initiative claims that in addition to having clean coastal waters and beaches for public health reasons, a healthy ocean could produce numerous pharmaceuticals, natural products and seafood that would enhance the human health. [EurekAlert!]
(Tues.) A new shellfish research institute is launched -- NOAA's Milford Laboratory in Connecticut and the East Coast Shellfish Growers Research Institute are collaborating to examine the effects that growing and harvesting shellfish have upon the marine ecosystem, primarily along the New England coastal waters. [NOAA News]
(Tues.) Climate change could exert a major impact on oceans -- A panel of scientists recently warned that changes in global climate have been changing the oceans through increases in the temperature and acidity of seawater, along with altered atmospheric and oceanic circulation patterns. [EurekAlert!]
Eye on the tropics -- Tropical cyclone activity continued across the South Indian Ocean during the last week. Tropical Cyclone Hondo, which formed early in the month and became a major category 4 tropical cyclone on the Saffir-Simpson Intensity Scale, continued to travel westward. This long-lasting cyclone passed La Reunion Island over the weekend.
Farther to the east, Tropical Cyclone Nicholas, a category 1 tropical cyclone, traveled to the southwest offshore of Australia and then finally dissipated by midweek after making landfall along the western coast of Australia. An image from the radar and the microwave units on the Tropical Rainfall Measuring Mission (TRMM) satellite shows the rainfall rate in the spiral bands surrounding Tropical Cyclone Nicholas. [NASA Hurricane Page]
Increased hurricane loss not necessarily due to stronger hurricanes -- A team of hurricane researchers including those from NOAA's National Hurricane Center report that the nearly doubled economic damages due to hurricanes during the last decade were not necessarily the result of increased intensity, but to the increased population and wealth along those sections of the Atlantic and Gulf coastline prone to hurricanes. [NOAA News]
Gulf fisheries sustainability analyses are challenged -- Researchers from Louisiana State University and the University of Washington are challenging recent reports indicating that the Gulf of Mexico fisheries offshore of the Louisiana coast are near collapse. [EurekAlert!]
A dilemma for the Atlantic bluefin tuna fishery -- Marine biologists at California's Hopkins Marine Station of Stanford University and the Monterey Aquarium have been investigating the population dynamics of two separate Atlantic bluefin tuna populations in the eastern and western sides of the North Atlantic basin in an attempt to assess the impact of fishing has upon these much sought after fish. [EurekAlert!]
Great Lakes and Seaway Ice -- An image from the MODIS sensor on NASA's Terra satellite at the end of last week shows the extent of the ice cover on the eastern sections of the St. Lawrence Seaway that include the lower St. Lawrence River and the Gulf of St. Lawrence. [NOAA OSEI] An image from this sensor on the previous weekend reveals the most of the Great Lakes were ice free, except for Lake Erie that was nearly ice covered. [NASA Earth Observatory]
Storing carbon dioxide below the ocean's surface -- An expert from the University of Calgary has proposed submerging gigantic inflatable bags that would hold 160 million metric tons of carbon dioxide as a means of sequestering this greenhouse gas. [EurekAlert!]
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.

Report From the Field:

Terri Kirby-Hathaway, LIT Leader and Marine Education Specialist for North Carolina Sea Grant is inviting all to view the blog http://antarctica-ncsu.blogspot.com/ maintained by a group of professors and graduate students from North Carolina State University who are currently on a research cruise around Antarctica.

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

25 February 1977...An oil tanker explosion west of Honolulu spilled 31 million gallons of oil into the Pacific Ocean.
26 February 1935...Robert Watson-Watt demonstrated RADAR (Radio Detection and Ranging) for the first time, using the BBC shortwave radio transmitter to successfully detect the distance and direction of a flying bomber during the so-called Daventry Experiment.
26 February 1938...The first passenger ship was equipped with radar.
27 February 1949...Aerial ice observation flights by long-range aircraft operated from Argentia, Newfoundland. An International Ice Patrol by vessels was neither required nor established during the 1949 season, and it was the first time that aircraft alone conducted the ice observation service. (USCG Historian's Office)
27 February 1988...A major rain event occurred across Saudi Arabia's Foroson Islands in the Red Sea and on the adjacent mainland around Jizon when 1.15 in. fell. The monthly average rainfall is only 0.02 in. On the following day, flash flooding south of Riyadh killed three children. (Accord's Weather Calendar)
28 February 1849...Regular steamboat service to California from the East Coast via Cape Horn arrived in San Francisco for the first time. The SS California had left New York Harbor on 6 October 1848 on a trip that took 4 months and 21 days. (Wikipedia)
28 February 1964...A world 12-hour rainfall record was set at Belouve, La Reunion Island in the western Indian Ocean when 52.76 inches of rain fell. World records for 9 hours and 18.5 hours were also set with 42.79 and 66.49 inches, respectively. (Accord's Weather Calendar) (The Weather Doctor)
29 February 1504...Christopher Columbus used his knowledge of a lunar eclipse that night to convince Native Americans to provide him with supplies. (Wikipedia)
1 March 1498...The Portuguese explorer, Vasco de Gama, landed at what is now Mozambique on his way to India.
1 March 1854...The SS City of Glasgow left Liverpool harbor for Philadelphia and was never seen again with 480 people on board.
1 March 1902...The first regular light stations in Alaska were established at Southeast Five Finger Island and at Sentinel Island--both on the main Inside Passage between Wrangell Strait and Skagway. (USCG Historian's Office)
1 March 1905...The first regular light stations in Alaska were established. (USCG Historian's Office)
1 March 1927...A system of broadcasting weather reports by radio on four lightships on the Pacific Coast was put into effect. (USCG Historian's Office)
1 March 1970...US commercial whale hunting was ended.
1 March 1977...The United States extended its territorial waters to 200 miles.
1 March 1983...A ferocious storm battered the Pacific coast. The storm produced heavy rain and gale force winds resulting in flooding and beach erosion and in the mountains produced up to seven feet of snow in five days. An F2 tornado hit Los Angeles. Thirty people were injured and 100 homes were damaged. (The Weather Channel) (Intellicast)