DATASTREME OCEAN WEEK EIGHT: 29 March-2 April 2010

Ocean in the News:

• Eye on the Tropics --
In the last week, the following tropical cyclones were detected:
• In the western North Pacific, Tropical Storm Omais developed at the start of last week to the east of Yap, Micronesia as the second named tropical cyclone of 2010 to form in the North Pacific west of the Dateline. This tropical storm traveled to the northwest before curving to the north as it weakened to a tropical depression this past weekend. Additional information and satellite imagery for Tropical Storm Omais can be found in the NASA Hurricane Page.
• In the western South Pacific basin, Tropical Cyclone 22 formed at the start of this weekend over the waters of the Gulf of Carpentaria near the coast of Australia.
• In South Indian Ocean, Tropical Cyclone Imani formed early last week west of Cocos Island and intensified into a category-1 cyclone in the Saffir-Simpson Scale by midweek as it traveled southward. By late in the week, Imani had weakened to a tropical storm before dissipating at the start of the weekend. See the NASA Hurricane Page for additional information and satellite imagery for Tropical Cyclone Imani.
• Public comments invited to help guide drafting of new national aquaculture policy --
NOAA officials have scheduled six listening sessions around the nation during April and May designed to encourage the public to make recommendations that will aid the agency in the development of a new national policy for sustainable marine aquaculture. [NOAA News]
• National Policy Advisory for Recreational Fisheries appointed --
Last week, Russell Dunn was appointed the new NOAA Fisheries National Policy Advisor for Recreational Fisheries, while 22 members of the nation's recreational fishing community were appointed to the Recreational Fisheries Working Group, which will provide expertise on saltwater recreational fishing to NOAA’s Marine Fisheries Advisory Committee. [NOAA News]
• Report indicates progress made in rebuilding and sustaining nation's fisheries and ocean ecosystems --
NOAA recently released the sixth edition of a report entitled "Our Living Oceans: Report on the Status of U.S. Living Marine Resources" that indicates progress has occurred in the last decade in rebuilding the nation's depleted fish stocks and maintaining the many fisheries populations. [NOAA News]
• Link found between climate change and an Atlantic fishery --
Scientists at NOAA's Northeast Fisheries Science Center who developed a new climate-population model to study rising ocean temperatures and fishing rates on East Coast fish population claim that they have found a link between changes in the Atlantic croaker fish stock and winter water temperatures associated with climate change. [NOAA Northeast Fisheries Science Center]
• Oceanographic expertise and technology employed in search for lost aircraft --
Three submersible vehicles with high resolution cameras developed at the Woods Hole Oceanographic Institution will be employed to search the seafloor for the wreckage of Air France Flight 447, which disappeared over the equatorial Atlantic on 1 June 2009, and then to retrieve the flight recorders from the Airbus A 330. [Woods Hole Oceanographic Institution]
• Atlantic "conveyor belt" shows no sign of slowing --
An oceanographer with NASA's Jet Propulsion Laboratory claims that a new monitoring technique that he developed using measurements from ocean-observing satellites and profiling floats indicates that the Atlantic Meridional Overturning Circulation, a part of the global ocean conveyor belt that helps regulate climate around the North Atlantic, has shown little sign of slowing over the last 15 years. [NASA JPL]
• Using a fan to model a tsunami --
Researchers and engineers at the United Kingdom's University College London and a consulting engineering firm have developed a 146-foot long wave channel with a pneumatically controlled fan, which serves as a better tsunami generator to simulate actual tsunami conditions than previously constructed piston driven models. [EurekAlert!]
• Northwest Greenland ice sheet losing mass --
Researchers at the Denmark Technical Institute's National Space Institute, the University of Colorado at Boulder, Ohio State University, NASA's Jet Propulsion Laboratory and the University of California-Irvine have concluded that the ice-loss along Greenland's northwest coast started in late 2005 and has been accelerating since then, based upon their comparison of data collected by NASA's Gravity and Recovery Climate Experiment satellite system (GRACE) with continuous GPS measurements made from long-term sites on bedrock on the edges of the ice sheet. [NASA JPL]
• Biodiversity found in the seabed below oxygen minimum zones --
Scientists from the United Kingdom's National Oceanography Centre, Southampton and colleagues from Mexico, India, Chile and the US have found that some regions on the deep ocean floor under seawater containing little oxygen do support abundant populations of organisms. However, these researchers warn that increased global temperatures could result in further oxygen depletion that would ultimately reduce biodiversity below the oxygen minimum zones. [EurekAlert!]
• Tectonic plate movements model developed --
After 20 years in building, geophysicists at the University of Wisconsin-Madison, Rice University and NASA's Jet Propulsion Laboratory have unveiled a new model of the Earth called MORVEL (for "mid-ocean ridge velocities) that provide a more precise three-dimensional model of the movement of 25 interlocking tectonic plates around the Earth's surface. [University of Wisconsin-Madison News] [NASA JPL]
• An All-Hazards Monitor --
This Web portal provides the user information from NOAA on current environmental events that may pose as hazards such as tropical weather, drought, floods, marine weather, tsunamis, rip currents, Harmful Algal Blooms (HABs) and coral bleaching. [NOAAWatch]
• Global and US Hazards/Climate Extremes --
A review and analysis of the global impacts of various weather-related events, to include drought, floods and storms during the current month. [NCDC]
• Earthweek --
Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Loss of Louisiana's Coast

According to the Louisiana Coastal Wetlands Conservation and Restoration Task Force, Louisiana has been losing its coastal wetlands (bayous, marshes, and swamps) to the waters of the Gulf of Mexico at an alarming rate of about 65 to 100 square km (25 to 38 square mi) per year for the past several decades. This loss adversely affects fisheries in the Gulf of Mexico and makes the coastal zone more vulnerable to storm surges such as that produced by Hurricane Katrina in August 2005. Since the early 1930s, the state's coastal wetlands have shrunk by an area equivalent to the state of Delaware. According to USGS estimates, an additional 1800 square km (700 square mi) could be lost by mid-century. The price tag for reversing this trend, restoring some marshes, and protecting the remaining 15,000 square km (5800 square mi) of wetlands could top $14 billion and take decades to complete. Many people argue that the value of Louisiana's coastal wetlands is well worth the expense.

As much as 75% of the fish and other marine life in the northern Gulf of Mexico depend on Louisiana's coastal wetlands. The wetlands are a nursery for commercially important catches of shrimp, crawfish, blue crab, and oysters. It is a food source for larger fish including yellow fin tuna, red snapper, and swordfish. In 2003, about three-quarters of the nation's fish and shellfish catch by weight came from Louisiana's waters. In addition, the wetlands are a stopover for millions of birds migrating between North and Central/South America. Furthermore, wetlands and associated barrier islands protect the ports, buildings, and other coastal zone structures from storm surges. Wetlands are particularly important in buffering the levees surrounding New Orleans, much of which is below sea level.

Many factors contribute to the loss of Louisiana's coastal wetlands. Thousands of kilometers of pipelines transporting oil and natural gas through the marshes plus the extensive network of navigation channels allow saltwater to intrude the wetlands. Increased salinity of the originally fresh or brackish waters kill wetland grasses, shrubs, and other vegetation that anchor soil in place. The canals also allow tidal currents to flow farther inland, accelerating erosion of wetland soils. The most important factor, however, is the consequence of flood control structures (levees) constructed along the banks of the Mississippi River. Levees constrict the flow of the river so that waters and suspended sediment discharge rapidly into the Gulf. Deprived of a continuous input of sediments and vegetation-supporting nutrients, existing sediments compact, wetlands subside and Gulf waters invade the wetlands. With the anticipated continued rise in sea level due to global climate change (discussed in Chapter 12 of your textbook), erosion of Louisiana's coastal wetland may accelerate in the future.

Plans to reverse the loss of Louisiana's coastal wetlands (the Coast 2005 plan and the Louisiana Coastal Area plan) seek to restore the structure and function of coastal wetlands. One proposal is to breach some levees along the lower Mississippi. This partial diversion of the Mississippi would increase the supply of sediments to the wetlands. Closing or installing locks on some navigation canals would reduce saltwater intrusion. In addition, dredged sediment would be used to re-build wetlands and restore barrier islands.

Concept of the Week: Questions

1. The most important factor contributing to erosion of Louisiana's coastal wetlands is [(saltwater intrusion)(levees along the banks of the Mississippi River)].
2. Global climate change that is accompanied by a rise in sea level is likely to [(accelerate)(have no effect on)] the rate of erosion of Louisiana's coastal wetlands.

Historical Events:

• 29-31 March 1848...An ice dam at the neck of Lake Erie and the entrance to the Niagara River between Fort Erie, ON and Buffalo, NY caused by wind, waves and lake currents stopped flow of water over Niagara Falls for 30 hours, commencing during the late hours of the 29^th. (Accord's Weather Guide Calendar) (The Weather Doctor)
• 29 March 1910...The world's largest oceanographic museum was opened in Monaco through the generosity of Prince Albert I of Monaco, a great oceanographer, statesman, and humanitarian. This museum, a part of the Oceanographic Institute, has a grandiose facade overlooking the Mediterranean Sea. (Today in Science History)
• 29 March 1914...The Canadian Pacific liner Empress of Ireland, which had departed Quebec the previous day for Liverpool, collided with the Norwegian collier Storstad in the fog along the St. Lawrence River, sinking with the loss of 1024 passengers and crew.
• 29 March 1985...The Nantucket I was decommissioned, ending 164 years of lightship service. (USCG Historian's Office)
• 30 March 1923...The Cunard liner Laconia arrived in New York City, becoming the first passenger ship to circumnavigate the world, a cruise of 130 days. (Today in Science History)
• 31 March 1932...The United States signed the Whaling Convention at Geneva with 21 other countries. (USCG Historian's Office)
• 31 March 1995...Coast Guard Communication Area Master Station Atlantic sent a final message by Morse code and then signed off, officially ending more than 100 years of telegraph communications. (USCG Historian's Office)
• 31 March 2000...The water temperature of Lake Erie at Buffalo, NY was 39 degrees Fahrenheit on the last day of March, tying the maximum temperature for the date with that of 1998. Ice was present in 61 of 74 years on the 31^st, but this was third year in a row with open water. (Accord's Weather Guide Calendar)
• 1 April 1873...The British White Star steamship Atlantic sank off Nova Scotia killing 547 after striking an underwater rock near Meagher's Island while on a voyage from Liverpool, England to New York City. Only 413 people survived. (Wikipedia)
• 1 April 1946...The Scotch Cap Lighthouse on Unimak Island in Alaska's Aleutian Islands was shaken by two earthquakes in a 27 minute span, then obliterated by a tsunami wave. The entire five-man crew was killed and the lighthouse antenna (105 ft above sea level) was washed away. Some debris was found 115 ft above sea level. The tsunami that propagated across the Pacific Ocean was responsible for more than 165 fatalities and over $26 million in damage. Many of the casualties were on the Hawaiian Islands, especially in Hilo on the Big Island. This tsunami was responsible for the development of the current Pacific Tsunami Warning System. (University of Washington) (Accord's Weather Guide Calendar) (US Coast Guard Historian's Office)
• 2 April 1513...Spanish explorer Juan Ponce de Leon came ashore on the Florida coast near present-day St. Augustine and claimed the territory for the Spanish crown. He is reported to be the first known European to set foot in Florida. (The History Channel)
• 2 April 1958...One of the most destructive coastal storms in years battered New England (31 March-3 April). Some beaches between Portland, ME and Cape Cod, MA were eroded by approximately 50 ft. Miles of sea walls and bulkheads were either breached or demolished. Many beachfront cottages in Massachusetts, New Hampshire and Maine were sandblasted. (Accord's Weather Guide Calendar)
• 2 April 1926....Baden-Baden, a rotor ship invented by Anton Flettner left Hamburg, Germany on a transatlantic crossing, arriving in New York on 29 May 1926. The ship used two 9-ft diameter, 50-ft high cylinders, mounted vertically on the deck at the bow and the stern for propulsion, utilizing the aerodynamic power of the Magnus Effect, which builds air pressure behind a rotating cylinder. (Today in Science History)
• 3 April 1797...Captain Thomas Truxtun, USN, devised and issued the first known American signal book using numerary system, encompassing 10 numeral pennants, made of combinations of red, white, blue, and yellow bunting, with flags for repeaters. This signal book contained approximately 300 signals. Fog signals were made by gunfire. Night signals were made by lanterns and gunfire. (Naval Historical Center)
• 4 April 1581...The famous English navigator, Francis Drake, completed his circumnavigation of the world (1577 to 1580) and was knighted by Queen Elizabeth I. (Wikipedia).

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Prepared by AMS DS Ocean Central Staff and Edward J. Hopkins, Ph.D., email hopkins@meteor.wisc.edu
© Copyright, 2010, The American Meteorological Society.