Weekly Ocean News

Weekly Ocean News

DATASTREME OCEAN WEEK FOUR: 16-20 February 2015

For Your Information

Reconstructing past oceanic conditions from marine sediment cores -- If you would like information on how scientists can reconstruct past environmental conditions in the oceans from the analysis of the physical, chemical and geological data in deep-sea sediment cores, please read this week's Supplemental Information...In Greater Depth.

Ocean in the News

Eye on the tropics --- Organized tropical cyclone (low pressure systems such as tropical storms and hurricanes that form over tropical oceans) activity was limited to the South Indian and western North Pacific basins last week:

In the South Indian Ocean Basin, Tropical Storm Fundi continued its travel to the south away from the southern coast of Madagascar at the start of last week. Eventually this tropical storm dissipated over the western South Indian Ocean nearly 1000 miles south of Antananarivo, Madagascar. The NASA Hurricane Page has additional information and satellite images on Tropical Storm Fundi.

In the western North Pacific basin, Typhoon Higos traveled in a somewhat erratic path toward the north and northwest early in the week before heading toward the west across waters to the east and northeast of Guam . As it traveled over these waters Typhoon Higos, intensified to become a major category 3 typhoon on the Saffir-Simpson Scale. However, this typhoon weakened rapidly to a tropical storm and then a tropical depression before dissipating by midweek. Additional information and satellite imagery on Typhoon Higos are available on the NASA Hurricane Page.

Fishing boat stuck in Antarctic ice towed by US Coast Guard -- Over this past weekend, the US Coast Guard icebreaker Polar Star began towing the 207-foot Australian fishing boat Antarctic Chieftan out of the heavy sea ice surrounding Antarctica near McMurdo Sound. After using an unmanned underwater vehicle to inspect the boat's damaged propeller blades, the Coast Guard decided to pull the boat with 26 people onboard that had been stuck in the ice for three days. [USA Today News]
US reaffirms commitment to address worldwide illegal, unreported and unregulated fishing -- During the last week, NOAA released its 2015 Biennial Report to Congress entitled "Improving International Fisheries Management" that highlights the agency's efforts at identifying foreign illegal, unreported, and unregulated (IUU) fishing activities along with the bycatch of protected species and shark catch on the high seas where nations do not have a regulatory program comparable to the United States. In this report six nations (Colombia, Ecuador, Mexico, Nigeria, Nicaragua and Portugal) were identified as having vessels engaged in IUU activity. The US plans to take the lead and work with these nations to address these issues. Additionally, ten previously identified nations have taken corrective actions against IUU fishing. [NOAA Fisheries News]
Expansion of designated critical habitat for endangered North Atlantic right whales proposed -- Late last week officials from NOAA Fisheries issued a proposal that would expand the designated critical habitat for endangered North Atlantic right whales in the northwestern Atlantic Ocean including the feeding areas in the Gulf of Maine/Georges Bank region. This region would also include areas that will support calving and nursing from southern North Carolina to northern Florida.. The agency will be requesting public comment on this proposal for a 60-day period. [NOAA Fisheries Newsroom]
Automatic detection devices employed to count migrating gray whales -- NOAA Fisheries scientists and their colleagues have been developing an automatic whale detector system that combine thermal imaging (or infrared) cameras with image recognition software to automatically detect and count gray whales migrating in the waters of the eastern North Pacific Ocean off the California coast south of Monterey Bay. [NOAA Fisheries Feature Stories]
Clues sought for causes of dolphin deaths in Gulf of Mexico -- A new study was recently released by a group of nationally-recognized marine mammal research institutions and the Working Group for Marine Mammal Unusual Mortality Events that examined the causes for the dolphin deaths within the Northern Gulf of Mexico Unusual Mortality Event (UME) that followed the Deepwater Horizon oil spill of 2010. Four distinct groupings of increased dolphin deaths were found and the study indicated that multiple contributing causes could have resulted in these deaths and the causes could vary among the different groupings. [NOAA Fisheries Feature Stories]
Large amounts of airborne dust carried over Atlantic from northern Africa in January -- An image generated from data collected by the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument onboard the NOAA/NASA Suomi NPP satellite shows the large concentration of aerosols that were being carried off the Sahara Desert of northern Africa and out over the waters of the equatorial and subtropical waters of the Atlantic Ocean during the month of January 2015. The image displays the aerosol optical thickness, a measure of the attenuation of visible light by the scattering and absorption of the airborne dust, clearly showing an intense Saharan Air Layer last month. [NOAA Environmental Visualization Laboratory]
Global view of the ocean temperature patterns for 2014 -- A map of the annual sea surface temperatures across all the worldwide ocean basins for the calendar year of 2014 was produced from global ocean temperature data obtained by the NOAA Climate Prediction Center. Overall, the surface ocean temperature for all oceans in 2014 was the highest for the record dating back to 1880 when a sufficiently dense collection of data became available. Furthermore, the temperatures of the Pacific and Indian Ocean basins were the second and third highest since 1982, respectively. Spatial variations in the sea surface temperatures across the various ocean basins were revealing. For example, the positive phase of the Pacific Decadal Oscillation was apparent in the northeastern Pacific. [NOAA Environmental Visualization Laboratory]
Call for massive overhaul of global rainfall satellites -- A study conducted by researchers at Cornell and Princeton Universities and the Aerospace Corporation warns that the existing fleet of Earth-orbiting satellites that make global rainfall estimates requires a serious overhaul. The researchers caution that the flood prediction efforts in many developing countries made from the data collected by these satellites may have weak spots, leading to the public being caught by surprise by major flooding events. Furthermore, four of the ten dedicated rainfall measuring satellites are past their design lifetime. [Cornell University Media Relations Office]
An All-Hazards Monitor -- This Web portal provides the user information from NOAA's National Weather Service, FAA and FEMA on current environmental events that may pose as hazards such as tropical weather, fire weather, marine weather, severe weather, drought and floods. [NOAA/NWS Daily Briefing]
Earthweek -- Diary of the Planet [earthweek.com] Requires Adobe Acrobat Reader.

Concept of the Week: Variations in Marine Sediment Thickness

Sediments are particles of organic or inorganic origin that accumulate in loose form in depositional environments such as lake or ocean bottoms. Marine sediments, the central focus of this week's investigations, have a variety of sources and exhibit a wide range of composition, size, and shape. Marine sediments settle to the ocean floor as unconsolidated accumulations but ultimately may be converted to solid sedimentary rock via compaction and cementation. The pattern of variations in marine sediment thickness on the ocean floor confirms some basic understandings regarding marine geological processes.

Go to the DataStreme Ocean Website and under "Geological," click on "Sediment Thickness." This map of marine sediment thickness in the ocean basins was compiled by the National Geophysical Data Center (NGDC), Marine Geology and Geophysics Division primarily based on existing maps, ocean drilling, and seismic reflection profiles. Sediment thickness is color-coded in meters from violet (thinnest) to red (thickest). Many factors account for the variation in the thickness of marine sediment deposits including type and location of sediment sources, sediment transport mechanisms, and the age of the underlying crust.

According to the map, sediment thickness generally increases with distance from near the central portion of an ocean basin to the continental margin. This pattern may be explained by the principal sediment source and/or the age of the underlying crust. Rivers and streams that empty into the ocean slow and diverge, releasing the bulk of their suspended sediment load in coastal environments (e.g., bays, estuaries, deltas) and onto the continental shelf. Ocean currents transport sediment along the coast. In some areas of the continental shelf, massive amounts of sediment accumulate, become unstable, and flow down the continental slope to the base of the continental rise and beyond. However, only the finer fraction of river-borne sediment is swept into the deep ocean waters. Thickening of marine sediments in the direction of the continental margin may also reflect the aging of oceanic crust with distance away from divergent (spreading) plate boundaries where new oceanic crust forms. The older the crust the longer is the period that sediment rains down on the ocean bottom and the thicker is the blanket of accumulated sediment.

The map indicates that the thickness of marine sediment deposits is greater in the continental margin along the Atlantic coast of North America than along the Pacific coast. The Atlantic coast of North America is a passive margin; that is, the continental margin is not affected significantly by tectonic processes (no plate boundary) and the principal geological processes consist of sedimentation along with erosion by ocean waves and currents. In fact, passive margins and relatively thick marine sediment deposits occur on both sides of the Atlantic. (Passive margins also occur around the Arctic Ocean and surrounding Antarctica.) On the other hand, the Pacific coast of North America is an active margin; that is, the continental margin is associated with plate boundaries and is subject to deformation by tectonic stresses. Active continental margins are relatively narrow so that sediment delivered to the coast by rivers and streams flows directly into deeper water or trenches--preventing thick accumulations of marine sediments from building in the continental margin.

Concept of the Week: Questions

The thickness of marine sediment deposits is greater in the [(continental margins)(deep-ocean basins)].
The thickness of marine sediment deposits generally is greater in [(active)(passive)]continental margins.

Historical Events

16 February 1832...The HMS Beagle with Charles Darwin onboard reached St-Pauls (1 degrees N, 29 degrees W).
16 February 1993...The Haitian passenger ferry Neptune sank, sending 1,215 Haitians to their deaths. Coast Guard units participated in the search and rescue operation but found no survivors. They then assisted in recovering the bodies of the victims. (USCG Historian's Office)
17 February 1836...The HMS Beagle and Charles Darwin left Tasmania.
17 February 1867...The first ship passed through the Suez Canal. (Wikipedia)
18 February 1828...More than 100 vessels were destroyed in a storm at Gibraltar.
18 February 1846...A General Order was issued by the Secretary of the US Department of Navy "on Port and Starboard," in which the term "port" replaced "larboard." (Naval Historical Center)
19 February 1473...Nicolaus Copernicus, the father of modern astronomy, was born in Torun in north central Poland. He was the first modern European scientist to propose that the Earth and other planets revolve around the Sun. (The History Channel)
19 February 1845...The Lighthouse Establishment was transferred to the Revenue Marine Bureau. Metal buoys were first put into service. They were riveted iron barrels that replaced the older wooden stave construction. (USCG Historian's Office)
19 February 1972...A vicious coastal storm dumped 10 to 20 inches of snow over interior sections of the mid-Atlantic and Northeast states and caused some of the worst coastal damage of the century in New England. Storm surges up to 4.5 ft and winds gusting over 80 mph along coastal Rhode Island, Massachusetts, New Hampshire, and Maine resulted in extensive property damage and tremendous beach erosion. Twenty-seven houses were destroyed and 3000 damaged in Massachusetts alone. (Intellicast)
19 February 1977...Using the research submersible Alvin, deep-ocean researchers John B. Corliss and John M. Elmond found an extraordinary oasis of life on the Pacific Ocean floor off the Galapagos Islands, including new types of worms, clams and crabs around geothermal hot water vents. These organisms appeared to depend upon bacteria oxidizing hydrogen sulfide contained in the volcanic gases spewing out of the hot springs. (Today in Science History)
20 February 1823...English Captain James Weddell and the brig Jane reached 74 deg 15 min S, or 940 mi (1520 km) from the South Pole. His voyage reached farther south than anyone had ventured until the 1850s, as it was 214 mi south of the latitude that Captain James Cook had sailed.
20 February 1835...While in Chile, Charles Darwin experienced a strong earthquake and shortly thereafter saw evidence of uplift in the region. From measurements, he determined that the land rose several feet, and later hypothesized that coral reefs in the Pacific could develop along margins of subsiding landmasses. (Today in Science History)
20 February 1856...The John Rutledge, an American steamer that sailed from Liverpool, England for New York, hit an iceberg in the North Atlantic. Most of the 155 people onboard were lost.
21 February 1835...The HMS Beagle, along with Charles Darwin left Valdivia, Chile.
21 February 1907...During an exceptionally heavy gale, the British-owned mail ship Berlin hit dangerous shoals and broke up while attempting to navigate around the Hook of Holland in the English Channel. Only 14 on board survived, while 127 were killed or drowned.
22-26 February 1995...Cyclone Bobby slammed into the Western Australia coast causing widespread flooding. Some areas reported up to 12 in. of rain from the storm. (The Weather Doctor)