Weekly Ocean News

DATASTREME OCEAN SPRING BREAK WEEK: 9-13 March 2015

This is Break Week for the Spring 2015 offering of the DataStreme Ocean course. This Weekly Ocean News contains new information items and historical data, but the Concept of the Week is repeated from Week 6.

For Your Information

Time change -- Daylight Saving Time went into effect this past Sunday morning for essentially the entire nation -- the exceptions include Arizona, Hawaii, Puerto Rico and about 18 counties in Indiana. These changes have been mandated by the U.S. Congress in the Energy Policy Act of 2005, which extended Daylight Saving Time across the nation, with the start on the second Sunday in March (8 March 2015) and end on the first Sunday in November (1 November 2015). In other words, following the old adage of "spring ahead, fall behind", you will need to turn your clocks ahead by one hour to conform with the local time observance. Most of Canada also observes Daylight Saving Time changes at the same time [National Research Council Canada].
What does this time change mean to you (other than later sunsets)? Contrary to a popular belief that has surfaced at times, the change from Standard to Daylight Saving Time does not add an extra hour of daylight to the day nor does it affect weather patterns. While the weather will not change because of the time change, the times when you will be able to obtain weather charts will now be one hour later. The reason is that the National Weather Service operates on "Z time" (variously called Greenwich Mean Time or Universal Coordinated Time) which does not observe Daylight Saving Time, and the charts are still produced and transmitted at the same Z time.
Biomixing in ocean motion -- If you would like information on recent findings that indicate marine organisms contribute to motion in the ocean, please read this week's Supplemental Information…In Greater Depth.

Ocean in the News

Eye on the tropics --- With the commencement of meteorological autumn in the Southern Hemisphere (December, January and February) at the start of last week, tropical cyclone activity remained limited to the southern Indian Ocean basin.
Tropical Storm 15S formed late last week approximately 450 miles to the north-northeast of Europa Island, an atoll in the Mozambique Channel between southern Madagascar and southern Mozambique. This tropical storm took an erratic path to the south, then to the west and finally toward the northwest before dissipating offshore of Mozambique over this past weekend. The NASA Hurricane Page has additional information and satellite images for Tropical Storm 15S.
Late in the weekend, Tropical Storm Haliba (or 16S) formed approximately 200 miles to the west-northwest of La Reunion. This new tropical storm was traveling to the southeast and should continue away from any major land mass during the next several days, with some intensification anticipated.
El Niño event has finally developed -- Late last week forecasters with NOAA's Climate Prediction Center in collaboration with colleagues at the International Research Institute for Climate and Society released their assessment that a weak El Niño event had finally arrived based upon their analysis of the average sea surface temperature data for February 2015 collected by the fleet of NOAA satellites. Consequently, these forecasters issued an El Niño Advisory to declare the arrival of the long-anticipated El Niño event, which is an ocean-atmospheric phenomenon marked by above-average sea surface temperatures in the central sections of the equatorial Pacific Ocean. The outlook indicates that an approximately 50-60% chance for the continuation of El Niño conditions through Northern Hemisphere summer 2015. Since the strength of this El Niño appears to be weak, widespread or significant global weather pattern impacts are not anticipated. [NOAA News]
Additional discussion as to the decision making process used by NOAA forecasters to declare the onset of the current El Niño conditions has been posted as a blog. [NOAA Climate.gov blog]
Certain impacts often associated with El Niño may appear this spring in the Northern Hemisphere, such as drier-than average conditions across the northern tier of states from the Pacific Northwest to the Great Lakes and Ohio Valley, while wetter-than-average conditions could prevail the US Gulf Coast.[NOAA Climate.gov News]
Final recovery plan for threatened corals is published -- NOAA Fisheries recently published its final recovery plan for threatened elkhorn and staghorn corals, in which threshold criteria are identified that would allow the coral species to be removed from the list of threatened species under the Endangered Species Act (ESA). The recovery plan contains two dozen actions needed to recover the species and addresses research and monitoring, ways to reduce threats, and enhance the population by actively growing corals in nurseries. [NOAA Fisheries]
Global coral bleaching event foreseen for 2015 due to warm oceans -- NOAA scientists recently released their agency's "Four-Month Coral Bleaching Thermal Stress Outlook" for March through June 2015 in which they foresee a global outbreak of coral bleaching in 2015 due to above-average ocean temperatures in the tropical Pacific and Indian Oceans. The coral bleaching represents a loss of the corals' food-producing algae. This thermal stress outlook depends on sea surface temperature forecasts from NOAA's operational climate forecast system model to show regions that are most likely to experience bleaching up to four months in advance. [NOAA Climate.gov News]
Busy sea lanes off China coast seen from space -- A natural color image made several weeks ago by the Operational Land Imager (OLI) on NASA's Landsat 8 satellite shows northbound and southbound shipping lanes off the coast of China's Shandong Peninsula. These sea lanes have been created by the International Maritime Organization (IMO) and other groups for congested waters such as off this peninsula in eastern China to maintain traffic separation schemes designed to reduce the risk of collisions. [NASA Earth Observatory]
Fjords become noisiest places in ocean due to melting glaciers -- A team of researchers from the University of Alaska-Fairbanks, the University of Texas at Austin, the University of Washington and the US Geological Survey recently reported on their study of the sounds found in the waters of three bays where glaciers flow into ocean fjords along the coasts of Alaska and Antarctica. All of the fjords had numerous icebergs created by glacial calving. Using underwater microphones to record the average noise levels in these three bays, the researchers found that the average underwater noise level from bubbles in these fjords exceeded ocean noise levels generated by all other sources, including weather, the movement and communication of fish, and machines such as ships and sonar devices. The sound waves were measured at frequencies that cover most of the hearing range of the average human. [University of Alaska Fairbanks Cornerstone News]
Yucatan Peninsula may have been hit by tsunami 1500 years ago -- Scientists at the University of Colorado Boulder and Mexico's Centro Ecological Akumal claim that their radiocarbon analysis of peat taken from a berm along the eastern coastline of Mexico's Yucatan Peninsula indicates that this peninsula may have been slammed by a tsunami consisting of two or three giant waves between 1,500 and 900 years ago. This tsunami may have been triggered by a variety of events ranging from earthquakes and underwater landslides to volcanic eruptions and oceanic meteor strikes. [University of Colorado Boulder News]
Ocean tides have changed over last century around the world -- Scientists from the United Kingdom's University of Southampton have found that the tide levels and tidal range of ocean tides have changed significantly over the last century at many coastal locations around the world. Increases in both high tide levels and in the tidal range were found to have been similar to increases in average sea level at several locations. The researchers used 220 sea level records from around the world that had lengths of records ranging from 30 to 150 years to changes in tidal levels. Apparently, these tidal changes are due to a combination of local to global mechanisms, including the rise in sea level associated with climate change. [University of Southampton News]
Unmanned aerial vehicle used to monitor flightless penguins -- NOAA Fisheries scientists recently used unmanned aerial vehicles for the last time this current field season to study penguins and other predators on an island near the tip of the Antarctic Peninsula. [NOAA Fisheries Stories]
Public input sought on environmental analysis of proposed Makah whale hunt -- During the last week NOAA Fisheries announced that it was inviting public comments on a new Draft Environmental Impact Statement that evaluates the request by the western Washington Makah Tribe to resume treaty-based hunting of eastern North Pacific gray whales for ceremonial and subsistence purposes. These gray whales from the eastern North Pacific stock have been removed from the list of threatened and endangered species in 1994. [NOAA Fisheries News]
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.

This Concept of the Week is repeated from Week 6.

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 152, in your 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 March 1454...Amerigo Vespucci, the Italian navigator, was born in Florence, Italy. The North and South American continents were named in his honor by Matthias Ringmann, a German mapmaker.
9 March 1995...The Canadian Navy arrested a Spanish trawler for illegally fishing off Newfoundland.
10 March 1496...Christopher Columbus concluded his second visit to the Western Hemisphere when he left Hispaniola for Spain. (Wikipedia)
10 March 1849...Abraham Lincoln applied for a patent for a device to lift vessels over shoals by means of inflated cylinders.
11 March 2002...The National Ice Center reported that satellite images indicated that an iceberg with an area larger than the state of Delaware had calved from the Thwaites Ice Tongue, a region of snow and glacial ice extending from the Antarctic mainland into the South Amundsen Sea (Accord's Weather Guide Calendar)
13-15 March 1952...The world's 5-day rainfall record was set when a tropical cyclone produced 151.73 inches rain at Cilos, Reunion Island in the Indian Ocean. The 73.62 inches that fell in a 24-hour period (15^th-16^th) set the world's 24-hour rainfall record. (Accord's Weather Calendar)
14 March 1891...The submarine Monarch laid telephone cable along the bottom of the English Channel to prepare for the first telephone links across the Channel.
14 March 1903...President Theodore Roosevelt issued an executive order making Pelican Island near Sebastian Florida a "preserve and breeding ground for native birds," including pelicans and herons, marking the birth of the National Wildlife Refuge System. (Wikipedia)
14 March 1918...The first US concrete seagoing ship was launched at Redwood City, CA. (Today in Science History)
15 March 1493...Christopher Columbus returned to Spain after his first voyage to the New World. (Wikipedia)
15 March 1778...Nootka Sound, Vancouver Island was discovered by Captain James Cook.
15 March 1946...For the first time, U.S. Coast Guard aircraft supplemented the work of the Coast Guard patrol vessels of the International Ice Patrol, scouting for ice and determining the limits of the ice fields from the air. (USCG Historian's Office)
15 March 1960...Key Largo Coral Reef Preserve in the Florida Keys was established as the nation's first underwater park. This preserve currently includes John Pennekamp Coral Reef State Park and the adjacent Florida Keys National Marine Sanctuary.