Talk:Cromwell Current

[Untitled]

I'm doing a web search for interesting material and I'm dumping these links here as I go along. Enjoy ! theresa knott 11:43, 30 Jan 2004 (UTC)

pengiuns rely on cromwell for food

Notes taken from [1]

Evidence suggests that El Nino Southern Oscillation, or ENSO, events cause changes in the ocean that deprive the penguins of the schools of small fish, mostly mullet, on which they feed. Typically a Cromwell current, basically a deep undersea cold-water river, is forced to the top by underwater volcanoes in the area of Fernandina and Isabella islands, where the penguins live. The current carries nutrients that sustain zooplankton and phytoplankton, which attract the fish.

But during El Nino, the Cromwell current disappears and the fish go elsewhere in search of food. That in turn deprives the penguins of nutrition or forces them to forage farther from home, Boersma says. They can't simply move to a new home because the nearest land is more than 600 miles away.

More on the Galapagos taken from [2]

Upwellings of cool water from the Cromwell current are responsible for high marine productivity levels, which support schools of small pelagic species, the invasion of many migratory species, and considerable colonies of sea birds, marine iguanas and sea lions, together with rich life around particularly lava reefs. However, El Nino events every several years, the last event in 1997/98, are responsible for the invasion of very warm water from the west, slowing down currents, and minimizing upwelling, with profound consequences for marine life and unpredictable recruitment patterns for marine species. A very visible sign of those impacts is the bleaching of coral, which in Galapagos is particularly serious because of the limited habitats available for their growth.

Key notes taken from [3] Equatorial Undercurrent Sometimes called the Cromwell Current Discovered about 40 years ago. It flows eastward on the equator' · Width about 1º - 2º of latitude · Core about 150 m deep · Maximum speeds about 1 ms-1 The Equatorial Undercurrent is most evident in the oxygen (it’s fresher).

Notes taken from [4]

1952 An oceanographer with the Honolulu Laboratory, Townsend Cromwell, discovers a major new ocean current, now named after him, in the tropical Pacific. It is about 3,000 miles long and carries more than 1,000 times the volume of the Mississippi River

This page looks particlualy interesting and has a lot of stuff on pacific ocean currents in general [5] the following quote is from it

In most places of the world ocean, the currents vary only gradually from surface to bottom - they are usually strongest at the surface where they are closest to the wind forcing, and gradually blend into the circulation of the abyss. However, within 2 or 3° latitude of the equator, the subsurface currents are much more complicated (Fig. 9a from Wyrtki and Kilonsky, 1984). Between 100 and 200 meters depth lies the strong eastward-flowing Equatorial Undercurrent. The undercurrent was originally discovered by Townsend Cromwell during a research expedition in the 1950's when the drogues deployed at that depth moved strongly eastward while the surface current was westward (see Knauss, 1960). In speed, the Equatorial Undercurrent matches the strongest currents in the world (> 100 cm/sec or 1 km/day). However, the undercurrent is vertically very thin (about 100 meters thick) in contrast with the other major currents such as the Kuroshio, Gulf Stream, and Antarctic Circumpolar Current which reach to the ocean bottom.

Below the undercurrent and flanking it on either side of the equator lie the North and South Subsurface Countercurrents, flowing eastward (at 2° on either side of the equator and below 150 meters depth in Fig. 9a). These were discovered by Tsuchiya (1968). Directly beneath the Equatorial Undercurrent lies a somewhat weaker westward flow, which extends to about 1000 meters depth

Here's a good page [6] look at page 42.(or is it section 42 -anyway it's the last page)

Lot's of technical detail here [7]

Is is related to climate change ? [8]