April 2011

The Agulhas Current is the Western Boundary Current of the southwest Indian Ocean. It flows down the east coast of Africa from 27°S to 40°S. It is narrow, swift and strong.
The Agulhas Current is the Western Boundary Current of the southwest Indian Ocean. It flows down the east coast of Africa from 27°S to 40°S. It is narrow, swift and strong.

Agulhas Current effect on European climate

The Gulf Stream which transports enormous amounts of warm tropical waters to the North Atlantic is the cause of Europe's habitable climate.

Climate predictions point to the fact that this will change in the future and affect especially the climate in countries of the Mediterranean region, with more dry spells. As global warming progresses, the North Atlantic will receive more precipitation and a greater amount of water from the melting of glaciers in Greenland, thus reducing the salinity of ocean water and weakening the Gulf Stream's effects.

Sea turtles’ magnetic sense

This behaviour seems to imply a map sense from which the creatures read either absolute or relative location from at least two coordinates. The direction is one thing but how about the position?

Latitude is fairly simple to judge, and there is good evidence that animals have this variable well under control. The elevation of the pole point at night, for example, gives the latitude directly; memorizing the constellations allows at least some species to infer the pole point through broken clouds.

The results demonstrate for the first time that longitude can be encoded into the magnetic positioning system of a migratory animal. Because turtles also assess north-south position magnetically, the findings imply that loggerheads have a navigational system that exploits the Earth’s magnetic field as a kind of bicoordinate magnetic map from which both longitudinal and latitudinal information can be extracted.

Where does the mercury in seafood come from? (filephoto)
Where does the mercury in seafood come from? (filephoto)

Why levels of mercury in fish vary

"It has to do with where they are feeding in the water column and what they're eating," said Anela Choy, University of Hawaii-Manoa

Mercury is a natural trace element in the environment that has never been associated with toxicity in Hawaii's ocean fish. But methyl-mercury, an organic form of the mineral converted by bacteria, can be toxic if eaten at high levels by animals or people.

Cuttlefish (Filephoto)

Cephalopods traumatized by ocean noise

Noise pollution in the oceans has been shown to cause physical and behavioral changes in marine life, especially in dolphins and whales, which rely on sound for daily activities. However, low frequency sound produced by large scale, offshore activities is also suspected to have the capacity to cause harm to other marine life as well.

Spanish researchers examining the effects of ocean noise pollution on different species of cephalopods have shown that exposure to low frequency sound can cause lesion that has been linked to squid deaths in the wild.