The Namib, a desert miracle: the Benguela Current

The Namib's most important feature of all is the life-giving, cold Benguela Current.
The great diversity and richness of the Namib Desert revolves around the plancton-rich waters of this ocean current which peels off the mighty West Wind Drift in the cold Southern Ocean. 

The Benguela Current flows northwards along the south-western coastline of Africa, causing deep cold water to be pushed onto the shallower coastal shelf in a process called upwelling.

As this nutrient-rich waters enters the light zone near the surface it supports unbelievably large populations of minute organisms known collectively as phytoplankton, which serve as bountiful grazing grounds for a host of zooplankton species.

This combination of minerals, including phosphorus, and energy-producing sunlight supports these pastures and their predators, which in their turn sustain vast shoals of pelagic fish.

These form the principal prey of huge flocks of Cape gannets, Cape cormorants and jackass penguins. Also not to be left out of the equation are the fish-eating Cape fur seals, cetaceans and predatory fish species.

But what really concerns us here is another feature of this cold, productive oceanic current ....... fog. 

Rainfall in the Namib, as is to be expected in a true desert, is minimal and rarely exceeds 100 mm each year.
It is more likely to be close to 15 mm, particularly along the coastal plain.

The cold Benguela Current, already fully established some five million years before present, is influenced by the South Atlantic Anticyclone pressure system.

Cool water flows close inshore, ensuring the frequent development of fog and maintaining high coastal humidity levels and the steep climatic gradient from the coast to the interior.

Great, rolling banks of fog push their way inland from the coast during the darkness of night, not infrequently penetrating more than 50 kilometers from the coast, and reaching their greatest density at altitude of 300 metres to 600 metres.


The inselbergs, hill ranges and in particular the sand dunes act as fog traps, and it is within these zones that the greatest species diversity is evident.






Questa foto di Cape Cross è offerta da TripAdvisor.