Galapagos Climate and Pacific currents

Galapagos climate is not usual for the tropics because of the Pacific

currents.

The Galapagos Islands lie on the equator, at the 90th meridian west.

There are thirteen large islands, six smaller ones, and about forty islets.

They are dispersed in the Pacific, a thousand kilometers from the main land

of South America. The largest, Isabela, has over 4800 square kilometres.

On the northeast side there is Volcano Wolf.

The Islands lie in the

equatorial zone, but

their climate is

subtropical, with

temperatures

lower than one would

expect for that region.

These are in fact peaks

of enormous volcanoes

that contain mostly basalt; hence the dark grey color of the islands.

While many have already been formed millions years ago, some islands are

still undergoing changes - the most recent volcanic eruption in 2007.

Over the centuries, new lava fields have been created.

The climate in the Galapagos is not typical for the tropics even if the

equator is just around. This is temperate zone because of the pacific

currents:

The Humbolt Current that circulates in the South Pacific

and

the California Current that circulates in the North

Pacific.

a. In the southern hemisphere the winds blowing in the northwest

direction;

b. In the northern hemisphere the winds are southwest bound.

There two main seasons here:

1. The warm and wet season, from January to May, with some rainfall, and

temperature up to 30 degrees Celsius;

2. The cool and dry season, from May to December, temperatures about

20 degrees Celsius;

The Galapagos climate is the result of two water currents in the ocean:

a) Humbolt, the northwards current that carries huge amounts of cold

water from the Antarctica. Before leaving northern Peru regions, Humbolt

bends to the left, westwards, and becomes the south Equatorial Current.

b) California Current, the southwards current that begins off southern

British Columbia. Before reaching South America, the California current

turns to the right, westwards and becomes the north Equatorial Current.

Patterns of the currents together with the winds are the reason for the

relatively moderate climate of the Galapagos:

Both water currents are being diverged toward the

west thus water is pushed away from the equator.

A wide area of water is moved out in the process,

but there can’t be an empty place left as the

result. To make up for it, the water from deeper

layers has to come up to the surface. The water

from depth, which is colder than the surface water,

contributes to the moderate climate of the Galapagos Islands.

The upwelling (rising of the depth water) assures that the nutrients,

normally hidden in the deep water, are brought up to the surface.



It's the food chain of the ocean:

When the marine organisms die

- they sink into the ocean

- their bodies are decomposed by microorganisms

– the decomposed bodies release nutrients

– the nutrients remain in the deep water

– the deep water comes up to the surface through upwelling, carrying

nutrients to the surface

- the nutrients cause algae and phytoplankton to grow

– marine organisms feed on algae and phytoplankton.

When this cycle is disturbed, animals can die. In the past, warm water

current El Nino caused damage to the marine life.

Approximately every seven years, a warming of Pacific waters occurs that

in the process prevents the deep ocean water from rising. No nutrients

from deep waters mean food shortage for marine life. For instance, in 1998

many marine iguanas died because there were not enough algae or

phytoplankton to eat.

Tropical Rainforest Animals: Spreading the knowledge about the current state of tropical rainforests and rainforest animals, with a special focus on their conservation.

Galapagos climate po polsku

Galapagos climate en francais

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