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Saturday, March 3, 2012

Antarctic Wildlife - Antarctic Fur Seal

Scientific name: Arctocephalus gazella

Physical description and related species

Antarctic Fur Seal at Davis Station February 2012
Photograph by David (Horse) Barringhaus
Fur seals are the smallest seals and closely related to dogs and sea lions, able to walk on all fours. The common name of fur seal includes several species: Antarctic fur seals, subantarctic fur seals and New Zealand fur seals.
They have teeth, whiskers and thick fur, similar to the coat of a dog. They don’t have layers of fat like other seals but rely on their thick fur coat to keep them warm.
Adult males can weigh up to 200 kg, adult females weigh about 40 kg, and pups weigh between 3–7 kg at birth. Occasionally these seals are pale blonde.

Distribution and abundance

At Macquarie Island three species of fur seal occur: Antarctic fur seals (Arctocephalus gazella) and subantarctic fur seals (Arctocephalus tropicalis) which both breed there and New Zealand fur seals (Arctocephalus fosteri), which occur in large numbers but do not breed.

 At Heard Island the population is increasing. In 1992 there were about 250 pups born at Heard Island, and by March an influx of adult males and juveniles increased the numbers to over 21 000 fur seals. See also Weddell Seals , Elephant Seal and Leopard Seal  Blogs

For images that are for sale in print,canvas, framed print and acrylic  go to my online store

Antarctic Fur Seal at Davis Station February 2012
Photograph by David (Horse) Barringhaus

Antarctic Fur Seal at Davis Station February 2012
Photograph by David (Horse) Barringhaus

Friday, March 2, 2012

Aurora Australis

Typically the aurora appears either as a diffuse glow or as "curtains" that approximately extend in the east-west direction. At some times, they form "quiet arcs"; at others ("active aurora"), they evolve and change constantly. Each curtain consists of many parallel rays, each lined up with the local direction of the magnetic field lines, suggesting that auroras are shaped by Earth's magnetic field. Indeed, satellites show electrons to be guided by magnetic field lines, spiraling around them while moving towards Earth.The similarity to curtains is often enhanced by folds called "striations". When the field line guiding a bright auroral patch leads to a point directly above the observer, the aurora may appear as a "corona" of diverging rays, an effect of perspective.

The Earth is constantly immersed in the solar wind, a rarefied flow of hot plasma (gas of free electrons and positive ions) emitted by the Sun in all directions, a result of the two-million-degree heat of the Sun's outermost layer, the corona. The solar wind usually reaches Earth with a velocity around 400 km/s,

If your wondering what the brilliant green line is in some of the images, it belongs to a Lidar Lazer which is used to collect weather data at 60km altitude.

The images included here were taken using:
Canon 5D Mk11
Lens: Sigma 24-70mm
Focal Length: 24mm
Manual Focus
Exposure Bias: 0
F stop: f2.8
Shutter Speed: 25 - 30 sec
ISO: 320 - 800
White Balance: AWB
Manfrotto 475B Tripod with 3 way pan head.