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Antarctica II

Antarctica II. Stuff you might not know about life on (and around) the frozen continent. Terrestrial animals. Rotifer. Nematode. Tardigrade. Springtail. Mite. Belgica antarctica – the Antarctic Midge. Truly weird habitats. Lake Vostok. Adelie penguin. Animalia; Chordata; Aves

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Antarctica II

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  1. Antarctica II Stuff you might not know about life on (and around) the frozen continent

  2. Terrestrial animals Rotifer Nematode Tardigrade Springtail Mite

  3. Belgica antarctica – the Antarctic Midge

  4. Truly weird habitats • Lake Vostok

  5. Adelie penguin • Animalia; Chordata; Aves • Sphenisciformes; Spheniscidae • Pygoscelis adeliae Dumont d’Urville (1790-1842)

  6. Adelie Penguin colonies • 500 – 250,000 individuals

  7. Adult Adelie penguins • Males arrive, build ‘nest’, compete for mates • Competition for stones • Females arrive, lay egg, share incubation with male (although she often disappears for 10 days at a time!) • Incubation and feeding shared

  8. Life cycle of an Adelie Penguin • Hatch, eat and eat and eat…

  9. Life cycle of an Adelie Penguin • Hatch, eat and eat and eat… • Get REALLY BIG • Nests break down and chicks form Creches • Chick goes through rebellious teen years, moults and goes to sea for 1-3 years, coming ashore only to moult once a year

  10. Thermal issues • Water is cold! • Ice is cold! • Nest is cold! • Air is cold (but doesn’t dissipate heat easily)

  11. Predators and mortality • Leopard seals (in water) • Skuas (of chicks and eggs) • ~95% mortality between fledging and first reproduction • Life history consequences

  12. Links to the ocean • Colony sites are all on ice-free ground near open water • Changes in availability of ice = changes in number of colonies • Walking to reach water = very expensive • Change in diet during season • If fishery crashes, so do the penguins

  13. Penguins track the environment The Adelie Penguin: Bellwether of climate change David Ainley

  14. Why don’t fish freeze? Water temperature?

  15. Why don’t fish freeze? • Seawater temperature: • -1.86 °C • Melting point of body fluids: • -0.6 °C

  16. Why don’t fish freeze? • Fish are regularly in contact with ice

  17. Why don’t fish freeze? • The freezing point is not the same as the melting point • “Thermal Hysteresis” • Antifreeze proteins Arthur L. De Vries

  18. Why don’t fish freeze? • Antifreeze proteins • Made in the pancreas • Circulate throughout body fluids • Prevent ice crystals in the fish from growing

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