Antarctica II Stuff you might not know about life on (and around) the frozen continent
Terrestrial animals Tardigrade Rotifer Mite Springtail Nematode
Belgica antarctica – the Antarctic Midge
Truly weird habitats Lake Vostok
Adelie penguin Animalia; Chordata; Aves Sphenisciformes; Spheniscidae Pygoscelis adeliae Dumont d’Urville ( )
Adelie Penguin colonies 500 – 250,000 individuals
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
Life cycle of an Adelie Penguin Hatch, eat and eat and eat…
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
Thermal issues Water is cold! Ice is cold! Nest is cold! Air is cold (but doesn’t dissipate heat easily)
Predators and mortality Leopard seals (in water) Skuas (of chicks and eggs) ~95% mortality between fledging and first reproduction Life history consequences
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
Penguins track the environment The Adelie Penguin: Bellwether of climate change David Ainley
Why don’t fish freeze? Water temperature?
Why don’t fish freeze? Seawater temperature: °C Melting point of body fluids: -0.6 °C
Why don’t fish freeze? Fish are regularly in contact with ice
Why don’t fish freeze? The freezing point is not the same as the melting point “Thermal Hysteresis” Antifreeze proteins Arthur L. De Vries
Why don’t fish freeze? Antifreeze proteins Made in the pancreas Circulate throughout body fluids Prevent ice crystals in the fish from growing