Lecture 15 - Extreme enviroments (Antarctica) Flashcards
what seasonal changes does changes does the Antarctic go through?
Over summer ice sheets retreat making the land smaller, in winter they grow
Explain biodiversity in the antarctic
due to extreme habitat diversity is reduced, but still wide range of oraganisms
What are primary producers found here
Planktonic algea - mainly diatoms, benthic algea, icea algea although some macroaglea
What are the consumers found here (8)
Zooplankton, soft corals, annelids, molluscs, crustaceans, fish, birds, mammals
List a simple food web for this
Diatoms -> zooplankton > fish, squid > sea birds, mammals > apex predators killer whale, leopard seal
What four organisms make up the “ice food web”
Worms, Bacteria, uniceullar algea and diatom chains, curstaceans
what is the keystone species of consumers in the antarctic
Krill, form dense swamps of up to 10,000 per square meter. Swams do not mix and have different sex rations, size and stage of moult. Also commerically fished
Explain the ecology of krill
Grow to up 6cm long, feed on other zooplankton and phytoplankton, have swimming legs, filter deeding appendages, will feed on sea ice algea like a “lawnmower”
Explain the cycle of life for a krill
Fast swimmers, mature after 3 years when mate by spawning, fertilised eggs released which sink to sediment (2000-3000)m deep, then hatch into larvae called naupliii, slowly ascend developing on the way over three years. Immature krill will hide in ice carvens to avoid >predation
Explain the four adaptations of higher organisms (vertebrates) to antarctic environment
> Body form - short and fat to reduce sa/v ration, young grow rapidly
Thick skinned with thick fur or feathers (birds have very thick downy under feathers)
Blubber
Antifreeze - have it in their blood to stop it solidifying
Give details on the antartic fish ecology
> have no swim bladder, neutrally buoyant
Dint have haemoglobin
have slow metabolism
Large gills and scale less skin
high cardiac output and high blood volume
Explain the antifreeze found in fish blood
Sythesized in the liver and secrete into the blood, prevent freezing by adsorbing and inhibiting growth of ice crystals, may have ice externally but inside is ice free. Possible removal of ice in the spleen
What is CCAMCR
Convention for conservation of Antarctic marine life resources
Give an example of two fish that are over exploited
Dissotichus spp. (2 types) are fished and sold in japan for £1000 per fish
Explain the birds that live / migrate here
All migrate away in the winter apart from penguins (only some species)
Explain the life of the South-polar Skua
It is the bird of prey here, arrives in September and leaves in march. Main food - Penguin chicks and eggs including fish. Parenting - lays on single egg
Explain the life of the Giant antartic petrel
Largest flying bird found here 2.2m wingspan and weigghts 5kg. Feeds on fish, offal and carrion. Arives august, leaves april
Explain the life of the Wilsons Storm petrel
Smallest bird at 10cm long, migrates 40000km per year! July feeds in Arctic, December breeds in Antarctica. Feeds on krill and organic waste
Explain the life cycle of the adelie penguin
Common, arrives in october and leaves in feb. 99% of food is krill, nests in rookeries and has the main apex predators to contend with
Explain the life cycle of the Emperor Penguin
Found on antarctic ice zones. Mating last 10 seconds and occurs one a year. Eggs laid in may male incubates the egg in large colony. During winter they are “packed in” with about 10 per square meter. Egg hatches in July
Two examples of marine mammals that are present here
Weddell seal, Leopard Seal
