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8 Cards in this Set
- Front
- Back
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How do light levels in polar environments change patterns of seasonal productivity?
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Reproduction of many zooplankton is timed to coincide with the spring bloom of phytoplankton. Whereas the phytoplankton bloom is triggered by increased day length and light availability, temperature is the reproductive cue for many zooplankton. Warmer temperatures are occurring earlier in spring, but day lengths and light levels are unchanged. Zooplankton may therefore be reproducing before peak in their phytoplankton food, with effects that transfer uo the rest of the food web.
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What are brine tubes and why do they form?
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1. A brine channel is a frozen tube of ice. Here's how it is formed: 1. as seawater freezes salts get trapped in the ice crystal lattice; 2. As the sea ice ages, the ice crystal structure becomes more organized and pushes out (excludes) the salt ions; 3. These salt ions collect in liquid pools and make a dense brine solution; 4. With air temps below 0 F, the brine pools become super-cooled (chilled below the freezing point of water), but because of the high salt content they do not freeze; 5. The dense, super-cooled brine water eventually flows down through the ice into the seawater; 6. As the dense cold brine hits the sea water, it immediately freezes it which forms these long, stalagtite-like ice tubes hanging from the botom of the sea ice. Note the one above was approximately 15 feet ( 4 m) in length.
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Describe how ice can impact benthic zonation in polar environments (be sure to define anchor ice).
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Anchor ice : submerged ice attached or anchored to the bottom, irrespective of the nature of its formation.
Its presence coincides with reduced abundance of the sponge Homaxinella balfourensis, which provides habitat for a diverse assemblage of benthic organisms. Anchor ice may also grow on animate or inanimate objects and lift them from the sea floor. In the Antarctic this will most likely result in the death of an organism, since during much of the year the ocean is covered by annual sea ice, and the organism is likely to become incorporated into this. |
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List 6 key characteristics of polar organisms.
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Slow growing
Slow development- Evolution Large Few young- well developed Lack ornamentation |
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How does ice algae avoid from freezing?
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Secretes Gel like mucus- antifreeze
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What organisms feed on ice algae?
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Krill
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What unique adaptation do some polar fish have?
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Notothenoids- antifreeze- glycoprotein
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List 10 features of polar bears that make them well adapted to their Arctic environment in relation to warmth, swimming, walking on ice, and predation.
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Dense fur , thick abundant
2 layers, guard hairs- hollow /under fur solid / adds buoyancy black skin blubber fur on feet- traction Stocky surface to volume |
