exam 2 quizes Flashcards
what is the main source of nutrients in most soils?
parent material
What are gelisols and how do they form?
below freezing soil but loose due to no moisture in the dry valleys
What are the major terrestrial species found in Antarctic soils?
- nematodes
- tadigrades
- mites
- fungi
- protozoa
- bacteria
What are cryptogamic soils?
type of soil crust that develops in arid regions includes lichens, fungi, bacteria
-allows gas exchange (nitrogen, carbon) and stabilizes the soil
what are the three main types of lichens found in antarctica
- foliage
- fructose
- crustose
what are the two flowering plants in Antarctica and where are they found
antarctic peninsula
- antarctic grass
- pearlwort
what are the five types of lakes found in Antarctica?
1, freshwater
- saline
- epishelf
- supraglacial
- subglacial
Why are many antarctic lakes considered to be ultra-oligotrophic?
because they are relatively low in plant nutrients and contain abundant oxygen in the deeper parts
What plant and animal life is found in antarctic freshwater lakes?
- Bacteria
- Viruses
- Protozoa
- Phytoplankton including algae and photosynthetic bacteria
- Zooplankton including cladocerans, rotifers, copepods, cyanobacterias mats in benthos
What is lake Washburn and how does it relate to current lakes in the dry valleys?
ast ice shelf movement blocked in the dry valleys causing lakes. Meltwater from the glaciers filled Taylor valley creating lake washburn 9500 ya. The lake begun evaporating causing a salinity variation 7000 ya.
What is blood falls and how did it form?
Located in Taylor valley, it’s a subglacial lake with water forced up from the lake through a vent release. The water from the bedrock is high in iron and turns bright red from interactions with air.
What is significant about Lake Vostok that makes it unique?
Lake Vostok is the largest (250 x 50 km) best known subglacial lake (4 km down in the glacier). It has another 300-400 m of sediment on the floor and hasn’t been exposed in 14 millino years.
What are the general characteristics of subantarctic islands?
- Moderate climate north of Antarctic convergence
- Strong westerly winds
- Precipitation (rain or snow) higher, 25-30 inches per yr
- Mountains and some with permanent glaciers
- Tussock grass communities dominate, few or no trees
- Support most of earth’s seabird and seal populations
What is the tussock grass community and how does it function?
The tussock has a thick growth of leaves from a fibrous pedestal
Highly tolerant of salt from sea spray
Forms a habitat for numerous species of birds, invertebrates
How are these islands impacted by introduced species and how did these species arrive at the islands
St George: reindeer for food rats by ships
Marion island: house mouse accident by sealers, cats to stop mice, who killed seabirds then were eradicated
Macquarie Island: sealers brought cats and introduced rabbits for meat plus rats and mice accidentally from ships
Basically destroy the grass or kill the seabirds
