APES memorize MIDTERM STUDY Flashcards
Soil: Residual vs. Transported
Residual will form on bare rock- this may occur, for example, during primary ecological succession
Transported soil may occur when glacial till is transported to an area- a mix of sand, silt, clay in various compositions- could also form from sediment transported by streams or wind
Soil Formation Factors- Climate
Perhaps most important is the rate of weathering- warm soils have more chemical reactions, while temperature fluctuations help weather parent material
Large amount of precipitation can weather parent material more quickly, speeding up soil formation
Soil Formation Factors- Biological
The plants and animals that live in or use soil help influence its formation
Gophers dig holes, helping aerate the soil- large ungulates may collapse those holes
Microorganisms break down other organic matter, or fix nutrients, influencing nutrient availability- as do plants that use or fix nutrients like nitrogen
Fungi live in soil as well, and often are very important for tree health.
Soil Formation Factors- Topography
Slope- steepness- flatter areas have more well developed areas because they maintain more of their soil- while steep areas may lose it more easily to weathering processes, slowing the formation process
Aspect- direction the slope faces relative to sun- souther aspect generally has warmer temps, less moisture, as opposed to northern aspect which has wetter soils, is cooler, and usually has lusher vegetation
Soil Horizons
O, A, B, and C are the major horizons, or layers of soil
O= organic material; decomposing leaves
A= Topsoil- minerals mixing with organic material- best growing material for plants
E= materials resistant to leaching accumulate, while nutrients move down to subsoil
B= Mineral layer of soil, usually lacking organic matter
C and R are parent material in various stages of breakdown- tree roots do not penetrate down to subsoil
Soil: Nutrient Availability
Different soils can hold different amounts of nutrients- typically sandy soils hold the least nutrients, and clay soils hold the most- but a mixture of sediment sizes, a nice loam, is often best. Loams are typically also rich in organic matter, which supplies nutrients. N, P, and K are often the most important nutrients in soil- we discussed these in Unit 1 on Ecosystems, but their levels can be tested in soils (we did water nitrogen tests).
Soil pH is generally important, too- acidic soils (especially below 6.5 pH) are generally nutrient poor, in part because they limit microbial activity that helps supply nutrients.
Soil Erosion and Water Quality
Soils effectively filter, clean, and buffer water that passes through them, but are similarly vulnerable to extreme rain (runoff) and wind which can erode them. If they erode, they end up in rivers and lakes, where they cloud the water, making it difficult for photosynthesis to occur, and harming aquatic ecosystems
The atmosphere is made up of major gases, each with its own relative abundance.
Nitrogen is the most common - 78%, followed by oxygen - 21% and argon - 0.934%
Carbon dioxide is a distant third - 0.04%
Know the %s.
Other ‘trace’ gases found in atmosphere- no need to memorize these
Thermosphere
5-600 km
High energy radiation from sun (X rays and UV light) absorbed in this layer, especially toward the top
Extremely hot- 2,000 C plus- but toward the bottom, can be - 120 C- thus temps DECREASE as you descend
Very thin (few molecules); Hot vacuum
Mesosphere
50- 85 km- temps INCREASE as you descend as air becomes thicker
Thick enough to burn up meteors
Stratosphere
10km-50km
Temperatures DECREASE as you descend
Heat production at higher layers related to ozone formation
This layer is normally the ceiling on clouds- because convection currents don’t work anymore if warm air is located above cooler air below
GET INFO ON WHY TEMPERATURE TREND
where the ozone layer is
Troposphere
Up to 20 km high (less near poles); temp INCREASES as you descend
All weather happens in this layer
GET INFO ON WHY TEMPERATURE TREND
La Nina
normal pattern intensifies, La Nina is intense version of normal
temperatures of water are more extreme
occurs when trade winds are stronger than normal
trade winds have been reestablished and even intensified, so greater than normal movement of warm surface water to the west and this results in warmer than normal weather and higher than everage rainfalll in Southeast Asia and Australia, may experience flash flooding
South American experiences colder and drier conditions than normal, whcih can cause droughts in the coastal regions especially, however, stronger than normal trade winds blow more warm surface water westward which creates a stronger upwelling along the coast of South American which brings up more cold deep ocean water that has more oxygen and nutrients to support the fisheries
El Niño
trade winds weaken, warm surface waters pool up along coast of South America instead of over in the west near Australia and Southeast Asia, flips normal weather
South America is now getting warmer weather, and low pressure systems, and higher than average rainfal, can lead to flooding and land slides, can suppresss upwelling, meaning that fisheries suffer b/c of warmer water and lack of nutrients
Southeast Asia and Australia meanwhile are receiving colder, drier than average weather which can bring about drought like conditions
Upwelling
Upwelling is when cooler water rises toward the surface to replace warmer water that has moved away. This happens along the Pacific Coast of the United States because trade winds push warmer water away from the Pacific Coast, so cold water rises up to replace it.
Water toward the bottom of the ocean has more nutrients in it, so when cold water rises higher, to the top, nutrients are brought to the surface where they can be productive and contribute to NPP, so NPP is higher
