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Ecosystems: trophic levels, soils and climate basics
Fichas del conjunto (20)
- 1What is an ecosystem?An ecosystem consists of all the organisms and abiotic components of the environment with which they interact.
- 2How big is an ecosystem?An ecosystem size can be described in many ways such as; the entire planet, a forest or even a rock surface
- 3What is the trophic-dynamic concept of the ecosystem?Lindemann adopted the ecosystem as the fundamental unit. Food webs are a good expression of an ecosystem structure. A food chain consists of steps/trophic levels.
Ecosystems processes both respond to and control the factors that govern their activity. - 4Name what influences ecosystem processes and give examples of each.Ecosystems are influences by:
state factors (climate, time, potential biota, parent material and topography)
interactive controls (human activities, biotic community, resources, modulators and disturbance regime - 5How can ecosystems be studied?Ecosystems can be studied by:
Toposequences
Chronosequences - 6What controls soil formation?1. Climate - temp and moisture influences rates of chemical reactions
2. Topography
3. Time - soils develop slowly so minerals in soil affect its properties
4. Potential Biota
5. Human Activities - nutrient inputs, irrigated and ploughed lands
6. Parent Material - rocks are weathered to form sediments - 7How does erosion effect on young and old landscapes?Young Landscapes:
Erosional losses reduce soil fertility by removing clays and organic matter that store water and nutrients
Highly Weathered Landscapes:
Renews soil fertility by removing highly weathered remnants such as iron oxides and sands. It exposes less weathered materials and therefore creates a new source of nutrients. - 8Name the key additions, transformation, transfers and losses in soil profilesADDITIONS:
Precipitation and Organic matter
TRANSFORMATION:
Organic matter -> humus
Primary minerals -> ions, clays, hydrous oxides
TRANSFERS:
Humus compounds, clays, ions and H4SiO4
LOSSES:
Ions and H4SiO4 - 9Name and describe types of weatheringPHYSICAL:
Fragmentation without chemical change, tectonic fracturing, abrasion by wind/glaciers/flood, freeze-thaw/heating-cooling/wetting-drying cycles, roots in fissures and fire
CHEMICAL:
Reactions with acidic or oxidising materials, primary minerals are dissolved and oxidised to secondary minerals. - 10What is a leaching?Vertical transfer of materials through soils generate distinctive soil profiles.
- 11What are the soil profiles horizons?O horizon - organic matter that is decomposed slightly
A horizon - mineral soil with mixed humus
E horizon - horizon of maximum leaching of silicate clays, Fe, Al oxides
B horizon - zone of Fe and Al accumulation
C horizon - zone of least weathering and accumulation contains parent material
R - bedrock (unweathered parent material) - 12Explain soil water in terms of the soilThe soil is water-saturated when all pore spaces are filled with water. The water drains under the influence of gravity. The adhesive forces that hold water equals pressure (this is known as field capacity). Plants continue to take up water until permanent wilting point - forces bind water too strongly to the soil.
- 13Explain bulk density in terms of soil textureBulk Density influences nutrient and water characteristics. Fine textured soil tend to have lower bulk density. If compacted, bulk density of clay soils can exceed sands.
Nutrient per soil volume = concentration x BD - 14Explain the global energy balance for the earth in the atmosphere systemThe Earths temperature varies to ensure that energy inflows from the sun balance the outflows to space.
Within the atmosphere, the shortwave radiation and absorbed longwave radiation and latent plus sensible heat flux are balanced by longwave emission to space and longwave emission to Earth's surface.
At the earth's surface the incoming shortwave radiation and longwave radiation are balanced by outgoing longwave radiation and latent plus sensible heat flux - 15What are Latitudinal and seasonal variation?Latitudinal variations refers to rays distance from the land hence longer distance at the poles and shorter at the equator
Seasonal variations refers to rays where the rays are hitting and tilting, for example the rays hitting the northern hemisphere when the earth is tilted up. - 16Explain the Earth's Latitudinal atmospheric circulationAir rises at the ICTZ (maximum solar input), after rising the air moves N or S where it descends and either moves towards the equator - creating a Hadley cell or polewards.
Cold dense air at the poles subsides and moves to the equator until it reaches poleward moving air. The air then rises and moves either poleward (creating polar cell) or equatorward (creating ferrell cell). - 17What is Long Term Climate variation?Long term change is driven by changes in solar input and atmospheric composition. For example, solar energy has increased over time and and solar inputs vary on shorter variations.
- 18What is interannual climate variation?El-Ninõ (Southern Oscillation) occurs every 3-7 years whilst North Atlantic Oscillation is associated with cold/dry or wet/warm winters in W.Europe. [look at slide for more info]
- 19Explain water movements J = Ls (Ψt / l)J = Rate of water flow through soil
Ψ = The gradient in water potential
Ls = Hydraulic conductivity
l = path length of column water travels - 20Explain Infiltration RatesInfiltration rates depend on soil texture, raindrop impaction of surface layer.
If PPT > infiltration rate then over land flow occurs.
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- Year 1 University Biology, Ecology and Environment Fichas sobre Sin título, creado por Jonathan Sharples el 29/04/2017.
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