BIOSPHERE Summary of What You Must Know You should be able to:

1. BIOSPHERE • Summary of What You Must Know • You should be able to: • describe and explain the effect of physical factors – climate, relief, drainage, parent material, soil biota and vegetation on soil formation. • draw annotated diagrams to describe the properties of podzols, brownearth soils and gley soils, referring to horizons, colour and texture. • recognise the type of soil shown in a profile diagram, and describe thefeatures which help to identify the soil type. • compare and contrast the appearance and soil forming factors of two of the three soil types. • explain the series of soils found in a soil catena. • explain fully what is meant by the term climax vegetation. • describe and explain the changes in the types of plants (succession) to be found across a coastal sand dune transect, referring to the names of specific plants. • explain the changing environmental factors that they must adapt to. Slide 25 Slide 30

2. The Biosphere • The Living environment • This consists of plants, animals, insects, micro-organisms and people. • The Non-living environment • This consists of • Water (rain or stored in the soil). • Air – provides oxygen and carbon dioxide which is essential for life. • Solar energy – provides heat and light. • Rocks – the lithosphere – provides nutrients • Soil – varies in depth, acidity, nutrients and fertility Slide 19

3. The Biosphere – where life is found 3m below to 30m above the ground. It comprises water areas, both salt and fresh and all land. • An Ecosystem –a natural system in which life of plants and animals are clearly linked to one another and to the non-living environment through food chains. • Ecosystems vary in size from extensive areas of rainforest to a micro system under a stone. • All ecosystems depend on two basic processes: • A flow of energy (heat and light) • The recycling of nutrients within the system • Ecosystems will remain in balance unless conditions change such as climate or through human interference. Slide 20

4. Soils Soil is the function of climate (water and temperature), organisms (bacteria, insects, plants etc.), parent material (rock under the soil), relief (steepness) and time. Factors affecting soil formation Relief Vegetation Climate Soil Formation Soil Biota Drainage Parent Material Slide 28

5. Soil formation – a profile Slide 38 Horizons A Organic matter Humus Translocation B Hard pan C Bed rock Classification of soils: When precipitation exceeds evaporation water washes down through the soils carrying minerals with it. These soils are called pedalfers and include podzols and brown earth soils. Hard pan – a resistant layer in the soil at or below the surface. Usually caused by illuviation (deposition of minerals, humus and other materials)after leaching of the upper horizons. Hard pans can be formed of clay humus or a compound of Calcium, iron and silicon. Slide 47

6. When describing any soil you must mention the impact of climate, vegetation, parent material, soil biota, drainage and relief on its development Brown Forest Soils Slide 31

7. Plentiful supply of deciduous vegetation – mildly acidic humus. • Moderate leaching occurs leading to a thin iron pan whenever leaching is more active. • Warm temperatures lead to more biotic activity and decomposition. This makes the horizons merge more gradually. • Soil is free draining so there is less likelihood of a hard pan layer. • Gentle sloping land has good drainage and moderate leaching. • This is the most fertile of the three soils we study and it can support agriculture which allows greater human development and higher population density.

8. Podzol Slide 32

9. High levels of precipitation plus spring snowmelts leads to a great deal of water flushing through the soil causing rapid leaching of minerals and the formation of a thick iron pan. • The Iron pan impedes drainage. • Pine cones and needles result in very acidic humus. • Soil horizons more clearly defined as there is little mixing due to restricted action of soil biota (this is a result of the cold climate). • Cold climate also leads to slow breakdown of plant materials. • Highlands: High precipitation and short growing season. • Steep slopes – downward movement of water increases leaching and iron pan formation.

10. Tundra/Gley Soils Slide 33

11. Gleys have damp waterlogged soils due to inadequate drainage resulting from permafrost layer found below the surface. Because there is waterlogging there is a lack of oxygen in the soil. • There is a lot of partially decomposed material due to the restricted level of biotic action. This is the result of a very short summer with low temperatures and the waterlogged soils. • Horizons are poorly defined due the movement caused by constant freezing and thawing. • Parent material is obvious within the B horizon. • The vegetation is dominated by mosses and lichens which produce acidic humus. • Large areas of flat land increase the drainage problems. REMINDER: When describing any soil you must mention the climate, vegetation, soil biota, reliefand the impact of each on the development of the soil.

12. Soil catena showing variations in soil processes and effects along a slope Slide 36

13. Biosphere: Summary Notes

14. Summary Notes

15. Ecosystems • The non-living environment includes: • Water: rain or water stored in the soil • Air: provide oxygen and carbon dioxide which are essential for life. • Rocks: provide the nutrients for the soil. • Soil: these vary in depth, nutrients and fertility. • Solar energy: the sun is the earth’s primary source of energy and provides light and heat. • Controls on ecosystems • The organism within an ecosystem are controlled by two main factors: • 1. Environmental factors (non-living environment) • 2. Competition (from other plants) • Succession • The change of community (plants and animals) and habitat over the years as a result of changing environmental conditions often brought about by the community. Slide 20

16. Environmental conditions Each species has its own preferred set of environmental conditions. Under these conditions the species will flourish. Obviously if these conditions differ markedly from the optimum the species will be unable to survive and will be replaced (competition). Competition Ecosystems are rarely composed of single species. The number and variety present is determined by the suitability of the environmental conditions, species diversification and the ability of species to compete for energy and nutrients.

17. The Nutrient Cycle Biomass = weight of living material (plants and organisms) Trees and animals die Nutrients taken up by plants and organisms Litter: surface layer of vegetation Soil Nutrients released as plants and leaves decompose Nutrients lost through leaching (down) or capillary action (up) Nutrients added by weathering of parent rock Slide 23

18. All ecosystems go through stages or seres when a different set of plants grow in the area. A sere is a process of succession. Climax vegetation An empty area of ground will always be colonised by plant species. The plants arrive as seeds or spores. The arrival and development of the vegetation is influenced by: 1. Climatic factors 2. Soil type 3. Biota 4. Time 5. Competition from other plants The first set of plants to arrive is the pioneer community. These first colonisers tend to be simple, hardy, low lying, lacking in diversity and unable to compete with other species as the ecosystem develops. Over the years the pioneer community is succeeded by other plants more suited to the new environment (natural selection). After many years climax vegetation is reached. Slide 37

19. Climax vegetation Climax vegetation is the final stage in the possible development of natural vegetation of a region or area. This is when the composition of the plant community is relatively stable and in balance with the existing environmental conditions which are normally determined by climate and soil. In sand dunes the climax vegetation is made up of pine and oak trees and flowering plants. Sand Dune Succession: psammosere Stage 1: At and behind the strandline, sea couch and sea rocket colonise. These are pioneer plants. It is a hostile environment (saline and strong winds) in which few plants can survive. An embryo gradually forms as the vegetation semi-stabilises the sand (through roots etc) and encourages a slight build up to form a dune. Stage 2: 20 metres or so from the strandline are the yellow dunes (formerly embryo dunes). Here the marram grass grows as it has adapted to harsh conditions and salinity. The marram grass stabilises the dunes which continues to grow higher. The marram grass roots go deep to reach the water table. Slide 38 Slide 41

20. Stage 3: As the marram grass begins to die (conditions have become less suitable for marram) and a humus forms. Therefore soils begin to form. Conditions have become suitable for plants like dandelions. • Stage 4: Soil becomes richer in nutrients and plants such as birdsfoot trefoilcolonise the fixed dune. The dune succession now reaches its climax vegetation with flowering plants, pine and oak trees growing. • Stage 5: Between some of the dunes ridges are low lying depressions called dune slacks. They are often covered in water from October till April submerging plants and creating very wet conditions. Rushesand sedgesgrow here. • Factors which affect changes in the soil • The embryo and yellow dune soils have a higher salt content and are therefore more alkaline. • The sandy texture of the soil means rapid drainage therefore there is a lot of leaching. Rainwater will remove the salt in the soil in the semi – fixed and fixed dunes (further away from sea spray). pH gets more acidic so different plants can now colonise. • With the addition of humus water retention will improve further away from the coast so the soil is wetter. The Humus encourages a decrease in pH. • Vegetation type depends on calcium carbonate. Where sand and shell fragments are found in high proportion rich grasslands flourish. Slide 40

21. What does soil contain? • Types of parent material • Solid bedrock • Alluvium • River terrace gravel • Wind blown sand (loess) • Glacial till (Inorganic) Slide 25 Mineral matter (inorganic): minerals derived from parent material by physical and chemical weathering. Usually dissolved by water in the soil. Organic material (humus): derived from decaying roots, leaves, needles and remains of dead animals. Air and Water: co-exist and occupy the spaces in the soil called voids. Organisms: the life in the soil. Living organisms include worms, fungi and bacteria, called biota. They assist in the decay of plants and they mix the soil by their movement.

22. Ecosystems can vary enormously in scale: • Small, or micro scale, e.g. under a leaf or stone • Medium scale, e.g.. a woodland, a sand dune, a salt marsh • Large, or global scale, e.g.. Tropical rainforests, hot deserts Slide 13

23. Ecosystems depend upon two basic processes: 1. A continuous flow of energy, the main source being sunlight. Slide 21 • Sunlight is taken in by the green leaves of plants. • It is then converted, by a process known as photosynthesis, into a form of energy which can pass through the ecosystem in the food chain.

24. Snowy Owl Lemming Slide 23 The food chain

25. 2.The recycling of nutrients: carbon, nitrogen, phosphorus and potassium. Slide 3 Slide 15

27. As they burrow through the soil, earthworms drag dead leaves and other organic matter down to the lower levels, and break them down into humus Slide 2 This earwig and her babies are among the thousands of insects and other small animals that live in soil. Dung beetle feeding on animal dung and so help to break down plant and animal matter.

28. Slide 27

29. Slide 29

30. TIME Slide 4 HUMAN INFLUENCE • 400 yrs for 10mm of soil to form Affects soil development by • 1000 yrs for 1mm in extreme conditions • Adding fertiliser • 3,000 – 12,000 yrs for farming soil • Breaking up horizons by ploughing, draining or irrigating land • Horizons develop when soil reaches maturity PARENT MATERIAL determines soil • Depth • Accelerating or controlling soil erosion • Texture (coarse or fine) Soil • Drainage (permeability) • Nutrient content RELIEF/TOPOGRAPHY • Colour • Altitude: soils are thinner higher up CLIMATE • Determines rate of weathering • Aspect: Northern Hemisphere south-facing slopes are warmer and drier. SOIL BIOTA • Precipitation affect type of vegetation • Nutrient cycle/recycling • Dictates leaching or capillary action • Bacteria and fungi decompose dead plants and animals • Slope angle affects drainage and soil depth • Temperature determines length of growing season and humus supply • Worms and termites aerate the soil

31. Slide 1

32. Slide 1 Distribution of 3 Major Soil Types: Brown Earths, Podzols and Gleys. Arctic Circle Gley Soil Gley Soil Podzol Brown Earth Podzol Brown Earth Tropic of Cancer Equator Tropic of Capricorn Slide 5

33. Brown Earth Profile Slide 6

34. Slide 7 Podzol Profile

35. Slide 34 Gley Soil Profile

36. Waterlogged Tundra in summer Gley Soil Profile Slide 8

37. A B Which soil type is which? C

38. Simplified stages in soil formation Slide 5

39. HYPOTHESES: The sequence of soil profiles found in western Britain 1. Soil depth will decrease as gradient increases.2. Soil moisture will decrease as gradient increases.3. Soil acidity will be highest where gradient is lowest and leaching predominates. 4. Soil texture will be sandier where slope gradient is greatest and clay particles have been washed down-slope.5. Organic content will be highest where slope gradient is lowest and soil depth greatest.6. Soil acidity will be positively related to vegetation density. Slide 10

40. The complete process, from bare ground to climax vegetation, is called a plant succession or sere Climax vegetation ( final stage in the succession) Pioneer community (first plants to colonise an area) Slide 16

41. Vegetation succession across a Coastal Sand Dune - psammosere Slide 17 Vegetation across a grey dune and a dune slack Embryo and fore- dunes

43. Slide 43 Sea rocket Lime grass

44. Marram grass Slide 42

45. How Marram Grass stabilises sand dunes Slide 17

46. Birdsfoot trefoil Cotton Grass Spruce Slide 18

47. Slide 32