Introduction to geography people places and environment 4e edward f bergman william h renwick
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Introduction to Geography People, Places, and Environment, 4e Edward F. Bergman William H. Renwick PowerPoint PPT Presentation

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Introduction to Geography People, Places, and Environment, 4e Edward F. Bergman William H. Renwick. Chapter 4: Biogeochemical Cycles and the Biosphere Victoria Alapo, Instructor Geog 1010. Biogeochemical Cycles.

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Introduction to Geography People, Places, and Environment, 4e Edward F. Bergman William H. Renwick

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Introduction to GeographyPeople, Places, and Environment, 4eEdward F. BergmanWilliam H. Renwick

Chapter 4: Biogeochemical Cycles and the Biosphere

Victoria Alapo, Instructor

Geog 1010

Biogeochemical Cycles

  • Pathways by which energy & matter are transformed & recycled in Earth systems. See Fig. 4-1, pg 133 (next slide).

    • In the Atmosphere, hydrosphere, lithosphere e.g. water cycle.

  • Law of conservation of energy and matter – “matter cannot be destroyed or created under ordinary conditions, but it may be changed from one form to another”.

  • Two important biogeochemical cycles

    • Hydrologic cycle

    • Carbon cycle

  • Hydrologic Cycle

    • Flows (cycles) of water among land (lithosphere), sea (hydrosphere) and air (atmosphere). See next slide, but use the simpler version for exam.

    • Water changes between 3 states, but the amount remains constant.

      • Gas

      • Solid

      • Liquid

    • All living things are primarily water

    Water Storage and Sources on Earth

    Water Budget

    • An accounting of inflows and outflows of water within a given system over some time period.

    • Evapotranspiration

      • Sum of evaporation and transpiration

      • Seasonal variation

        • Low in winter

        • High in summer

    • Local water budgets

      • Compares precipitation and evapotranspiration

    Vegetation and Hydrologic Cycle

    • Trees and forests require large amounts of water. E.g. one tree in the Amazon can transpire an average of 1000 liters per day into the atmosphere!

    • Therefore, trees play key role in returning rainwater to the atmosphere

      • So deforestation affects water balance of regions. Ex. Amazon, and other parts of the world.

    The Carbon Cycle

    • Processes that cycle carbon and oxygen between the environment and living things (next slide).

      • Photosynthesis

        • Determined by climate/ more in summer

      • Respiration

        • Opposite reaction of photosynthesis (Oxygen is used)

      • Combustion

        • Coal, oil, natural gas

        • Industrial Revolution

    • The lithosphere stores carbon (from 1000s of years e.g. coal).


    • Is a dynamic, porous layer of mineral and organic matter

    • Six principal components of soil

      • Rocks and rock particles

      • Humus

      • Dissolved substances

      • Organisms

      • Water from rainfall

      • Air

    Soil Formation

    • Weathering

      • The first step in soil formation

      • Mechanical and chemical

    • Soil horizons (next slide)

      • Layers of substances found in soils

      • Formed through vertical movement of water, minerals and organic matter

    Soil Horizons

    Types of Soils

    • Soil orders

      • 11 orders (next slide)

        • 47 suborders

        • 230 great groups

        • 1,200 subgroups

        • 6,000 families

        • Thousands of soil series

        • There’s nothingsimple about “ordinary dirt”!

    • USDA Natural Resource Conservation Service maps (soils maps used in Planning Commissions & by farmers).


    • Includes all living organisms and the physical area in which they exist

    • Fundamental elements

      • Producers

      • Consumers

      • Decomposers

      • Material/energy needed for production

    Food Chains

    • Food that plants produce are distributed via a food chain (distribution)

    • Trophic level – each step in the food chain.

    • Biomagnification – e.g. when persistent chemicals remain in animal tissues and magnifies as it goes up the food chain. As in the case of humans, lions, etc.

    Food Chains

    • These 3 are all “consumers” (i.e. they’re just types of consumers):

    • Herbivores

    • Carnivores

    • Omnivores

    • What category does a “Venus fly trap” fall in???

    Community Succession

    • Sequence – how comm. succession happens

    • Succession – each plant community is succeeded by a new one until…

    • Climax community – when the community or environment becomes stable


    • Named for dominant vegetation/climate

    Major Biomes

    • Forest

      • Tropical & temperate rainforest (based on location).

      • Boreal – needle leaf/coniferous evergreen found closer to poles e.g. Alaska & Canada. Called Taiga in Russia.

      • Savannah – Woodland & Scrubland

        Location of the Serengeti National Park (“Safari”) found in Tanzania & Kenya – also a world heritage site.

    • Grassland – Prairies

    • Desert

    • Tundra

    Human & Natural Effects on the Environment

    • Humans influence ecosystems

      • 37% of land area = cropland or pasture (see next slide)

      • Desertification – when a previously non-desert area becomes one over time. E.g. fringes of the Sahara, etc. See further slide. This could be due to misuse by humans or because of global warming.

    Desertification Hazard

    The most severe desertification hazards are in northern Africa,

    central Australia, and the southwestern parts of Africa, Asia, North America,

    and South America (the fringes of the major deserts of the world).

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