Introduction to Geography People Places and Environment 6

Introduction to Geography People, Places, and Environment, 6 e Carl Dahlman William H. Renwick Chapter 4: Biogeochemical Cycles & the Biosphere & the Four Laws of Ecology Holly Barcus Morehead State University And Joe Naumann UMSL

Biomes • Global patterns in the biosphere – Associations of plant and animal types – Similar distributions: highly interconnected • Soil • Vegetation • Climate – Human impacts • Population growth • Consumption of natural resources 2

Recycled & Recycling World • Studying patterns and relationships, one discovers that the world is one gigantic system composed of intrerconnected and interdependent cycles and sub-systems. • Everything & everyone is connected! 3

Solar Powered World • Directly or indirectly, all the biochemical systems depend on the energy from the sun. 4

Cycles & Balances • The state of the earth today is the result of past actions, creating a somewhat stable, selfperpetuating ecosystem (at least in human terms). In that system, we can identify cycles (and recycling) and balances that help perpetuate the “climax” condition. • Human actions can fit in two ways: – Respect cycles & balances and work with them – Upset the cycles & balances to obtain short-term benefits & then deal with the consequences. 5

Systems • System: any working thing composed of two or more interrelated parts – Closed System: is self-maintaining or perpetuating – doesn’t need something to start or maintain it. Example: Hydrologic cycle – Open System: needs something to start or maintain its operation. Example: an automobile • The entire earth may be seen as a complex, gigantic ecosystem composed of many interconnected subsystems. 6

Biogeochemical Cycles • Recycling processes that supply essential substances to the biosphere – Connect Earth’s subsystems • Atmosphere, hydrosphere, lithosphere • Law of conservation of energy and matter – states that energy cannot be created or destroyed, but can change its form. The total quantity of matter and energy available in the universe is a fixed amount and never any more or less. • Two important biogeochemical cycles – Hydrologic – Carbon 7

Key Cycles • Rock Cycle (see chapter 3) 8

Hydrologic Cycle • Flows of water among land, sea and air • 3 states of water – Gas – Solid – Liquid • All living things are primarily water 9

The range of earth temperatures allows water to exist in all three states.

Water: Where is it? • • • 96. 5% stored in oceans 2% stored in glacial ice 0. 9% is saline groundwater 0. 8% available as fresh water 0. 014% in rivers and lakes 0. 001% is contained in the atmosphere 11

Water Budget • Accounting of inflows and outflow within a given system • Evapotranspiration – Sum of evaporation and transpiration – Seasonal variation • Low in winter • High in summer • Local water budgets – Compares precipitation and evapotranspiration 13

Generalized Water Budget:

Water Budget • Variations reflect the different budgets that exist in different climates in different locations around the world.

Soil and the Water Budget • Critical to water budget: soil stores and makes water available to plants. • Stores water for evapotranspiration (ET) – Soil texture & composition affect how much water soil can hold • Size of soil particles • Quantity of humus (organic matter) • Degree of compaction • Infiltration capacity – Good -– Poor -- 16

Vegetation and Hydrologic Cycle • Trees and forests require large amounts of water • Trees play key role in returning rainwater to the atmosphere – and oxygen – Deforestation affects water balance of regions • Reduces evapotranspiration • Promotes a less humid climate – climate change – Ex. Amazon & Congo basins • Grasses – produce less oxygen than forests – Shallow roots – Variable transpiration rates 17

The Carbon Cycle • Processes that cycle carbon and oxygen between the environment and living things – Photosynthesis • Determined by climate • Seasonal cycles of solar radiation – Respiration • Opposite reaction of photosynthesis – Combustion • Coal, oil, natural gas • Industrial Revolution • Lithosphere stores carbon 18

Most Life is based on carbon

Nitrogen Cycle • Nitrogen is essential for plant growth 20

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Food Chain 23

Food Chain Cycle Related to Seasons • Stage 1 24

Aphids Stage 2 25

Aphids Stage 3 26

Deforestation (particularly tropical rainforests) • Important influence on biosphere-atmosphere exchanges • Biomass – – Stores carbon & releases oxygen Forests and trees are key storage sites Forests filter impurities from the atmosphere Deforestation through cutting and burning releases carbon into atmosphere • Critical regions – Central and South America – West Africa – Southeast Asia 27

Soil • Dynamic, porous layer composed of weathered mineral matter, organic matter (living & dead), water and air. Soil is a “living thing. ” • 5 factors that affect soil properties – – – Climate Parent material Biological activity Topography Time 29

Soil Formation • Weathering – Mechanical and chemical • Water – Volume that passes through rock is important factor – Large volumes of water = lower amounts of soluble minerals • Plant and animal activities • Topography 30

Soil Characteristics • Six principal components of soil – – – Rocks and rock particles Humus Dissolved substances Organisms Water from rainfall Air • Soil horizons – Layers of substances found in soils – Formed through vertical movement of water, minerals and organic matter 31

Topsoil

Types of Soils • Soil orders (related to climate & vegetation – a relatively stable symbiosis in nature) – 11 orders • 47 suborders • 230 great groups • 1, 200 subgroups • 6, 000 families • Thousands of soil series • USDA Natural Resource Conservation Service maps 33

Climatic Soil Regions • Humid tropical and subtropical soils – Oxisols and ultisols – Highly weathered & leached - practically no humus accumulation • Arid region soils – High in soluble minerals & very little humus • Midlatitude humid soils – Moderately leached – Moderate amount of humus • Midlatitude subhumid soils – Fertile – high humus content – “Chernozem” – Associated with grain-producing regions 34

Soil Regions of the World

Differing climate & vegetation = different soil types • How much humus? • Acid, neutral, or base? • What texture? 36

Soil Problems and Fertility • Problems – Artificial nutrients not replaced fast enough • Manure, inorganic fertilizers • High intensity agriculture – Erosion and desertification – highly related to human use/abuse • Fertility – Factors = plowing, planting cycles, availability of nutrients – Restoration of fertility • Fallow periods • Organic and inorganic fertilizers • Concern about soil degradation and future food production capacity 37

The Four Laws of Ecology • Human survival may depend on humans understanding and valuing these laws and in considering them whenever decisions affect the environment. 38

Four Laws of Ecology: From Barry Commoner’s book The Closing Circle • Everything is connected – Everything on earth is interconnected much like a huge spider web • Everything goes somewhere – Elements of the system may change but don’t cease to exist • Nature knows best – What nature creates is biodegradable • There’s no such thing as a free lunch – There are consequences (costs) for every action 39

Everything is Connected • It may take some time to see some connections. 40

Everything Goes Somewhere • Winter road salt contaminates ground water, eventually causing 41 damage far away.

Nature Knows Best • Non-biodegradable chemicals remain in the ecosystem indefinitely, being recycled through the food chain over and over. 42

There’s no such thing as a free lunch! • Left –Action: clear cutting by lumber companies • Right –Consequence: mudslide resulting from clear cutting – costs to repair damages 43

1. DDT molecules in the ocean are ingested by plankton, storing DDT 2. Plankton eaten by small fish, storing & concentrating DDT 3. Small fish eaten by larger fish, storing & concentrating DDT 4. Larger fish eaten by seagulls, storing & concentrating DDT 5. Seagulls produce thin-shelled eggs – no chicks hatch 6. 7. Eggs decompose and DDT returns to soil or water to be absorbed at the food chain base and start another cycle Seagull dies returning DDT to soil or water to be absorbed at the food chain base and start another cycle -- #8 Seagull Example 3 2 1 8 4 DDT is non. Biodegradable and recycles. 7 6 5 44

Ecosystem • Includes all living organisms and the physical area in which they exist • Fundamental elements – – Producers Consumers Decomposers Material/energy needed for production 45

Food Chains • • • Distribution Herbivores Carnivores Omnivores Trophic level (Place in the food chain) Biomagnification 47

Biological magnification • Generally, the higher a species is on the food chain, the greater the magnification of “stored” chemicals. • Humans are at the top of the food chain 49

Why understand the 4 laws? • Every change in the ecosystem has consequences • In the past the consequences were relatively small and we could learn from our mistakes • The technology of today makes it possible for us to make changes with possibly catastrophic consequences • We must try to ascertain possible consequences before we initiate changes in the ecosystem 50

The Reality of the 4 Laws 51

Example • Pollution of the oceans plus the thinning of the ozone layer could be harmful to the phytoplankton (and zooplankton) in the sea – Phytoplankton (microscopic plants) form the basis of the entire food chain of the ocean – Phytoplankton produce much oxygen (I’ve read estimates as high as 70% of the oxygen produced come from the phytoplankton) • Do we really want to risk harming phytoplankton? A mistake can’t be easily undone! 52

Four Requirements of Life All life on earth depends on four requirements: 1. Sunlight – the power source or enabler for the life system (climate, plants, animals, etc. ) 2. Water 3. Air 4. Soil (land) 53

Pyramid of Life • A change at any level may have serious consequence s for everything above it on the pyramid. 54

Community Succession • Sequence • Succession • Climax community 55

Biodiversity • Diversity of species • Stability of community • Biosphere reserves – UN Biosphere Reserve Program • Importance of size • Managed landscapes 56

Biodiversity is essential • Do we know the niche of each member of a biotic community? • Gene pool for future hybrids • Undiscovered values – don’t throw out baby with the bath 57

Biodiversity on a Coral Reef: Click the picture for the video 58

Biomes • Ecosystems grouped by: – Plant types – Animal types • Named for dominant vegetation/climate • Typically contain many ecosystems 59

Major Biomes • Forest – Tropical & temperate rainforest – Boreal • • • Savannah Woodland Scrubland Grassland Desert Tundra 60

Tropical Rainforest Biome • Click the picture to see the video 61

Desert Biomes • Click the picture to see the video 62

Biomes - Bioregions

Human and Natural Effects • Humans influence ecosystems – 37% of land area = cropland or pasture – Desertification • Local topography and geology – Vegetation and evapotranspiration vary regionally – Wind erosion 64

Dangers to Biochemical Systems and Cycles from Human Actions • • Desertification Deforestation (particularly tropical) Loss of biodiversity Threats to the base of the food chain – Eutrophication – Pollution – Over fishing • Soil: erosion & salinization • Global Warming & ozone depletion • Water & air pollution 65

Changing the “Mix” of a Biome • Subtraction from a biome – Removing a species – Removing or altering a natural condition • Adding to a biome – Introduction of exotic plants – Introduction of exotic animals – Introduction of exotic diseases 66

Removing species • Predators in North County & most of MO – Deer – Rabbits & squirrels • Removing forest fires? ? ? ? ? – Jack pine • Crocodiles in African rivers • Removing a vital link in the biome may remove all that was dependent on it. 67

Introducing Exotics • • Rabbits in Australia Kudzu in USA Fungus carrying moth in USA Smallpox, diphtheria, whopping cough, syphilis, “childhood diseases” etc. , to the Americas – Danger today of terrorists using exotic microbial agents as weapons • Historians call this the Columbian Exchange! 68

Saltcedar: shrub native to Eurasia & Africa • 12 varieties in USA – natural, vigorous hybrid • Long taproot depletes springs in US West • Salt accumulates on leaves – when leaves fall, soil becomes to salty for native plants • Vigorous grower – crowds out native plants • Threatens habitat of 31 endangered species • Spreading to 40, 000 acres per year • Resists fire & chemical sprays - insects (hybrid) • Clogged California rivers • Displaced shorebirds in Kansas 69

Land Use in the USA

Human Interaction with Water Upsets Many Cycles 71

Water & Water Quality • • Availability of Water Modification of Streams Water Quality Agricultural Sources of Water Pollution – Fertilizers, Biocides, Animal Wastes • Other Sources of Water Pollution – Mining & Industry – Municipalities and Residences • Controlling Water Pollution 72

Modification of Streams • Levees increase flooding downstream and across the river. • “straightening” streams increases the volume of water downstream • Dams may impede the movement of fish – fish ladders needed for salmon in northwest • Canals connecting streams may allow the spread of undesirable species – zebra mussel and sea lamprey • Destruction of wetland habitats 73

Levee – modifications of streams Levee More flooding Man-made levees are higher than natural ones. • The floodplain (basin) is nature’s release valve for floods and provides a wetland habitat for many species of plants and animals. A levee reduces its ability to moderate flooding 74 and sustain a wide variety of plants and animals

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Water Quality • Nature pollutes water at a rate which nature can process in a reasonable time and/or distance from the contamination. – Animal feces – Decaying plant and animal material • Humans have overloaded the natural system and that is what we call “pollution. ” – More than nature can process in a reasonable time and/or distance – Non-biodegradable chemical compounds 77

Sources of Water Contamination • Microbiological contamination – septic tanks & sewage discharges – sanitary landfill sites – farms (liquid manure storage, animal production) • Chemical contamination – septic tanks (organic contaminants, disinfectants, etc. ) & sewage discharges – sanitary landfill sites – farms (fertilizers, pesticides, herbicides) – leakage from oil tanks or chemical spills – highways (de-icing salt) 78

Water Quality continued. . . • Agricultural run-off creates problems – Causes excessive growth of algae and other plants, leading to eutrophication – Nitrate build-up in reservoirs threatening the life of infants and very 79 ill persons – nitrates to nitrites.

Urban Run-off Contributes More to Flooding Natural surface Urban surface • Farmland natural land retains water longer, releasing it more slowly to the streams • Urban surfaces are non-absorbent of water and produce greater volumes of run-off more rapidly 80

Urban -- Rural • Consider this: In most urban areas, the finest, level farmland is used to build subdivisions, shopping malls, etc. – retiring the best farmland increasing runoff/flooding. 81

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Damage to the seas and delicate biomes like the tundra 83

Danger at sea Accidental oil spills can harm the sea biome and 84 nearby coastal biomes.

Each Citizen Has a Role to Play • Different world views cause cultures to respond to nature, the physical world, in different ways – some life-affirming and others life-negating. 85

Many problems don’t start within or stop at our borders! End of Chapter 4 86