Environmental Science

1
Environmental Science

• Chp. 3
• Earths Environmental Systems
• The Dynamic Earth

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Chp. 3 vocabulary terms (40)

• Lipid
• pH
• Feedback loop
• Erosion
• Geosphere
• Lithosphere
• Biosphere
• Atmosphere
• Hydrosphere
• Crust
• Mantle
• Core
• Primary producer

• Matter
• Atom
• Element
• Nucleus
• Molecule
• Compound
• Hydrocarbon
• Solution
• Macromolecule
• Protein
• Nucleic acid
• Carbohydrate
• Photosynthesis
• Cellular Respiration

• Tectonic plate
• Landform
• Deposition
• Evaporation
• Transpiration
• Precipitation
• Condensation
• Aquifer
• Groundwater
• Nutrient
• Biogeochemical cycle
• Eutrophication
• Nitrogen fixation

3
The Gulf of Mexicos Dead Zone

• Page 63 in textbook
• Apply the Decision-Making Template to analyze
  your small groups proposed solution.

4
Building Blocks of Chemistry

• Matter all material in the universe that has
  mass and volume
• Atoms basic unit of matter
• Nucleus central core of an atom, protons,
  neutrons
• Atomic number of protons in atoms nucleus
• Electrons negatively charged particles
• Element smallest unit of a chemical substance
  with a given set of properties

5
Bonding

• Bonding is an attraction that involves sharing or
  transfer of electrons
• Covalent bond sharing of electrons and forming a
  molecule
• When the electrons are shared unequally, it is a
  polar covalent bond
• Ionic bond electrons transfer completely from
  one atom to another, forming oppositely charged
  ions

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Molecules Compounds

• Molecule 2 or more atoms of same element joined
  by covalent bonds (ex. O2, N2)
• Compound substance composed of atoms of 2 or
  more different elements (H2O, CO2)
• Organic compounds associated with living
  organisms, chains of carbon
• Inorganic compounds lack carbon-to-carbon bonds
• Hydrocarbons organic compounds containing only
  hydrogen carbon some hazardous when burned

7
Solutions

• Solution mixture in which ingredients are evenly
  distributed
• Solutions can be liquids, gases or solids
• Mixture without chemical bonding, will separate
  out in time

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Macromolecules

• Proteins, nucleic acids, carbohydrates, and
  lipids are the building blocks of life
• Organic compounds combine to form long chains of
  repeated molecules called polymers
• Lipids are not polymers but are essential to life
• They are called macromolecules because of their
  large size

9
Proteins

• Organic compounds (C chains)
• Made up of C,H,O,N
• Make tissue, support, store energy, transport
  substances, immune system
• Hormones (chem. messengers)
• Enzymes (catalysts)

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Nucleic Acids

• Direct protein synthesis
• DNA hereditary information
• RNA- copies of DNA used in making the proteins
• Sugar-phosphate backbone with nitrogenous bases

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Carbohydrates

• Polymers with CH2O formula
• Glucose monomer/simple sugar that provides a
  building block for complex carbohydrates
• Provides energy
• Cellulose in plants

12
Lipids

• Fats/oils store energy, which is released when
  they burn (ex petroleum fuels release
  hydrocarbons)
• Phospholipids primary component of cell
  membranes
• Waxes make up biological structures
• Steroids/hormones cell membrane component,
  chemical messengers

13
Water Molecule

• H2O
• Over 70 of our planet
• 97 is salt water
• 3 freshwater more than 2/3 is frozen,
  unavailable
• Life on Earth depends on water
• Scientists believe life began in water
• Every organism relies on water for its survival

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Properties of Water

• Waters single Oxygen atom attracts electrons
  stronger than its 2 Hydrogen atoms
• Polar molecule with a more negative oxygen end
  and more positive hydrogen ends
• Water molecules are attracted to each other and
  therefore form hydrogen bonds

15
Cohesion/Adhesion

• Water sticks to itself
• Allows transport of materials
• Graduated cylinderyou measure the amount by the
  bottom of the meniscus
• Think of water on a penny that bubbles up until
  finally gravity is stronger than the hydrogen
  bonds and it flows over

16
Resistance to Temperature Change

• Heating weakens hydrogen bonds, but it doesnt
  initially increase molecular motion
• So, water can absorb more energy with only a
  small temperature change
• This stabilizes aquatic climates
• Coastal areas are cooler in hot weather and
  warmer in cold weather
• Ex. Seattle, London

17
Ice Density

• Water molecules when frozen are further apart
  than in liquid water
• Therefore, ice is less dense than liquid water,
  which is the reverse of most other compounds
• So, ice floats!!!
• Ice insulates bodies of water, preventing them
  from freezing solid in winter

18
Universal Solvent

• Water molecules bond well with other polar
  molecules
• Positive end of one molecule is attracted to the
  negative end of the other molecule
• Therefore, water can hold or dissolve many other
  molecules
• Because of this property, water is often called
  the universal solvent

19
Acids, Bases, pH

• In any water solution, some molecules separate
  into ions (hydrogen ion H and hydroxide ion OH-)
• Acids release H ions
• Bases release OH- ions
• pH scale measures acidity
• Neutral 7
• Acids less than 7 pH
• Bases greater than 7 pH
• Each point is a tenfold difference

20
Small Group Activity

• Is table salt (NaCl) a compound? How can you
  tell?
• List the 4 types of macromolecules. Explain one
  role of each in the human body.
• What are 4 properties of water? How would each of
  these help fish living in a freshwater pond?

21
Interacting Systems

• Systems receive inputs, process these inputs, and
  produce outputs
• Earths environment consists of complex,
  interlinked systems
• Systems seldom have defined boundaries
• Systems may exchange energy, matter and
  information with other systems
• Ex. Gulf of Mexico inputs of water, sediments,
  nutrients, pollutants outputs of shrimp and fish
  which then become inputs to other systems

22
Feedback Loops

• Involves cause (input) and effect (output), and
  can be cyclical
• Negative feedback loop output acts as input that
  causes the system to move in the other direction
  stabilizes the system
• Positive feedback loop rather than stabilizing,
  it drives a system to an extreme and can alter it
  dramatically rare, but are common in systems
  changed by humans (Ex. Erosion)

23
Earths Spheres

• Geosphere all the rock at and below Earths
  surface (crust, mantle, outer core, inner core)
• Lithosphere outermost layer of the geosphere
• Biosphere 7km above below Earths surface that
  supports life, includes nonliving
• Atmosphere layers of gases surrounding our
  planet
• Hydrosphere all the water on Earths surface,
  underground, in the atmosphere

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The Geosphere

• Crust thin layer of relatively cool rock that
  forms the Earths outer skin
• Mantle very hot but mostly solid rock
• Core lies below the mantle, HOT
• Outer core is molten metals (iron, nickel)
• Inner core is a dense ball of solid metal
• Convection current heat from the outer core
  pushes soft rock upward as it warms rock sinks
  downward as it cools creates a giant conveyer
  belt that drives plate tectonics

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Plate Tectonics

• Tectonic plates large plates of lithosphere
  dragged along by the asthenosphere
• 15 major tectonic plates
• Move 2-15 cm/year
• Collisions separations of plates result in
  landforms (ex. Mountains), islands continents
• Landforms influence climate
• Climate, soil formation, erosion, deposition
  affect life inhabiting different regions

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Types of Plate Boundaries

• Divergent plate boundary magma surges upward,
  pushing plates apart and creating new crust as it
  cools
• mid-Atlantic ridge
• Transform plate boundary when 2 plates meet,
  they slip grind alongside one another, creating
  friction (earthquakes)
• Convergent plate boundary plates collide,
  causing one plate to subduct (trench volcanoes)
  and/or mountain-building

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Biosphere Atmosphere

• Biosphere is where living nonliving things
  interact (the living Earth)
• Atmosphere is the gases that support protect
  the entire biosphere
• Ozone layer of O3 gas that protects the
  biosphere from the suns UV radiation
• Greenhouse gases help keep the Earth warm enough
  to support life (CO2, methane) human activity
  has increased the greenhouse gases, leading to
  global warming.

28
Hydrosphere

• Water cycles through the lithosphere, biosphere
  atmosphere endlessly
• As a means of transport as a solvent, water
  plays key roles in nearly every ecosystem
• 97.5 of Earths water is salt water
• 2.5 is freshwater
• 75 of freshwater is tied up as ice
• 0.5 is unfrozen fresh water available for
  drinking and watering crops
• Shortages conflicts occur

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The Water Cycle

• Roles that water plays in our environment
• Water moves into the atmosphere by evaporation
  transpiration
• Natural distillation process, creating pure water
  by filtering out minerals pollutants
• Warm temperatures strong winds speed up
  evaporation (liquid to gas)
• Water returns to Earths surface through
  precipitation as water vapor condenses from gas
  to liquid)

30
Ground Water

• Some precipitation surface water soaks down
  through soil and rock to recharge underground
  reservoirs (aquifers)
• Aquifers are layers of rock soil that hold
  groundwater
• Water table is the upper limit of the groundwater
• Groundwater takes 100s-1000s of years to recharge
  fully, if ever

31
Nutrient Cycling

• Nutrients matter organisms require for life
• Matter may be transformed but it cannot be
  created or destroyed (law of conservation of
  matter)
• Macronutrients required in large amounts (ex. N,
  C, P)
• Micronutrients needed in small amounts
• Nutrients cycle through the environment endlessly
  in biogeochemical cycles.

32
The Carbon Cycle

• Producers play vital roles in cycling of carbon
  in ecosystems
• Carbon atoms are everywhere, from fossil fuels to
  DNA to plastics to medicines

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Photosynthesis/Producers

• Primary producers are organisms that produce
  their own food (plants, algae and bacteria)
• Producers use the suns energy and chemical
  energy along with CO2 to produce carbohydrates
  (C6H12O6)
• Photosynthesis uses the suns energy with CO2 out
  of the environment H2O, breaking the bonds to
  give off O2 and produce carbohydrates

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Consumers/Decomposers

• Carbon in a producer is passed on to a consumer
  or a decomposer
• Consumers are organisms that must eat other
  organisms to obtain their nutrients
• Decomposers are organisms that break down wastes
  dead organisms (ex. Bacteria, Fungi)

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Cellular Respiration

• Is NOT breathing
• Process in which organisms use O2 to release the
  chemical energy of sugars and give off CO2 and
  H2O
• It is the chemical reverse of photosynthesis
• Organisms do not release all of the carbon they
  take in, making them a major carbon sink
• EnergyATP

36
Wheres the Carbon???

• Sediments when organisms die in water, their
  remains settle in sediments
• Sedimentary rock, limestone, fossil fuels
• Oceans absorb carbon from the atmosphere,
  runoff, undersea volcanoes, and wastes/remains of
  organisms
• Human impacts shift carbon from lithosphere
  (burning fossil fuels) to the atmosphere (CO2)
  deforestation reduces plants available to use it
• Missing carbon sink 1-2 billion metric tons
  unaccounted for by scientists

37
The Phosphorus Cycle

• Involves mainly the lithosphere and the oceans
• Key component of cell membranes, DNA, RNA
• Released naturally when rocks are worn down by
  water/wind
• Minimal availability to organisms, so plant/algae
  growth jumps when available, causing
  eutrophication
• Extreme cases cause hypoxia/?O2
• Found in fertilizers, detergents

38
The Nitrogen Cycle

• Relies on bacteria to make nitrogen useful to
  organisms and to return it to the atmosphere
• Nitrogen 78 of atmosphere
• Essential ingredient in proteins, DNA, RNA
• Nitrogen gas cannot cycle out of the atmosphere
  and into organisms without lightning, bacteria or
  human technology
• Nitrogen fixation nitrogen gas to ammonia by
  nitrogen fixing bacteria
• Nitrification ammonia to nitrates
• Denitrification nitrates to nitrogen gas
• Legumes roots host nitrogen-fixing bacteria

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Conflicting Interests

• Humans learned to fix nitrogen to synthesize
  ammonia, increasing its flow out of the
  atmosphere and into other reservoirs
• Burning fossil fuels releases NO, which forms
  NO2, leading to acid rain
• Ns natural scarcity reintroduction by man
  leads to eutrophication (ex. Dead Zone in Gulf of
  Mexico)
• US Congress passed the Harmful Algal Bloom
  Hypoxia Research and Control Act in 1998/2004

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Proposals for Reducing Gulf of Mexico Dead Zone

• Reduce nitrogen fertilizer use on Midwest farms
• Change the timing of fertilizer use to minimize
  runoff during the rainy season
• Plant alternative crops
• Manage nitrogen-rich livestock manure better
• Restore nitrogen-absorbing wetlands in the
  Mississippi River basin
• Construct artificial wetlands to filter farm
  runoff
• Improve sewage treatment
• Restore frequently flooded lands to reduce runoff
• Restore wetlands near the Mississippi Rivers
  mouth to improve nitrogen-absorbing ability