12. Nutrients cycle

Question 1

What is the chemical composition of trees?

Answer 1

Carbon (50%), Oxygen, Hydrogen, Nitrogen, others

Question 2

Where do trees get their chemical composition elements from?

Answer 2

Water/Soil, but mostly from the air (CO2)

Question 3

Explain the first law of thermodynamics (sort of)

Answer 3

Conservation of energy/mass: in a chemical reaction, mass is neither created nor destroyed. Atoms/molecules are rearranged and recycled. Nutrients cycle. Energy flows, but nutrients cycle.

Question 4

Energy flows, but nutrients ___.

Answer 4

Cycle

Question 5

What are some consequences of nutrient cycling?

Answer 5

Anything we create may not go away. If biodegradable: eaten by microbes. Decomposed into molecules or atoms. If not, around “forever”. Plastics are barely decomposable. Most of our pollution problems are linked to “nutrient” cycling.

Question 6

Match the pollutant with the problem:

a) Sulfur dioxyde
b) CO2
c) Nitrates
d) DDT
e) Chlorofluorocarbons

Problems: Climate change, Ocean dead zones, Acid rain, Depletion of ozone layer, Egg-shell thinning in birds

Answer 6

a) Acid rain
b) Climate change
c) Ocean dead zones
d) Egg-shell thinning in birds
e) Depletion of ozone layer

Question 7

Who am I?

Synthesis of nutrient cycling and energy flow

Answer 7

Biomagnification

Question 8

Explain biomagnification

Answer 8

Synthesis of nutrient cycling and energy flow. Whenever ingestion: excretion. Chemicals increase in an organism’s body over time. Typically: fat-soluble compounds. When that organism is eaten, pass the pollutants up the food chain. DDT: first major environmental problem

Question 9

What is the first major environmental problem?

Answer 9

DDT (insecticides)

Question 10

Explain Silent Spring from Rachel Carson

Answer 10

She began the modern environmental movement. Added a “nutrient cycling” perspective to our ecocentric ethic

Question 11

Explain the banning of DDT in 1972

Answer 11

It was the first major environmental problem to be tackled/solved. Bald eagles listed as endangered in 1967 in US. 417 breeding pairs in “lower 48”. Changed to threatened in 1995. Not at risk in 2007: 10,000 breeding pairs.

Question 12

Why does the St-Lawrence river not run dry?

Answer 12

Hydrologic cycle.

Question 13

What are the implications of the water cycle (hydrologic cycle)

Answer 13

1-way flow of nutrients. Land to water: Anything we do on land affects aquatic ecosystems. Sewage: where does it go? The City of Victoria is the last city to stop dumping raw sewage into the ocean.

Question 14

What limits primary production in aquatic ecosystems?

Answer 14

Nutrients.
Limiting nutrients in oceans? Nitrogen
Limiting nutrients in freshwater? Phosphorus

Question 15

Discuss Dr. David Schindler, DFO and U Alberta

Answer 15

Schindler’s (1974) study gave the most compelling evidence for phosphorus being the cause of man-made eutrophication.
Legislation was later adopted limiting P in detergents and effluents. Fertilizing with P, N, and C: white reflection is the algae bloom the resulted from phosphorus fertilization. Bassin fertilized with only C and N

Question 16

Where does phosphorus come from?

Answer 16

Fertilizers. No atmospheric phase: local effects. Largely unavailable in rocks. Tight cycling of available phosphorus. Sources: Fertilizers and sewage. Hydrological cycle: eutrophication of receiving waters. i.e. over-fertilization of freshwater.

Question 17

Discuss the nitrogen cycle

Answer 17

Has an atmospheric component. Inorganic. N makes up 80% of air, but is unavailable. All available N was fixed by bacteria until 20th century. Haber-Bosch process: Nobel Prize in 1918. We now make an equal amount of fixed nitrogen as all the bacteria on earth (we have doubled the nitrogen budget on earth)

Question 18

Why care about fertilizer production?

Answer 18

They are energy/carbon intensive. Anything we put on lands ends up in the water. Pollute receiving waters. Particularly oceans for Nitrogen. Ocean Dead zone: 6000 square mile area of the Gulf of Mexico where sea life can’t survive (no oxygen) Phytoplankton bloom “dead zone”

Question 19

What is the second environmental problem to be solved?

Answer 19

Eutrophication

Question 20

Discuss the eutrophication problem

Answer 20

Each day, Detroit, Cleveland and 120 other municipalities fill lake Erie with 1.5 billion gallons of “inadequately treated wastes, including nitrates and phosphates..” These chemicals act as fertilizer for growths of algae that suck oxygen from the lower depths and rise to the surface as odoriferous green scum.. Commercial and game fish - blue pike, whitefish, sturgeon, northern pike - have nearly vanished, yielding the waters to trash fish that need less oxygen.

Weeds proliferate, turning water frontage into swamp. In short, Lake Erie is in danger of dying by suffocation”. (August 1969)

Question 21

What strategy has been adopted for the eutrophication problem. Was it successful?

Answer 21

1972: Great Lakes Water Quality Agreement. Target: <1mg/L of P in municipal sewage. Action: $7.5 billion
Results: success

Question 22

Is eutrophication still a problem?

Answer 22

Yes, but manageable. Climate change, invasive species, agriculture: we can handle these problems.

Question 23

Discuss the carbon cycle

Answer 23

Primarily run by living organisms. Photosynthesis vs respiration. We intruded by burning fossil fuels. Releasing of unavailable carbon that was fixed about 300 million years ago. Climate change. Ocean acidification. Carbonic acid (acid that is causing ocean acidification). Acid rain is caused by burning fossil fuels. Burnin of coal heavy in sulfur. Oxides of N and Sulfuric acid

Question 24

What is the 3rd major environmental problem tackled by humanity?

Answer 24

Acid rain

Question 25

Acid rain: Fill in the blank

a) What is the pH of a neutral solution?
b) What is the pH of unpolluted rain water? Why?
c) What is the issue then?
d) Acid rain is stabilized or improving?

Answer 25

a) 7
b) 5.6, since there is natural carbon dioxide in the atmosphere, but ok because soil can buffer that
c) when you add sulfur and nitrogen, the pH goes way below 5.6
d) Switching to low sulfur coal. Switching to other energy sources. Scrubbers in smokestacks. Canada: 50% reduction in Sos emissions 1980-2001. So: Not solved everywhere, but getting better

Question 26

Is CO2 in the atmosphere a good or bad thing?

Answer 26

Bad news! Increasing over time.

Question 27

What is the 4th major success story in environmental problems?

Answer 27

Montreal Protocol signed in 1987 addressing the CO2 in the atmosphere. Ozone hole has stabilized and should decline.

Question 28

Fill in the blank: Implications of nutrients cycles

a) Things we make (eventually go away/don’t necessarily go away)
b) All of our pollution problems are because of ___ ___.
c) what we do on land affects ___ ____.
d) We have solved or stabilized __ major environmental issues in the past (Name them, in order)
e) What is the current problem to tackle?

Answer 28

a) don’t necessarily go away
b) nutrients cycle
c) aquatic ecosystems
d) 4: DDT, phosphorus in freshwater, acid rain, depletion of ozone
e) Climate change

Question 29

Fill in the blank: Last word to Daniel Kozlovsky: an ecological and evolutionary ethic.

a) Because of the nutrient cycle: Atoms are ___. What is environment today is ___ tomorrow.
b) Why should we be careful about what we dump into the environment?
c) Do unto the environment… (and why)
d) Stop making things that are __ ___.

Answer 29

a) transient. organism
b) Because tomorrow, it’s likely to be us.
c) what you would do unto you. Because we are linked by nutrient cycles to the environment (ecosystems ethic)
d) not biodegradable