topic 3

Question 1

What is a compensation point of a plant?

Answer 1

Rate of photosynthesis is equal to rate of respiration
Store as much energy as it uses

Question 2

What is biological amplification/magnification?

Answer 2

• Toxin concentrations increase up the food chain.

Question 3

What is bioaccumulation?

Answer 3

The longer an animal lives, the more it consumes (DDT)

Question 4

Xylem vs Phloem

Answer 4

Water flows through xylem
Nutrients flow through Phloem

Question 5

Rank biomes in terms of NPP

Answer 5

Rain forest> Temperate deciduous forest > Boreal forest > Temperate grassland > Tundra > desert

Question 6

What is a biogeochemical cycle?

Answer 6

Circuit of flowing elements and materials that combine Earth’s biotic and abiotic systems

Question 7

Where is long term storage of Carbon vs short term?

Answer 7

• Long term storage is in peat, swamps marshes
• Short term is in vegetation and soil

Question 8

What is blue carbon?

Answer 8

The Carbon held in mangrove swamps and salt marshes
World’s most effective carbon sinks

Question 9

What are 5 main human contributors of CO2 in the atmosphere?

Answer 9

• Oil
• Coal
• Carbonate used for cement production
• Small amount of CO2 from volcanoes
• Burning of wood and plant matter

Question 10

How is CO2 emissions not a smooth line?

Answer 10

Due to hemispheres having different land masses
- Goes up in northern hemisphere’s winter (less trees photosynthesizing)

Question 11

How has climate warming impacted Adelie penguins?

Answer 11

Less ice, but more rocks available for female efficiency
More adelie penguins!

Question 12

Lianas and atmospheric CO2

Answer 12

Increase in lianas, decrease in forest biomass
- Increased fragmentation in forest
- Lianas reduce total carbon fixation, and compete with trees for light, causing decreased tree growth and tree mortality
- Shift carbon to aboveground plants that will eventually release it

Question 13

Increase temperature impact on fire frequency in boreal region when comparing spruce and birch

Answer 13

• Lower mineral layer in spruce forest held more carbon, with higher carbon-nitrogen ratio
• Carbon cycling birch is higher due to shorter life
• Fires mean spruce may not have chance to mature, impacting succession
• Early succession forest fires means shallower permafrost will therefore melt even more
• Absence of moss and shade means continued soil warming
• Deciduous landscape has higher albeado after a fire so could contribute longer interval til fire return

Question 14

How is arctic tundra affected by carbon storage and greenhouse gas emissions?

Answer 14

• CO2 flux and methane flux
  Saw increase in loss in warm and dry soils
  This is arctic amplification

Question 15

What is fate of tundra ponds with increased temperatures?

Answer 15

• 30% decrease in pond area and 17% decrease in number of ponds
  Conclusion:
• longer and warmer summers
• greater growth of aquatic plants around margins
• increase transpiration
• increase in active layer
• loss of organisms

Question 16

What are main Primary producers in estuaries and ocean

Answer 16

• Diatoms
• Dinoflagellates

Question 17

What is a diatom?

Answer 17

Microalgae that photosynthesize
- single celled, float in upper water layers
- In clear waters some live at the bottom, on the mud surface
- Major component of phytoplankton

Question 18

What are dinoflagellates?

Answer 18

• part of phytoplankton and single celled
• Will eat diatoms and use their chloroplasts for photosynthesis

Question 19

Describe succession of phytoplankton in marine waters

Answer 19

A yearly, seasonal succession
- there is a diatom “bloom” in spring when nutrients are abundant
- As diatoms remove nutreints, N becomes limitng
- Diatoms are replaced by dinoflagellates, as they are more mobile and better at getting scarce nutrients

Question 20

Describe cultural eutrophication

Answer 20

Fertilization of lakes, rivers or coastal waters with previously scarce nutrients, boosts primary production of algae

• Algae blocks light, as it decomposes, periods of oxygen depletion occur
• This causes blooms of toxic plankton (red tide) species and decrease in diversity

Question 21

What is nutrient pollution?

Answer 21

Nutrient over-enrichment - both nitrogen and phosphorus are vital to planat growth

• Phosphorus in freshwater
• Nitrogen in ocean and estuaries

Question 22

What is an estuary?

Answer 22

• Mix of freshwater and saltwater, where the river meets the sea

Question 23

What are two types of nutrient sources?

Answer 23

• non-point: nutrients run into water from clear cutting of forests, or run-off of agricultural fields
• point: discharge from sewage treatment plant

Question 24

Describe nitrogen deposition from the air

Answer 24

Input of nitrogen into land from the air
Through industrially produced fertilizers and overuse
Can see predictions of increasing deposition of nitrogen in the future

Question 25

Explain case in New Bedford Harbor

Answer 25

Development took place:
- land clearing, wetland loss, sewage infrastructure, release of heavy metals into water, and fishing

1) Land clearance brings nitrogen - increase in diatoms (less living at bottom)
2) Increase in bridges, wharves and turbidity, blocking light and inhibiting photosynthesis. As land clearing stops too, nitrogen decreases - decrease in diatoms
3) Untreated sewage - increase in diatoms
4) Sewage diverted to harbour - decrease in diatoms
5) PCB (chemicals) causes bloom of dinoflagellates

Question 26

Explain Chesapeake Bay case

Answer 26

Large watershed
- Point sources: industry, wastewater treatment plants
- Non-point sources: runoff from farmland, lawns and paved areas

Nutrient enrichment do to these sources caused excessive growth of microflora (epiphytes), shading the grass and eventually killing it
This changed entire ecosystem in area

Question 27

Explain the case in the Gulf of Mecixo

Answer 27

Nitrogen and Phosphorus run down river into the gulf.
Creates oxygen dead zone:
1) Freshwater runoff from the river creates a barrier at the top of the ocean, cutting off salty water from contact with oxygen in the air
2) High N and P in freshwater causes algae blooms. When it dies, it sinks and decomposes, using up all oxygen in the deep water
3) Deeper water becomes a dead zone due to no oxygen

Question 28

Explain the case of estuaries of North Carolina and Maryland

Answer 28

Water sheds with high content of pig waste becomes stored in the lagoons.
- the lagoons overflow and run into estuaries, urea stimulates dinoflagelatte to create pfisteria - damages fish
- Toxin volatizes water which is toxic to humans
- Can create anoxic area