topic 3 Flashcards
What is a compensation point of a plant?
Rate of photosynthesis is equal to rate of respiration
Store as much energy as it uses
What is biological amplification/magnification?
- Toxin concentrations increase up the food chain.
What is bioaccumulation?
The longer an animal lives, the more it consumes (DDT)
Xylem vs Phloem
Water flows through xylem
Nutrients flow through Phloem
Rank biomes in terms of NPP
Rain forest> Temperate deciduous forest > Boreal forest > Temperate grassland > Tundra > desert
What is a biogeochemical cycle?
Circuit of flowing elements and materials that combine Earth’s biotic and abiotic systems
Where is long term storage of Carbon vs short term?
- Long term storage is in peat, swamps marshes
- Short term is in vegetation and soil
What is blue carbon?
The Carbon held in mangrove swamps and salt marshes
World’s most effective carbon sinks
What are 5 main human contributors of CO2 in the atmosphere?
- Oil
- Coal
- Carbonate used for cement production
- Small amount of CO2 from volcanoes
- Burning of wood and plant matter
How is CO2 emissions not a smooth line?
Due to hemispheres having different land masses
- Goes up in northern hemisphere’s winter (less trees photosynthesizing)
How has climate warming impacted Adelie penguins?
Less ice, but more rocks available for female efficiency
More adelie penguins!
Lianas and atmospheric CO2
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
Increase temperature impact on fire frequency in boreal region when comparing spruce and birch
- 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
How is arctic tundra affected by carbon storage and greenhouse gas emissions?
- CO2 flux and methane flux
Saw increase in loss in warm and dry soils
This is arctic amplification
What is fate of tundra ponds with increased temperatures?
- 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
What are main Primary producers in estuaries and ocean
- Diatoms
- Dinoflagellates
What is a diatom?
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
What are dinoflagellates?
- part of phytoplankton and single celled
- Will eat diatoms and use their chloroplasts for photosynthesis
Describe succession of phytoplankton in marine waters
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
Describe cultural eutrophication
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
What is nutrient pollution?
Nutrient over-enrichment - both nitrogen and phosphorus are vital to planat growth
- Phosphorus in freshwater
- Nitrogen in ocean and estuaries
What is an estuary?
- Mix of freshwater and saltwater, where the river meets the sea
What are two types of nutrient sources?
- non-point: nutrients run into water from clear cutting of forests, or run-off of agricultural fields
- point: discharge from sewage treatment plant
Describe nitrogen deposition from the air
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
Explain case in New Bedford Harbor
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
Explain Chesapeake Bay case
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
Explain the case in the Gulf of Mecixo
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
Explain the case of estuaries of North Carolina and Maryland
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
