Lecture 18: Ecosystems: Water cycle, carbon cycle, & nitrogen cycle Flashcards

1
Q

Major physical and biological processes couple water movement to ____________________ and _______________ in ecosystems.

A
  • energy transformation
  • element cycling
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2
Q

Water movement is therefore a ______________________________________ and for understanding energy flow in an ecosystem

A

valuable proxy for element cycling

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3
Q

Direct human impacts on the water cycle

A
  • Land conversion impacts water runoff pathways and rates
  • Altered water runoff pathways and rates
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4
Q

Direct human impacts on the water cycle - land conversion

A
  • Developed areas (city-building and especially concrete).
  • Agricultural land conversion.
  • Dams
  • Irrigation.
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5
Q

Direct human impacts on the water cycle - Altered water runoff pathways and rates

A
  • substantial impact on soil erosion — direct impact and indirect impact on crops
  • can further impact vegetation cover,
    droughts, and fire
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6
Q

The movement of major organic elements serves as a _____________________________

A

good proxy to energy flow

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7
Q

Carbon is ____________________________ and transferred in ___________________________________, so carbon transfer is directly coupled with energy flow.

A
  • generated from photosynthesis
  • trophic interactions and decomposition
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8
Q

Net ecosystem production

A

a measure of the balance of carbon gain and loss in an ecosystem

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9
Q

Positive net ecosystem production

A

serves as a carbon sink

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10
Q

carbon sink

A

Removes carbon, as the main “greenhouse gas”, from the atmosphere

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11
Q

what happens when carbon sources outweigh carbon sinks

A
  • results in an increase in greenhouse gases and temperatures
  • as we are seeing from human activity
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12
Q

what are the 6 major transformations that drive the carbon cycle

A
  1. photosynthesis
  2. respiration
  3. sedimentation and burial
  4. exchange
  5. extraction
  6. combustion
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13
Q

6 major transformations drive the carbon cycle - photosynthesis

A

Biological removal from the environment

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14
Q

6 major transformations drive the carbon cycle - respiration

A

Biological return to the environment

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15
Q

6 major transformations drive the carbon cycle - sedimentation and burial

A

carbon storage

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16
Q

6 major transformations drive the carbon cycle - exchange

A

Balanced gain/loss between ocean and atmosphere

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17
Q

6 major transformations drive the carbon cycle - extraction

A

Removal of carbon storage by human activity

18
Q

6 major transformations drive the carbon cycle - combustion

A
  • Burning of stored carbon sources
  • rapid return of carbon to the environment
  • and especially the atmospheric “compartment” of the carbon cycle
19
Q

define residence time

A

Time spent in any stage of the cycle by the average carbon molecule

20
Q

The global carbon cycle – Photosynthesis & respiration

A
  • Biological exchange between the environment and organisms
  • Biological material is a major “sink” for carbon
21
Q

What have humans done to the carbon sink of biological material?

A
  • Humans have reduced the amount of biological material
  • Results in more carbon in the air becuase it isn’t going to the sink
22
Q

The global carbon cycle – ocean-atmosphere exchange

A
  • Physical exchange of carbon dioxide between the atmosphere and all water bodies
  • Carbon dioxide uptake by the oceans and the process of sedimentation has offset the atmospheric increases from human activity.
23
Q

Carbon dioxide __________________ in water at the interface between air and water, and is also lost back to the atmosphere.

A

readily dissolves

24
Q

Oceans contain about ______ the carbon dioxide found in the atmosphere – _____________

A
  • 50 times
  • major carbon sink
25
The global carbon cycle – Sedimentation & burial
- Process occurs only in aquatic systems - The excessive “consumption” of carbonate ions due to ocean acidification is also impacting shell formation in marine animals
26
What happens to ocean water when carbon dioxide absorption levels increase
It becomes more acidic - coral reef bleaching
27
explain the sedimentation process
- When carbon dioxide dissolves in water it forms carbonic acid. - Carbonic acid dissociates into hydrogen ions (source of elevated pH!), bicarbonate ions, and carbonate ions. - Carbonate ions combine with calcium to form calcium carbonate. - Calcium carbonate has low solubility and precipitates out of the water to form sediment — a long-term carbon store
28
The average ________________ of carbon in the atmosphere is only 5 years — contrasting 31 years for autotroph material.
residence time
29
The ________________ and ______________________________ makes atmospheric carbon dioxide levels sensitive to increased inputs from sources outside the normal cycle — ______________________
- short residence time - relatively low level of atmospheric carbon - like a river bursting its banks
30
changes in carbon dioxide, even the steady decline to present day levels, were coupled with ___________________________________
massive shifts on global land cover and weather patterns
31
Emerging consequences of elevated carbon dioxide in plants
- Elevated growth for some plants - Reduced plant quality, even if abundance is greater - Reduced growth or die-off - Overall, shifts in community structure, including subsequent changes in competitive dynamics
32
Emerging consequences of elevated carbon dioxide - elevated growth for some plants
results in important changes in relative abundance of certain species
33
Emerging consequences of elevated carbon dioxide - reduced growth or die-off
it is due to complex interactions with related temperature increases, and nutrient and temperature availability
34
define the greenhouse effect
- Carbon dioxide absorbs infrared thermal radiation from the earth and re-radiates it - More carbon dioxide = more re-radiation. - A steady, recorded rise in annual temperature is tightly correlated with steady rise atmospheric carbon dioxide
35
food production can suffer large ______ with increasingly _________________ patterns
- loses - unpredictable weather
36
__________ of relatively small change in global climate patterns can have severe impact on established _______________________.
- Speed - expectations of human activity and especially food production
37
Why do we care about a 1ºC increase in temperature?
Small change in mean annual temperatures may hide increasingly erratic temperature patterns
38
why isn't the term global warming accurate
it hides the far more significant issue of global climate change
39
what is more accurate than the term global warming
global climate crisis is more accurate and all-encompassing
40
While we wait for global governmental efforts, individual changes do make a difference, and ________________________
collective individual efforts change markets