Chapter 5 - Ecosystems and Matter Cycling Flashcards
1
Q
What are the 3 most critical environmental challenges facing the earth resulting from cycle disturbance?
A
- Global Warming
- Acid Deposition
- Spread of oceanic dead zones
2
Q
Understanding the nature of _________________ cycles is necessary to be able to fully appreciate the nature of these problems and their potential solutions.
A
biogeochemical
3
Q
What two disturbances do Emissions from Stacks cause?
A
- Acid Deposition
- Global Warming
4
Q
Everything is either _________ or __________.
A
matter, energy
5
Q
What is Matter made of?
A
- Atoms (smallest particles)
- Protons, neutrons, and electrons (subatomic particles)
6
Q
___________ are more than one atom joined together.
A
Molecules
7
Q
What is it called when two or more different atoms come together?
A
Compound
8
Q
What are the four kinds of organic compounds that make up living organisms?
A
- Carbohydrates
- Fats
- Proteins
- Nucleic Acids
9
Q
What three forms does Matter exist in?
A
- Solid
- Liquid
- Gas
10
Q
What does the Law of Conservation of Matter state?
A
Matter can neither be created nor destroyed, only transformed from one form into another
11
Q
Define Biogeochemical Cycles:
A
The flow of chemical matter through biotic (biosphere) and abiotic (lithosphere, atmosphere, and hydrosphere) compartments of Earth
12
Q
____________ are needed in fairly large amounts by all organisms.
A
Macronutrients
13
Q
___________ are required in smaller amounts by most species.
A
Micronutrients
14
Q
About ______% of organic mass is composed of:
- Carbon
- Oxygen
- Hydrogen
- Nitrogen
- Phosphorus
- Sulphur
A
97
15
Q
True or false: Ecosystems vary substantially in terms of the speed of cycling and the relative proportion of nutrients in each compartment.
A
True
16
Q
Define Residence Time:
A
The typical length of time something stays in one compartment.
17
Q
Cycles can be classified according to the main source of their __________.
A
matter
18
Q
________ cycles have most of their matter in the atmosphere.
A
Gaseous
19
Q
________ cycles hold most of their matter in the lithosphere.
A
Sedimentary
20
Q
Which of the two, Sedimentary or Gaseous cycles, tend to cycle more slowly?
A
Sedimentary
21
Q
Under what conditions do recycling rates between components achieve a balance over time in which inputs and outputs are equal?
A
Natural Conditions
22
Q
Define the Sedimentary Cycle:
A
These cycles mobilize materials from the lithosphere to the hydrosphere and back to the lithosphere
23
Q
What do Sedimentary cycles rely upon?
A
Geological Uplift
24
Q
____________ is a macronutrient incorporated into many organic molecules.
A
Phosphorus
25
True or false: Phosphorus is relatively rare on Earths surface in relation to biological demand.
True
26
Phosphorus is often the ______________________ in freshwater aquatic ecosystems and for plant growth in terrestrial soil.
dominant limiting factor
27
What is the availability of phosphorus in the soil influenced by? Explain.
Soil Acidity; it gets bound into insoluble compounds under very acidic and basic conditions.
28
What are the main reservoir for phosphorus?
Rocks in the earths crust
29
What two things are large sources of P to the soil?
Animal Wastes and Decomposition
30
How can P be transported?
Through streams into lakes.
31
What is the significance of a Guano and Phosphorus?
A Guano is a marine bird droppings that return P for marine food chain back to the land.
32
What are some ways humans interfere in the phosphorus cycle?
- Mining P-rich rock
- Removing biomass (runoff)
- Concentrating organisms that produce P in waste
- Removing P from oceanic ecosystems through fishing
33
What is the result of excessive P accumulation in freshwater systems?
Eutrophication
34
Phosphorus in surface water causes ____________.
algal blooms (eutrophication)
35
What two ways does Sulphur differ from Phosphorus?
1. It is not a limiting factor for growth
2. Has strong dependencies on microbial activity
36
True or false: Sulphur is available in the lithosphere.
False, it is stored over long periods in oceans.
37
How is sulphur transformed?
Bacteria turns it into sulphates to be absorbed by plants
38
_________ lowers PH of soil, lakes, rivers, damages organisms and reduces productivity of plants.
Acid rain
39
The formation of Sulphur in soils depends on what two conditions?
1. Aerobic conditions
2. Anaerobic conditions
40
What two ways do humans intervene in the sulphur cycle?
1. Burning sulphur-containing coal
2. Smelting of metal ores that contain sulphates
41
Almost ____% of sulphur dioxide and _____ of sulphur compounds reaching the atmosphere comes from these activities.
99, 1/3
42
How does acid rain get produced?
Sulphur compounds react with oxygen and water vapour to produce sulphuric acid.
43
What is Nitrogen?
A colourless, tasteless, doorless gas required by all organisms for life.
44
The __________________ interface is where most important N cycling occurs through biological activity
atmosphere-lithosphere
45
Define Mineralization:
decomposing biomass (dead plants) is converted back to ammonia (NH3) and ammonium salts (NH4) by bacteria
46
Define Nitrification:
Chemotrophic bacteria convert NH3 and NH4 into nitrites (NO2-) and nitrates (NO3-).
47
Define Denitrification:
anaerobic bacteria convert nitrates (NO3-) into nitrogen gas (N2), returning it to the atmosphere.
48
What is the main way in which the atmospheric reservoir is linked to the biotic compounds of the food chain?
Through Microbial activity, which consists of; nitrogen fixation and denitrification
49
N is often a ____________ in terrestrial soils
limiting factor
50
When does Nitrogen Fixation occur?
As bacteria transform atmospheric nitrogen into various forms that are available to plants, such as nitrate and ammonium
51
What is the most important nitrogen fixer?
Bacteria of the Rhizobium.
52
What kind of bacteria fix nitrogen?
Chemoautotrophic Bacteria
53
___% of nitrogen occurs in the atmosphere via lightening
5
54
Define Mineralization:
The process by which **decomposing biomass** is **converted** back to **ammonia** (NH3) and **ammonium salts** (NH4) by bacterial action and returned to the soil
55
True or false: Nitrates are highly soluble in water
True
56
Nitrogen is not immobilized in deep-ocean sediments but has an effective feedback mechanism to the atmosphere from the ocean through ________________.
microbial denitrification.
57
What are some ways that humans interfere in the N Cycle?
- chemical fixation to supply nitrates and ammonia as fertilizer, leading to runoff of excess fertilizer and denitrification
- removal of nitrate and ammonium ions from agricultural soils through the harvesting of nitrogen-rich crops.
- high-temperature combustion
58
Carbon dioxide makes up only ____% atmospheric gases
0.03
59
What is the building block for all necessary fats, proteins and carbohydrates?
Carbon Dioxide
60
Carbon is incorporated in _______ and passed along the food chain.
biomass
61
______________ by organism transforms some carbon in biomass back into CO2 which enters atmosphere
Respiration
62
True or false: Carbon can be stored in the lithosphere for extended periods of time as organisms become buried before they decompose
True
63
Carbon dioxide can be dissolved in shallow ocean waters for up to __ years, or deeper ocean waters for up to ___ years
6, 350
64
What are some ways humans are interfering with the Carbon Cycle?
- Replacing natural ecosystems with land uses (urban and agricultural systems)
- Industrial activity has mobilized large amounts of fossil fuel from the lithospheric components into the atmospheric component.
65
What are the main means by which nutrients in the biotic component of the ecosphere are recycled to the abiotic component for future reuse?
Detritus Food Chains
66
What are the Earths major mediator in nutrient recycling?
Detritus Food Chains
67
Provide some examples of Decomposer Organisms:
- fungi
- earthworms
- slugs
- snails
- beetles
- ants
- termites
- heterotrophic bacteria
68
Organisms are ___% water
70
69
The oceans store ____% of earths water.
97
70
Agricultural practices use ____% of earths water consumption.
85
71
How long does water stay in ice as glaciers?
>100,000 years
72
How long does water stay in the deep ocean?
37,000 years
73
How long does water stay in groundwater?
Days to 1,000,000 years
74
How long does water stay in the atmosphere?
9-12 days
75
Define the Hydrological Cycle:
Involves movement of water amongst the oceans, atmosphere, and terrestrial systems, all fuelled by energy from the sun
76
Define Transpiration:
Evaporation from the leaves of plants
77
Define Evapotranspiration:
Evaporation from soil and plants
78
When does precipitation occur?
When H2O in the atmosphere cools and condenses into liquid form on tiny particles called condensation nuclei, and falls as rain, snow, or hail.
79
Define Relative Humidity (RH):
The amount of **moisture held in the air** compared to how much could be held if fully saturated at a particular temperature
80
At what % of RH does air get saturated?
100%
81
76% of precipitation falls over _____
oceans
82
True or false: Water is the only matter that exists in all three phases of matter
True
83
Define Sublimation:
The process for direct transfer between the solid and vapour phases of matter, regardless of direction
84
How much of the global fresh water does Canada have?
1/3
85
What are some ways humans have interfered in the Hydrologic Cycle?
- the storage and redistribution of runoff to augment water supplies for domestic, agricultural, and industrial uses
- the building of storage structures to control floods
- the drainage of wetlands
- the pumping of groundwater
- cloud seeding
- land-use changes such as deforestation, urbanization, and agriculture that affect runoff and evapotranspiration patterns
- climatic change caused by interference with biogeochemical cycles
86
What are the two main limiting factors in plant growth in aquatic ecosystems?
Phosphorus and Nitrogen
87
Mesotrophic systems have _________ levels of nutrients
intermediate
88
Oligotrophic systems have relatively ____ nutrient levels.
low
89
Eutrophic systems have _____ nutrient levels
high
90
True or false: About eight times the natural amount of phosphates and nitrates currently enter the oceans each year
True
91
What are four effects of Eutrophication?
- Nutrient enrichment encourages **increased growth** of aquatic plants
- Benthic plants get shaded out and thus **produce less oxygen** at depth
- **Oxygen depletion** is further increased by the decay of the large mass of phytoplankton produced
- **Fish decline** due to oxygen depletion
92
_________________: When organic wastes are added to a body of water, oxygen levels fall as the number of bacteria rises to help break down the waste
Oxygen Sag Curve
93
_________________: the amount of dissolved oxygen needed by aerobic decomposers to break down the organic material in a given volume of water at a certain temperature over a given period
Biological Oxygen Demand (BOD)
94
What is the main way to control eutrophication?
To limit the inputs of nutrients into water bodies
95
Oceans are now developing eutrophic ________
‘dead zones’
96
Why is Lake Erie an example of Eutrophication Control?
Up to 90% of the bottom layer of the central zone of the lake became oxygen deficient in the summer, causing huge algae mats and beach closures
97
What are Acids?
Chemicals that release Hydrogen ions when dissolved in water.
98
What is a Base?
A chemical that releases hydroxyl ions
99
Acid deposition is a term that includes rainfall, snow and fog from dust with a pH lower than ___.
5.6
100
What are some of the aquatic effects of Acid Deposition?
- Disfigurement, death, and extirpation of insects and fish
- Acid Shock
101
Define Acid Shock:
Pulse of activity in spring with the snow melt
102
What are some of the terrestrial effects of Acid Deposition?
- Tissue death in plant leaves
- Nutrient deficiencies
- Inhibited microbial activity
103
Define Critical Load:
The maximum level of acid deposition that can be sustained in an area without compromising ecological integrity
104
Ecosystem Sensitivity includes what type of aspects?
1. Critical Load
2. Buffering Capacity
105
What are the four key affected areas from Acid Deposition?
- Aquatic Life
- Terrestrial Life
- Ecosystem Sensitivity
- Socio-Economic Effects
106
What are two ways to address Acid Deposition?
1. Policy Target Values (PTV)
2. Scientific Target Values (STV)
107
What do PTVs' say about Acid Deposition?
The annual target deposition of 20 kilograms per hectare as an acceptable goal, taking political and economic costs into account
108
What do STVs' say about Acid Deposition?
A further reduction of 75% in SO2 emissions is needed to address the situation adequately according to scientific research
109
True or false: Canada has met all its goals and commitments for acid deposition reductions
True
110
Acid deposition, eutrophication, and global change all have their roots in disruption of _____________ cycles.
biogeochemical
