Effect of Wildfires on ALL Geochemical Cycles:

SummaryWater Carbon Oxygen Nitrogen

water vapour is produced in a combustion reaction:

C6H12O6(s) + 6 O2(g) 6 CO2(g)+ 6 H2O(g)

combustion produces CO2

(carbon source): C6H12O6(s) + 6 O2(g)

6 CO2(g) + 6 H2O(g)

heat breaks nitrogen compounds down into

nitrates & ammonia; same effect as nitrogen

fixationdramatic increase in

nitrogen levels in soil: more viable for bacteria

less tree roots & vegetation means less

retention of water in the soil

loss of green plants to undergo photosynthesis

(loss of a carbon sink)

loss of plants to undergo photosynthesis (loss of an

oxygen source) AND combustion reactions

uses O2 from the atmosphere

C6H12O6(s) + 6 O2(g) 6 CO2(g) + 6 H2O(g)

increa

se

decrea

se

The Recycling of Matter: Water and Biogeochemical Cycles

Practice QuestionsAnswer Key

( / 18)

Click icon to add picture

Question 1: Use the information below to answer question 1

Prescribed burning is a practice in which forestry personnel deliberately set small, controlled fires under ideal weather conditions — low winds and reasonably high moisture content. This strategy attempts to mimic the historical pattern of more frequent, low-intensity burns that are an integral part of the forest ecology.

1.Explain how this practice may actually enhance public safety and ensure the long-term health of the forest. (2 marks)

A prescribed burn mimics a natural wildfire, but b/c they occur MORE frequently, they burn with LESS intensity, than be SMALLER .

Another advantage of is that it reduces the accumulation of “fuel” , (old dry branches and pine needles), so that a large catastrophic fire is less likely.

AND helps maintain the long-term health and diversity of the forest habitat, since fires ARE needed for conifers to reproduce.

Question 2:1. AA

2. For organisms that live in the forest floor’s soil, identify at least two abiotic factors significantly affected by wildfires. (2 marks) Wildfires remove the surface vegetation

Abiotic factor affected: shade

Wildfires are an exothermic combustion reaction Abiotic factor affected: temperature (experienced by organisms

living within the soil). Wildfires are an exothermic combustion reaction, which break

down nitrogen molecules Abiotic factor affected: nitrogen (availability for plants in ashy soil

left after fire is extinguished). Wildfires REMOVE atmospheric oxygen and ADDS carbon

dioxide. Abiotic factor affected: O2 and CO2 levels

Wildfires REMOVE water from the ecosystem (b/c vegetation is removed). Abiotic factor affected: water levels

Question 3:

1. AA2. Mmf

3. What is a biogeochemical cycle? (1 mark) A series of reactions that move elements and compounds between

the living and non-living components of an ecosystem. Ex. carbon cycle, oxygen cycle, and the nitrogen cycle

Question 4: 1. AA2. A3. Nnnb

4. Water is often applied to lawns and gardens to keep plants healthy and green.

a) Use your knowledge of the water cycle to explain why it is more effective to water lawns in the early morning rather than the middle of the afternoon. (1 mark) because LESS water will be is lost to evaporation b/c the

Sun’s rays are less intense, in the morning than at mid-day AND the air is cooler.

b) Use your knowledge of the water cycle to explain why it is better to use a soaker hose instead of a sprinkler to water trees and shrubs. (1 mark) A soaker hose is more effective than a sprinkler, b/c a

sprinkler shoots water into the air—(increasing the surface area of water exposed to the air, which leads to greater losses due to evaporation)

AND the soaker hose directs water directly to the root of the plant where it can be effectively absorbed.

Question 5 & 6:1. Aa2. Aa3. Aa4. Aa

5. Explain the following statement. “There is no need to memorize a separate chemical equation for photosynthesis and another one for cellular respiration. One equation can describe both.” (1 mark)

There is no need to memorize both equations because the reactants of one equation are simply the products of the other-and vice versa.

Photosynthesis: 6 CO2(g) + 6 H2O(g) C6H12O6(s) + 6 O2(g)

Cellular Respiration: C6H12O6(s) + 6 O2(g) 6 CO2(g) + 6 H2O(g)

6. Decomposition, combustion of fossil fuels, cellular respiration, volcanic activity, and wildfires all have something in common when it comes to the carbon cycle. Identify the common feature. (1 mark)

all of these activities RELEASE carbon dioxide into the atmosphere.

Question 7 & 8:1. cvc2. bhfsdf3. Bfsbs4. Ndndsn5. Fgmndgmng6. Mfhmf7. vvasd

8. Cellular respiration is said to be an exothermic reaction because energy is released. If photosynthesis is an endothermic reaction because energy is required, identify the source of the energy for photosynthesis. (1 mark)

The source of energy for photosynthesis is solar (or radiant) energy from the Sun.

1. cvc

2. bhfsdf

3. Bfsbs

4. Ndndsn

5. Fgmndgmng

6. Mfhmf

7. Identify the key forms in which carbon and oxygen will occur within both the oxygen cycle and the carbon cycle. (1 mark)

Carbon and oxygen both occur in glucose (C6H12O6(aq)) and carbon dioxide (CO2(g)).

Question 9 & 10:

1. Vv2. Vadvadv3. Vaddas4. Vdavdavad5. Vadvadv6. Vadvad7. Vadvd8. Vadvad

9. Concisely explain why plants cannot use the air as a source of nitrogen. (2 marks)

because nitrogen in the air is N2, which is VERY stable. Plants don’t have the structures required to break the bonds,

into nitrogen's more usable forms.

10.Explain why many plants thrive in a post-fire habitat (2 marks)

The soil in a post-fire habitat tends to have LOTS of nitrogen.

Soil is warmer and less acidic, which increases the number of nitrogen fixing bacteria, which plants need to grow..

Question 11 & 12:

1. Nvnvan2. knaskv3. V knaklnbk4. skb naskl5. kslb 6. k sb 7. Bsb sfb 8. Bsbsbsf9. Bsbsbs 10. Ndn

11. Since you cannot obtain the nitrogen you need from breathing, what is the source of your nitrogen? (1 mark)

nitrogen is a critical element in biological structures of protein.

We meet our nitrogen needs, by eating foods high in protein, like:

Meats, eggs, nuts and beans/ soybeans, and dark green vegetables, like kale, spinach and Swiss chard.

1. Nvnvan

2. knaskv

3. V knaklnbk

4. skb naskl

5. kslb

6. k sb

7. Bsb sfb

8. Bsbsbsf

9. Bsbsbs

10. Ndn

11. Mndg

12. Sewage often contains high concentrations of nitrates that could be harmful if released directly into the environment. Explain the role that denitrifying bacteria could play in sewage treatment plants. (2 marks)

Denitrifying bacteria are used b/c they convert nitrates BACK into nitrogen gas.

Harmless, pure N2 is released into the atmosphere and harmful nitrates are removed from the aquatic environments.

The Biosphere of Life

Section 1.6Human impact on ecosystems

Human Activities

• Human activities have a significant effect on the cycling of matter

– deforestation– forest fires– burning of fossil fuels– industry– fertilizer use– irrigation

The Result?

• Polluting of water sources ( in H2O quality & quanity)

• Over-reliance on fertilizers ( N-compounds)

• Clear-cutting ( O2, CO2)

• Burning of fossil fuels ( O2, CO2)

• Use of CFCs ( O3, UV radiation)

Human Impacts on Ecosystems

• Now you will examine the human impact on biotic factors

Read Ch 1.6: Biodiversity and the Heritage of Our Lands (pg’s 454-462) in your Textbook

Complete the “Biodiversity Worksheet” in your note package.

Assignment:

Biodiversity Worksheet

Answer Key( /24 )

Question 1:In the definition of lichen, it was stated that lichen is formed by the symbiotic association of a fungus and a photosynthetic algae.

a. Explain what a “symbiotic association” is…(1 mark)b. The fungus in the lichen contains microscopic fibres that provide the alga with a place to grow. The fungus also supplies the alga with water and minerals that these fibres filter from dust particles and moisture in the air. Identify the contribution that the alga makes to this association. (1 mark)

a. A symbiotic association is a long-term relationship between two species where one and/or both benefit.

b. The alga is a photosynthetic organism, so it converts CO2 & H2O into glucose (aka nutrients) for the fungus to ingest.

The following illustrates the sequence of events that led to a decline in the caribou population due to habitat

fragmentation.I. Cleared forest areas attract caribou to live in the area. II. Human activities create open areas and cut lines throughout a habitat. III. The caribou population declines due to increased predation. IV. More wolves move into the area. V. Cutline and open areas allow wolves to spot and capture prey more easily.

2. The order of events beginning with habitat fragmentation and resulting in a decline in the caribou population is: (1 mark)

A. I, II, III, IV, V B. V, I, II, IV, III C. II, I, V, IV, III D. II, III, I, IV, V

Question 2:

3. Match each description with the appropriate term listed. Place your answer in the blank space given. (2 marks) i. biodiversity ii. habitat destruction iii. invasive species iv. habitat fragmentation

•_______ a. a species introduced to an area by human action that expands to threaten the area’s variety of life • _______ b. the conversion of formerly continuous habitat into patches separated by non-habitat areas • _______ c. the variety of life in all its forms • _______ d. the permanent alteration of vital characteristics in an organism’s habitat

iii

iv

i

ii

Question 3:

4. Suggest one reason why an invasive species is able to establish itself in a new area. (1 mark)

• An invasive species is able to establish itself in a new area because it has no natural predators in the new location to reduce its numbers.

Question 4:

5. Decide whether each statement is true (T) or false (F). Place your answer in the

blank space given. CORRECT ANY FALSE STATEMENTS (3 marks)_______ a. Only an animal can be an invasive species. (1

mark)

_______ b. Clearcutting an area of forest results in habitat destruction. (0.5 mark)

_______ c. The elimination of one key species can affect the health of an entire ecosystem. (0.5 mark)

_______ d. You should Rethink your basic assumptions about your lifestyle after you Reduce, Re-use, and Recycle materials you require for your lifestyle.

F

T

T

F

Plants AND Animals can both be invasive species

“rethinking” should occur BEFORE, then changes can be made to your lifestyle.

Question 5:

6. Your ecological footprint is affected by (1 mark) A. the type of food you consume B. the type of transportation you use C. the type of housing you maintain D. all of the above

Question 6:

In the middle of the nineteenth century, it was estimated that the population of prairie dogs in North America was about four billion animals. When the prairie grassland was converted into farmland, farmers dramatically reduced the prairie dog numbers; prairie dogs were thought to eat too much vegetation that farmers wanted to save for cattle AND the entrance-holes to the prairie dogs burrows were considered a tripping hazard for livestock. To reduce their numbers, prairie dogs were poisoned.

7. The swift fox and the black-footed ferret are two species that feed on prairie dogs, what effect would the mass poisoning of prairie dogs would have on each of these animals. (2 marks)• Mass poisoning of the prairie

dogs would remove the main food source for both the foxes & the ferrets.

• Both predators populations would go down either b/c of starvation or by becoming poisoned themselves (by eating the poisoned prairie dogs).

Question 7:

8. Prairie dogs require a habitat of low grasses for good visibility and hard-packed soil to prevent their burrows from collapsing. In much of southern Alberta, the original prairie grassland ecosystem was converted into farmland to grow tall grain crops. Explain why habitat destruction is listed as the key reason why the burrowing owl is on the list of species at risk. (2 marks)•The burrowing owl relies upon the prairie dog to produce its habitat

– short vegetation so they can find food, use the abandoned burrows to make their own burrows.

•Farmland removed the habitat of the prairie dog and, subsequently removing the habitat of the burrowing owl.

Question 8:

In the middle of the nineteenth century, it was estimated that the population of prairie dogs in North America was about four billion animals. When the prairie grassland was converted into farmland, farmers dramatically reduced the prairie dog numbers; prairie dogs were thought to eat too much vegetation that farmers wanted to save for cattle AND the entrance-holes to the prairie dogs burrows were considered a tripping hazard for livestock. To reduce their numbers, prairie dogs were poisoned.

Question 9:9. A keystone species is a type of organism whose disappearance will be followed by a decrease in many other community species. Explain why the black-tailed prairie dog is considered to be a keystone species in prairie grassland ecosystems. (2 marks)•Since so many other species cannot survive without prairie dog, it would be the keystone species.

– The disappearance of the prairie dog means no/less food for both the ferret and the fox (predators can’t survive without their prey).

– The owl cannot survive without the prairie dog b/c it depends on the prairie dog to create its habitat.

In the middle of the nineteenth century, it was estimated that the population of prairie dogs in North America was about four billion animals. When the prairie grassland was converted into farmland, farmers dramatically reduced the prairie dog numbers; prairie dogs were thought to eat too much vegetation that farmers wanted to save for cattle AND the entrance-holes to the prairie dogs burrows were considered a tripping hazard for livestock. To reduce their numbers, prairie dogs were poisoned.

10. Three things that the boreal forest provides are: (1 mark) A. carbon dioxide, oxygen, and a reservoir for fresh water B. oxygen, a sink for carbon, and a reservoir for fresh water C. oxygen, nitrates, and carbon dioxide D. oxygen, nitrogen, and a sink for carbon

Question 10:

11. a. Why are the Earth’s boreal forest important to the entire biosphere? (1 mark)

b. Explain how biodiversity is linked to the health of boreal forest ecosystems. (1 mark)

a. Since the boreal forest covers most of the Northern Hemisphere, it provides Earth’s biosphere with most of its oxygen AND acts as a carbon sink (absorbing CO2 from the atmosphere) AND is a huge reservoir of fresh water.

b. The more healthy organisms there are, the greater the quantity of organisms that can be sustained by the ecosystem there are. • food webs and biogeochemical cycles are

so interconnected, that the prosperity and health of one will automatically affects the other.

• Similarly, if biodiversity is NOT maintained, there can be many negative consequences to key species in the ecosystem.

Question 11:

b. species no longer exists anywhere on Earth

e. species no longer exists in a region, but lives elsewhere in the world

a. species numbers becoming dangerously low. Will soon become extinct or extirpated, if conditions do not change to improve their survival

c. species faces endangerment in the near future, unless the circumstances threatening its survival and reproduction improve.

d. species are monitored closely to try to prevent them from becoming “threatened”.

iii. Banff longnose dace

ii.

v.

i. anatum peregrine falcon

iv. Wolverine

Question 12: (5 marks)

Submit your MARKED assignment now.

Tally up the marks /24 If you wish to hand in question 13 (a,b & c) for BONUS

MARKS, please include it with your MARKED Ch 1.6 Biodiversity Assignment.

12. Some ecologists are suggesting that a dollar value be assigned to the ecological services that a forest provides. Services like carbon storage, soil formation, and the maintenance of biodiversity would each be appraised as being worth so many dollars for an area of forest. a.Explain how this idea attempts to address one of the fundamental differences between the ecological system and the economic system.

a.This proposal attempts to use money -- an understandable unit of measurement in both systems.

• This idea addresses how each system views “value” and tries to quantify the ecological system in an economic way, so decision can be made using one common denominator: net worth.

12. Some ecologists are suggesting that a dollar value be assigned to the ecological services that a forest provides. Services like carbon storage, soil formation, and the maintenance of biodiversity would each be appraised as being worth so many dollars for an area of forest. b.Explain how this system could promote a new style of decision making when it comes to economic development in the boreal forest.

b. If a decision is being debated that might lessens the ability of the boreal forest to provide its ecological “service”, then the “cost” associated with that decision will be able to be weighted out with other financial decisions, like profits, cost of labor/transportation, etc.

12. Some ecologists are suggesting that a dollar value be assigned to the ecological services that a forest provides. Services like carbon storage, soil formation, and the maintenance of biodiversity would each be appraised as being worth so many dollars for an area of forest. c. Identify some of the challenges of implementing this approach.

c. Difficult to: agree on the dollar value of each

environmental service. determine a dollar value to carbon

storage, oxygen production, biodiversity maintenance, personal enjoyment.

monitor and enforce implement world wide