Copy of #1010 NPP and GPP Virtual Lab
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School
Northampton County Area Community College *
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Course
101-106
Subject
Biology
Date
Feb 20, 2024
Type
docx
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5
Uploaded by ColonelArt13319
Mini Lab: Calculating GPP and NPP
Please complete the following questions using your online textbook, and attached links, and the AP classroom videos. Please record your answers in red
, blue or purple
1.
Look at the diagram above. Write a caption/description for this diagram. Make it detailed-
similar to what you see in your textbook figures. 2.
Open this Video and answer the questions while watching the video: a.
GPP and NPP Video Lab
3.
Where and what is the sample of water used in this lab?
She is using some of her fish tank water (freshwater) for this lab.
4.
What is the dissolved oxygen (DO) reading of the water sample? Record your answer in mg/L
7.4 mg/L
5.
How many bottles are filled? 2
6.
Why was the lid of the bottle put on under the water?
She put the lid on under water to remove the presence of the air in the bottle.
7.
What plant is put in each bottle? elodia
8.
Describe the treatment to each bottle. (What was done differently to each bottle?) Why?
One was painted black, and was covered with a cup, to measure the cellular respiration.
Pause the video and use what you’ve learned about experimental design to answer these questions:
9.
List 4 constants (the things that are the same for each bottle) in this lab:
The size of the plant, the water, the amount of oxygen in the bottle, and the species of plant (elodia)
10.What is the independent variable
?
The amount of sunlight 11.What is the dependent variable? (What will we measure?) The rate of cellular respiration
Play
the video to get the results and answer these questions:
12.What is the DO level of the bottle that was in the light? 10.0 mg/L
13.What is the DO level of the bottle that was in the dark? 5.3 mg/L
Fill in this chart:
Initial Dissolved Oxygen (ppm) (both bottles) Final Dissolved Oxygen in Dark Bottle (no photosynthesis, only respiration)
Final Dissolved Oxygen in Light Bottle (both respiration
and photosynthesis)
7.4 mg/L
5.3mg/L
10.0mg/L
14.
Calculating Respiration Rate: Only respiration (and not photosynthesis) can occur in a dark bottle. Respiration rate is the
decrease in DO over time. To
determine this for your sample,
subtract the dark DO from the initial DO, then divide it by the time (usually in days). This will give an answer in mg O
2
/L/day. Use the formula below to assist you. In a water solution, ppm = mg/L (
Show your work for credit
)
R = (7.4 mg/L-5.3 mg/L) / 2 days=1.05 mg O
2
/L/day.
15.
Calculating Gross
Primary
Productivity: Gross Primary Productivity (GPP) is the total amount of carbon that was fixed by organisms over a period of time. To determine this for your sample, subtract the dark bottle DO from the light DO values, then divide it by the time (usually in days). This will give an answer in mg O
2
/L/day. Use the formula below to assist you. (
Show your work for credit)
GPP =(10.0 mg/L-5.3 mg/L) / 2 days-2.35
mg O
2
/L/day.
16.
Calculating Net Primary Productivity: Net Primary Productivity (NPP) is the total amount of carbon that was fixed by organisms into living tissue minus that used for respiration over a period of time To determine this for your sample, subtract the respiration rate in mg O
2
/L/day from GPP in mg O
2
/L/day. This will give an answer in mg O
2
/L/day. Use the formula NPP = GPP - R (
Show your work for credit)
NPP =2.35
mg O
2
/L/day.- 1.05mg O
2
/L/day.=1.3mg O
2
/L/day.
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17.You can also use the formula
below to calculate the net
primary productivity since the
difference between the light bottle DO and the initial DO is essentially the same algebraic
expression as GPP minus respiration rate.
NPP = (10.0
mg O
2
/L/day.
-7.4
mg O
2
/L/day.
) / 2 =1.3
mg O
2
/L/day.
In this lab, we measured the amount of oxygen which is proportional to the amount of carbon
dioxide that was laid down into biomass. In other words, the amount of carbon dioxide that was turned into tissues on the bodies of the plant. In other productivity labs, we would grow and mass the producers and calculate the amount of calories available for consumers as energy if they ate the producers.
More Practice: (yes you must complete this) (
Please show all units
)
18.
The gross primary productivity of an ecosystem is 3.5 kgC/m
2
/year, and the energy needed
by the producers for their own respiration is 3.0 kgC/m
2
/year. What is the net primary productivity of such an ecosystem?
3.5
kgC/m
2
/year - 3.0kgC/m
2
/year=0.5 kgC/m
2
/year
19.
The net annual primary productivity of a particular wetland ecosystem is found to be 2,000 kcal/m
2
. If respiration by the aquatic producers is 18,000 kcal/m
2
per year, what is the gross annual primary productivity for this ecosystem, in kcal/m
2
per year?
18000+2000=20,000 kcal/m^2
Energy flow in Lake Fremont (kcal/m
2
/year)
Trophic Level
Energy Consumed
Waste Energy
GPP
NPP
Producer
-
1,500,000
10,000
8,000
Primary Consumer
2,000
1,600
200
180
Secondary Consumer
160
100
40
10
20.
In the community described in the table above, which of the following represents the respiratory energy (kcal/m
2
/year) used by autotrophic organisms?
a) 10 b) 200 c) 1,600 d) 2,000 e) 10,000
21.
Connecting Ideas
! When is an ecosystem said to have high net primary productivity?
When there is a high presence of rain and sunlight, to offset the costs of respiration.
22.Which 3 ecosystems have the highest productivity and which 3 have the lowest productivity?
Highest-Tropical Rainforests, Temperate, Temperate Deciduous Forests
Lowest-Tundra, Temperate grassland,Subtropical desert
23.How does productivity increase in terrestrial ecosystems? In aquatic ecosystems?
Productivity increases as more moisture and sunlight becomes present in terrestrial ecosystems, and when more sunlight becomes present in aquatic biomes.
24.Is our biome/ecosystem highly productive? Explain why or why not. (Hint, we have mostly shrubs on our hills)
Yes our biome is productive because we have plants that grow year round (like shrubs) and while there are times where they become more abundant, they are always present and accommodated for.
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