Calculating Net Primary Productivity in Aquatic Plants

Mr. Smeeds guides students through calculating net primary productivity (NPP) of aquatic plants. The video covers the importance of NPP, formulating scientific questions and hypotheses, and the lab procedure. It explains variables, controls, and constants, and demonstrates calculations for NPP and gross primary productivity (GPP). The video concludes with a Q&A invitation.

What is the main difference between Net Primary Productivity (NPP) and Gross Primary Productivity (GPP)?

• NPP includes energy lost to respiration, while GPP does not.

• NPP is the energy stored after respiration, while GPP is the total energy produced.

• GPP is the energy stored by plants, while NPP is the total energy produced.

• GPP is the energy used by plants for growth, while NPP is the energy lost to respiration.

Why is it important to formulate a scientific question before conducting a lab experiment?

• It allows for the collection of more data.

• It helps in determining the lab materials needed.

• It guides the direction of the experiment and helps in forming a hypothesis.

• It ensures the experiment will be successful.

Which of the following is an example of a testable hypothesis?

• Plants need sunlight to survive.

• Increasing sunlight will increase the rate of photosynthesis.

• Photosynthesis occurs during the day.

• Oxygen is produced by plants.

What is the purpose of using a dissolved oxygen probe in the lab procedure?

• To measure the amount of sunlight the plants receive.

• To determine the initial and final oxygen levels in the water.

• To calculate the temperature of the water.

• To assess the growth rate of the plants.

Why is it important to control variables such as the amount of water and plant species in the experiment?

• To ensure that the results are due to the independent variable only.

• To prevent any changes in the experiment setup.

• To make the experiment more interesting.

• To ensure the experiment is easy to replicate.

What is the role of a control group in an experiment?

• To ensure the experiment is conducted correctly.

• To provide a baseline for comparison with the experimental group.

• To increase the number of variables tested.

• To manipulate the independent variable.

In the context of this lab, what is considered the independent variable?

• The initial dissolved oxygen level.

• The amount of sunlight the plants receive.

• The species of aquatic plant used.

• The temperature of the environment.

How is the respiration rate calculated in this experiment?

• By measuring the increase in plant biomass.

• By subtracting the final dissolved oxygen level from the initial level in the dark bottle.

• By measuring the amount of sunlight absorbed by the plants.

• By adding the initial and final dissolved oxygen levels.

What does the change in dissolved oxygen in the light bottle represent?

• The oxygen produced through photosynthesis minus the oxygen used for respiration.

• The total amount of oxygen consumed by the plant.

• The initial oxygen level in the water.

• The amount of sunlight absorbed by the plant.

How can Gross Primary Productivity (GPP) be calculated from NPP and respiration loss?

• By dividing NPP by respiration loss.

• By subtracting respiration loss from NPP.

• By multiplying NPP by respiration loss.

• By adding NPP and respiration loss.