APES Math Practice: Productivity Calculations

Scientific Notation
Convert the following numbers into scientific notation.

1

One thousand

1

One million

1

One billion

1

One trillion

1

twenty-three thousand

1

256,000

Do the following calculations in scientific notation:

1

(2.96 x 107) + (1.0 x 108)

1

Five hundred billion times thirty-five thousand

1

six thousand divided by 300 billion

1

one ten thousandth of three million

Metric Conversions
Memorize the conversions that follow the table of prefixes. (These answers are not in scientific notation)

1

1200 watts = ____________ kW (kilowatts)

1

1200 kW = ____________ MW (megawatts)

1

500 km = ____________ meters

1

60 grams = ____________ milligrams

1

14,000 milliliters = ____________ liters

Productivity
Gross primary production (GPP) is the total amount of carbon dioxide "fixed" by land plants per unit time through the photosynthetic reduction of CO2 into organic compounds. A substantial fraction of GPP supports plant autotrophic respiration (Ra), with the remainder allocated to the net primary production (NPP) of plant structural biomass in stems, leaves, and fruit, carbohydrates such as sugars and starch, and, to a much lesser extent, volatile organic compounds used in plant defense and signaling. 
Terrestrial GPP, therefore, relates to NPP as follows:
NPP = GPP - Ra
Net Primary Productivity = Gross Primary Productivity - Energy used for respiration.
Production rates are usually expressed as grams of organic carbon per unit area per unit time.

1

A round pot measures 50 cm in diameter and in it 125 grams of lettuce grew in 95 days. Calculate the NPP of the lettuce in g/m2 per day.

1

A square flower box measures 22 cm on one side. After drying, 34 grams of flowers were grown in that flower box in 145 days. Calculate the NPP of the flowers in g/m2 per day.

1

The gross primary productivity of an ecosystem is 3.5 kgC/m2/year, and the energy needed by the producers for their own respiration is 3.0 kgC/m2/year. What is the net primary productivity of such an ecosystem? (include units in your answer)

1

The net annual primary productivity of a particular wetland ecosystem is found to be 2,000 kcal/m2. If respiration by the aquatic producers is 18,000 kcal/m2 per year, what is the gross annual primary productivity for this ecosystem, in kcal/m2 per year? (include units in your answer)

1

One thousand

One million

One billion

One trillion

twenty-three thousand

256,000

(2.96 x 107) + (1.0 x 108)

Five hundred billion times thirty-five thousand

six thousand divided by 300 billion

one ten thousandth of three million

1200 watts = ____________ kW (kilowatts)

1200 kW = ____________ MW (megawatts)

500 km = ____________ meters

60 grams = ____________ milligrams

14,000 milliliters = ____________ liters

Productivity

A round pot measures 50 cm in diameter and in it 125 grams of lettuce grew in 95 days. Calculate the NPP of the lettuce in g/m2 per day.

A square flower box measures 22 cm on one side. After drying, 34 grams of flowers were grown in that flower box in 145 days. Calculate the NPP of the flowers in g/m2 per day.

The gross primary productivity of an ecosystem is 3.5 kgC/m2/year, and the energy needed by the producers for their own respiration is 3.0 kgC/m2/year. What is the net primary productivity of such an ecosystem? (include units in your answer)

The net annual primary productivity of a particular wetland ecosystem is found to be 2,000 kcal/m2. If respiration by the aquatic producers is 18,000 kcal/m2 per year, what is the gross annual primary productivity for this ecosystem, in kcal/m2 per year? (include units in your answer)

In the community described in the table above, which of the following represents the respiratory energy (kcal/m2/year) used by autotrophic organisms?